Aqueous extraction process of hydrophobic metabolites present in a plant

Abstract

Aqueous extraction process for hydrophobic metabolites present in a plant. The invention relates to a process for obtaining a plant extract with an aqueous-based solvent containing a cosmetic ingredient used in a specific proportion to exert a hydrotropic effect on the plant metabolites in order to increase their solubility in water. The cosmetic ingredient can be chosen from natural organic molecules comprising a pyridine or oxolane ring. Fig. 1.

Description

Title of the invention: Aqueous extraction process for hydrophobic metabolites present in a plant. Technical field

[0001] The present description relates to a process for obtaining a plant extract with an aqueous-based solvent containing a specific non-volatile cosmetic ingredient, in order to extract rather hydrophobic metabolites of interest. The cosmetic ingredient is used in a specific proportion to exert a hydrotropic effect on the metabolite in order to increase its solubility in water. The cosmetic ingredient can be selected from natural organic molecules comprising a nitrogenous aromatic heterocycle, or an oxygenated aliphatic heterocycle, saturated or unsaturated. Previous technique

[0002] Water is a very good natural, non-toxic and non-flammable extraction solvent commonly used for the preparation of plant extracts. However, its high polarity does not allow for the optimal extraction of certain metabolites, particularly low-polarity metabolites.

[0003] Organic solvents such as alcohols and ketones are therefore frequently added to water to improve extraction yields. Some studies have proposed the introduction of cumene sulfonates or xylene sulfonates into the aqueous extraction medium to isolate metabolites such as geraniol and reserpine from plants. These processes have the disadvantage of using synthetic molecules, volatile solvents, or solvents of petrochemical origin.

[0004] Increasing the temperature and pressure of the aqueous extraction medium can be a complementary or alternative means of modifying the solubility of hydrophobic metabolites in water. For example, aqueous extraction can be carried out under hot reflux or subcritical conditions. However, these processes require a significant energy input.

[0005] The need therefore remains to propose extraction processes in aqueous media that are simple to implement and free from the drawbacks of the prior art. In particular, it is desirable to avoid the use of synthetic solvents, volatile solvents, and demanding physical extraction conditions that consume energy, such as pressurizing or raising the temperature of the medium. It is also desirable that the duration of the process be as short as possible.

[0006] Furthermore, there remains a need to propose extraction processes for rather hydrophobic metabolites such as stilbenoids, xanthones and hydroxynaphthoquinones found in plants, which use a natural solvent like water, and which are profitable.

[0007] It would also be beneficial to increase the biological cosmetic activity of extracts obtained from certain plants, including plants of the genus Vitis sp., Alkanna sp. and Garcinia sp.

[0008] In conclusion, the need remains to propose an aqueous extraction process that is at least partially free from the drawbacks inherent in the prior art. In particular, it would be desirable to improve the extraction yields of plant metabolites that are poorly soluble in water, to avoid introducing volatile organic and / or synthetic solvents into the extraction medium, and to benefit from gentle extraction conditions. A process that is easy to implement and energy-efficient is also expected. Description of the invention

[0009] Also, according to one of its aspects, the invention relates to a method for extracting at least one metabolite contained in a plant in an aqueous medium, said method comprising: (i) a step of preparing an extraction solution comprising water and at least one cosmetic ingredient at a concentration chosen to exert a hydrotropic function, ii) a step of introducing at least a part of the plant into the extraction solution, iii) a metabolite extraction step, iv) a step of recovering an aqueous solution comprising the metabolite and the cosmetic ingredient.

[0010] The plant can be chosen from plants of the genus Vitis sp., Alkanna sp. and Garcinia sp.

[0011] The metabolite can be chosen from stilbenoids, xanthones and hydroxynaphthoquinones.

[0012] In a particular case, the cosmetic ingredient is a natural nonionic compound selected from among nitrogen-containing aromatic heterocyclic compounds and oxygen-containing aliphatic heterocyclic compounds. The cosmetic ingredient may, in particular, be selected from among natural nonionic compounds comprising a pyridine ring and / or an oxolane ring.

[0013] According to one variant of the process, the extraction step is carried out by macerating the plant material in the extraction liquid comprising 20% ​​w / w to 40% w / w of the cosmetic ingredient.

[0014] The invention addresses at least one of the previously stated needs and proposes an extraction process in which a particular cosmetic ingredient is introduced into the aqueous extraction medium to exert a hydrotropic function by increasing the solubility of the metabolite in the water of the extraction medium. This cosmetic ingredient is advantageously natural and non-volatile. It may possess biological cosmetic activity that interacts synergistically with that of the extracted metabolite.

[0015] The process of the invention makes it possible to obtain plant extracts of a new composition under operating conditions that respect the environment and whose biological activity can be increased.

[0016] The process of the invention has the advantage of increasing the extraction yield of poorly soluble metabolites that are extracted in the prior art with hydroalcoholic solvents, by replacing weight for weight the alcohol of the hydroalcoholic medium with a particular cosmetic ingredient, which may advantageously be non-volatile and natural.

[0017] The inventors have found surprisingly that the use of particular non-ionic organic compounds, such as niacinamide, pantolactone or dimethylisosorbide, in a dissolved state in water at a particular concentration, makes it possible to boost the extraction of metabolites of interest which are rather hydrophobic in aqueous media.

[0018] These organic compounds can advantageously be biologically active. For example, niacinamide has antioxidant activity, pantolactone acts as a humectant, and dimethyl isosorbide is a propenetrant. The use of these compounds in plant extraction thus makes it possible to obtain an aqueous extract enriched in metabolites compared to conventional extracts.

