Dye composition containing a combination of two henna plant extracts

Abstract

The present disclosure relates to a dye composition comprising a combination of two henna extracts, and a method for preparing the same. The disclosure also relates to the cosmetic use of the composition for dyeing keratinous fibers. Finally, the disclosure relates to a cosmetic method for dyeing keratinous fibers, comprising the application of such a composition.

Description

[Technical field]

[0001] The present invention relates to a dye composition comprising a combination of two natural dyeing agents, in particular two extracts of henna (Lawsonia inermis). The invention also relates to the cosmetic use of said composition for dyeing keratinous fibres. Finally, the invention relates to a cosmetic method for dyeing keratinous fibres, comprising applying such a composition. [Background technology]

[0002] Hair dyeing processes include oxidation or permanent dyes. This chemical dyeing process is carried out using one or more oxidation dye precursors, usually one or more oxidation base components, optionally in combination with one or more couplers.

[0003] These oxidation bases are colorless or faintly colored compounds which, in combination with the oxidation products, allow access, through the oxidative condensation process, to the colored species that remain trapped within the hair fiber.

[0004] However, oxidative dyes are known to cause skin problems, and it has been demonstrated that they are endocrine disruptors that negatively impact the ecosystem, and may cause cancer, allergies, etc.

[0005] Colored molecules and dyes can also be natural compounds derived from plants or trees. Henna (Lawsonia inermis), commonly referred to as henna, belongs to the Lythraceae family. This shrub can reach a height of 6 meters and is native to tropical and subtropical regions of Africa and Asia, among others. The bark is gray and the branches are dense, with older ones having quadrangular and thorny branches. The leaves are opposite and simple overall. The fragrant white or red flowers are arranged in large pyramidal spikes up to 25 cm long.

[0006] Henna leaves, which produce red and orange hues, have been used for over 5,000 years to dye hair and skin, and to dye textiles.

[0007] Their staining properties are due to lawsone (2-hydroxy-1,4-naphthoquinone), which reacts with keratin present in the skin or nails by Michael addition. [ka]

[0008] However, with henna alone, it is difficult to take into account all the dyeing shades of hair ranging from blonde to dark blonde or black.

[0009] Other plants have been described as sources of dyes, particularly dye extracts or powders for dyeing hair or other keratinous materials, but each plant derives a specific color.

[0010] Furthermore, combining multiple plant extracts carries the risk of inducing undesirable interactions between the pigments or extracted compounds, which may result in staining, dye accidents or dermatological side effects, etc.

[0011] Also, it is difficult to provide a full range of dyeing, particularly hair shades, ranging from blonde to deep blonde or black, using only compatible plant extracts or powders, thus limiting the number and use of henna extracts as a base ingredient.

[0012] It is even more difficult to use a single plant source to obtain a dye composition that allows obtaining a wide dye range from blonde to dark blonde. Such a solution would also be highly desirable and would simplify the acquisition of plant materials and allow the rationalization of the production of extracts and dye compositions on an industrial scale.

[0013] In the field of hair dyes, the present specification refers to tone-on-tone dyes or permanent or semi-permanent dyes, the latter generally making more use of hydrogen peroxide and alkaline chemicals.

[0014] Tone-on-tone dyes are commonly used to enhance or accentuate the natural color of the hair and to give the hair highlights and extra shine.

[0015] Therefore, in most cases, they are chosen to be the same or a darker shade than the natural hair. In the field of permanent or semi-permanent hair dyes, it is desirable that the dye be shampoo-resistant.

[0016] Henna is used to give the hair a copper or red color, by using more or less standardized extracts, in which case, as mentioned above, it has not been described before that a wide range of shades can be obtained with dye compositions based only on henna.

[0017] The present invention relates to both tone-on-tone dyes and permanent dyes.

[0018] Therefore, there is a real need to develop hair dyes that cover the full range of hair colours from natural products, especially henna, especially for tone-on-tone or permanent dyeing approaches, even up to grey hair, while limiting the number of plant extracts to simplify the formulation and avoid interactions and incompatibilities. In particular, there is a need to develop and provide dye compositions based on a single plant source that cover the full dye range.

[0019] In particular, the present invention provides - Natural and free of animal products, i.e. based on dye active ingredients from plants, microorganisms or microalgae; - short exposure times, advantageously shorter than the time required for dyeing the hair; -preferably in a single application, including for dyeing hair; -Preferably organic and vegan; for hair dyes, allowing good color retention after 10 shampoos, including after several washes, advantageously including after 15 shampoos, The present invention aims to provide a dye composition.

[0020] There is also a need for permanent hair dyes that avoid the use of hydrogen peroxide and alkaline chemicals.

[0021] Additionally, it is desirable to be able to achieve any desired color.

[0022] The inventors of the present invention have therefore developed a dye composition based on the combination of two henna extracts, making it possible to achieve a wide range of colours, particularly for use in the hair sector, which covers the full range of shades from black to very light blonde.

[0023] The inventors of the present invention have therefore developed a dyeing composition based on the combination of two henna extracts, which makes it possible to achieve set objectives including a wide range of colours, particularly for use in the hair sector, which covers a very wide range of shades whilst using a single source of plant raw material. Summary of the Invention

[0024] The present invention relates to a process for the preparation of a dye composition, in particular a cosmetic dye composition for dyeing keratinous fibers, comprising the following steps: - providing an extract A of the aerial parts of henna containing between 7% and 60% by weight of lawsone relative to the total weight of the dry extract, the lawsone being obtained in particular from the enzymatic hydrolysis of glycosylated lawsone derivatives, such as hennosides; and - providing an extract B of the aerial parts of henna, containing less than 0.6% by weight of lawsone, at least 15% by weight of phenolic compounds and at least 60% by weight of saccharide (including polysaccharide) compounds relative to the total weight of the dry extract; - mixing extract A and extract B; obtaining a dye composition.

[0025] The present invention further relates to a dye composition obtainable by the disclosed method and its use for dyeing keratinous fibers.

[0026] The present invention also relates to a method for dyeing human keratin fibres, comprising the steps of: a) providing a dye composition of the present disclosure in powder form; b) adding an aqueous composition, in particular water, to the powder of step a) at a temperature between 20°C and 98°C and mixing to obtain an aqueous composition; c) applying to keratinous fibers, optionally treating said fibers with heat, d) a washing step; e) optionally repeating steps c) and d).

[0027] Further aspects of the present invention are set out in the claims and / or as described herein below.

[0028] Detailed Description The present invention relates to a process for the preparation of a dye composition, in particular a cosmetic dye composition for dyeing keratinous fibers, comprising the following steps: - providing an extract A of the aerial parts of henna containing between 7% and 60% by weight of lawsone relative to the total weight of the dry extract, the lawsone being obtained in particular from the enzymatic hydrolysis of glycosylated lawsone derivatives, such as the henosides; and providing an extract B of the aerial parts of henna, containing less than 0.6% by weight of lawsone, at least 15% by weight of phenolic compounds and at least 60%, in particular between 60% and 80% by weight of saccharide compounds (including polysaccharides, for example mucilages), relative to the total weight of the dry extract; - mixing extract A and extract B; obtaining a dye composition.

[0029] The present invention also relates to dye compositions obtainable by the disclosed method.

[0030] definition The following terms, as used herein, shall have the following meanings:

[0031] By "plant extract" is meant the product extracted from the plant, whether the whole plant, the above-ground parts, the underground parts, the flowers, or the fruits, including the dried fruits. The extraction may consist simply of squeezing or may involve the use of an extraction solvent. The solvent is advantageously water, a hydroalcoholic solvent or an alcoholic solvent, although other types of solvents may be considered, particularly for the extract A of henna.

[0032] The present invention is part of the desire to set up a synthetic route that is more environmentally friendly and allows the active ingredients obtained in this way to claim to be natural.The solvents used in the present invention are therefore preferably natural solvents and / or of natural origin from renewable resources, as opposed to fossil resources, and these solvents can advantageously be obtained by methods that respect the environment.The extracts thus obtained are natural extracts and / or of natural origin from renewable resources, as opposed to fossil resources.

[0033] By "dry extract" is meant an extract that does not contain the extracting solvent or medium or that contains only trace amounts of them. Thus, such a dry extract contains only material from the plant, in particular henna for Henna Extract A.

[0034] "Standardized extract" means an extract containing at least one of the dye components of the plant extract in a selected content. Standardized extracts are generally obtained by adding an inert carrier to the plant extract in an amount that may vary from batch to batch.

[0035] The "carrier" must be inert towards the extract and its components: it does not interact with the extract or its components, especially lawsone, but contributes to its protection and makes it possible to standardize the final content of active extract or molecule.

[0036] The carrier may be selected from among propanediol, pentanediol, glycerin, propylene glycol, methyl THF and amyl alcohol.

[0037] The carrier may be selected from among sugars and polysaccharide derivatives, such as fructose, glucose, saccharose, maltodextrins, cellulose derivatives, starches (such as corn, wheat or rice starch), agar-agar, gums, mucilages; and polyols, such as mannitol, sorbitol, xylitol, etc. In particular, the support is selected from fructose, maltodextrins and starches, in particular rice starch.

[0038] The supports are preferably natural supports and / or of natural origin from renewable sources as opposed to fossil sources, and these supports can advantageously be obtained by methods that respect the environment.

[0039] By "dry standardized extract" is meant a standardized extract that is free of the extracting solvent or that contains only insignificant trace amounts of the extracting solvent.

[0040] By "powder" is meant a product in the form of fine particles with an average particle size between 0.1 μm and 250 μm, in particular between 1 μm and 250 μm. These fine particles can be obtained by grinding. Grinding can be carried out by any suitable means that allows the reduction in size and the obtaining of such fine particles.

[0041] Advantageously, the powder according to the invention is a dry powder product whose moisture content is negligible.The powder according to the invention is water-soluble or easily water-dispersible, i.e. it can be used to obtain an aqueous or hydroalcoholic liquid composition containing 20-60% by weight of dry matter, more particularly 30-50% by weight of dry matter, more particularly about 40% by weight of dry matter.

[0042] "Plant powder" means the pure natural product from a plant, whether the whole plant, aboveground parts, belowground parts, flowers, or fruits, including dried fruits, that has been powdered by grinding or other mechanical means.

[0043] By "aerial parts" is meant the above-ground parts of the plant, such as leaves, petioles, flowers, seeds and branches, in particular leaves, branches and petioles or mixtures thereof, preferably leaves, branches or mixtures thereof.

[0044] "Glycosylated lawsone derivatives" are also called lawsone glycosides or heterosides and have the following general formula (I): [ka] [In the formula, R 1 , R 2 and R 3 are each independently H or a sugar, e.g. glucose, R 1 ~R 3 at least one of them is different from H] In this compound, an aglycone is formed by hydrolysis of the glycosidic bond, and this aglycone is autoxidized to form lawsone.

[0045] In particular, henosides A, B and C are glycosylated lawsone derivatives.

[0046] By "enzymatic hydrolysis" is meant a hydrolysis reaction catalyzed by an enzyme, which may be an endogenous henna enzyme or an enzyme from an exogenous source, preferably an endogenous henna enzyme, it being understood that the enzyme is a glucosidase, e.g., β-glucosidase [Gallo et al.], the action of which cleaves the glucosidic bond of a glycosylated lawsone derivative.

[0047] The term "stable over time" in relation to the henna extract disclosed herein means that at room temperature (15°C to 25°C), at a relative humidity (RH) of 60% and protected from light, the amount of lawsone originally present in the extract does not decrease by more than 50% over a period of one month, advantageously by more than 40%, in particular by more than 30%, advantageously by more than 20%, in particular by more than 15%, advantageously by more than 10%. The room temperature values ​​are those specified in the European Pharmacopoeia.

[0048] The stability of extract A disclosed herein may also be evaluated under so-called accelerated stability conditions. These conditions are a temperature of 40° C. (±2) and a relative humidity of 75% (±5). The lawsone content of the extract is “stable over time” in accelerated stability conditions if the amount of lawsone originally present in the extract does not decrease by more than 50% over a period of one month, advantageously by more than 40%, preferably by more than 30%, in particular by more than 20%, in particular by more than 15%, advantageously by more than 10%.

[0049] By "neutral pH" is meant a pH range of 6.5 to 7.5, in particular about pH 7.

[0050] By "acidic pH" is meant a pH below 7, advantageously below 6.5, and more advantageously below 6.

[0051] By "weakly polar" is meant a solvent characterized by a dipole moment of less than 2.0D.

[0052] "Alcohol" means a compound of the formula: R 4 -OH[wherein, R 4 is a hydrocarbon group, especially (C1 -C 6 ) alkyl group or C 4 -C 12 (C 1 -C 6 Alcohols containing a C alkyl group are referred to herein as "C 1 -C 6 Alcohol". 4 -C 12 Alcohols containing a hydrocarbon group are referred to herein as "C 4 -C 12 It is called "alcohol."

[0053] By "chlorinated solvent" is meant alkanes, ie, saturated hydrocarbons, containing from 1 to 6 carbon atoms, particularly from 1 to 3 carbon atoms, some or all of whose hydrogen atoms have been replaced by chlorine atoms.

