New cosmetic use of an extract from the microalga T isochrysis lutea.

Abstract

The invention relates to the cosmetic use of an extract of Tisochrysis lutea or a composition containing it to reduce dandruff and / or prevent its appearance and / or recurrence. Another aspect relates to a cosmetic treatment method comprising the topical application to the scalp, eyebrows, and / or beard of an extract of Tisochrysis lutea or a composition containing it, to reduce dandruff and / or prevent its appearance and / or recurrence, particularly in individuals with a dry scalp.

Description

Title of the invention: New cosmetic use of an extract of the microalgae Tisochrysis lutea.

[0001] Introduction

[0002] The invention relates to a new use of an extract of the microalga Tisochrysis lutea or a composition comprising it in the field of cosmetics. State of the art

[0003] Dandruff on the hair corresponds to scales of the scalp due in part to a faster renewal of scalp cells than in so-called "classic" conditions and / or dryness of the skin. Dandruff is also observed on dry eyebrows or a dry beard. There are two types of dandruff: dry dandruff and oily dandruff. The latter are generally thicker and colored and are the result of seborrheic dermatitis. On the contrary, dry dandruff, which is more frequent, is not the result of seborrheic dermatitis: it is due to dryness of the skin on the scalp and the hair on the eyebrows and beard. Particularly frequent in winter, when the skin tends to dry out, they can be visible due to their propensity to creep along the hair or hair.

[0004] Environmental factors including stress or pollution can also contribute to a worsening of this condition. Dandruff can also be accompanied by irritation or itching of the scalp, although this is not systematic.

[0005] Dandruff affects all hair types and scalps and affects 1 in 2 people. Individuals with dry skin may be more prone to dandruff formation. Being quickly visible and uncomfortable, the psychosocial consequences of this condition are generally not negligible for those affected by it.

[0006] The field of cosmetics has therefore looked into this disorder and solutions exist for the prevention or elimination of dandruff. Thus zinc pyrithione, salicylic acid, selenium sulfide or certain essential oils including tea essential oil have already shown their beneficial effect on the reduction of dandruff but these active ingredients can cause irritation of the scalp. Few natural alternative solutions exist. Examples include white clay, an extract of cade (cade juniper) or an extract of bark of the Ziziphus joazeiro plant. There is therefore a need for alternative, effective and natural active ingredients.

[0007] Unexpectedly, the Applicant discovered that an extract of the microalgae T. lutea had the ability to reduce dandruff on the scalp in vivo, particularly dry scalp, but also to prevent its reappearance (residual effect over time).

[0008] One advantage of the extract is that it is made from natural microalgal biomass. The extract is obtained naturally using a bio-sourced solvent. It is easily produced on an industrial scale. In addition, it is not irritating to the scalp.

[0009] The extract according to the invention comes from a biomass of the microalga Tisochrysis lutea, formerly called Isochrysis galbana var. Tahiti, a species of the Iso-chrysidaceae family. This strain was isolated for the first time in French Polynesia in 1977.

[0010] The Applicant has described in application WO2023111440 the use of a composition which can be prepared from an extract of T. lutea to provide a soothing effect on the skin and / or maintain the homeostasis of sensitive skin. However, this is a separate use, moreover on a scalp with dry dandruff.

[0011] Thus, to the knowledge of the Applicant, no prior art describes the use of an extract of the microalgae Tisochrysis lutea to reduce the number and / or visibility of dandruff or to prevent its appearance or reappearance, in particular on the scalp, dry eyebrows and / or dry beard.

[0012] The present invention thus relates to the cosmetic use of an extract of the microalga Tisochrysis lutea, advantageously in the form of an oily ingredient as will be described in the remainder of the application, or of a cosmetic composition comprising it to reduce dandruff and / or prevent its appearance and / or reappearance. Another subject relates to a cosmetic care method comprising the topical application, to the scalp, dry eyebrows and / or dry beard, of the extract of T. lutea, advantageously in the form of an oily ingredient or of a composition comprising it, to reduce dandruff and / or prevent its appearance and / or reappearance, in particular on dry scalp, dry eyebrows and / or dry beard, advantageously dry scalp.