[0019] The invention advantageously makes it possible to obtain a liquid aqueous extract enriched in rather hydrophobic metabolites of interest using a natural or naturally derived cosmetic ingredient.

[0020] The aforementioned features and advantages, as well as others, will become apparent upon reading the detailed description that follows. Brief description of the drawings

[0021] Fig. 1 and Fig. 2 present the measurement results of the resveratrol content and the viniferine content measured in the extracts of Vitis vinifera shoots obtained according to the process of the invention and according to the prior art.

[0022] Figure 3 shows the mangostine content of extracts obtained according to the process of the invention from mangosteen fruit peel, and according to the prior art.

[0023] Fig. 4 and Fig. 5 respectively represent the acetylshikonin and deoxyshikonin contents in extracts of Alkanna tinctoria roots obtained according to the process of the invention and according to the prior art.

[0024] Figures 6, 7, and 8 represent the percentage of inhibition of Vitis vinifera vine shoot extracts obtained according to the process of the invention, using niacinamide, dimethylisosorbide, and pantolactone respectively in the aqueous extraction medium, and according to the prior art.

[0025] Fig. 9, Fig. 10 and Fig. 11 represent the percentage of inhibition of Garcinia mangostana fruit peel extracts obtained according to the process of the invention, using respectively niacinamide, dimethylisosorbide and pantolactone in the aqueous extraction medium, and according to the prior art.

[0026] Fig. 12, Fig. 13 and Fig. 14 represent the percentage of inhibition of Alkanna tinctoria root extracts obtained according to the process of the invention, using respectively niacinamide, dimethylisosorbide and pantolactone in the aqueous extraction medium, and according to the prior art. Description of the implementation methods

[0027] A first object of the invention relates to a method for extracting at least one metabolite contained in an aqueous medium from a plant selected from plants of the genera Vitis sp., Alkanna sp. and Garcinia sp., said method comprising: (i) a step of preparing an extraction solution containing water and at least one cosmetic ingredient at a concentration chosen to exert a hydrotropic function, ii) a step of introducing at least a part of the plant into the extraction solution, iii) an extraction step of said at least metabolite, and (iv) a step of recovering an aqueous solution containing the metabolite and the cosmetic ingredient.

[0028] A second object of the invention relates to a process for the aqueous extraction of at least one metabolite present in a plant, said metabolite being chosen from among stilbenoids, xanthones and hydroxynaphthoquinones, and said process comprising: (i) a step of preparing an extraction solution containing water and at least one cosmetic ingredient at a concentration chosen to exert a hydrotropic function, ii) a step of introducing at least a part of the plant into the extraction solution, iii) an extraction step of said at least metabolite, and (iv) a step of recovering an aqueous solution containing the metabolite and the cosmetic ingredient. Cosmetic ingredient

[0029] The term "in sufficient quantity to exert a hydrotropic function" refers to a concentration at which the cosmetic ingredient is soluble in water and increases the solubility of the metabolite in water. At this concentration, the cosmetic ingredient is a hydrotropic agent. The concentration of the cosmetic ingredient in the extraction liquid is higher than its minimum hydrotropic concentration (MHC) and lower than its solubility limit in water. Those skilled in the art will be able to find this information in reference manuals. For example, the mass of the cosmetic ingredient is between 30% and 40% of the mass of water in the extraction liquid.

[0030] The cosmetic ingredient of the process of the invention is preferably a natural organic molecule. It can be chosen from among cyclic non-ionic molecules, the ring preferably being a nitrogenous aromatic ring or a saturated or unsaturated heterocycle comprising an oxygen atom.

[0031] In a particular embodiment, the cosmetic ingredient is chosen from natural ingredients whose chemical structure includes at least one carbon aromatic ring comprising 1 or 2 nitrogen atoms, the ring being optionally substituted by a carbonyl, hydroxyl or amine group.

[0032] The cosmetic ingredient can be represented by the formula (I):

[0033] [Chem.l] RI R4 (I)

[0034] in which RI represents -H, -C(H)=O, -COOH; R2 represents -H, -CH2-O-PO3H2, -COOH; R3 represents -H, -OH; R4 when present represents -H; R5 represents -H, -OH, -CH3; and R6 represents -H, -OH.

[0035] The cosmetic ingredient can also be represented by the formula (II):

[0036] [Chem.2] X1 X4 (II)

[0037] in which XI represents -NH2, or =0; X2 represents a hydrocarbon radical; X3 represents -H; X4 when present, represents -H; X5 represents -CH3, =0 or -NH2; and X6 when present, represents -H.

[0038] In this case, the cosmetic ingredient can be chosen from niacinamide (CAS 98-92-0).

[0039] In another embodiment, the cosmetic ingredient is chosen from natural ingredients whose chemical structure includes at least one ring comprising 4 carbon atoms and one oxygen atom, unsaturated or saturated, the ring being optionally substituted by a carbonyl, hydroxyl, alkoxyl, or alkyl group, possibly hydroxylated.

[0040] The ring comprising 4 carbon atoms and one oxygen atom can be an oxolane (also called tetrahydrofuran).

[0041] The cosmetic ingredient can in this case be represented by the formula (I):

[0042] [Chem.3] (III)

[0043] in which ZI represents -H, -OH, -CH3, -COOH and Zl' when present, represents -H, -CH3; Z2 represents -H, -OH, -OCH3 and Z2' when present, represents -H; Z3 represents -H, -OH, -CH3, -COOH and Z3' when present, represents -H; Z4 represents -CH3, -CH2OH, -CH(OH)-CH2OH, -COOH and Z4' when present, represents -H; Zl and Z4 can together represent -O-CH2-CH(OH)-; Z2 and Z2' can together represent =0; and Z3 and Z3' can together represent =0.