[0054] "Ketone" means a compound of the formula: R 5 -CO-R 6 [In the formula, R 5 and R 6 are the same or different (C 1 -C 6 ) alkyl group.

[0055] "Ether" means a group of the formula: R 7 -OR 8 [In the formula, R 7 and R 8 are the same or different (C 1 -C 6 ) alkyl group.

[0056] An "ester" is a compound of the formula: 9 -COO-R 10 [In the formula, R 9 and R 10 are the same or different (C 1 -C 6 ) alkyl group. Esters are in particular acetates, i.e., CH 3 COO-R 10 It may be a compound.

[0057] "(C 1 -C 6 ) Alkyl" group advantageously denotes a saturated, straight or branched hydrocarbon chain containing 1 to 6, preferably 1 to 4, carbon atoms. Examples include the following groups: methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl or hexyl.

[0058] "C 4 -C 12 The term "hydrocarbon chain" refers to a linear or branched, saturated or unsaturated hydrocarbon chain, preferably a saturated hydrocarbon chain, containing 4 to 12 carbon atoms, preferably 4 to 8 carbon atoms. 4 -C 12 Examples of "hydrocarbon chains" include, but are not limited to, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl (including positional isomers thereof).

[0059] By "saturated or unsaturated hydrocarbon" is meant a compound composed solely of hydrogen and carbon atoms.

[0060] By "keratin fibres" is meant keratin present in the epidermis and integument, such as skin, hair, eyelashes and eyebrows, in particular hair.

[0061] "Cosmetically acceptable" means useful in the preparation of cosmetic compositions and generally safe, non-toxic, biologically or otherwise desirable and acceptable for use in cosmetics, especially for topical application to keratinous fibers, especially the hair and scalp.

[0062] By "cosmetically acceptable vehicle" is meant a vehicle containing ingredients suitable for formulating a cosmetic composition, such as a cream, lotion, shampoo, emulsion or any formulation suitable for application to keratinous fibers, particularly hair.

[0063] Henna Extract A The dye compositions of the present invention contain at least one specific henna extract, referred to herein as "Extract A."

[0064] This extract A is characterized by a high lawsone content.

[0065] Extract A therefore contains between 7% and 60% by weight of lawsone relative to the total weight of the dry extract. This lawsone content is advantageously stable over time, even under accelerated stability conditions.

[0066] In some embodiments, the lawsone oil content of Extract A does not decrease by more than 50%, advantageously by more than 40%, particularly by more than 30%, advantageously by more than 20%, and more advantageously by more than 10%, over a period of 3 months at room temperature (15° C.-25° C.), 60% relative humidity (RH) and protected from light.

[0067] Advantageously, the lawsone content of extract A does not decrease by more than 50%, advantageously by more than 40%, in particular by more than 30%, advantageously by more than 20% and more advantageously by more than 10%, over a period of 6 months at room temperature (15°C to 25°C), at a relative humidity (RH) of 60% and protected from light.

[0068] Preferably, the lawsone content of extract A does not decrease by more than 50%, advantageously by more than 40%, in particular by more than 30%, advantageously by more than 20% and more advantageously by less than 10%, at room temperature (15°C to 25°C), at a relative humidity (RH) of 60% and protected from light, over a period of 12 months. Advantageously, the lawsone content of extract A does not decrease by more than 50%, advantageously by more than 40%, in particular by more than 30%, advantageously by more than 20% and more advantageously by less than 10%, over a period of 3 months at a temperature of 40°C (±2) and a RH of 75% (±5).

[0069] In particular, the lawsone content of extract A does not decrease by more than 50%, advantageously by more than 40%, in particular by more than 30%, advantageously by more than 20% and more advantageously by more than 10% in 6 months at a temperature of 40°C (±2) and a RH of 75% (±5).

[0070] Thus, Extract A disclosed herein contains a high and stable amount of lawsone, unlike many commercially available henna extracts that have insufficient lawsone content, which decreases rapidly over time due to condensation with various compounds containing amino groups, such as proteins, peptides or amino acids.

[0071] The lawsone in extract A is generally due to the enzymatic hydrolysis of glycosylated lawsone derivatives such as hennosides. Methods for preparing such extracts are described herein below.

[0072] Extract A may further contain luteolin, apigenin and 2,3,4,6-tetrahydroxyacetophenone.

[0073] In some embodiments, extract A from the aerial parts of henna containing 7% to 60% by weight of lawsone based on the total weight of the dry extract, where the lawsone is obtained by enzymatic hydrolysis of glycosylated lawsone derivatives, such as henosides, and further containing luteolin, apigenin and 2,3,4,6-tetrahydroxyacetophenone, may be prepared by the method described below.

[0074] Extract A is further characterized by one or more, advantageously all, of the following advantageous properties: - Extract A contains 7% to 50% by weight, or 10% to 50% by weight, in particular 15% to 40% by weight, of lawsone relative to the total weight of the dry extract. Advantageously, Extract A contains at least 7% by weight, advantageously at least 10% by weight, at least 15% by weight, preferably at least 20% by weight, more advantageously at least 25% by weight, of lawsone relative to the total weight of the dry extract; the percentages are given relative to the total weight of the dry extract (before any final addition of dry carrier). The lawsone content can be measured by the HPLC assay method (Method 1) described after the examples.

[0075] extract A does not contain more than 2% by weight of proteins, peptides or amino acids, preferably not more than 1.5% by weight and in particular not more than 1% by weight, relative to the total weight of the dry extract; The dry extract contains proteins, peptides or amino acids, advantageously in an amount of 0% to 1% or 0.1% to 1% by weight, based on the total weight of the dry extract. The free amino acids, peptides and proteins can be determined by ninhydrin spectrophotometry according to the method described in the Examples below (Method 2).

[0076] - Extract A contains chlorophyll, in particular chlorophyll a and / or chlorophyll b, with a total chlorophyll content of less than 25% by weight, or less than 20% by weight, advantageously less than 10% by weight, based on the total weight of the dry extract. In some embodiments, Extract A does not contain more than 5% by weight, preferably less than 2% by weight, of chlorophyll based on the total weight of the dry extract. In some embodiments, Extract A does not contain chlorophyll. Chlorophyll can be assayed by gravimetric assay according to the method described after the examples (Method 3).

[0077] Extract A contains between 1% and 40% by weight, advantageously between 2% and 30% by weight, of phenolic compounds relative to the total weight of the dry extract. The phenolic compounds content can be determined spectrophotometrically according to the method described after the examples (Method 4).

[0078] Extract A does not contain more than 5% by weight of saccharides relative to the total weight of the dry extract, advantageously between 0.1% and 5% by weight, more advantageously between 0.5% and 5% by weight, relative to the total weight of the dry extract. The saccharide content can be measured by a colorimetric assay with dinitrosalicyl (method 5).

[0079] - Extract A is rich in phenolic compounds, such as gallic acid, coumaric acid (especially para-coumaric acid), 2,3,4,6-tetrahydroxyacetophenone and 3,4,5-trihydroxyacetophenone; flavonoids, such as luteolin, apigenin, catechin, 3',4',5,7-tetrahydroxyflavanone, 3',5,7-trihydroxy-4'-methylflavone; sterols, such as β-sitosterol, triterpenes, such as ruthenium. peol; and / or their heterosides, such as larioside, myrciaphenone A, 1,2-dihydroxy-4-O-glycosyloxynaphthalene (also called 4-O-β-D-glucopyranoside), luteolin-4'-O-glucoside, apigenin-7-O-β-glucoside, luteolin-3'-O-glucoside, apigenin-4'-O-β-glucoside and luteolin-6-C-neohesperidoside. In some embodiments, Extract A contains phenolic compounds such as gallic acid, coumaric acid (especially para-coumaric acid), 2,3,4,6-tetrahydroxyacetophenone and 3,4,5-trihydroxyacetophenone; flavonoids such as luteolin, apigenin, catechin, 3',4',5,7-tetrahydroxyflavanone, 3',5,7-trihydroxy-4'-methylflavone; and / or their heterosides such as larioside, myrciaphenone A, 1,2-dihydroxy-4-O-glycosyloxynaphthalene, luteolin-4'-O-glucoside, apigenin-7-O-β-glucoside, luteolin-3'-O-glucoside, apigenin-4'-O-β-glucoside and luteolin-6-C-neohesperidoside.

[0080] The extract comprises 2,3,4,6-tetrahydroxyacetophenone and, optionally, further contains 3,4,5-trihydroxyacetophenone and / or 1,2-dihydroxy-4-O-glycosyloxynaphthalene. extract A further contains coumaric acid, in particular para-coumaric acid; Extract A further contains 3,4,5-trihydroxyacetophenone and / or 1,2-dihydroxy-4-O-glycosyloxynaphthalene: The extract further contains glycosylated luteolin, in particular luteolin-6-C-neohesperidoside.

[0081] Flavonoids such as luteolin and apigenin have many interesting biological properties, such as free radical scavenging and antioxidant effects [Romanov et al., Neoplasma 2001, 48(2), 104-107] as well as anti-inflammatory activity, which, combined with their ability to absorb ultraviolet light, are responsible for their ability to provide protection from UV rays [Saewan et al., JAPS 2013, 3(9), 129-141]. Although hair photoprotection is a topic that is not commonly addressed, the chemical effects of UV rays and their influence on the hair shaft cannot be ignored [Draelos, Dermatol. Clin. 2006, 24, 81-84]. The presence of compounds with photoprotective effects in cosmetic compositions intended for hair dyeing is therefore of particular interest.

[0082] Luteolin and apigenin are also known as natural dyes and can be used for coloring hair and fabrics.

[0083] Furthermore, apigenin has been shown to be a hair growth promoter [Huh et al. Arch. Dermatol. Res., 2009, 301, 381-385].

[0084] Polyphenols, such as 2,3,4,6-tetrahydroxyacetophenone, and phenolic acids, such as para-coumaric acid, also have antioxidant and photoprotective properties [Nichols et al., Arch. Dermatol. Res. 2010, 302, 71-83]. Extract A may also contain any compound naturally occurring in the aerial parts of henna, in particular in the leaves and / or branches of henna.

[0085] In some embodiments, Extract A disclosed herein may be in the form of a dry extract, advantageously in powder form, especially with a particle size of less than 250 μm.

[0086] In some embodiments, the extract A disclosed herein may be in the form of a standardized extract AN, particularly in the form of a standardized dry extract AN. The standardized extract AN, particularly the standardized dry extract AN, comprises extract A of the aerial parts of henna and a carrier.

[0087] Thus, in some embodiments, which are particularly advantageous when the dye composition is a cosmetic composition, the composition comprises a standardized extract AN, in particular a standardized dry extract AN, obtained by adding an inert carrier to the extract A disclosed herein to standardize the lawsone content of the extract. In other words, the dye composition of the present invention comprises the extract A disclosed herein and an inert carrier, and the extract A and the carrier form a standardized extract AN, in particular a standardized dry extract AN.

[0088] The standardized extract AN is characterized by one or more, advantageously all, of the following advantageous properties (percentages are given by weight relative to the total weight of the standardized dry extract): the standardized extract AN contains between 0.6% and 1.4% by weight, advantageously between 1% and 1.3% by weight, in particular about 1.3% by weight of lawsone; - the inert carrier does not contain proteins; - the inert carrier is cosmetically acceptable; the carrier is selected from the group consisting of propanediol, pentanediol, glycerin, propylene glycol, methyl THF and amyl alcohol; or the carrier is selected from the group consisting of sugars or polysaccharide derivatives, such as fructose, glucose, saccharose, maltodextrin, cellulose derivatives, starches (e.g. corn, wheat or rice starch), agar-agar, gums, mucilages and polyols, such as mannitol, sorbitol, xylitol, etc.;

[0089] -Standardized extract AN contains luteolin, apigenin and 2,3,4,6-tetrahydroxyacetophenone; -Standardized extract AN contains 3,4,5-trihydroxyacetophenone and / or 1,2-dihydroxy-4-O-glycosyloxynaphthalene; - the standardized extract AN contains coumaric acid, in particular para-coumaric acid; -Standardized Extract AN contains the compounds listed above for Extract A; -Standardized dry extract AN contains 0.2% to 3.0% by weight of phenolic compounds; - the standardized dry extract AN contains glycosylated luteolin, in particular luteolin-6-C-neohesperidoside; - the standardized dry extract AN contains 0.05% to 1.0% by weight of luteolin; - the standardized dry extract AN contains 0.01% to 0.5% by weight of apigenin; - the standardized dry extract AN contains 0.01% to 0.1% by weight of coumaric acid, in particular para-coumaric acid; - the standardized dry extract AN contains 0.05% to 1.0% by weight of 2,3,4,6-tetrahydroxyacetophenone; - the standardized dry extract does not contain more than 0.2% by weight of proteins, peptides or amino acids, advantageously it contains between 0% and 0.2% by weight, advantageously between 0.1% and 0.2% by weight of proteins, peptides or amino acids; -Standardized dry extract AN does not contain chlorophyll; the standardized dry extract AN does not contain more than 0.5% by weight of saccharide compounds, advantageously between 0.01% and 0.5% by weight, advantageously between 0.05% and 0.5% by weight; - the Standardized Dry Extract AN complies with the stability specifications, including under accelerated conditions, defined above for Henna Extract A; The standardized dry extract AN contains at least 80% by weight, advantageously at least 90% by weight, in particular at least 92% by weight, in particular at least 95% by weight of carrier.