[0013] A first subject of the invention therefore relates to the cosmetic use of an extract of T. lutea or of a composition comprising it to reduce dandruff and / or prevent its appearance and / or reappearance. For the purposes of the invention, the term “cosmetic use” means a non-therapeutic, non-pharmaceutical, and therefore non-dermatological use, according to a specialist in the field, a dermatologist. Thus, the use is not intended to treat a scalp requiring dermatological or pharmaceutical treatment. Advantageously, the use is intended for so-called healthy scalps (or eyebrows and / or beards), i.e. those which do not present infection, wound, eczema, psoriasis, injury, allergy, scar, pruritus, inflammation, or atopic or seborrheic dermatitis. Advantageously, the use is intended for dry scalps, dry eyebrows and / or dry beards, it being understood within the meaning of the invention that a dry scalp is a healthy scalp; the same applies to dry eyebrows and / or dry beards which are within the meaning of the invention healthy eyebrows or a healthy beard. Very advantageously, the dry scalp, dry eyebrows and / or dry beard have dry dandruff.

[0014] The use according to the invention may be by oral route or by topical route. It is advantageously by topical route. Here, the term "topical route" means the vaporization or application to at least one area of ​​the scalp, eyebrows and / or beard, of the T. lutea extract according to the invention, advantageously in the form of an oily ingredient as will be defined in the remainder of the application, or of a composition comprising it. Preferably, it is a topical application. The area of ​​the scalp, eyebrows and beard may have a dry appearance, subject to the formation of dry dandruff.

[0015] The T. lutea extract according to the invention is topically acceptable, that is to say that it does not induce an inflammatory reaction, it is not toxic to the scalp and does not induce itching or irritation.

[0016] In an advantageous embodiment of the invention, the extract of T. lutea, advantageously in the form of an oily ingredient, or a cosmetic composition comprising it, is applied topically to a dry scalp, dry eyebrows and / or dry beard, again advantageously presenting dry dandruff. Preferably, it will be a dry scalp presenting dry dandruff.

[0017] For the purposes of the invention, the expression "reducing dandruff" means reducing the quantity and / or size of dandruff, advantageously dry dandruff. The aim is thus to reduce the number and / or visibility of dandruff. Thus, in one embodiment of the invention, the T. lutea extract, advantageously in the form of an oily ingredient, and even more advantageously a composition comprising it, make it possible to reduce by at least 4%, and very advantageously by at least 40%, the quantity of dandruff measured in a population of individuals with a dry scalp, as presented in the context of the clinical trial described in Example 2. Very advantageously, this is a reduction in the number of dandruff flakes.

[0018] The term “preventing the appearance of dandruff” means preventing the appearance or increase of dandruff on the scalp, eyebrows and / or beard, advantageously dry dandruff, advantageously on a dry scalp not exhibiting dandruff. Indeed, a dry scalp, which lacks hydration, is more prone to flaking and forming dry dandruff. The use of the T. lutea extract or a composition comprising it according to the invention is therefore advantageous in treatment preventing the appearance of dandruff on a dry scalp that does not yet have dandruff. The term "preventing the reappearance of dandruff" also means preventing their reappearance after the action of the T. lutea extract or a composition comprising it. The T. lutea extract in fact has a lasting action on dandruff, as illustrated in the examples, that is to say a beneficial effect that persists over time after the end of its use. In an advantageous embodiment of the invention, the T. lutea extract, advantageously in the form of an oily ingredient and even more advantageously a composition comprising it, makes it possible to prevent the reappearance of dandruff, advantageously dry dandruff, for at least 7 days, advantageously for at least 14 days after the end of the cosmetic use of the T. lutea extract.lutea, advantageously in the form of an oily ingredient, still advantageously of a composition comprising it, as described in the context of the clinical trial appearing in example 2. The Applicant has in fact observed a lasting effect 42 days after the first application, and 14 days after the end of the last application. Very advantageously, this is a lasting action on the number of dandruff flakes. Extract from T. lutea

[0019] The extract used according to the invention is obtained from the microalga T. lutea cultivated under controlled conditions within dedicated systems such as open culture tanks of the “race-ways” or “open ponds” type or closed systems of the photobioreactor type. The photobioreactors used can be of any existing type such as horizontal tubular photobioreactors, vertical photobioreactors such as so-called “green wall panel” systems, flat or column photobioreactors. Preferably, the production of the biomass is carried out within a closed culture system of the photobioreactor type. The culture of the microalga is carried out according to the batch, fed-batch, continuous, semi-continuous, turbidostat or chemostat culture modes. Advantageously, the culture of T. lutea is carried out in autotrophic mode.

[0020] Crude extract of T. lutea

[0021] The extract of T. lutea according to the invention as described below corresponds to a crude extract, also called “dry extract”, distinct from the oily extract described below corresponding to the crude (or dry) extract dispersed in an oil.