[0044] The 5-carbon ring can be a furan, a dihydrofuran, or a tetrahydrofuran (also called oxolane). In this case, the cosmetic ingredient fulfilling a hydrotropic function is chosen from dimethylisosorbide (CAS 5306-85-4), pantolactone (CAS 599-04-2), gamma-valerolactone (CAS 108-29-2).

[0045] Finally, in a last embodiment, the cosmetic ingredient comprises both at least one aromatic ring with 6 carbon atoms, the aromatic ring comprising 1 or 2 nitrogen atoms, and at least one ring with 5 carbon atoms, unsaturated or saturated, comprising one oxygen atom.

[0046] For the purposes of this invention, "natural" means a natural or naturally derived ingredient as defined by ISO 16128 (including ISO 16128-2:2017, ISO 16128-2:2017 / Amd 1:2022 and ISO 16128-1:2016), which standard provides technical definitions (part 1) and criteria (part 2) applicable to natural and organic cosmetic ingredients and products.

[0047] According to ISO Standard 16128 and for the purposes of the present invention, a so-called "natural" ingredient is an ingredient whose naturalness index is equal to 1. Natural ingredients are obtained exclusively from plants (including fungi and algae), animals, microorganisms or minerals, including ingredients obtained from these materials resulting from (i) physical processes (such as grinding, drying, distillation), (ii) fermentation reactions existing in nature and leading to molecules existing in the natural state, and (iii) other methods of preparation, including traditional methods (for example, extraction using solvents) without any intention of chemically altering the ingredient.

[0048] According to ISO 16128 and for the purposes of the present invention, a "natural ingredient" is defined as an ingredient having a naturalness index strictly greater than 0.8 and less than or equal to 1. A cosmetic ingredient of natural origin is obtained by defined chemical and / or biological processes aimed at chemically modifying it, either in its molecular structure or in its composition. The use of enzymatic and microbiological processes can also result in ingredients derived from natural materials, when an intentional chemical modification takes place.Chemical and / or biological processes may be selected from acylation, addition, C, O, N alkylation, calcination, carbonization, carbonation, condensation, enzymatic and microbiological processes, glycosylation, hydrogenation, hydrogenolysis, hydrolysis, ion exchange, olefin metathesis, oxidation, phosphorylation, reduction, or sulfation. Extraction process.

[0049] The extraction process of the invention comprises i) a step of preparing an extraction solution comprising water and the cosmetic ingredient, ii) a step of introducing the plant part into the extraction solution, iii) a step extraction of the metabolite and iv) a step of recovering an aqueous solution comprising the metabolite and the cosmetic ingredient.

[0050] The extraction medium is prepared by dissolving the cosmetic ingredient in water, then dispersing the plant material in the resulting mixture. The mass of the cosmetic ingredient can represent 30% to 40% of the mass of water contained in the extraction liquid.

[0051] The extraction liquid comprises water and the cosmetic ingredient. According to one embodiment, the extraction liquid essentially consists of water and the cosmetic ingredient.

[0052] The extraction medium preparation step includes preparing the plant material from the whole plant or a part of the plant. The plant material may be dried (by freeze-drying or otherwise) and / or ground before being mixed with water and the cosmetic ingredient. Alternatively, the plant material may be used fresh. In a particular method, the plant material is ground before being introduced into the extraction liquid, for example, using a mortar, a blender, a traditional grinder, or any other method commonly used by those skilled in the art. The particle size of the ground plant material is, for example, on the order of 1 mm.

[0053] The ratio between the mass of plant matter (expressed in dry mass) and the mass of water can be between 1 / 20 and 1 / 1. For example, it is on the order of 1 / 10.

[0054] The extraction step can be carried out under heat by reflux, or by maceration. Physical means such as agitation, high-pressure homogenization, ultrasound or microwaves can be applied to the extraction medium during this step.

[0055] In the case of extraction by maceration, the duration of the extraction can range from 15 minutes to 3 hours, preferably from 1 to 2 hours.

[0056] After the extraction step, the insoluble materials are advantageously separated from the metabolite-enriched extraction liquid by filtration and / or centrifugation.

[0057] It is possible to carry out several sequences, each comprising an extraction step and a separation step, in order to deplete the plant material of the more hydrophobic metabolites. At the end of each sequence, the enriched extraction liquid can be replaced with fresh extraction liquid. The various extraction liquids collected can then be combined.

[0058] The step of recovering the metabolite and the cosmetic ingredient may include a concentration consisting of removing some of the water present in the enriched extraction liquid, or even removing all of the water to obtain an anhydrous mixture comprising the metabolite and the cosmetic ingredient.

[0059] A water removal step combined with a step separating the metabolite and the cosmetic ingredient can lead to a dry extract containing the metabolite hydrophobic. Water removal can be achieved by drying (freeze-drying or spray-drying, for example) to obtain a powder.

[0060] The metabolite-enriched extraction liquid that is directly obtained from the extraction step can be formulated as an active ingredient in a cosmetic formulation, and mixed with other raw materials during the formulation preparation process. hydrophobic metabolite

[0061] The plant extract obtained by the process described above includes a metabolite which is rather hydrophobic.