[0090] In some embodiments, the standardized dry extract of henna AN contains 0.6% to 1.4% by weight of lawsone based on the total weight of the dry extract, and further contains luteolin, apigenin, and 2,3,4,6-tetrahydroxyacetophenone.

[0091] In some embodiments, the standardized dry extract of henna, AN, based on the total weight of the dry extract, is: 0.05% to 1.0% by weight of luteolin; 0.01% to 0.5% by weight of apigenin; 0.01% to 1% by weight, or 0.05% to 1.0% by weight of 2,3,4,6-tetrahydroxyacetophenone.

[0092] Preferably, the standardized extract AN is in the form of a dry extract, advantageously in the form of a powder, in particular with a particle size of less than 250 μm.

[0093] Preparation of extract A The amount of lawsone found in free form in henna leaves is actually quite low, and the preparation of a henna extract with high lawsone content may be tedious.

[0094] In plants, lawsone exists mainly in the form of a heteroside [Gallo et al. Rev. Bras. Pharmacogn. 2014, 23, 133-140; COLIPA no. C169, 2013].

[0095] The monoglycosylated lawsone derivatives hennosides A, B, and C have been specifically identified.

[0096] Hydrolysis of these precursors followed by autoxidation of the resulting aglycone leads to the formation of lawsone according to the reaction scheme shown below. [ka] R 1 = glucose, R 2 =R 3 =H; R 2 = glucose, R 1 =R 3 =H; or R 3 = glucose, R 1 =R 2 =H.

[0097] Therefore, most of the known methods for the extraction of henna involve the hydrolysis of the hennasides in an acidic medium, typically at a pH of 1-3.

[0098] The inventors of the present invention have developed a method for the extraction of henna which allows obtaining an extract with a high lawsone content by carrying out the enzymatic hydrolysis of glycosylated lawsone derivatives, which is also characterized by its stability over time.

[0099] Thus, advantageously, the extract A of the aerial parts of henna is obtained by a process comprising the following steps: a) soaking (softening) the aerial parts of henna in water having a pH range of 4 to 8 in order to partially or completely enzymatically hydrolyze the glycosylated lawsone derivatives, e.g. henosides, originally present in the aerial parts of henna, to provide an aqueous solution containing lawsone; b) adding an organic solvent to the solution obtained from step a) to provide an aqueous phase and an organic phase, the organic solvent being selected from the group consisting of C 4 -C 12 a linear or branched chain alcohol or a solvent having a miscibility with water of less than 10% by weight at 25° C., advantageously less than 5% by weight; c) recovering the organic phase obtained from step b); and d) concentrating the organic phase recovered from step c) to obtain Lawsone-enriched Extract A.

[0100] In particular, the above-ground parts of henna to be immersed in step a) are leaves, branches or a mixture thereof. The leaves may be fresh or dried, preferably dried. Step a) is preferably carried out at a temperature in the range of 20°C to 60°C, or 20°C to 50°C, in particular 25°C to 45°C, more particularly 30°C to 45°C, typically about 40°C.

[0101] It is understood that step a) is carried out at a pH that allows the enzyme or enzymes catalyzing the hydrolysis of the glycosylated lawsone derivatives to function. In particular, step a) is carried out at a pH between 4 and 8, preferably between 5 and 7.5, advantageously between 5.5 and 7.5, typically at neutral pH.

[0102] The aerial parts of the henna are typically soaked for a period of from 15 minutes to 2 hours, preferably from 15 minutes to 1 hour, advantageously for about 30 minutes.

[0103] In some embodiments, step (a) is carried out under stirring for 15 minutes to 2 hours, preferably for 15 minutes to 1 hour, advantageously for about 30 minutes.

[0104] The aerial parts of henna are typically soaked in a volume of water whose weight is 2 to 15 times greater than the weight of the aerial parts of henna, advantageously 5 to 15 times greater, more advantageously 6 to 10 times greater, typically 10 times greater. For example, when carrying out the method on 100 g of aerial parts of henna, the volume of water used in step a) may range from 200 mL to 1500 mL, or from 500 mL to 1500 mL, advantageously from 600 mL to 1000 mL, typically being 1000 mL.

[0105] In some embodiments, a pectinase type enzyme may be added in step a).

[0106] In some embodiments, the organic solvent may be added directly to the aqueous solution obtained in step a), which comprises the plant material and the soaking water. It should be understood that in these embodiments, the organic solvent is added directly to the aqueous solution obtained in step a), i.e., no filtration step is performed between steps a) and b).

[0107] In some embodiments, the method comprises, between steps a) and b), a filtration step that allows the aerial parts of henna to be separated from the aqueous solution containing lawsone. Alternatively, in some embodiments, the method comprises, between steps c) and d), a filtration step that allows the aerial parts of henna to be separated from the organic phase recovered / collected in step c).

[0108] Next, an organic solvent is added to the aqueous solution obtained in step a), which comprises the plant material and the soaking water. It should be understood that the organic solvent is added directly to the aqueous solution obtained in step a), i.e., no filtration step is performed between steps a) and b).

[0109] Step b) may be carried out batchwise or continuously.

[0110] In some particular batch-type embodiments, step b) of the process comprises the following three substeps: b.1) adding an organic solvent to the aqueous solution obtained in step a); b.2) stirring the solution obtained in step b.1) for 15 minutes to 2 hours, in particular for 15 minutes to 1 hour, typically for about 30 minutes; b.3) Decanting the mixture obtained in step b.2) until two distinct phases, i.e. an aqueous phase and an organic phase, are obtained.

[0111] Thus, the substeps b.1), b.2) and b.3) are carried out successively to form an aqueous phase and an organic phase.

[0112] The volume of organic solvent added in step b), in particular in step b.1), is such that the volume ratio of organic solvent added in b) to the volume of water used in step a) is from 0.25 to 2, in particular from 0.5 to 2, in particular from 0.8 to 1.5, in particular from 1 to 1.3.

[0113] In some embodiments, the organic solvent added in step b) of the method disclosed herein, particularly in step b.1), is a weakly polar solvent.It is understood that the organic solvent solubilizes Lawsone while being weakly polar.Therefore, the solubility of Lawsone in the organic solvent added in step b), particularly in step b.1), at 25°C is more than 70% by weight, particularly more than 80% by weight, advantageously more than 90% by weight; the percentage is indicated relative to the total weight of Lawsone present in the aqueous solution containing Lawsone obtained from step a).

[0114] In some embodiments, the organic solvent added during step b) of the method disclosed herein, in particular during step b.1), is a C 1 -C 6 Selected from the group consisting of alcohols, chlorinated solvents, ketones, ethers, esters and mixtures thereof: the miscibility of water in said organic solvent is less than 10% by weight, advantageously less than 5% by weight, at 25° C.; the miscibility of said organic solvent in water is less than 10% by weight, advantageously less than 5% by weight, at 25° C.

[0115] In particular, the organic solvents are n-amyl alcohol, dichloromethane, chloroform, methyl isobutyl ketone, diethyl ether, diisopropyl ether, dibutyl ether, methyl tert-butyl ether, (C 1 -C 6 ) alkyl acetates, such as ethyl acetate, isopropyl acetate, butyl acetate, isoamyl acetate, and mixtures thereof.

[0116] In some embodiments, the organic solvent added in step b), particularly in step b.1), is 1 -C 6 ) alkyl acetate or, preferably, selected from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, isoamyl acetate and any mixture thereof (C 1 -C 6 ) a mixture of alkyl acetates. Preferably, the organic solvent is isopropyl acetate.

[0117] In some embodiments, the organic solvent added in step b) is 4 -C 12 A straight or branched chain alcohol, preferably 4 -C 8 It is a straight or branched chain alcohol. Advantageously, the organic solvent is biosourced.

[0118] Advantageously, the organic solvent is a C 2 O 4 selected from the group consisting of n-butanol, sec-butanol, isobutanol and any mixture thereof. 4 -C 12 It is a straight or branched chain alcohol, more specifically n-butanol.

[0119] C 4 -C 12Alcohols have the advantage that, unlike esters such as ethyl acetate or isopropyl acetate, or certain ketones (especially acetone), they do not decompose during the recycling operation. Furthermore, the presence of residual water in the recycled solvent does not pose any practical problems. In conclusion, this type of solvent therefore facilitates the recycling of the solvent at an industrial level.

[0120] Step c) consists of recovering the organic phase obtained from step b).

[0121] Step b) can be repeated on the aqueous phase obtained in the previous iteration of step b), and the new organic phase thus obtained is then recovered (iteration of step c)) and combined with the one obtained from the previous iteration of step b).

[0122] Thus, in a process variant, step d) consists of a step d') of concentrating the combination of organic phases recovered from step b) followed by several repetitions of step c).

[0123] In some embodiments, the method may include an additional step e) of drying the lawsone-rich extract obtained from step d). At the end of step e), the obtained lawsone-rich extract is a dried extract.

[0124] The drying step e) can be carried out by methods well known to those skilled in the art. In particular, the drying step can be carried out by pallet drying, vacuum drying, atomization, microwave, zeodration or freeze drying.

[0125] In some embodiments, the method may comprise an additional step c') of adding a carrier between steps c) and d), and step d) is followed by the drying step e) described above. At the end of said step e), the obtained lawsone-rich extract is a standardized dry extract.

[0126] According to some preferred embodiments, the method does not include any step of changing the pH of the aqueous solution or phase by addition of an acid or base.

[0127] In some preferred embodiments, the method further comprises a pigment extraction step, also referred to as a decolorization step.

[0128] The pigments extracted during the decolorization process are, inter alia, chlorophyll, but it is understood that lawsone is not part of the pigments that are sought to be removed in the decolorization process.

[0129] The pigment extraction process may be carried out using organic solvents that do not sufficiently solubilize the lawsone, among others, and therefore the solubility of the lawsone in the organic solvents used in the decolorization process is less than 15% by weight at 25° C., in particular less than 10% by weight, advantageously less than 5% by weight, the percentages being given relative to the total weight of the lawsone contained in the extract or solution subjected to the decolorization process.

[0130] Preferably, the lawsone is not soluble in the organic solvent used in the pigment extraction process.

[0131] Advantageously, the organic solvent is a saturated or unsaturated hydrocarbon. In particular, the saturated hydrocarbon may be chosen from pentane, hexane, heptane, nonane, decane, cyclohexane and mixtures thereof. The unsaturated hydrocarbon may notably be benzene.

[0132] Preferably, the extraction process for pigments such as chlorophyll is carried out with heptane. The pigment extraction process carried out with organic solvents may consist of a liquid-liquid extraction or a liquid-solid extraction.

[0133] In the case of liquid-liquid extraction, said step is inserted between steps a) and b) of the disclosed method.

[0134] Advantageously, the liquid-liquid extraction decolorization step using an organic solvent comprises the following four substeps: i) adding said organic solvent to the aqueous solution obtained from step a); ii) stirring the solution obtained from step i), the stirring time being comprised between 15 minutes and 2 hours, in particular between 15 minutes and 1 hour, typically the stirring time being about 30 minutes; iii) decanting the mixture obtained from step ii) until two distinct phases, i.e. an aqueous phase and an organic phase, are obtained; and iv) Removing the organic phase.

[0135] Step b) of the process is then carried out with the aqueous phase obtained from step iii).

[0136] If it is a liquid-solid extraction, this step is followed by the drying step e) of the method. The liquid-solid extraction can be carried out according to methods well known to those skilled in the art.

[0137] Alternatively, the decolorization step can be carried out using supercritical CO with or without the addition of a co-solvent. 2 Chlorophyll can be extracted directly from the dried extract using supercritical CO 2 The residue is the decolorized dry extract.

[0138] Henna extract B The dye composition of the present invention includes a second specific henna extract, referred to herein as "Extract B." Extracts A and B together provide the dye composition.

[0139] This extract B is characterized by a low lawsone content.

[0140] Extract B therefore contains less than 0.6% by weight of lawsone relative to the weight of the dry extract, advantageously less than 0.5% by weight, more advantageously less than 0.4% by weight, for example between 0% and 0.6% by weight, in particular between 0.05% and 0.6% by weight, more particularly between 0.1% and 0.5% by weight, in particular between 0.1% and 0.4% by weight, better still approximately about 0.2% by weight of lawsone relative to the total weight of the dry extract.

[0141] Lawsone content can be measured by the HPLC assay method (Method 1) described in the Examples below.

[0142] Extract B includes phenolic compounds such as tannins, phloroglucinol derivatives, naphthoquinone derivatives, flavonoids, and combinations thereof.

[0143] In particular, the phenolic compound may be selected from gallic acid, coumaric acid, and / or heterosides of such compounds and combinations thereof; in particular it may be gallic acid.