[0022] The biomass obtained from the culture can be used fresh or frozen and / or dried before preparing the extract. It can be concentrated by removing all or part of the water using processes such as centrifugation, filtration, flocculation, sedimentation, coupled, or not, with drying steps by lyophilization, vacuum drying, drum drying, atomization or any process allowing the water content of the biomass to be reduced. Cell lysis processes can then be implemented such as the application of pressures, electrical flows, shear forces, the use of enzymes, or any other process allowing the destructuring of tissues, organs, cells or organelles.

[0023] Here, the term "dry biomass" means a dehydrated microalgal biomass comprising less than 15%, advantageously less than 10%, even more advantageously less than 5% of water. Preferably, in the context of the invention, the biomass obtained after cultivation is frozen before drying. The biomass may be centrifuged beforehand and then filtered to remove the residual water before extraction.

[0024] In one embodiment of the invention, the extraction of the biomass is a solid-liquid extraction in the presence of a solvent or solvent mixture chosen from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol chosen from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or glycol / water in a proportion of 99 / 1 to 1 / 99 (w / v).

[0025] The solid-liquid extraction of biomass according to the invention is generally carried out from a quantity of biomass of 0.1 to 20% by weight, advantageously of 1% to 20%, very advantageously of 5% to 15%, and even more advantageously of 10% by weight relative to the total volume of the biomass and the extraction solvent.

[0026] The extraction can be carried out at a temperature ranging from 4°C to 300°C, including room temperature, i.e. a temperature of 25°C. It is advantageously carried out at a temperature between 20°C and 50°C, even more advantageously at 30°C.

[0027] According to a first embodiment of the invention, the extraction of the biomass is carried out in water under subcritical conditions, at a temperature ranging from 100°C to 300°C, advantageously from 120°C to 250°C, still advantageously at 120°C. The extraction can be carried out at a given temperature or at successive increasing temperatures. In an advantageous embodiment of the invention, the extraction is carried out at a temperature of 120°C. In an alternative mode, it will be carried out according to a gradient of three increasing temperatures between 100°C and 200°C, such as 120°C, 140°C then 160°C or 110°C, 130°C then 150°C, or even 120°C, 145°C then 170°C.

[0028] Extraction under "subcritical conditions" means extraction in the presence of water, under conditions of temperature above 100°C and pressure below 221 bars, the water remaining in the liquid state but having a viscosity and surface tension lower than that of water at room temperature, increasing its dielectric constant. Thus, the extraction pressure is between 150 bars and 250 bars, preferably between 200 and 221 bars, advantageously in a pressurized extraction autoclave.

[0029] According to another embodiment of the invention, the extraction of the biomass is carried out by supercritical CO2 extraction. In this case, said extraction may optionally be carried out in the presence of a co-solvent chosen from ethanol, acetone, methanol or any combination thereof. Alternatively, the supercritical CO2 extraction may be carried out alone without the presence of a co-solvent and continued by an additional extraction with a polar solvent chosen from ethanol, acetone, methanol, hexane, heptane, advantageously ethanol. Advantageously, within the scope of the invention, the supercritical CO2 extraction is carried out in the presence of ethanol (10%) as co-solvent. The supercritical CO2 extraction conditions are such that the pressure measured in bar is greater than 74 bar, advantageously greater than 100 bar, and even more advantageously 150 bar. The temperature is greater than 35°C, advantageously greater than 45°C, and even more advantageously 50°C.

[0030] According to a particular and preferred embodiment of the invention, the extract of T. lutea is obtained by solid-liquid extraction in an alcohol / water mixture, in a proportion of 99 / 1 to 1 / 99 (w / v), advantageously still in a proportion of 95 / 5 to 90 / 10 (w / v). This is referred to as 'solid-liquid' extraction. According to a particularly preferred embodiment, the crude extract of T. lutea is obtained by extraction in an ethanol / water mixture in a proportion of 90 / 10 (w / v).