[0062] The hydrophobic metabolite of the invention can be defined as a polar molecule that is sparingly soluble in water. It can also be characterized by a non-zero polarity of low or medium value defined by any physicochemical parameter known to those skilled in the art, such as the logP parameter. The value of the logP parameter can be obtained by any method known to those skilled in the art, from tables in reference manuals, by calculation using software from Advanced Chemistry Development Inc., for example, or by experimental measurement. The metabolite of the invention can have a logP value between 2.5 and 6.5.

[0063] It can be chosen from among stilbenoids, xanthones and hydroxynaphthoquinones.

[0064] The stilbenoid can be selected from resveratrol and its oligomers, such as epsilon-viniferin, delta-viniferin, gnetin C, alpha-viniferin, beta-viniferin and vaticanol C. The stilbenoid can also be selected from coelonine, a derivative of coelonine and gigantol.

[0065] The stilbenoid can also be selected from pinosylvin and piceatannol and pterostilbene.

[0066] Stilbenoid can be present in many plants such as Vitis vinifera, Pinus sylvestris and Morus alba.

[0067] Xanthones are illustrated by compounds selected from alpha-mangostin, gamma-mangostin.

[0068] In a particular embodiment, the extract comprises at least one xanthone selected from the group consisting of alpha-mangostin, beta-mangostin and gamma-mangostin, 1-isomangostin, 3-isomangostin and normangostin.

[0069] Xanthone can be present in many plants such as Garcinia mangostana, Calophyllum caledonicum, Garcinia vieillardii and Centaurium erythraea.

[0070] In another embodiment, the metabolite is a hydroxynaphthoquinone such as shikonine, acetylshikonine or deoxyshikonine.

[0071] Hydroxynaphthoquinone can be present in many plants such as Alkanna tinctoria, Lithospermum erythrorhizon, Lithospermum canascens, Echium vulgare and Onosma echioides. Plants

[0072] The plant used in the process of the invention can be chosen from plants of the genera Vitis sp., Alkanna sp., Garcinia sp., Iris sp., Poterium sp. and Pinus sp. in particular plants of the species, Garcinia mangostana (also called mangosteen), Vitis vinifera, Alkanna tinctoria, Iris florentina, Poterium sanguisorba, Pinus pinaster, and species of the genus Rosa sp. and their hybrids such as the Granville rose.

[0073] The process of the invention can be implemented to extract metabolites from plants but also from microalgae such as, for example, Porphyridium cruentum, Tisochrysis lutea, Phaeodactylum tricomutum, and Dunaliella terliolecta.

[0074] The mangosteen is a plant whose scientific name is Garcinia mangostana. It is a tropical tree of the Clusiaceae family, bearing one or two male or female flowers at the end of each branch. The fruit, spherical and smooth, is initially greenish-white, turning purplish-red when ripe. The ripening of the mangosteen fruit generally takes between two and three months. The fruit's rind is 6 to 10 mm thick and surrounds the edible part of the fruit.

[0075] The plant Alkanna tinctoria is a woody perennial herbaceous plant of the genus Alkanna that can reach several tens of centimeters in height. The roots have a flaky bark of a purplish-red color. All the aerial parts of the plant are densely hairy and the blue flowers are grouped in clusters.

[0076] The plant Vitis vinifera is, for example, a vine from Château d'Yquem. Plant extract

[0077] The term "plant extract" generally refers to an isolated substance obtained by extraction from a plant raw material, and which does not pre-exist in nature as such. The plant extract is preferably a plant extract enriched in metabolites of interest, particularly metabolites that are rather hydrophobic. An "aqueous plant extract" within the meaning of the invention is an extract obtained by contacting a plant material with a liquid containing water.

[0078] The term “plant material” or “plant raw material” means all or part of the plant from which the extract according to the invention is prepared.

[0079] The extract containing the hydrophobic metabolite can in particular be prepared from a chosen plant material such as leaves, buds, calyces, stamens, rhizomes, bulbs, roots, canes, vine stocks, stems, flowers, petals and the entire plant

[0080] For example, the following plant material will be used: Vitis vinifera shoots, Garcinia mangostana fruit peels, Alkanna tinctoria roots.

[0081] More specifically, we will seek to prepare an extract of Vitis vinifera enriched in stilbenoids (in particular resveratrol and viniferin), an extract of Garcinia mangostana rich in xanthones (in particular mangostin), and an extract of Alkanna tinctoria rich in hydroxynapthoquinones (in particular acetylshikonin and deoxyshikonin).

[0082] In the present description, the extraction yield is the measure of the amount of hydrophobic metabolite(s) contained in the extraction liquid. This measurement can be carried out by any method known to those skilled in the art, for example by high-performance liquid chromatography (HPLC).

[0083] In a first particular embodiment of the invention, the plant material is derived from the Vitis vinifera plant, for example, from the vine shoots of said plant. The metabolites are extracted therefrom in a significant yield, which is, for example, greater than a value chosen from the group consisting of 0.80 mg / g, 1.2 mg / g, 1.5 mg / g, 1.8 mg / g, 2.0 mg / g, 2.1 mg / g, and 2.2 mg / g of vine shoots. The metabolite extraction yield achieved by the process of the invention may be greater than the yield obtained by prior art processes, in particular greater than the yield obtained by a process identical to that of the invention except that the cosmetic ingredient would be replaced by water or an alcohol, for example, a mixture of 35% by volume ethanol in water. In this embodiment, the extracted metabolites can be chosen from resveratrol, viniferine and mixtures thereof.Niacinamide, in particular, increases the extraction yield of a mixture of resveratrol and viniferine by a factor of at least 2 compared to the prior art. Dimethylisosorbide and pantolactone each independently increase the extraction yield of a mixture of resveratrol and viniferine by a factor of at least 3 compared to the prior art.