[0144] In particular, the phloroglucinol derivative is selected from the group consisting of 2,3,4,6-tetrahydroxyacetophenone, 1,3,6,7 tetrahydroxyxanthone, phloroacetophenone, myrciaphenone A, larioside, and / or heterosides of such derivatives, such as polygoacetophenosides, and combinations thereof.

[0145] In particular, the naphthoquinone derivative is selected from isonaphthazarin and / or heterosides of such derivatives, such as 1,2,4-trihydroxynaphthalene-1-O-glucoside, and combinations thereof.

[0146] In particular, the flavonoid derivative is selected from luteolin and / or heterosides of such derivatives, such as luteolin-4'-O-glucoside, luteolin-7-O-glucoside, and combinations thereof.

[0147] In some embodiments, the phenolic compound of Extract B is tannins, especially hydrolyzable tannins, more particularly gallic tannins; -Gallic acid; - luteolin and its heterosides, in particular its glycosylated derivatives; -Apigenin; -2,3,4,6-Tetrahydroxyacetophenone; -1,3,6,7-tetrahydroxyxanthone.

[0148] In some embodiments, the phenolic compound of Extract B is - gallic acid, coumaric acid, and / or heterosides of such compounds, and combinations thereof; -Tannins, especially gallic tannin; Phloroglucinol derivatives, such as 2,3,4,6-tetrahydroxyacetophenone, and - flavonoid derivatives, such as luteolin, apigenin and / or heterosides of such derivatives, and combinations thereof.

[0149] In some embodiments, extract B is present in an amount of 0.05% by weight to 0.5% by weight based on the total weight of the dry extract. It is characterized by a luteolin content of 0.5% by weight, in particular 0.1% to 0.3% by weight.

[0150] In some embodiments, extract B is characterized by an apigenin content of 0.01% to 0.75% by weight, in particular 0.05% to 0.5% by weight, relative to the total weight of the dry extract.

[0151] In some embodiments, extract B is characterized by a 2,3,4,6-tetrahydroxyacetophenone content of 0.01% to 0.5% by weight, in particular 0.02% to 0.1% by weight, relative to the total weight of the dry extract.

[0152] In some embodiments, extract B is characterized by a gallic acid content of 0.05% to 0.5% by weight, in particular 0.1% to 0.3% by weight, relative to the total weight of the dry extract.

[0153] The amount of phenolic compounds contained in extract B is at least 10% by weight, in particular at least 15% by weight, relative to the total weight of the dry extract. In particular, extract B comprises 10% to 35% by weight, advantageously 15% to 35% by weight, more advantageously 15% to 30% by weight, of phenolic compounds relative to the total weight of the dry extract.

[0154] The content of phenolic compounds is expressed with reference to the pyrogallol content (method 4).

[0155] Extract B comprises, as major amount of saccharide type compounds, at least 60% by weight, advantageously at least 65% by weight, more advantageously at least 70% by weight, for example 60% to 80% by weight, in particular 70% to 75% by weight, of saccharide compounds (including polysaccharides) relative to the total weight of the dry extract.

[0156] The saccharide compounds may further include monosaccharides, disaccharides and combinations thereof. In particular, polysaccharides predominate by weight, i.e. they typically constitute more than 50% by weight, advantageously more than 60% by weight, more advantageously more than 70% by weight, even more advantageously more than 80% by weight, and even more advantageously more than 90% by weight of the total saccharides present in the extract.

[0157] In particular, extract B may contain mucilage as a polysaccharide.

[0158] Mucilage is a plant substance consisting of polysaccharides or proteosaccharides that swells on contact with water and becomes viscous, sometimes sticky, similar to gelatin.

[0159] Mucus is a compound with large, more or less branched polymeric structures built up from several different sugar or uronic acid units (uronic acids are carboxylic acids derived from sugars), which are very hydrophilic and can trap water (and other molecules) in their cage-like structures to form gels.

[0160] The saccharide compound content can be measured by the dinitrosalicyl colorimetric assay (Method 5).

[0161] Extract B may further comprise an organic acid. The organic acid content may be at least 2% by weight, advantageously at least 3% by weight, more advantageously at least 4% by weight, for example 2% to 8% by weight, in particular 4% to 8% by weight, of organic acid relative to the total weight of the dry extract.

[0162] The organic acids of extract B include, in particular, hydroxy acids, i.e. hydrocarbon compounds having at least one carboxylic acid -COOH functional group and at least one alcohol -OH functional group, advantageously with at least one alcohol functional group in the alpha position of the carboxylic acid functional group (i.e. on the carbon atom adjacent to the carbon atom carrying the carboxylic acid functional group). The organic acids, in particular the carboxylic acids, of extract B are advantageously carboxylic acids whose linear, branched or ring-containing alkyl chain contains 4 to 8 carbon atoms, advantageously 4 to 6 carbon atoms. The carboxylic acids are in particular selected from the group consisting of succinic acid, ascorbic acid, malic acid and combinations thereof. Organic acids such as malic acid, succinic acid and ascorbic acid can be measured by enzymatic or spectrophotometric methods known to those skilled in the art, in particular HPLC (method 6).

[0163] These organic acids contribute to promoting the attachment of lawsone to keratin fibers.

[0164] These organic acids also contribute to the coloring and hydration of the fibers, giving the hair a particular shine.

[0165] Lactones can also be found in Extract B, typically in amounts of less than 10% by weight relative to the total weight of the dry extract.

[0166] Extract B may contain proteinaceous compounds, such as peptides, amino acids and proteins, in an amount of 5% to 10% by weight relative to the weight of the dry extract.

[0167] Extract B is further characterized by one or more, advantageously all of the following advantageous properties (percentages given relative to the total weight of dry extract B): extract B contains less than 0.6% by weight of lawsone, advantageously less than 0.5% by weight and more advantageously less than 0.4% by weight, for example between 0% and 0.6% by weight of lawsone; extract B comprises at least 15% by weight of phenolic compounds, in particular tannins; extract B comprises gallic acid, advantageously with a content ranging from 0.1% to 0.3% by weight; extract B comprises 2,3,4,6-tetrahydroxyacetophenone, advantageously in a content ranging from 0.02% to 0.1% by weight; extract B comprises luteolin, advantageously in a content ranging from 0.1% to 0.3% by weight; extract B comprises apigenin, advantageously in a content ranging from 0.05% to 0.5% by weight; - Extract B contains 1,3,6,7-tetrahydroxyxanthone; - extract B contains 60% to 80% by weight of saccharide compounds, mainly polysaccharides (including mucilage); Extract B contains 2% to 8% by weight of organic acids (including malic acid, succinic acid and ascorbic acid).

[0168] In some embodiments, Extract B may be in dry form, advantageously in powder form, especially with a particle size of less than 250 μm.

[0169] It has been observed that this extract B, when combined with extract A, makes it possible: - To expand the color range and access to color charts, especially for hair coloring; - improving the adhesion of extract A to fibres, especially keratin fibres; -Adds shine to keratin fibers, especially hair.

[0170] Method for obtaining extract B

[0171] The Applicant has developed a method for obtaining an extract B from henna, which makes it possible to obtain an extract having a weak dyeing effect due to its low lawsone content, but rich in compounds that make it possible to obtain dyeing effects and benefits on keratin fibres, such as the phenolic and saccharide compounds described below.

[0172] The present invention reflects the desire to set out a synthetic route which is more environmentally friendly and which allows the active ingredients thus obtained to claim naturalness.

[0173] Advantageously, therefore, the extract B of the aerial parts of henna is an extract obtained by aqueous, hydroalcoholic or alcoholic extraction.

[0174] Henna extract B can be obtained from the crushed leaves by water extraction at room temperature or higher, which can be carried out at temperatures ranging from 20° C. to 180° C., at atmospheric or supercritical pressure. After liquid / liquid separation, the filtrate is sterilized by standard sterilization methods (pasteurization, flash pasteurization, etc.) and subsequently dried and concentrated by standard drying methods known to those skilled in the art (vacuum drying, freeze drying, microwave, etc.).

[0175] Advantageously, before liquid / liquid separation, a water-miscible alcohol, in particular ethanol or ter-butanol, preferably ethanol, can be added to facilitate filtration and solubilization of weakly polar compounds.

[0176] The extraction can be carried out using various techniques, in particular so-called "green" techniques, such as water at atmospheric pressure (possibly with the aid of extraction means such as ultrasound, microwave, leaching, soaking, percolation, etc.) or at elevated pressure, in particular in the subcritical state, at temperatures between 20°C and 250°C, with or without co-solvents such as ethanol.

[0177] In some embodiments, the extract B of the aerial parts of henna is an extract obtained by a method comprising the steps of: a) mixing the aerial parts of henna, in particular the crushed leaves, in water, in particular in a plant / water w / v ratio comprised between 1 / 2 and 1 / 10, advantageously between 1 / 4 and 1 / 8; b) stirring the resulting mixture at a temperature ranging from 30°C to 50°C; c) optionally adding an alcohol, such as ethanol; d) stirring and recovering the liquid phase; e) concentrating the liquid phase obtained in step d) to obtain extract B.

[0178] In particular, the above-ground parts of henna which are subjected to the immersion in step a) are the leaves, which may be fresh or dried, preferably dried, and the branches or a mixture of both, preferably finely ground.

[0179] According to one particular embodiment, an enzyme of the pectinase type may be added in step a).

[0180] Advantageously, the stirring can be obtained by any method well known to the person skilled in the art.

[0181] Similarly, the aqueous or hydroalcoholic liquid phase may be recovered by any liquid-solid separation technique known to those skilled in the art, such as, for example, filtration, centrifugation or decantation.

[0182] The stirring time is advantageously comprised between 15 minutes and 2 hours, in particular between 15 minutes and 1 hour, advantageously about 30 minutes.

[0183] The volume of alcohol added during step b) is in this case such that the mixture obtained contains 30-90% v / v alcohol, advantageously 50-80% v / v alcohol. Alcohol such as ethanol, in addition to facilitating the extraction of hydrophilic compounds, sterilizes and decontaminates the mixture.

[0184] Alternatively, step c) where an alcohol such as ethanol is added may also be replaced by a decontamination and / or sterilization step by alternative and equivalent techniques known to the skilled person, such as heating, for example by steam injection, or by microwave treatment, or any other suitable decontamination process.

[0185] In one embodiment, the method can contain an additional step f) of drying the extract obtained from step e).At the end of said step f), the extract B obtained is a dry extract.The drying step f) can be carried out by any method well known to those skilled in the art.In particular, the drying step can be carried out by paddle dryer, vacuum drying, atomization, microwave, zeolite drying or freeze drying.

[0186] Alternatively, extract B can be obtained by the following method: a) immersing the aerial parts of henna in water having a pH range of 4-8 in order to partially or completely enzymatically hydrolyze the glycosylated derivatives of lawsone, such as hennosides, naturally present in the aerial parts of henna, thereby producing an aqueous solution containing lawsone; b) adding an organic solvent to the aqueous solution obtained in step a) to obtain the formation of an aqueous phase and an organic phase, the organic solvent being C 4 -C 12 being selected from linear or branched chain alcohols or solvents having a miscibility with less than 10% by weight, advantageously less than 5% by weight, of water at 25°C; c') recovering the aqueous phase obtained at the end of step b); and d') concentrating the aqueous phase recovered from step c') to obtain Extract B which is low in Lawsone.

[0187] Thus, extract B can be obtained by a process implementing steps a) and b) of the process for obtaining extract A described above, but then the phase recovered is the aqueous phase.

[0188] Advantageously, steps a) and b) are according to the method for obtaining extract 1 described above.

[0189] Step c') consists of recovering the aqueous phase and concentrating it to obtain extract B.

[0190] The method may also comprise, between steps c') and d'), a decontamination and / or sterilization step by any technique known to the person skilled in the art, such as, for example, heating with steam injection, or microwave treatment, or any other suitable decontamination treatment.

[0191] In one embodiment, the method can include an additional step e) of drying the low-lawsone extract obtained from step d'). At the end of said step e'), the low-lawsone extract obtained is a dry extract. The drying step e) can be carried out by methods well known to those skilled in the art. In particular, the drying step can be carried out by paddle dryer, vacuum drying, atomization, microwave, zeolite drying or freeze drying.

[0192] Mixture of Extracts A and B The above henna extracts A and B disclosed herein are mixed to provide the dye composition of the present invention. Surprisingly, the weight ratio of one to the other influences the dye obtained, and by varying this ratio it is possible to access a wide color spectrum. The composition of the two henna extracts A and B makes it possible to obtain a palette of shades, both in color and reflect.

[0193] In some embodiments of the method of the present invention, extract A is mixed with extract B in a B / A weight ratio of 1 or more. According to certain embodiments, the B / A weight ratio may be comprised between 1 and 10 / 1, where this means the ratio of dry extracts, extract A being a standardized dry extract.

[0194] According to an alternative method, extract A can be mixed with extract B with a B / A weight ratio of less than 1, advantageously ranging from 1 / 10 to 1, where the ratio of dry extracts is meant and extract A is a standardized dry extract. According to a particular embodiment, the B / A weight ratio includes 1 / 10 to 10 / 1, for example 8 / 1 to 1 / 3, where the ratio of dry extracts is meant and extract A is a standardized dry extract.