[0031] Thus, in a preferred embodiment of the invention (Example 1a), the crude extract is obtained from the frozen and then dried biomass of T. lutea, by solid-liquid extraction in the ethanol / water mixture in a proportion of 90 / 10 (w / v) at 30°C. The quantity of biomass used for the extraction is 10% by weight relative to the total volume of the biomass and the ethanol / water mixture. The crude extract obtained is filtered. The residual ethanol is evaporated and then the extract can be used as is ("crude extract") in powder form after drying or dispersed in an oil (we will then speak indifferently of "oily ingredient" or "oily extract" or "oily preparation" according to the invention) or even incorporated into a final cosmetic composition (incorporation of the crude extract or advantageously of the oily ingredient into the final cosmetic composition).When the crude extract is used as is, it can be dried by freeze-drying, vacuum drying, drum drying, or atomization, by fluidized bed coupling by any technique allowing encapsulation or microencapsulation via a support matrix and / or the formation of an emulsion. In this case it is advantageously dried by freeze-drying.

[0032] According to another preferred embodiment, the crude extract is obtained from the frozen and then dried biomass of T. lutea, by supercritical CO2 extraction at a temperature of 50°C and a pressure of 150 bars in the presence of ethanol as cosolvent (10%). The extract obtained is rinsed with water and then filtered under the conditions described in example 1b). The extract obtained can be used as is (crude extract) in the form powder after drying via a technique described above and advantageously by lyophilization, or dispersed in an oil (we will speak of “oily preparation” or “oily ingredient” according to the invention), or even incorporated into a final cosmetic composition (incorporation of the crude extract or advantageously of the oily ingredient in the final cosmetic composition) with a “cosmetically acceptable excipient” as described below.

[0033] Oily ingredient or oily extract of T. lutea

[0034] In particular, the crude extract of T. lutea according to the invention is dispersed in at least one vegetable oil to form an “oily ingredient” (also called “oily extract” or “oily preparation”), which can be used as is or constitute an intermediate preparation of a final composition comprising other additional ingredients.

[0035] According to a particular embodiment, the extract used according to the invention can be dispersed in any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil. By medium-chain triglycerides (MCT), we mean esters of glycerol and saturated fatty acids, the hydrocarbon chain of which has from 6 to 12 carbon atoms. An MCT oil can thus be chosen from coconut oil, advantageously coconut oil, palm kernel oil and palm oil but can be obtained from other fats or oils. Advantageously for the purposes of the invention, the vegetable oil is an MCT oil, very advantageously coconut oil.

[0036] According to a particular embodiment, said oil is present in an amount by weight ranging from 50 to 99.8% by weight relative to the total weight of the composition, advantageously from 85% to 94%, very advantageously in an amount ranging from 89 to 94%, in particular ranging from 89% to 90% by weight relative to the total weight of the composition, otherwise called an oily preparation when the oil content represents from 85% to 94% by weight relative to the total weight of the composition. This oily preparation can be used as is or serve as an intermediate preparation for a nutraceutical composition or a cosmetic composition further comprising other cosmetic ingredients and excipients such as those described above.

[0037] Thus, in a preferred embodiment of the invention, the oily ingredient comprises coconut oil. According to a particular and preferred embodiment, to the crude extract of T. lutea obtained according to examples 1a) or 1b), is added a quantity of coconut oil ranging from 85% to 94% by weight, advantageously ranging from 89 to 94%, in particular 89 to 90% by weight relative to the total weight of the oily ingredient.

[0038] According to a particular and preferred embodiment, the oily ingredient advantageously comprises vitamin E in an amount ranging from 0.3% to 1% by weight relative to the weight total of the oily preparation. Advantageously, vitamin E is present in an amount of 0.5% by weight relative to the total weight of the oily preparation. Here, the term "vitamin E" means a tocopherol chosen from α-tocopherol, γ-tocopherol, [3-tocopherol or δ-tocopherol, or a tocotrienol chosen from α-tocotrienol, [3-tocotrienol, γ-tocotrienol or δ-tocotrienol. Advantageously, it is α-tocopherol. Thus, according to a particular and preferred embodiment, the extract of T. lutea is in the form of an oily ingredient comprising: i. from 5 to 15% by weight, preferably 9 to 10% by weight of an extract of T. lutea according to the invention, relative to the total weight of the oily ingredient, ii. from 85 to 94%, preferably from 89 to 94%, in particular from 89.5 to 90.5% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and more preferably a coconut oil, relative to the total weight of the oily ingredient, and iii. from 0.3% to 1% by weight, preferably 0.5% by weight of vitamin E, more preferably α-tocopherol, relative to the total weight of the oily ingredient.

[0039] In particular, the oily ingredient comprises 10% by weight of a T. lutea extract prepared according to example 1a), 89.5% by weight of a coconut oil, and 0.5% by weight of α-tocopherol.