[0084] In a second particular embodiment of the invention, the plant material is derived from the Garcinia mangostana plant, for example, from the fruit peels of said plant. The metabolites are extracted therefrom in a significant yield, which is, for example, greater than a value chosen from the group consisting of 1.40 mg / g, 5.0 mg / g, 10.0 mg / g, 12.0 mg / g, 14.0 mg / g, 16.0 mg / g, and 18.0 mg / g of fruit peel. The metabolite extraction yield achieved by the process of the invention may be greater than the yield obtained by prior art processes, in particular greater than the yield obtained by a process identical to that of the invention. The difference is that the cosmetic ingredient would be replaced by water or an alcohol, for example, a mixture of 35% ethanol in water. In this embodiment, the extracted metabolite can be mangostine. Niacinamide, in particular, increases the extraction yield of mangostine by a factor of at least 8 compared to the prior art. Dimethylisosorbide, in particular, increases the extraction yield of mangostine by a factor of at least 11 compared to the prior art. Pantolactone, in particular, increases the extraction yield of mangostine by a factor of at least 13 compared to the prior art.

[0085] In a third particular embodiment of the invention, the plant material is derived from the Alkanna tinctoria plant, for example, from the roots of said plant. The metabolites are extracted therefrom in a significant yield, which is, for example, greater than a value chosen from the group consisting of 0.20 mg / g, 0.5 mg / g, 0.6 mg / g, 0.7 mg / g, 0.8 mg / g, 0.9 mg / g, and 1.10 mg / g of Alkanna. The metabolite extraction yield achieved by the process of the invention may be greater than the yield obtained by prior art processes, in particular greater than the yield obtained by a process identical to that of the invention except that the cosmetic ingredient would be replaced by water or an alcohol, for example, a mixture of 35% by volume ethanol in water. In this embodiment, the metabolites can be chosen from acetylshikonin, deoxyshikonin and mixtures thereof.Niacinamide, in particular, increases the extraction yield of a mixture of acetylshikonin and deoxyshikonin by a factor of at least 5 compared to the prior art. Pantolactone, in particular, increases the extraction yield of a mixture of acetylshikonin and deoxyshikonin by a factor of at least 4 compared to the prior art.

[0086] Each of these three particular embodiments of the invention may satisfy one or both of the following characteristics: - the cosmetic ingredient is niacinamide, pantolactone, dimethylisosorbide or a mixture thereof, - the extraction solvent for the prior art is chosen from water, a C2-C6 alcohol and mixtures thereof.

[0087] The increase in extraction yield can also be significant when the cosmetic ingredient performing a hydrotropic function is pantolactone and the extracted metabolite is mangostine. In this embodiment, the extraction yield can be multiplied by a factor of more than 10, preferably more than 13, compared to 35% by volume ethanol in water.

[0088] The increase in extraction yield can be significant when the hydrotropic solvent is niacinamide and when the extracted metabolite is chosen from among the hydroxynaphthoquinones. In this embodiment, the yield can be multiplied by a factor of more than 5, preferably more than 6, compared to 35% by volume ethanol in water.

[0089] A cosmetic ingredient such as niacinamide, dimethylisosorbide, or pantolactone significantly improves the extraction yield of hydrophobic metabolites contained in a plant, such as stilbenoids, xanthones, and hydroxynaphthoquinones, compared to water or a hydroalcoholic mixture containing 35% ethanol, in particular: - resveratrol and viniferine contained in plants of the genus Vitis sp., such as Vitis vinifera, particularly in the vine shoots of Vitis vinifera, - mangostin present in plants of the genus Garcinia sp., such as Garcinia mangostana, in particular the fruit rinds of Garcinia mangostana. - acetylshikonin and deoxyshikonin contained in plants of the genus Alkanna sp., such as Alkanna tinctoria, in particular the roots of Alkanna tinctoria.

[0090] Niacinamide and pantolactone make it possible to significantly increase the extraction yield of acetylshikonin and deoxyshikonin, and more particularly acetylshikonin and deoxyshikonin contained in plants of the genus Alkanna sp., such as Alkanna tinctoria, in particular the roots of Alkanna tinctoria.

[0091] This description also relates to the use of cosmetic ingredients capable of exercising a hydrotropic function to extract at least one hydrophobic metabolite from a plant, said metabolite being chosen from stilbenoids, mangostine and hydroxynaphthoquinones.

[0092] The use of pantolactone to extract at least one metabolite from plant material is also part of the invention, and in particular allows the extraction of mangostine.

[0093] The liquid extract obtained according to the process of the invention can be endowed with in vitro inhibitory activity against the xanthine oxidase enzyme. In particular, the percentage of xanthine oxidase inhibition of the liquid extract obtained is advantageously greater than 20%, preferably greater than 40%, or even greater than 60%, when the cosmetic ingredient is niacinamide and the plant is Garcinia mangostana. The percentage of inhibition is advantageously significantly greater than that of a liquid extract obtained by a prior art extraction process, in particular a process identical to that of the invention except that the cosmetic ingredient would be replaced by water or an alcohol. The percentage of xanthine oxidase inhibition of the liquid extract obtained - may be significantly greater than the sum of i) the percentage of inhibition of an extract obtained by a process identical to that of the invention in which the cosmetic ingredient is replaced by water or an alcohol, and ii) the percentage of inhibition of an aqueous solution comprising niacinamide

[0094] When the cosmetic ingredient is not removed in a step subsequent to the extraction step, the product directly obtained at the end of the extraction step contains the cosmetic ingredient, and the aqueous plant extract obtained by the process may include the cosmetic ingredient and the hydrophobic metabolite, which makes it possible to provide an additional cosmetic function to that of an extract comprising only the hydrophobic metabolite.