[0195] Beneficial Agent The method according to the invention also includes providing a benefit agent, particularly an agent that promotes the adhesion of the dye to the substrate, especially cellulosic and / or keratinous fibers. Extract A, Extract B and the benefit agent can then be mixed to provide the dye composition.

[0196] The beneficial agent is preferably in dry form, advantageously in powder form, especially with a particle size of less than 250 μm.

[0197] The beneficial agent may also be a plant extract or a plant powder.

[0198] For example, cassia (neutral henna) can be used to promote adhesion of henna extract A to cellulose and / or keratin fibers, which can also provide shine to the hair.

[0199] For example, Aloe vera, and in particular the juice extract of Aloe vera leaves, can be used as a natural mordant, i.e. as a compound that promotes the adhesion of dyes, and can also nourish and hydrate keratin fibers and protect them from UV rays.

[0200] Aloe vera also contains anthraquinones, such as aloin and aloe-emodin, resins, tannins and polysaccharides. A juice / gel may be extracted from the leaves of Aloe vera that contains mainly water and polysaccharides, such as pectin, hemicellulose, glucomannan, acemannan and mannose derivatives. The juice / gel may also contain amino acids, lipids, sterols, such as lupeol and campesterol, and enzymes.

[0201] The benefit agent may be a fructan such as inulin for its tendency to coat keratin fibers.

[0202] composition The composition obtained by the method of the present invention comprises Henna Extract A and Henna Extract B. The composition further comprises a benefit agent as disclosed herein above and / or one or more additional staining agents as disclosed herein below.

[0203] Advantageously, it may also include the addition of a limited number of dyes, preferably not more than 5 additional dyes, more preferably not more than 3 additional dyes, more preferably not more than 2 additional dyes, and even more preferably not more than 1 additional dye. In one advantageous embodiment, the composition includes only henna extracts A and B as dyes.

[0204] In particular, the combination of two extracts obtained from the same plant, namely henna, allows a wide color palette to be obtained, in both colors and reflects, all of which are desired in particular for hair dyeing, and therefore has the advantage that a limited number of dyes can be used, which reduces the risk of intolerance and incompatibility and is more economical.

[0205] Furthermore, the combination according to the present invention - natural, free of animal products, i.e. based on dye active ingredients derived from plants, microorganisms or microalgae; - short exposure times, advantageously shorter than the time required for dyeing the hair; - preferably in a single application (including dyeing the hair); -Preferably organic and vegan; - in the case of hair dyes, to provide a dye composition that allows good color retention, including after several washes, including after 10 shampoos, advantageously after 15 shampoos.

[0206] There is also a need for hair dyes that avoid the use of hydrogen peroxide and alkaline chemicals.

[0207] A particularly favorable combination is - Henna Extract A, in particular Henna Extract AN, and Henna Extract B - Henna Extract A, in particular Henna Extract AN, Henna Extract B and logwood powder - Henna Extract A, especially Henna Extract AN, Henna Extract B, and Sorghum Extract -Henna Extract A, especially Henna Extract AN, Henna Extract B, and Sorghum Powder Henna extract A, in particular Henna extract AN, Henna extract B, and Gardenia extract - Henna Extract A, in particular Henna Extract AN, Henna Extract B, and Gardenia Powder - Henna Extract A, especially Henna Extract AN, Henna Extract B, and Chlorophyllin Henna extract A, in particular Henna extract AN, Henna extract B, and Indigofera plant extract - Henna extract A, especially Henna extract AN, Henna extract B, and Indigofera plant powder.

[0208] In certain embodiments, the dye composition obtained by the method of the invention comprises 10-90% by weight, in particular 10-50% by weight or 50-90% by weight, of standardized henna extract AN, the weight of the standardized extract being expressed as dry extract relative to the total dry weight of the composition.

[0209] In one particular embodiment, the dye composition obtained by the method of the invention comprises from 10 to 90% by weight, in particular from 10 to 50% by weight or from 50 to 90% by weight, of henna extract B, the weight of extract B being expressed as dry extract relative to the total dry weight of the composition.

[0210] The extract, particularly Henna Extract A, may be standardized and a carrier will be found in the composition.

[0211] The carrier may be selected from propanediol, pentanediol, glycerin, propylene glycol, methyl THF and amyl alcohol, among others.

[0212] When the dye composition according to the invention is in powder form, the carrier is preferably selected from sugars and polysaccharide derivatives such as fructose, glucose, saccharose, maltodextrins, cellulose derivatives, starches (e.g. corn, wheat or rice starch), agar-agar, gums, mucilages and polyols such as mannitol, sorbitol, xylitol, etc. In particular, the carrier is selected from fructose, maltodextrins and starches, in particular rice starch.

[0213] When the dye composition according to the present invention is in powder form, its particle size can be adjusted by any method well known to those skilled in the art.

[0214] In particular, the dye composition according to the invention may be in the form of a powder with a particle size of less than 250 μm.

[0215] The composition further comprises one or more acceptable excipients, in particular one or more cosmetically acceptable excipients (as disclosed below) suitable for application to human keratinous fibers.

[0216] Advantageously, the composition does not contain any stabilizers normally present in henna compositions to stabilize the lawsone.

[0217] Advantageously, the dye composition according to the invention is free of additives consisting of synthetic dyes such as diaminotoluenes and diaminobenzenes, especially the most commonly used PPD (paraphenylenediamine), or heavy metals [Wang et al. J. environ. Anal. Toxicol. 2016, 6(3); Wang et al. J. Chromatogr. B 2011, 879, 1795-1801].

[0218] The dye composition according to the invention may also be a printing ink comprising extract A, extract B and suitable excipients, especially selected from oils and resins and mixtures thereof.

[0219] Another dye C The composition according to the invention may further comprise a dye C derived from a dye plant other than henna or from a microorganism or microalgae.

[0220] Thus, the method of the present invention further comprises the step of providing a staining agent C as disclosed herein.

[0221] Preferably, dye C is in dry form, advantageously in powder form, and in particular in the form of a particle size of less than 250 μm.

[0222] Dyeing agent C can be a powder of a dyeing plant other than henna, or of a microorganism or microalgae. Dyeing agent C can also be an extract of a dyeing plant other than henna, or of a microorganism or microalgae. The extract is most often an aqueous extract or a hydroalcoholic or alcoholic extract.

[0223] Advantageously, the dye C is derived from at least one non-henna dyeing plant selected from the Indigofera plant, red pigment source plants, red or purple to black pigment source plants, yellow pigment source plants, red to blue-green pigment source plants, tannin source plants, maroon pigment source plants and combinations thereof.

[0224] In particular, the Indigofera plant includes the true indigo tree (Indigofera tinctoria), dyer's knotweed (Polygonum tinctorium or Persicaria tinctoria), dyer's woad (Isatis tinctoria L.), Couroupita guianensis (Cannon ball tree), wild indigo (Baptisia tinctoria), dyed croton (Chrozophora tinctoria), dyed oleander (dyer's oleander (Wrightia tinctoria), Yoruba indigo (Philenoptera cyanescens = Lonchocarpus cyanescens), L. laxiflorus (Lonchocarpus laxiflorus), Marsdenia tinctoria (Asclepiadaceae), Chinese rain bell (Strobilanthes cusia or Strobilanthes flaccidifolius) and combinations thereof.

[0225] Advantageously, the dye C comprises indirubin and / or leucoindigo.

[0226] Advantageously, dye C is an extract of indigo leaves, in particular an aqueous or hydroalcoholic or alcoholic extract of indigo leaves, or indigo leaf powder.

[0227] Advantageously, the dyeing agent C is an extract of dyed knotweed leaves, in particular an aqueous or hydroalcoholic or alcoholic extract of dyed knotweed leaves, or in particular a powder of dyed knotweed leaves.

[0228] Advantageously, the dyeing agent C is an extract of dyer's woad leaves, in particular an aqueous or hydroalcoholic or alcoholic extract of dyer's woad leaves, or a powder of dyer's woad leaves.

[0229] Advantageously, the dye C is an extract of the flowers and / or fruits of Couroupita guianensis, in particular an aqueous or hydroalcoholic or alcoholic extract of the flowers and / or fruits of Couroupita guianensis, or a powder of the flowers and / or fruits of Couroupita guianensis.

[0230] Advantageously, dye C is an extract of the whole wild indigo plant, in particular an aqueous or hydroalcoholic or alcoholic extract of the whole wild indigo plant, or a powder of the whole wild indigo plant.

[0231] Advantageously, the dyeing agent C is an extract of the whole dyed croton plant, in particular an aqueous or hydroalcoholic or alcoholic extract of the whole dyed croton plant, or a powder of the whole dyed croton plant.

[0232] Advantageously, the dyeing agent C is an extract of the whole dyed oleander plant, in particular an aqueous or hydroalcoholic or alcoholic extract of the whole dyed oleander plant, or a powder of the whole dyed oleander plant.

[0233] Advantageously, dye C is an extract of Yoruba indigo leaves, in particular an aqueous or hydroalcoholic or alcoholic extract of Yoruba indigo leaves, or a powder of Yoruba indigo leaves.

[0234] Advantageously, the dye C is an extract of L. laxiflorus leaves, in particular an aqueous or hydroalcoholic or alcoholic extract of L. laxiflorus leaves, or a powder of L. laxiflorus leaves.

[0235] Advantageously, the dye C is an extract of the whole Marsdenia tinctoria plant, in particular an aqueous or hydroalcoholic or alcoholic extract of the whole Marsdenia tinctoria plant, or a powder of the whole Marsdenia tinctoria plant.

[0236] Advantageously, dye C is an extract of the whole Ryukyuai (Chinese rain bell) plant, in particular an aqueous or hydroalcoholic or alcoholic extract of the whole Ryukyuai plant, or a powder of the whole Ryukyuai plant.

[0237] Advantageously, the dye C is derived from at least one dye plant source of red pigment, in particular the plant source of red pigment is chosen from sorghum, hibiscus and combinations thereof.

[0238] Advantageously, dye C comprises an anthocyanin.

[0239] Advantageously, the dye C is an aqueous or hydroalcoholic extract of the aerial parts of sorghum, in particular the stems, or a powder of the aerial parts of sorghum, in particular the stems. In the case of an extract, the extraction solvent is advantageously aqueous or hydroalcoholic, advantageously with an acidic pH, advantageously below 6. In the case of a hydroalcoholic extract, the alcohol is advantageously one that can be mixed with water, such as ethanol. Advantageously, the dye C is an aqueous or hydroalcoholic extract of hibiscus flowers, in particular dried flowers (karkade), or a powder of hibiscus flowers, in particular dried flowers (karkade). In the case of an extract, the extraction solvent is advantageously aqueous or hydroalcoholic, advantageously with an acidic pH, advantageously below 6. In the case of a hydroalcoholic extract, the alcohol is advantageously one that can be mixed with water, such as ethanol.

[0240] Advantageously, the dye C is derived from at least one dyeing plant which is a source of red or violet to black pigments. In particular, the source plant of the red or violet to black pigments is logwood.

[0241] Advantageously, the dye C is an aqueous or hydroalcoholic extract of logwood wood, in particular of the heartwood, or a powder of logwood wood, in particular of the heartwood. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0242] Advantageously, the dye C is derived from at least one dyeing plant source of yellow pigments, in particular chosen from gardenia, turmeric, saffron, birch, chamomile, reseda and combinations thereof.

[0243] Advantageously, the dye C comprises crocin.

[0244] Advantageously, the dye C is an aqueous or hydroalcoholic extract of Gardenia fruits or a powder of Gardenia fruits. Such dye C may be extracted from Gardenia as described in application WO2018162760. In particular, the Gardenia extract or powder contains a fraction of crocin comprised between 0.1% and 10% by weight, preferably between 1% and 5% by weight, relative to the total weight of the dry extract or powder.

[0245] The gardenia extract may be a fluid, aqueous or hydroalcoholic extract, or a dry extract. In particular, it is an aqueous extract. The fluid gardenia extract, more particularly an aqueous or hydroalcoholic gardenia extract, may be in the form of a liquid fraction (more or less viscous) obtained after extraction and liquid-solid separation and may contain 20% to 60% of dry extract, more particularly 30% to 50% of dry extract, even more particularly about 40% of dry extract in the aqueous or hydroalcoholic solvent. The extract may also be in the form of a dry extract, once the aqueous or hydroalcoholic solvent has evaporated from the fluid extract. This extract is typically powdery and has an average particle size comprised between 0.1 μm and 250 μm, in particular between 1 μm and 250 μm.

[0246] Advantageously, the dye C is an aqueous or hydroalcoholic extract of the rhizome of turmeric, or a powder of the rhizome of turmeric. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0247] Advantageously, dye C is an aqueous or hydroalcoholic extract of the stigmas of saffron, or a powder of saffron stigmas. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0248] Advantageously, the dye C is an aqueous or hydroalcoholic extract of birch leaves or a birch leaf powder. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0249] Advantageously, the dye C is an aqueous or hydroalcoholic extract of chamomile flowers, in particular of the ligules, or a powder of chamomile flowers, in particular of the ligules. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0250] Advantageously, dye C is an aqueous or hydroalcoholic extract of the root of reseda, or a powder of the root of reseda. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0251] Advantageously, the dye C is derived from at least one dye plant source of green-blue pigments, in particular the plant source of green-blue pigments is chosen from among the elderberry, blueberry, chocolateberry and combinations thereof.