[0040] Cosmetic composition

[0041] This oily ingredient (or oily extract) can be used as is for the uses described or be incorporated into a final cosmetic composition. Here, the term "final composition" means a composition comprising at least a) the crude (or dry) extract of T. lutea, and advantageously the oily ingredient as described above, and b) at least one cosmetically acceptable excipient chosen from additional oils such as vegetable oils, in particular chosen from argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, moisturizers, thickeners,glossing agents, texturizing agents, film-forming agents, pigments, colorants, perfumes, biological additives, chelating agents, astringent agents, polymers, reducing agents, pH regulating agents, humectants, conditioning agents, and mixtures thereof.

[0042] The composition may also comprise any active cosmetic ingredient having the same dandruff-reducing effect or a dandruff-preventing effect. dandruff, or a complementary effect, in particular an active ingredient on cell renewal, a so-called anti-pollution ingredient, an active ingredient on hair growth, an active ingredient against hair loss, an anti-whitening ingredient for hair or a colorant, or a soothing ingredient.

[0043] As an anti-hair loss and anti-whitening active ingredient, mention may in particular be made of an extract of flowers and leaves of the plant Leontopodium alpinum marketed by the company DSM under the name Alpaflor® Edelweiss CB. As a soothing ingredient, the extract according to the invention may be combined with an extract of aniseed myrtle marketed by the company Lucas Meyer under the name ReviScalp™, and / or an extract of pink berries (seeds of Schinus terebinthifolia) marketed by the same company under the name WASTAR™ Pink Berry to soothe scalp irritations. These ingredients may be advantageously combined with the oily ingredient comprising the extract of T. lutea according to the invention, optionally in the form of an emulsion.

[0044] Other active ingredients such as an extract of patchouli leaves marketed under the name Patchoul'Up™ by the company Givaudan, and / or propanediol caprylate marketed by the company Symrise under the name Crinipan® PMC green, and / or a combination of Chlorella vulgaris extract, Lavandula stoechas extract, and Laminaria digitata extract in particular, marketed by the company Codif under the name Capibiome, can be combined with the T. lutea extract according to the invention and advantageously the oily ingredient comprising it.

[0045] The extract used according to the invention, advantageously in the form of the oily ingredient comprising it, also advantageously prepared from the crude extract of T. lutea according to example 1a), can moreover be combined in a final cosmetic formulation with one or more other algal or microalgal extracts including an aqueous extract or a lipophilic extract of Porphyridium cruentum, and advantageously the aqueous extract marketed by the Applicant in the form of the product Renouvellance™ known as an anti-aging active ingredient and protector against the combined effects of UV rays and pollution, and this in particular in a weight ratio of the extract according to the invention relative to the extract of P.cruentum ranging respectively from 1 / 10 to 10 / 1, advantageously ranging from 1 / 5 to 5 / 1, still advantageously ranging from 1 / 2 to 2 / 1; and / or a hydrolyzate of co-product of extraction of Phaeodactylum tri-comutum, in particular a hydrolyzate of co-product of an ethanolic extraction of P. tricomutum, in particular marketed by the Applicant under the name PhycoSi™ useful for exfoliating the skin and / or reducing the microrelief of the skin but also known for moisturizing the skin and therefore the scalp, in particular in a weight ratio still respectively ranging from 1 / 10 to 10 / 1, advantageously ranging from 1 / 5 to 5 / 1, still advantageously ranging from k? to 2 / 1; and / or an extract of the microalga P. tricornutum, . in particular an ethanolic extract marketed under the name PhycoAge™ by the Applicant and known to increase and / or maintain the volume of the skin and / or lips and in particular in a weight ratio still respectively ranging from 1 / 10 to 10 / 1, advantageously ranging from 1 / 5 to 5 / 1, still advantageously ranging from ^2 to 2 / 1. The extract according to the invention, advantageously in the form of the oily ingredient already described, and advantageously prepared from the crude extract of T. lutea according to example 1a), can also be combined with an extract of the microalga Dunaliella tertiolecta, in particular an ethanolic extract or a supercritical CO2 extract, in particular known as an astringent agent and for reducing skin imperfections, and in particular in a weight ratio still respectively ranging from 1 / 10 to 10 / 1, advantageously ranging from 1 / 5 to 5 / 1, still advantageously ranging from ^2 to 2 / 1.The extract according to the invention and advantageously in the form of the oily ingredient described, advantageously also prepared from the crude extract of T. lutea according to example 1a), can also be combined with an extract of the microalga Dunaliella salina, in particular a hydroalcoholic extract, the alcohol advantageously being a C1-C6 alcohol, still advantageously ethanol, or a supercritical CO2 extract of the microalga Dunaliella salina.