[0095] The aqueous plant extract of the invention can therefore possess at least two cosmetic functions: that of a hydrotropic agent and that of a metabolite extracted from the plant. For example, a hydrotropic agent such as niacinamide confers antioxidant activity to the extract obtained by the process of the invention. Pantolactone can provide its humectant function. The use of dimethyl isosorbide can increase the biological activity of an aqueous plant extract thanks to its penetrating action on the skin.

[0096] In the case where the cosmetic ingredient has a biological skin care function identical to that of the metabolite, the cosmetic ingredient and the metabolite can enter into synergy.

[0097] A significant synergistic effect between the cosmetic function of the cosmetic ingredient used and the biological activity of the hydrophobic metabolite extracted from the plant can be observed. The definition of the synergistic effect is that at least one cosmetic effect of a given mass quantity of the extract obtained according to the process of the invention, comprising the cosmetic ingredient and the metabolite, is significantly greater than the sum of the cosmetic effect of the same mass of the cosmetic ingredient alone and the cosmetic effect of the same mass of aqueous plant extract containing the metabolite alone.

[0098] Also included in this description are: - an aqueous plant extract comprising an acetylshikonin content greater than a value selected from 0.02 mg / g, 0.05 mg / g, 0.10 mg / g, 0.15 mg / g, 0.20 mg / g, 0.25 mg / g and 0.30 mg / g, relative to the mass of the dry plant, in particular the plant Alkanna tinctoria. - an aqueous extract of plants comprising a deoxyshikonine content greater than a value chosen from 0.10 mg / g, 0.30 mg / g, 0.40 mg / g, 0.50 mg / g, 0.60 mg / g and 0.70 mg / g, relative to the mass of the dry plant, in particular the plant Alkanna tinctoria. - an aqueous plant extract comprising a mangostine content greater than a value selected from 3.0 mg / g, 6.0 mg / g, 8.0 mg / g, 10.0, 12 mg / g, 14 mg / g, 16 mg / g and 18 mg / g, relative to the mass of the dry plant, in particular the plant Garcinia mangostana. - an aqueous plant extract comprising a viniferine content exceeding a value selected from 0.5 mg / g, 0.6 mg / g, 0.7 mg / g, 0.8 mg / g, 0.9 mg / g, 1.0 mg / g and 1.5 mg / g relative to the mass of the dry plant, in particular the plant Vitis vinifera. - an aqueous plant extract comprising a resveratrol content exceeding a value selected from 0.15 mg / g, 0.20 mg / g, 0.25 mg / g and 0.4 mg / g, relative to the mass of the dry plant, in particular the plant Vitis vinifera. Cosmetic composition

[0099] The aqueous plant extract can be incorporated into a cosmetic skincare or makeup composition, and be associated with one or more cosmetic excipients known to those skilled in the art, chosen in particular from polymers, surfactants, rheology agents, perfumes, electrolytes, pH adjusters, antioxidants, preservatives, colorants, mother-of-pearls and pigments.

[0100] The extract is used in cosmetic compositions in an effective quantity to obtain the desired effect. In a particular embodiment, the extract is present in said cosmetic composition in a content ranging from 0.1% to 10% by mass.

[0101] The cosmetic composition may also include at least one cosmetic active ingredient, different from the aqueous plant extract obtained according to the process of the invention, said active ingredient being chosen from emollient agents, moisturizing agents and anti-aging agents.

[0102] The cosmetic composition can be formulated to give a texture chosen from milks, creams, ointments, balms, sticks, gels, lotions and serums.

[0103] The extract described above can be used as an agent to prevent and / or reduce the signs of skin aging, including loss of firmness, loss of elasticity, thinning of the skin, and the appearance of wrinkles and / or fine lines.

[0104] The extract can also be used in a cosmetic process for the care and / or makeup of keratinous materials, in particular of the skin, including the topical application of the extract or of a cosmetic composition as described above in the container.

[0105] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments mentioned can be combined in ways additional implementation. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0106] It is also evident that all the characteristics described with reference to a process are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a process.

[0107] EXAMPLE 1: Extraction and quantification process for extracted metabolites Various metabolites were extracted by maceration in an aqueous solution containing 35% w / w of hydrotropic agent (niacinamide, pantolactone or dimethylisosorbide) at 30°C for 2 hours from several plant materials which had been previously ground. All the extracted metabolites and plant materials used are presented in the following Table X.

[0108] [Tables] Plant material Metabolite extracted from Vitis vinifera shoots Resveratrol Viniferine Garcinia mangostana fruit peels Mangostin Alkanna tinctoria roots Acetylshikonin Deoxyshikonin 1 / Materials and methods 1.1 / Materials and method for extraction The Yquem vine shoots (Vitis vinifera) were supplied by Château d'Yquem and were harvested and dried in Sauternes. The mangosteen fruit peels (Garcinia mangostana) were harvested and dried in El Salvador. The Alkanna tinctoria roots were harvested and dried in Morocco.

[0109] The dried plant material was ground using a knife mill (Retsch SM2000) to obtain a powder with an average particle size of less than 1 mm. Plant samples were extracted once in triplicate from 500 mg of the ground plant using 5 g of an aqueous solution supplemented with 35% w / w of the hydrotropic agent (niacinamide, pantolactone, or dimethylisosorbide). The mixture was vortexed for a few seconds to ensure uniform sample wetting. Then, maceration extraction was performed under stirring (400 rpm) at 30°C using a Buchi Syncore apparatus. Maceration was carried out for 2 hours. After centrifugation, the supernatants were collected and then filtered using 0.45 µm PTFE syringe filters.