[0252] Advantageously, the dye C is an aqueous or hydroalcoholic extract of elderberry fruits, or a powder of elderberry fruits. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0253] Advantageously, the dye C is an aqueous or hydroalcoholic extract of blueberry fruits or a powder of blueberry fruits. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0254] Advantageously, the dye C is an aqueous or hydroalcoholic extract of chocolateberry fruits or a powder of chocolateberry fruits. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0255] Advantageously, the dye C is derived from at least one dye plant source of tannins, in particular from chestnut, Emblica officinalis, pomegranate and combinations thereof.

[0256] Here, tannin plants are sought to darken the color, especially to gray or deep chestnut.

[0257] Advantageously, the dye C comprises a tannin.

[0258] Advantageously, the dye C is an aqueous or hydroalcoholic extract of chestnut wood, or chestnut wood powder. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0259] Advantageously, the dye C is an aqueous or hydroalcoholic extract of the fruits of Emblica officinalis or a powder of the fruits of Emblica officinalis. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0260] Advantageously, the dye C is an aqueous or hydroalcoholic extract of the fruits of the pomegranate, in particular the peel, or a powder of the fruits of the pomegranate, in particular the peel. In the case of a hydroalcoholic extract, the alcohol is advantageously one that is miscible with water, such as ethanol.

[0261] Advantageously, the dye C is derived from at least one dyeing plant which is the source of the maroon pigment, in particular the plant which is the source of the maroon pigment is rhapontic. Advantageously, dye C is an aqueous or hydroalcoholic extract of rhapontic root or rhapontic root powder (powder of the root of Rheum rhaponticum).

[0262] All of the above extracts and powders can bear the "organic" label, that is, they do not involve chemical synthesis steps and can be obtained in an environmentally friendly manner.

[0263] These may also be referred to as "vegan".

[0264] The present invention also provides for the use of extracts obtained by semi-synthetic or synthetic methods.

[0265] In particular, stain C may be chlorophyllin, which is a source of green pigment.

[0266] Chlorophyllin can be obtained by extraction using a semi-synthetic method involving a chlorophyll saponification step.

[0267] Plants rich in chlorophyll are selected from alfalfa, white mulberry, nettle, algae, and combinations thereof, among others.

[0268] Chlorophyll can be dissolved in, for example, acetone, alcohol, alkanes (hexane or heptane) or supercritical CO 2 Alfalfa can be extracted from the aerial parts of the plant with organic solvents such as ethanol.

[0269] Chlorophyll can be dissolved in, for example, acetone, alcohol, alkanes (hexane or heptane) or supercritical CO 2 It can be extracted from the aerial parts of white mulberry with organic solvents such as .

[0270] Chlorophyll can be dissolved in, for example, acetone, alcohol, alkanes (hexane or heptane) or supercritical CO 2 It can be extracted from the aerial parts of the nettle with an organic solvent such as ethylhexyl ether.

[0271] Chlorophyll can be dissolved in, for example, acetone, alcohol, alkanes (hexane or heptane) or supercritical CO 2 The algae may be extracted from the thallus with an organic solvent such as ethanol.

[0272] The composition may comprise at least 5% by dry weight of dye C relative to the dry weight of the composition.

[0273] Cosmetic Composition The composition obtained by the method of the present invention is preferably a cosmetic composition, which may be formulated to be administered by the external topical route.

[0274] The cosmetic compositions may be formulated into various preparations suitable for topical administration, such as creams, emulsions, milks, ointments, lotions, oils, aqueous or hydroalcoholic or glycolic solutions, powders, sprays, shampoos, varnishes, or other products for external application.

[0275] The dye cosmetic composition advantageously comprises at least one cosmetically acceptable excipient.

[0276] In particular, the compositions according to the invention may also comprise at least one cosmetically acceptable excipient known to those skilled in the art, selected from surfactants, texture and / or feel agents, preservatives, fragrances, dyes, chemical or mineral UV filters, hydrating agents, mineral water, acidity correctors, etc. The skilled artisan will know, using his general knowledge, how to adapt the formulation of the compositions according to the invention.

[0277] In particular, the composition may advantageously contain at least one acidity corrector selected from organic acids, in particular citric acid, acetic acid, carbonates and bicarbonates, in particular sodium bicarbonate, calcium bicarbonate or potassium bicarbonate.

[0278] In particular, the composition may advantageously comprise at least one texture and / or feel agent selected from maltodextrin, fructans such as inulin, bamboo silica cellulose, polysaccharides such as guar gum, xanthan gum, alginates, carrageenans, locust bean gum, gum arabic, acacia gum, konjac, pectin, and combinations thereof, and advantageously the composition comprises xanthan gum or a xanthan gum-acacia gum combination. The cellulose may be, inter alia, a cellulose ether, such as carboxymethylcellulose or hydroxypropylmethylcellulose.

[0279] Kits or Combination Products The present invention also relates to a kit or combination product comprising the following components: component (X) comprising a combination of extracts A and B of the aerial parts of Henna, and component (Y) comprising at least one cosmetically acceptable excipient.

[0280] This excipient may be as defined above for the cosmetic composition and may in particular be selected from the group comprising texture and / or feel agents, acidity correctors and mixtures thereof.

[0281] Advantageously, component (Y) is a hair care product selected from the group comprising shampoos, conditioners, hair balms, hair lotions, hair creams, etc. Component (X) is advantageously in dry form, especially a powder.

[0282] Methods and Uses The present invention also relates to the use of the composition obtained by the method of the invention for the cosmetic dyeing of keratin fibres, in particular human. In such a case, preferably a standardised henna extract AN is used.

[0283] The composition may contain a limited number of dyes, in particular dyes derived from a single plant, henna, but it is nevertheless considered to be capable of covering the entire range of colors required for hair dyes, whether tone-on-tone or permanent. The two compositions of henna extracts A and B allow a palette of shades to be obtained, both in color and reflect (tone). The dye also allows for more effective coverage of white hair.

[0284] Another advantage of the method according to the invention and of the composition according to the invention is that the color obtained, especially on keratinous fibers such as hair, is maintained despite repeated washings.

[0285] Thus, advantageously, the colored keratin fibers exhibit a loss in shine of not more than 8 units after 10, advantageously not more than 15 washes after dyeing, advantageously not more than 6 units, more advantageously not more than 5 units, even more advantageously not more than 4 units, even more advantageously not more than 3 units, the shine being assessed by measuring the dE* parameter according to the protocol described in the examples.

[0286] Another advantage of the invention, and of the compositions according to the invention, is that the dyeing is obtained after a short exposure time, advantageously less than one hour for hair dyes, and can be obtained after a single application.

[0287] The present invention also relates to a cosmetic method for dyeing keratinous fibers, comprising applying to the keratinous fibers an aqueous composition comprising a composition according to the invention, optionally followed by rinsing.

[0288] In particular, the cosmetic method for dyeing keratinous fibers, especially human, comprises the following steps: a) providing the composition according to the invention, in particular in dry form, especially in powder form; b) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a) at a temperature between 20°C and 98°C and mixing. c) applying to keratinous fibers, optionally treating said fibers with heat, d) Rinsing process e) optionally repeating steps c) and d).

[0289] Advantageously, steps c) and d) are not repeated.

[0290] It has been observed that a small amount of the composition according to the invention, together with a small amount of water, is sufficient to dye adult hair. Traditionally, for natural dyes containing plant powders or extracts, it is recommended to mix at least 100 g of powder with at least 300 g of water, which results in a "poultice" that is very thick and uncomfortable to handle and apply.

[0291] According to the present invention, during step a), advantageously less than 50 g, more advantageously less than 30 g, even more advantageously less than 25 g, for example between 15 g and 30 g, advantageously between 15 g and 25 g, more advantageously about 20 g, of powder of the composition according to the present invention is provided.

[0292] During step b), water is advantageously added in a sufficient amount to prepare a composition ranging from 100 g to 150 g.

[0293] The water added can be water at ambient temperature or hot water (boiling water). The hot water temperature can be at least 50° C., advantageously at least 70° C., or at least 90° C., as is readily obtained in a kettle.

[0294] Thus, 100 or 150 g of the aqueous composition are sufficient to obtain a preparation that can be applied to the head. The composition obtained is a pleasant preparation, unlike the very thick and uncomfortable "poultice" aspect of known natural dyes.

[0295] The application step may be one already used for chemical hair dyes, with an exposure time step before the rinsing step. In particular, the exposure time step also comprises a heating step, which is carried out at a temperature comprised in particular between 25°C and 65°C, advantageously between 30°C and 60°C, in particular at 55°C or in particular at 35°C. Alternatively, the exposure time step may be carried out at room temperature, in particular in the range between 20°C and 30°C, without additional heat input and therefore without a heating step. Advantageously, the exposure time is short, i.e. less than 1 hour, preferably less than 45 minutes.

[0296] Advantageously, the application of step c) is carried out at a temperature comprised between 20° C. and 55° C., for a time comprised between 15 minutes and 1 hour, and more advantageously between 15 minutes and 45 minutes.

[0297] The application of step c) may be carried out on dry or wet keratin fibre strands.

[0298] In one embodiment, the dye is a tone-on-tone dye.

[0299] In particular, the dye is a blonde dye with reflects and shades that can vary from warm copper tones to cool blonde / chrysotile tones, especially for blonde hair. Advantageously, in this variant, the exposure time is less than 1 hour, preferably less than 45 minutes.

[0300] In particular, the dye is a dark blonde dye with reflects and shades that can vary from warm copper tones to cool golden / chrysotile tones, especially for blonde-red or dark blonde hair. Advantageously, in this variant, the exposure time is less than 1 hour, preferably less than 45 minutes.

[0301] Alternatively, a cosmetic method for dyeing keratinous fibers, in particular human, comprising the steps of: a.1) providing extract A according to the invention, optionally together with at least one cosmetically acceptable excipient as defined above, in particular in dry form, especially in powder form; b.1) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a.1) at a temperature between 20° C. and 98° C. and mixing. c.1) applying the composition of step b.1) to keratin fibers, optionally while treating said fibers with heat; d.1) Rinsing process.

[0302] a.2) providing the extract B according to the invention, optionally together with at least one cosmetically acceptable excipient as defined above, in particular in dry form, especially in powder form; b.2) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a.2) at a temperature comprised between 20° C. and 98° C. and mixing. c.2) applying the composition of step b.2) to the keratin fibers, optionally while treating said fibers with heat. d.2) Rinsing process e) Optionally repeating steps c.1) and d.1) and / or c.2) and d.2) (not preferred).

[0303] Alternatively, a cosmetic method for dyeing keratinous fibers, especially human, comprises the following steps: a.1) providing the extract B according to the invention, optionally together with at least one cosmetically acceptable excipient as defined above, in particular in dry form, especially in powder form; b.1) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a.1) at a temperature comprised between 20° C. and 98° C. and mixing. c.1) applying the composition of step b.1) to keratin fibers, optionally while treating said fibers with heat; d.1) Rinsing process a.2) providing the extract A according to the invention, optionally together with at least one cosmetically acceptable excipient as defined above, in particular in dry form, especially in powder form; b.2) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a.2) at a temperature comprised between 20° C. and 98° C. and mixing. c.2) applying the composition of step b.2) to the keratin fibers, optionally while treating said fibers with heat. d.2) Rinsing process e) Optionally repeating steps c.1) and d.1) and / or c.2) and d.2) (not preferred).

[0304] These two alternative steps are advantageously carried out as described above, with necessary adjustments to take into account sequencing.

[0305] In either step a.1) or a.2), it is also possible to add a dye C according to the invention or, alternatively or additionally, a sequence of steps a.3) to c.3) can be provided which is similar to steps a.1) to c.1), but in which the dye is dye C.

[0306] The present invention also relates to a method of tattooing skin.

[0307] The present invention also relates to the use of the dye compositions obtained according to the invention as vegetable inks, for example for printing on paper or cardboard.

[0308] The present invention also relates to a textile dye or furniture stain comprising a composition according to the invention.

[0309] Such dyes or stains may also contain one or more additional dyeing agents or pigments.

[0310] The dyes or stains according to the invention may also contain any adjuvant known to a person skilled in the art who, using his general knowledge, knows how to adjust the dye or stain formulations according to the invention.

[0311] The invention also relates to the use of such dyes or stains for dyeing textile fibres or for staining wood fibres.

[0312] The present invention is therefore also directed to the use of the compositions according to the invention for colouring cellulosic materials such as textile fibres, wood fibres, etc.

[0313] The following examples illustrate the invention. [Brief description of the drawings]

[0314] [Figure 1] FIG. 1 shows the normalized UHPLC-UV chromatogram of the extract (sample E2) obtained by the method according to example 1.2.

[0315] [Diagram 2] FIG. 2 shows the same chromatogram as FIG. 1: the filled peaks correspond to those seen in FIG. 1, the flat line corresponds to a zoom of the chromatogram.