[0046] Finally, the extract according to the invention, advantageously in the form of the oily ingredient already described, and advantageously also prepared from the crude extract of T. lutea according to example 1a) can be combined with astaxanthin or with any extract of the microalga Haematococcus pluvialis containing it.

[0047] The quantity of oily ingredient as defined above, and still advantageously the oily ingredient as obtained from the extracts of T. lutea according to examples 1a) or 1b), in the final cosmetic composition, can range from 0.1% to 10% by weight relative to the total weight of the final composition, advantageously from 0.25% to 5% by weight, still advantageously it is 0.5% by weight relative to the total weight of the final cosmetic composition.

[0048] The cosmetic composition comprising the crude extract of T. lutea according to the invention, and advantageously the oily ingredient comprising it, is in the form of a care composition for the scalp, dry eyebrows, or dry beard, in particular a dry shampoo, a shampoo, a conditioner, an aftershave for the beard, a hairspray, a hair serum, an oil, a gel, a mousse, a lotion, an eyebrow pencil, or a spray. Those skilled in the art will know how to adapt the type of composition to be used depending on the area of ​​application.

[0049] According to a particular embodiment, it will be a rinse-off care composition.

[0050] According to another particular embodiment, it will be a leave-in care composition.

[0051] Cosmetic care process

[0052] Another object of the invention relates to a non-therapeutic cosmetic care method peutic, that is to say intended for healthy scalps, eyebrows or beards, comprising the topical application of the extract of T. lutea, advantageously in the form of an oily ingredient, or of a cosmetic composition comprising it, to reduce dandruff and / or prevent its appearance and / or reappearance. In an advantageous embodiment of the invention, the cosmetic care method comprises said application to a dry scalp, dry eyebrows or a dry beard, preferably a dry scalp.

[0053] Advantageously, the method comprises the application of the oily ingredient comprising by weight relative to the total weight of the oily ingredient: i. from 5 to 15% by weight, preferably 9 to 10% by weight of an extract of T. lutea according to the invention, relative to the total weight of the oily ingredient, ii. from 85 to 94%, preferably from 89 to 94%, in particular from 89.5 to 90.5% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and more preferably a coconut oil, relative to the total weight of the oily ingredient, and iii. from 0.3% to 1% by weight, preferably 0.5% by weight of vitamin E, more preferably α-tocopherol, relative to the total weight of the oily ingredient.

[0054] In another embodiment, the cosmetic care method comprises the topical application of a final cosmetic composition comprising by weight relative to the total weight of the composition an amount ranging from 0.1 to 10% by weight, preferably from 0.25 to 5% by weight, advantageously still 0.5% by weight of the oily ingredient relative to the total weight of the final composition, and at least one cosmetically acceptable excipient chosen from additional oils such as vegetable oils, in particular chosen from argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and their mixtures, preservatives, emulsifiers, emollients,surfactants, moisturizers, thickeners, glossing agents, texturizing agents, film-forming agents, pigments, colorants, perfumes, biological additives, chelating agents, astringent agents, polymers, reducing agents, pH regulating agents, humectants, conditioning agents, and mixtures thereof.

[0055] Examples referring to the description are presented below. These examples are illustrative and do not limit the scope of the invention. The examples are an integral part of the present invention and any new feature compared to a state of the prior art from the description taken as a whole is integral part of the invention. Unless otherwise stated, temperature is expressed in degrees Celsius (°C), pressure in bar, percentages are given in weight / weight (w / w). Ppm means Parts Per Million (0.01% = 100ppm). Examples:

[0056] Example 1: Method of preparing a crude extract of Tisochrysis lutea and an oily extract comprising it

[0057] The strain used to prepare the extract according to the invention is the strain CCAP 927 / 14 available from the Scottish Marine Institute via the Culture Collection of Algae and Protozoa (CCAP) bank.

[0058] Example 1a) Obtaining a crude hydroalcoholic extract:

[0059] A crude extract was obtained by extraction in an ethanol-water mixture (90:10; w / v) from a quantity by weight relative to the total volume of biomass and solvent of 10%, of frozen and dried biomass from a photobioreactor culture in autotrophic mode of the microalga T. lutea (Strain CCAP 927 / 14). The extract obtained was rinsed and then filtered (Ipm).