[0110] 1.2 / Materials and methods for HPLC analyses The gigantol, coelonine, mangostine, and resveratrol standards were provided by Sigma Aldrich. The epsilon-viniferine standard was provided by Phytolab. The acetylshikonin and deoxyshikonin standards were provided by ChemFaces.

[0111] HPLC analyses were performed on an Agilent 1260 system equipped with a low-pressure quaternary pump, an automatic injector, a column oven, a DAD detector, and an ELSD detector. Chromatographic separation was performed on a Kinetex C18 100 x 3 mm x 2.6 pm column heated to 35°C in gradient mode with an injection volume of 1 pL and a flow rate of 0.4 mL / min. Mobile phase A consisted of a 95 / 5 H₂O / acetonitrile mixture acidified with 0.1% formic acid. Mobile phase B consisted of acetonitrile acidified with 0.1% formic acid. The samples were analyzed three times.

[0112] 1.2.1. / Quantification of stilbenoids Resveratrol and viniferin were quantified in pure liquid extracts of dried Vitis vinifera vine shoots. The HPLC conditions are given in Table 2.

[0113] [Tables2] Time (min) A (%) B (%) 0.00 100.0 0.0 1.00 100.0 0.0 20.00 52.6 47.4 21.00 5.3 94.7 25.00 5.3 94.7 26.00 100.0 0.0 Detection was performed on the UV signal obtained at 280 nm from the different standards. The quantification of each compound was obtained from the areas of the detected peaks analyzed on calibration curves from 25 to 200 pg / mL.

[0114] 1.2.2 / Quantification of mangostine Mangostin was quantified by HPLC-DAD in liquid extracts of dried mangosteen fruit peels replenished at 10% in ultrapure water. The HPLC conditions are given in Table 3.

[0115] [Tableaux3] Time (min) A (%) B (%) 0.00 100.0 0.0 1.00 100.0 0.0 10.00 76.3 23.7 12.00 5.3 94.7 25.00 5.3 94.7 26.00 100.0 0.0 Detection was performed on the signal obtained in UV at 280 nm from the mangostine standard. Quantification was obtained from the area of ​​the detected peak, analyzed on the calibration curve from 25 to 200 pg / mL.

[0116] 1.2.3 / Quantification of hydroxynaphthoquinones Acetylshikonin and deoxyshikonin were quantified by HPLC-DAD in pure liquid extracts of dried Alkanna tinctoria roots. The HPLC conditions are given in Table 4.

[0117] [Tables4] Time (min) A (%) B (%) 0.00 70.0 30.0 5.00 70.0 30.0 12.00 5.3 94.7 20.00 5.3 94.7 21.00 70.0 30.0 The detection was performed on the signal obtained in UV at 520 nm from the different standards. The quantification of each compound was obtained from the areas of the detected peaks. exploited on calibration curves from 25 to 200 pg / mL.

[0118] 1.3 / Materials and methods for statistical analyses Statistical analyses and plots (boxplots and barplots) were performed using RStudio with the "agricolae" and "ggplot2" packages. A difference was considered significant when samples did not have the same letter. If two different samples had the same letter, the difference was not significant. Data were expressed as mg of metabolite / g of dry plant material, n=3, p<0.0001. HSD Turkey.

[0119] 2 / Results of measurement of the metabolite content measured in the extracts The extraction of resveratrol and viniferin from vine shoots is significantly improved by the presence of niacinamide, dimethylisosorbide, or pantolactone compared to 35% ethanol. Dimethylisosorbide and pantolactone extract viniferin similarly. Water does not allow the extraction of stilbenoids from Vitis vinifera (values ​​below the limit of detection).

[0121] The results concerning resveratrol are shown in the graph in [Fig. 1], and the results relating to viniferine are shown in the graph in [Fig. 2]. The following is the legend for these two figures. H2O = Aqueous extract of Vitis vinifera; EtOH35= Hydroalcoholic extract of Vitis vinifera obtained with 35% ethanol; N35= Aqueous extract of Vitis vinifera obtained with 35% niacinamide; D35= Aqueous extract of Vitis vinifera obtained with 35% dimethylisosorbide; P35= Aqueous extract of Vitis vinifera obtained with 35% pantolactone. Maceration 2h, 30°C, 400 rpm.

[0122] 2.2 / Fruit peel of Garcinia mangostana (Mangosteen) Niacinamide, dimethylisosorbide, and pantolactone allow for significantly greater extraction of mangostin from mangosteen compared to 35% ethanol. Water does not allow for the extraction of mangostin from mangosteen (value below the detection limit).

[0123] Figure 3 is a graph representing the results of measurements of the mangostin content measured in the peel of the mangosteen fruit. The legend is as follows: H2O = Aqueous extract of Garcinia mangostana; EtOH35= Hydroalcoholic extract of Garcinia mangostana obtained with 35% ethanol; N35= Aqueous extract of Garcinia mangostana obtained with 35% niacinamide; D35= Aqueous extract of Garcinia mangostana obtained with 35% dimethylisosorbide; P35 = Aqueous extract of Garcinia mangostana obtained with 35% pantolactone. Maceration 2h, 30°C, 400 rpm.

[0124] 2.3 / Roots of Alkanna tinctoria The extraction of hydroxynaphthoquinones from alkanna roots is significantly improved by the presence of niacinamide or pantolactone compared to 35% ethanol. Dimethylisosorbide and 35% ethanol extract hydroxynaphthoquinones similarly but in very small quantities (values ​​below the limit of quantification). Water does not extract acetylshikonin or deoxyshikonin (values ​​below the limit of detection).