[0316] [Diagram 3] Figures 3a, 3b, 3c, 3d and 3e show the UV spectra of lawsone, luteolin, apigenin, para-coumaric acid and 2,3,4,6-tetrahydroxyacetophenone isolated from sample E2.

[0317] [Figure 4] FIG. 4 shows the normalized UHPLC-UV chromatogram of the extract obtained by the method according to example 1.4.

[0318] [Diagram 5] FIG. 5 shows the color difference dE* after 10 washes of product I1 (vertical line) or control T1 (horizontal line).

[0319] characteristics A) Structural analysis material and method Chromatographic separation was performed using quaternary pumps, automatic sample injectors, and on-line The analysis was performed on a Waters ACQUITY UHPLC system equipped with a degasser, thermostatic column oven and a DAD detector (200-500 nm). TM An ACQUITY UPLC BEH Shield RP18 column (100 mm × 2.1, 1.7 μm) equipped with a precolumn (5 mm × 2.1) (Waters Corporation, Milford, USA) was used at 35 °C and the flow rate was set at 0.4 mL / min. The mobile phase consisted of a linear gradient system of (A) water with 0.1% formic acid, (B) acetonitrile and (C) methanol as a washing solvent: 0-9 min, 2%-100% B; 9-9.55 min, maintain 100% B; 9.55-9.70 min, 0%-100% C; 9.7-10.2 min, maintain 100% C; 10.20-10.35 min, 0%-100% B; 10.35-10.85 min, maintain 100% B; 10.85-11 min, 0%-98% A; 1 min hold at 98% A-2% B for column equilibration. Compounds were analyzed by high-resolution mass spectrometry, 1D- and 2D-NMR experiments ( 1 H NMR, 13 The compound was identified using C NMR, DEPT, COSY, HMBC, and HSQC.

[0320] B) Quantitative analysis: Experimental conditions Luteolin and apigenin were purified using a C18 column (XBridge 100 C18; 3.5 mm, 150 mm x 4.6 mm) with H 2 The titration was carried out by analytical HPLC using gradient conditions (see below) with 0 / trifluoroacetic acid 0.1% (A) and acetonitrile / trifluoroacetic acid 0.1% (B). Gradient Condition :t0 A 18% B 82%;t1 min:A 18% B 82%;10 min A 50% B 50%;10.1 min:A 18% B 82%

[0321] UV detection was at 340 nm for apigenin and 310 nm for luteolin. The flow rate was 1 mL / min and the temperature was 40° C. Pure luteolin, apigenin and p-coumarin were used for calibration. EXAMPLES

[0322] Example 1: Synthesis of Extract A

[0323] Example 1.1: Isopropyl acetate extract according to the invention. 50 g of unground henna leaves are extracted with 500 mL of water at 30-40°C for 30 minutes. 600 mL of isopropyl acetate is added to the solution. This is mixed for 30 minutes. After decantation, the upper isopropyl acetate phase (480 mL) is collected and the aqueous phase is separated as it is practically free of lawsone. The isopropyl acetate phase is filtered and subsequently dried in a Rotavapor. The residue is the dry henna extract. The plant contains 1.5 g of lawsone / 100 g of dried plant.

[0324] The upper phase of isopropyl acetate contains 80.7% of the lawsone that may be present in the plant.

[0325] The dried henna extract contains 30.2% lawsone by weight, i.e. 71% of the lawsone present in the plant.

[0326] Stability test: Samples were stored at 25°C, 60% relative humidity and protected from light: At T0: lawsone content = 30.2 wt% lawsone relative to the weight of the dry extract. At T1 month: lawsone content = 29.7% by weight of lawsone relative to the weight of the dry extract; therefore, there is no significant loss within the meaning of the present invention.

[0327] Example 1.2: Isopropyl acetate extract N°2 according to the invention. 49.5 g of unground henna leaves are extracted with 500 mL of water at 30-40 °C for 30 min. 600 mL of isopropyl acetate are added to this solution. This is mixed for 30 min. After decantation, the upper isopropyl acetate phase is collected and filtered through a Buchner (K900) and the residue is washed with 50 mL of isopropyl acetate. The resulting solution is subsequently dried in a Rotavapor. The residue is the dried henna extract (sample E2). The dried henna extract (sample E2) contains 30.9 wt.% lawsone.

[0328] result UHPLC-UV chromatogram

[0329] The resulting UHPLC-UV chromatograms are shown in Figures 1 and 2. The peaks observable in the zoom of the chromatogram (Figure 2, flat line) are associated with the following compounds: [Table 1]

[0330] UV spectrum The UV spectra of the compounds corresponding to peaks No. 15, 20, 22, 10 and 5 are shown in Figures 3a, 3b, 3c, 3d and 3e, respectively.

[0331] B) Quantitative analysis material and method Batch Sample - LP110: Henna extract AN, ethyl acetate extract standardized with maltodextrin - industrial scale. - ES310: Henna extract AN, ethyl acetate extract standardized with maltodextrin - laboratory scale. - JQ137A: Henna Extract AN, Isopropyl Acetate Henna Extract with Fructose - Lab Scale.

[0332] The amount of lawsone in each of the above standardized extracts corresponds to 1.1 wt.%. result [Table 2] [Table 3]

[0333] Example 1.3: Ethyl acetate standardized dry extract according to the invention. 50 g of crushed henna leaves are extracted with 500 mL of water at 30-40°C for 30 minutes. 600 mL of ethyl acetate is added to the solution. This is mixed for 30 minutes. After decantation, the upper ethyl acetate phase is collected and the aqueous phase is removed as it has a very low lawsone content.

[0334] The lawsone content of the ethyl acetate phase is determined by HPLC, and sufficient maltodextrin is added to obtain a mixture containing 1.3 wt % lawsone, which is then lyophilized.

[0335] Dried henna extract standardized with maltodextrin contains 1.1 wt.% lawsone, or 71% of the original lawsone oil content in the plant.

[0336] Example 1.4: n-Butanol extract according to the invention 50 g of unground henna leaves are extracted with 6 volumes of water at 30-40°C for 30 minutes. 6 volumes of n-butanol are added to the solution at room temperature. The mixture is stirred for 30 minutes. After decantation, the upper butanol phase is recovered and the aqueous phase is removed since it is substantially free of lawsone. The organic phase is concentrated by passing water through it.

[0337] The lawsone content in the n-butanol phase is measured by HPLC. Maltodextrin is added in an amount sufficient to obtain a mixture containing 1.1 wt.% to 1.3 wt.% lawsone.

[0338] A calibration curve is prepared for each control and sample amounts are estimated. Furthermore, the present invention includes the following aspects. [1] A method for preparing a dye composition, in particular a cosmetic dye composition for dyeing keratin fibers, comprising the steps of: - providing an extract A of the aerial parts of henna containing between 7% and 60% by weight of lawsone relative to the total weight of the dry extract, the lawsone being obtained in particular from the enzymatic hydrolysis of glycosylated lawsone derivatives, such as henosides; and - providing an extract B of the aerial parts of henna containing less than 0.6% by weight of lawsone, at least 15% by weight of phenolic compounds and at least 60% by weight of saccharide compounds (including polysaccharides) relative to the total weight of the dry extract; - mixing extract A and extract B; obtaining a dye composition. [2] The method according to [1], wherein the extract A from the aerial parts of henna further contains luteolin, apigenin and 2,3,4,6-tetrahydroxyacetophenone. [3] The method according to [1] or [2], wherein the extract A from the aerial parts of henna further contains coumaric acid. [4] The method according to any one of [1] to [3], wherein extract A of the aerial parts of henna does not contain more than 2% by weight of proteins, peptides or amino acids based on the total weight of the dry extract. [5] The method according to any one of [1] to [4], wherein the dye composition comprises a standardized dry extract AN of henna comprising an extract A of the aerial parts of henna and a carrier, and the standardized dry extract AN contains 0.6% by weight to 1.4% by weight of lawsone based on the total weight of the standardized dry extract. [6] Standardized dry extract of henna, AN, based on total weight of dry extract 0.05% to 1.0% by weight of luteolin; 0.01% to 0.5% by weight of apigenin; 0.01% to 1.0% by weight of 2,3,4,6-tetrahydroxyacetophenone The method according to claim 5, comprising: [7] The method according to any one of [1] to [6], wherein the extract A of the aerial parts of henna is obtained by a method comprising the following steps: a) immersing the aerial parts of henna in water having a pH ranging from 4 to 8 in order to partially or completely enzymatically hydrolyse the glycosylated lawsone derivatives, such as henosides, originally present in the aerial parts of henna, thereby providing an aqueous solution containing lawsone; b) adding an organic solvent to the solution obtained from step a) to provide an aqueous phase and an organic phase, the organic solvent being selected from the group consisting of C 4 -C 12 a linear or branched chain alcohol or a solvent having a miscibility with water of less than 10% by weight at 25° C., advantageously less than 5% by weight; c) recovering the organic phase obtained from step b); and d) concentrating the organic phase recovered from step c) to obtain extract A according to any one of claims [1] to 3. [8] The method according to [7], wherein step a) is carried out under at least one of the following conditions: - step a) is carried out at a temperature ranging from 20°C to 60°C; - step a) is carried out at a pH in the range of 5 to 7.5; - step (a) is carried out under stirring for 15 minutes to 2 hours; Step (a) is carried out in water having a volume between 2 and 15 times greater than the weight of the aerial parts of the henna to be soaked. [9] The method according to any one of [1] to [8], wherein the saccharide compounds of extract B further include monosaccharides, disaccharides, and combinations thereof.

[10] The method according to any one of [1] to [9], wherein extract B further contains 2 wt% to 8 wt% of an organic acid relative to the total weight of dried extract B, and the organic acid is preferably selected from the group consisting of succinic acid, ascorbic acid, malic acid, and combinations thereof.

[11] The phenolic compounds in extract B - gallic acid, coumaric acid, and / or heterosides of such compounds and combinations thereof; - tannins, -phloroglucinol derivatives; and -Flavonoid derivatives The method according to any one of [1] to

[10] , selected from the group consisting of:

[12] The method according to any one of [1] to

[11] , wherein extract B is an aqueous, hydroalcoholic or alcoholic extract of henna.

[13] The method according to any one of [1] to

[12] , wherein extract A is mixed with extract B in a B / A weight ratio of 1 or more, and extract A is a standardized dry extract.

[14] The method according to any one of [1] to

[12] , wherein extract A is mixed with extract B in a B / A weight ratio of less than 1, and extract A is a standardized dry extract.

[15] A dye composition obtained by the method according to any one of [1] to

[14] .

[16] The dye composition according to

[15] , further comprising one or more cosmetically acceptable excipients suitable for application to human keratinous fibers.

[17] Use of a dye composition according to

[15] or

[16] for the cosmetic dyeing of keratin fibres, in particular human keratin fibres.

[18] A cosmetic method for dyeing human keratin fibers, comprising the steps of: a) providing a composition according to claim 15 or 16 in powder form, b) preparing an aqueous composition by adding an aqueous composition, in particular water, to the powder of step a) at a temperature between 20°C and 98°C and mixing; c) applying to keratinous fibers, optionally treating said fibers with heat; d) a washing step; e) optionally repeating steps c) and d).

[0339] result UHPLC-UV chromatogram The resulting UHPLC-UV chromatogram is shown in Figure 5. The observable peaks are associated with the following compounds: [Table 4]

[0340] The presence of glycosylated luteolin, particularly luteolin-6-C-neohesperidoside and coumaric acid, has been noted.

[0341] Example 2: Synthesis of Extract B: Example 2.1: The ground henna leaves are added to a 50 g reactor containing 6 volumes of water. The resulting paste is stirred for 30 minutes at 50° C. Then, 16 volumes of ethanol are added to the mixture, i.e. to a final alcohol content of 80% v / v, followed by vigorous shaking for 30 minutes. The entire paste is filtered (through an AF15 filter) and the hydroalcoholic filtrate is collected, sterilized and then concentrated by evaporating the ethanol. The aqueous concentrate is then dried. The dry product corresponds to the dry henna extract (yield by weight: 54%).

[0342] The extract so obtained was (expressed by weight as a percentage of the total weight of the dry extract) -Lawson 0.6%; - Saccharide compounds: 69.9 % (total sugars) (polysaccharide content 59.3%); -Apigenin 0.05%; - Contains 0.17% Luteolin.

[0343] Example 2.2 : The ground henna leaves are added to a 50 g reactor containing 6 volumes of water. The resulting paste is stirred at 50° C. for 30 minutes. Stir vigorously for another 30 minutes. The entire paste is filtered (through an AF15 filter) and the aqueous filtrate is collected and pasteurized at 120° C. for 20 minutes, followed by concentration. The aqueous concentrate is dried. The dry product corresponds to the dried henna extract (yield by weight: 60%).

[0344] The extract thus obtained contains 0.4% by weight of lawsone, the percentages being expressed by weight relative to the total weight of the dry extract.