[0060] Example 1b) Obtaining a crude extract at CCLsupcrcritique:

[0061] A crude extract was obtained in a second preferred embodiment of the invention from a frozen and dried biomass of a photobioreactor culture in autotrophic mode of the microalga T. lutea (Strain CCAP 927 / 14) by supercritical CO2 extraction at a temperature of 50°C and a pressure of 150 bars in the presence of ethanol as co-solvent (10%). The extract obtained was rinsed and then filtered (Ipm).

[0062] Obtaining the oily ingredient (oily extract):

[0063] The crude extract obtained in example 1a) or 1b) was then supplemented with coconut oil (Medium Chain Triglyceride Oil) in an amount of between 90% and 94% by weight, at room temperature, i.e. at 25°C. The mixture was stirred until a homogeneous mixture was obtained and the residual ethanol was evaporated. A final amount by weight relative to the total weight of the oily ingredient of 0.5% of α-tocopherol was added. The extract obtained is referred to indifferently as oily ingredient or oily extract and was subsequently used in the example below. In particular, the oily ingredient comprises from 9 to 10% by weight of a T. lutea extract prepared according to example 1a) or example 1b), from 89.5 to 90.5% by weight of a coconut oil, and 0.5% by weight of α-tocopherol.

[0064] In the following examples, an oily ingredient comprising from 9 to 10% by weight of an extract of T. lutea prepared according to example 1a), from 89.5 to 90.5% by weight of a coconut oil, and 0.5% by weight of α-tocopherol will be used.

[0065] Example 2: effect of a composition comprising Tisochyris lutea extract on the reduction of dandruff.

[0066] Protocol: a double-blind clinical trial was conducted on a population of 36 male and female volunteers (in equal proportion) aged 25 to 40 years and having a dry scalp with the presence of dry dandruff for at least 2 months before the start of the clinical trial. The trial consisted of the daily application for a period of 28 days of a serum comprising the oily ingredient as prepared according to Example 1 (with the crude extract of Example 1a) or a placebo serum (of the same composition as the previous serum but without the oily ingredient).

[0067] The serum used in this example comprises the following composition:

[0068] Table 1 [Table 1] Ingredient (INCI name) % by weight Water QSP 100 Sodium benzoate 0.70 Sodium polyacrylate 0.60 Copolymer of hydroxyethyl acrylate and sodium acryloyldimethyl taurate 0.80 Undecane and tridecane 6.50 Oily ingredient according to example 1a) 0.50

[0069] The number of dandruff flakes was measured at time 0 (T0), after 7 days (T7) and 28 days (T28) of application, as well as 42 days after the start of the clinical trial (without additional daily application after 28 days, to evaluate the persistence of the effect over time) using a dedicated device (DandruffMeter DA20®) after collecting the dandruff flakes for a period of 15 seconds on a black sheet of paper (shaking of the head and collection by the fingertips only, in order to avoid desquamation of the scalp by the nails). The dandruff flakes were then collected on a Petri dish containing a black felt-tip pen.

[0070] The films were inserted into the dedicated device. The device includes a circular LED light source illuminating the sample evenly against a dark background and a high-resolution camera located above the sample to take pictures. The software connected to the device made it possible to classify the films into 9 categories according to their size.

[0071] The exact number of films as well as the area occupied by the films (Total surface covered in mm2, reflecting the size of the films) were analyzed.

[0072] The results are presented in Table 2 below and are expressed as a percentage of film number or as a percentage of film area relative to time 0 (T0).

[0073] Results:

[0074] Table 2 [Table 2] Number of films (% compared to time 0) Area occupied (% compared to time 0) Placebo Serum (T. lutea ) Placebo Serum (T. lutea ) T0 100 100 100 100 T7 105.6 95.1 190.1 116 T28 98.8 56.4 114.2 40.5 T42 (Remanence) 111.2 91.9 ND ND

[0075] ND: not determined (not measured).

[0076] The results show that at T7, a decrease in the number of dandruff flakes was observed with a slight increase in size, the latter being much greater for the placebo than for the serum containing the T. lutea extract. The serum according to the invention therefore allows a reduction in the size of dandruff flakes, compared to the placebo.

[0077] At T28, a strong decrease in the number of films as well as a decrease in their size was observed for the composition of the invention.

[0078] At T42, i.e. 14 days after the last application (T28), a reduction in the number of dandruff flakes was still observed, compared to the placebo and at time T0, indicating a persistence of the effect of the serum according to the invention, even after the last application.