[0345] Example 3: Comparison of Characteristic Compounds of Extract A and Extract B The characteristic compounds of the extracts obtained according to Example 1 or Example 2 are reported in the table below; the percentages are given by weight relative to the total weight of the dry extract. [Table 5]

[0346] Example 4: Evaluation of color retention on natural white human hair after washing: Extract A according to the invention (Example 1.2) is mixed with extract B according to the invention (Example 2.2) in a B / A weight ratio of 1 / 1. This mixture is called product I1. Conventional henna powder (finely ground henna leaves (<250 μm)) is also used as a control. This powder is called product T1.

[0347] In each case, 10 g of powder is mixed with 40 g of water and then applied to the strands. The dye content after washing was evaluated for the two products I1 and T1. All strands were subjected to standard washing up to 10 times with a neutral shampoo.

[0348] For products I1 and T1 respectively, the colour of 5 strands of natural white human hair, colour 10 (white) are tested using a reflectometer (CR400 Croma Meter, Minolta, France). The colour parameters L*a*b* measured with this instrument describe the colour of the strands. The parameter evaluated is the L*a*b derivative, or color difference (dE*).

number

[0349] In this case, "1" is the Lab value of the dyed strand before washing and "2" is the value obtained after 10 washes.

[0350] Statistical studies concluded that the color difference of the combination according to the invention I1 was significantly smaller than that of the control T1 (*p<0.05).

[0351] The results are reported in FIG.

[0352] Method 1: Lawsone assay by HPLC

[0353] This method is A. Assay of Lawsone in Extracts B. Assay of the total lawsone present in the aerial parts of henna in free form or in the form of glycosylated lawsone derivatives, obtained by acid hydrolysis, and thus quantifying the potential amount of lawsone in the plant; C. Assay of lawsone formed by the enzyme.

[0354] reagent Lawson>97% (HPLC) SIGMA- Reference: H46805 Dichloromethane for analysis. Analytical sulfuric acid. Methanol for analysis. HPLC grade water. HPLC grade acetonitrile. HPLC grade trifluoroacetic acid.

[0355] HPLC conditions -Column: XBridge C18, 3.5μm, 4.6 x 150 mm Waters Furnace: 40℃ - Solvent: SA: 0.1% trifluoroacetic acid in water. SB: 0.1% trifluoroacetic acid in acetonitrile. - Gradient: T0 min 40%SA; T1 min 40%SA; T10 min 5%SA; T11 min 5%SA; T11.1 min 40%SA. -Wavelength: λ=278nm. -Flow rate: 1mL / min -Injection: 10 μL.

[0356] Sample preparation: For whole or nearly whole crushed leaves: 50 g of leaves are ground and subsequently sieved through a 0.355 μm sieve. For leaf powder: Use 50g of leaf powder as is.

[0357] Preparation of solutions Control solution: Lawsone solution at 0.3 mg / mL in 1 / 1 methanol / ethanol. Dilute 1 / 10, 1 / 20, 1 / 100 in 1 / 1 methanol / water. Test solution: - Test solution A (assay of lawsone present in the extract) Dissolve 50 mg of extract in 100 mL 1 / 1 methanol / water. Sonicate. Filter through Acrodisc GFGHP. Inject 10 μL. - Test solution B (total lawsone assay) Add 80 mg of leaf powder to a volumetric flask. 2 SO 4 Add 50 mL. Heat at 97 °C for 30 min. Allow to cool. Add methanol to 100 mL. Filter the solution through an Acrodisc GF GHP 0.45 μm. Inject 10 μL of the filtrate. - Test solution C (assay of the enzymatic formation of lawsone) Place 80 mg of leaf powder in a volumetric flask. Add to 50 mL of demineralized water. Place in an ultrasonic bath at 30-40 °C for 30 min. Allow to cool. Add methanol to 100 mL. Filter the solution through an Acrodisc GF GHP 0.45 μm. Inject 10 μL of the filtrate.

[0358] result The regression line calculated using the control solutions is used to determine: A. Lawsone content of the extract. B. Total Lawsone Content, and / or C. Lawsone content formed by the enzyme.

[0359] Method 2: Assay of nitrogen-containing compounds (amino acids, proteins) Free amino acids and protein can be assayed before or after hydrolysis by ninhydrin spectrophotometry, and the results are expressed as the percentage of amino acids relative to asparagine.

[0360] Total protein and amino acid assays

[0361] principle Colorimetric assay of amino acids with ninhydrin reagent after acid hydrolysis. Results are expressed as percentage of total amino acids relative to asparagine.

[0362] reagent Citrate buffer (pH=5) Dissolve 2.1 g of citric acid in 20 mL of water, add 20 mL of 1N sodium hydroxide, and adjust to 50 mL with water. Ninhydrin Reagent: Tin(II) chloride (SnCl 2、 2H 2 O) 0.08 g is dissolved in 50 ml of citrate buffer (pH = 5). Dissolve 2 g of ninhydrin in 50 mL of ethylene glycol monomethyl ether (EGME). These two solutions are mixed. 6N Hydrochloric Acid Dilute with 1 / 2 the amount of concentrated hydrochloric acid (36%). Diluents Mix 100 mL of 1-propanol with 100 mL of water.

[0363] Preparation of solutions · Preparation of calibration range Dissolve 17 mg of asparagine in 100 mL of water. Preparation of test solutions Sample to be analyzed (pe 1 ) Approximately 30-200 mg of extract is weighed into a screw thread tube and 2 mL of 6N HCl is added.

[0364] Seal and place at 110°C for approximately 16 hours.

[0365] Neutralize with 3N sodium hydroxide (the color will change to methyl red), then adjust to 20 ml with water. [Table 6]

[0366] Stir and place in a water bath at 100°C for 20 minutes. Cool in an ice bath. Adjust to 10 ml with diluent.

[0367] The absorbance at 570 nm of the various solutions is measured against a blank.

[0368] calculation A calibration curve is created from which the total amino acid concentration (Q AAT The total amino acid content of the extract (T AAT ) is expressed by the following formula:

number

[0369] Method 3: Gravimetric Assay of Chlorophyll The chlorophyll content in the extract can be estimated by the weight obtained after washing the extract with heptane. The extract is taken up in 10 volumes of methanol. After stirring for 15 minutes, the solution is filtered. The supernatant is dried and constitutes the chlorophyll-containing fraction.

[0370] Method 4: Spectrophotometric assay of phenolic compounds The content of phenolic compounds in the extract can be assessed spectrophotometrically according to the method of the European Pharmacopoeia, edition 9.0, 2.8.14.

[0371] The solution to be tested is prepared by dissolving 25 mg of the extract in 100 mL of water. The phenolic compound content is expressed based on pyrogallol.

[0372] Method 5: Colorimetric assay of saccharide compounds before and after hydrolysis Principle: Colorimetric determination of saccharide compounds with dinitrosalicylic acid (DNS) in comparison with glucose before and after hydrolysis. Results are expressed as the percentage of saccharide compounds relative to glucose.

[0373] reagent: DNS Reagent: Dissolve 30 g of sodium and potassium bitartrate in 50 ml of water. Add 20 mL of 2N sodium hydroxide. Dissolve 1 g of dinitrosalicylic acid (DNS) with slight heating. Make up to 100 mL with water.

[0374] Preparation of solutions: Preparation of the calibration range: Dissolve 5 mg of glucose in 10 mL of water.

[0375] Preparation of hydrolyzed test solution (total saccharide compounds): Weigh out approximately 1 g of extract (pe2). 2 SO 4 Add 1 mL. Heat at reflux for 2 hours. Neutralize with 1N sodium hydroxide and transfer to a 20 mL volumetric flask. Make up to 20 mL with water.

[0376] Preparation of non-hydrolyzed test solution (free saccharide compounds = monosaccharides): Weigh approximately 10 g of extract (pe3) into a 20 mL volumetric flask. Make up to 20 mL with water.

[0377] Dosage: The solution is administered according to the following table: [Table 7]

[0378] Shake, then place in a water bath at 100° C. for 5 min. Cool in an ice bath and make up to 10 mL with water. Measure the absorbance at 540 nm of the various solutions against a blank.

[0379] Calculation:

[0380] Create a calibration curve.

[0381] The concentrations of total saccharide compounds (QSRT) and free saccharides (QSRL) represented by glucose in the test solution are estimated. The titer (TSRT) of the total saccharide compounds in the extract is expressed by the following formula:

number

[0382] The titer of free saccharide compounds (TSRL) of the extract is given by the following formula:

number

[0383] Method 6: HPLC assay of organic acids

[0384] Principle: HPLC assay of organic acids from plant extracts. The organic acids measured are succinic acid, malic acid and ascorbic acid.

[0385] Chromatography System: -Column: Atlantis dc18 5μm 5μm 250x4.6mm Waters or equivalent; -Temperature: 25℃; - Mobile phase: Solvent A: 50 mM phosphate buffer, pH 2.8; Solvent B: acetonitrile; - Gradient: T0 %A: 100%; 7.5 min %A: 100%; 15 min %A: 90%; 16 min %A: 50%; 23 min %A: 50%; 24 min %A: 100%; 40 min %A: 100%; -Flow rate: 1 mL / min; - 200 at λ = 400 nm (extracted at 214 nm); -Injection volume: 5μL.

[0386] Preparation of solutions: Control solution: Weigh out 10 mg of control and dissolve in 20 mL of purified water. Dilute 1 / 5, 1 / 10, or 1 / 20. Test solution: In a 20 mL volumetric flask, weigh out 250 mg of the substance to be analyzed. Add water - sonicate if necessary. Results: The chromatograms of the control and test solutions have several characteristic and identical peaks.

[0387] The control retention time is -Malic acid 5.5 minutes, - Ascorbic acid: 7.7 min, -Ascorbic acid: 11.7 min.

[0388] A calibration curve is prepared for each control and sample amounts are estimated.

Claims

1. A method for preparing a dye composition comprising the steps of: - providing an extract A of the aerial parts of henna containing between 7% and 60% by weight of lawsone relative to the total weight of the dry extract, the lawsone being obtained by enzymatic hydrolysis of a glycosylated lawsone derivative; and - providing an extract B of the aerial parts of henna containing less than 0.6% by weight of lawsone, at least 15% by weight of phenolic compounds and at least 60% by weight of saccharide compounds (including polysaccharides) relative to the total weight of the dry extract; - mixing extract A and extract B; obtaining a dye composition.

2. 2. The method according to claim 1, wherein the extract A from the aerial parts of henna further contains luteolin, apigenin and 2,3,4,6-tetrahydroxyacetophenone.

3. 3. The method according to claim 1 or 2, wherein the extract A from the aerial parts of henna further comprises coumaric acid.

4. 4. The method according to claim 1, wherein extract A of the aerial parts of henna does not contain more than 2% by weight of proteins, peptides or amino acids relative to the total weight of the dry extract.

5. Method according to any one of claims 1 to 4, in which the extract A of the aerial parts of henna is obtained by a process comprising the following steps: a) immersing the aerial parts of henna in water having a pH ranging from 4 to 8 in order to partially or completely enzymatically hydrolyse the glycosylated lawsone derivatives originally present in the aerial parts of henna, thereby providing an aqueous solution containing lawsone; b) adding an organic solvent to the solution obtained from step a) to provide an aqueous phase and an organic phase, the organic solvent being selected from the group consisting of C 4 -C 12 a straight or branched chain alcohol or a solvent having a miscibility with less than 10% by weight of water at 25°C; c) recovering the organic phase obtained from step b); and d) concentrating the organic phase recovered from step c) to obtain extract A according to any one of claims 1 to 3.

6. The method of claim 5, wherein step a) is carried out under at least one of the following conditions: - step a) is carried out at a temperature ranging from 20°C to 60°C; - step a) is carried out at a pH in the range of 5 to 7.5; - step (a) is carried out under stirring for 15 minutes to 2 hours; Step (a) is carried out in a volume of water that is 2 to 15 times greater than the weight of the aerial parts of the henna to be soaked.

7. The method according to any one of claims 1 to 6, wherein the saccharide compounds of extract B further comprise monosaccharides, disaccharides and combinations thereof.

8. 8. The method according to claim 1, wherein extract B further comprises from 2% to 8% by weight of organic acids relative to the total weight of the dry extract B.

9. The phenolic compounds in extract B are - gallic acid, coumaric acid, and / or heterosides of such compounds and combinations thereof; - tannins, -phloroglucinol derivatives; and -Flavonoid derivatives The method according to any one of claims 1 to 8, selected from the group consisting of:

10. 10. The method according to claim 1, wherein extract B is an aqueous, hydroalcoholic or alcoholic extract of henna.

11. A dye composition obtainable by the process according to any one of claims 1 to 10.

12. 12. The dye composition according to claim 11, further comprising one or more cosmetically acceptable excipients suitable for application to human keratinous fibers.

13. 13. A dye composition according to claim 11 or 12 for the cosmetic dyeing of keratin fibres.

14. A cosmetic method for dyeing human keratin fibers, comprising the steps of: a) providing a composition according to claim 11 or 12 in powder form, b) preparing an aqueous composition by adding the aqueous composition to the powder of step a) and mixing at a temperature between 20°C and 98°C; c) applying to keratinous fibres; d) Rinsing process.

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