[0079] Thus, the serum comprising the oily ingredient according to Example 1 (crude extract of T. lutea, MCT coconut oil, α-tocopherol) showed a reduction in the number and size of dandruff from 28 days of application, respectively of more than 40% and more than 55% compared to the number of dandruff and their size at time 0 of the start of the clinical trial, on a population of individuals having a scalp with dry dandruff. The crude extract of T. lutea according to the invention, as well as the oily ingredient comprising it, are therefore particularly effective in reducing dandruff but also in preventing its reappearance (residual effect at T42) on the scalp.

[0080] These results therefore demonstrated a rapid action on the number of films, then a medium-term action (between T7 and T28) on their very strong reduction in number, concomitant with a reduction in their size, and a lasting effect over time (T42), leading to a strong reduction in the quantity and visibility of films after application of the composition of the invention.

[0081] Similar results of reduction in the number and visibility of dry dandruff could also be observed after application of the composition of the invention to dry eyebrows and / or a dry beard.

Claims

Claims

1. Cosmetic use of an extract of Tisochrysis lutea or a composition comprising it to reduce dandruff and / or prevent its appearance and / or reappearance.

2. Cosmetic use according to claim 1, characterized in that said extract of Tisochrysis lutea is obtained by extraction in a solvent or a mixture of solvents chosen from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol chosen from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or glycol / water in a proportion of 99 / 1 to 1 / 99 (w / v), or by supercritical CO2 extraction.

3. Cosmetic use according to claim 1 or 2, characterized in that said extract of Tisochrysis lutea is obtained by extraction in an alcohol / water mixture, in a proportion of 99 / 1 to 1 / 99 (w / v), advantageously still in a proportion of 95 / 5 to 90 / 10 (w / v).

4. Cosmetic use according to any one of claims 1 to 3, characterized in that said extract of Tisochrysis lutea is obtained by extraction in an ethanol / water mixture in a proportion of 90 / 10 (w / v).

5. Cosmetic use according to any one of claims 1 to 4, topically, in particular on a dry scalp, dry eyebrows and / or a dry beard.

6. Cosmetic use according to any one of claims 1 to 5, characterized in that said extract of Tisochrysis lutea is in the form of an oily ingredient comprising, by weight relative to the total weight of the oily ingredient: i. from 5 to 15% by weight, preferably 9 to 10% by weight of an extract of T. lutea according to the invention, relative to the total weight of the oily ingredient, ii. from 85 to 94%, preferably from 89 to 94%, in particular from 89.5 to 90.5% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and more preferably a coconut oil, relative to the total weight of the oily ingredient, and iii. from 0.3% to 1% by weight, preferably 0.5% by weight of vitamin E, more preferably α-tocopherol, relative to the total weight of the oily ingredient.

7. Cosmetic use of the oily ingredient according to claim 6 in a final cosmetic composition, characterized in that the oily ingredient is present in the final cosmetic composition in an amount ranging from 0.1 to 10%, preferably from 0.25 to 5% by weight, more preferably an amount of 0.5% by weight relative to the total weight of the final cosmetic composition.

8. Use according to claim 7, characterized in that the final cosmetic composition comprises at least one cosmetically acceptable excipient chosen from additional oils such as vegetable oils, in particular chosen from argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, moisturizers, thickeners, shine agents, texturizing agents, film-forming agents, pigments, colorants, perfumes, biological additives, chelating agents, astringent agents, polymers, reducing agents,pH regulating agents, humectants, conditioning agents, and mixtures thereof.,

9. Use according to one of claims 7 or 8, characterized in that the final cosmetic composition is in the form of a dry shampoo, a shampoo, a conditioner, an aftershave, a hairspray, a serum, an oil, a gel, a mousse, a lotion, an eyebrow pencil or a spray.

10. Cosmetic care method comprising the topical application to the scalp, eyebrows and / or beard of an extract of Ti-sochrysis lutea, advantageously the extract as defined according to any one of claims 2 to 4, or of an oily ingredient comprising it, advantageously the oily ingredient according to claim 6, or of a final cosmetic composition comprising the extract of T. lutea or the oily ingredient comprising it, advantageously the final cosmetic composition according to claim 8 or 9, to reduce dandruff and / or prevent its appearance and / or reappearance.

11. Cosmetic care method according to claim 10, characterized in that the T. lutea extract, the oily ingredient comprising it or the final cosmetic composition, is applied to dry scalp, dry eyebrows and / or dry beard, advantageously to a dry scalp.