[0125] The results concerning Acetylshikonin are shown in the graph in [Fig. 4], and the results relating to Deoxyshikonin are shown in the graph in [Fig. 5]. The following is the legend for these two figures: H2O = Aqueous extract of Alkanna tinctoria; EtOH35 = Hydroalcoholic extract of Alkanna tinctoria obtained with 35% ethanol; N35 = Aqueous extract of Alkanna tinctoria obtained with 35% niacinamide; D35 = Aqueous extract of Alkanna tinctoria obtained with 35% dimethylisosorbide; P35 = Aqueous extract of Alkanna tinctoria obtained with 35% pantolactone. Maceration 2h, 30°C, 400 rpm.

[0126] 3. Conclusion The results demonstrate the effectiveness of three cosmetic ingredients with a hydrotropic function in obtaining plant extracts containing targeted metabolites, with the following observations:

[0127] • Niacinamide significantly improves the extraction of all the metabolites compared to water alone and 35% ethanol. • Niacinamide has proven to be the best for the extraction of hydroxynaphthoquinones. • Pantolactone has proven to be the most effective for extracting mangostine. • Dimethylisosorbide improves the extraction of stilbenoids as well as that of mangostine compared to water alone and to a mixture of water and 35% ethanol.

[0128] EXAMPLE 2: Biological activity of extracts of the invention and comparison with extracts of the prior art The liquid extracts obtained in Example 1 were tested in-tubo on the xanthine oxidase model to evaluate their inhibitory activity against this enzyme. 1 / Materials and methods for in-tubule analyses

[0129] In this test, xanthine oxidase is an enzyme that catalyzes the oxidation of purine bases (hypoxanthine or xanthine) to uric acid and superoxide ions. The superoxide ion spontaneously degrades to hydrogen peroxide (H₂O₂), which, in the presence of horseradish peroxidase (HRP), reacts stoichiometrically with Amplex Red reagent to generate a red-fluorescent oxidation product: resorufin. The intensity of resorufin is monitored by spectrophotometry at λ = 570 nm. Inhibition of the enzyme results in a decrease in color and therefore in absorbance.

[0130] The different samples were reconstituted at 1% in UltraPure water and tested in triplicate. Three controls were carried out to validate the test: a control without enzyme, a positive control (with catechin as an inhibitor) and a 100% control (where 100% (of the reaction occurs). The percentage of xanthine oxidase inhibition was calculated as follows:

[0131] [Math.l] . ~ ~ ((Absàrbanœ extract-Absorbent white «xtraih * 1001 100 ™ ---------------------------------------------i. (Ass»»» T100¾ “Abs® osnœ m&nc)

[0132] This test was performed following the protocol provided by the Amplex Red Xanthine / Xanthine Oxidase Assay Kit (A22182) from Molecular Probes - Invitrogen Detection Technologies. The proportions were optimized so that the reaction would complete in 30 minutes: Blank (control without enzyme) = 200pL of distilled water + 25 pL of reaction mix T100% = 100 pL of enzyme + 100 pL of distilled water + 25 pL of reaction mix Blank sample = 100pL of water + 100pL of sample + 25 pL of reaction mix Sample = 100pL of enzyme + 100pL of sample + 25 pL of reaction mix Positive control (inhibitor) = 100pL of enzyme + 100pL of 0.1% catechin + 25 pL of reaction mix. 2 / Result

[0133] 2.1 / Vitis vinifera shoots Liquid extracts of dry Vitis vinifera shoots obtained with 35% niacinamide, 35% dimethylisosorbide or 35% pantolactone have a synergistic and significant positive effect on the inhibition of xanthine oxidase (*observed in-tubo) compared to aqueous extract of Vitis vinifera.

[0134] The results are presented in [Fig. 6], [Fig. 7] and [Fig. 8] in the form of a graph representing the measurement of the inhibitory effect of xanthine oxidase by liquid extracts of Vitis vinifera at 1% in water. The legends are as follows: [Fig. 6] SH2O = Aqueous extract of Vitis vinifera; N35 = Niacinamide at 35% in water; N35_SH2O = sum of the % inhibition of the aqueous extract of Vitis vinifera and of niacinamide at 35% in water; SN35= Aqueous extract of Vitis vinifera obtained using 35% niacinamide; [Fig.7] D35 = Dimethylisosorbide at 35% in water; D35_SH2O = sum of the % inhibition of the aqueous extract of Vitis vinifera and of dimethylisosorbide at 35% in water; SD35= Aqueous extract of Vitis vinifera obtained using 35% dimethylisosorbide; [Fig.8] P35 = Pantolactone at 35% in water; P35_SH2O = sum of the % inhibition of the aqueous extract of Vitis vinifera and of pantolactone at 35% in water; SP35= Aqueous extract of Vitis vinifera obtained using 35% pantolactone.

[0135] 2.2 / Fruit peels of Garcinia mangostana (Mangosteen) Liquid extracts of dried mangosteen bark obtained with 35% niacinamide, 35% dimethylisosorbide or 35% pantolactone have a synergistic and significant positive effect on the inhibition of xanthine oxidase (*observed in-tubo) compared to aqueous mangosteen extract.

[0136] The results are presented in [Fig. 9], [Fig. 10], and [Fig. 11] in the form of a graph representing the measurement of the inhibitory effect of xanthine oxidase by liquid extracts of Garcinia mangostana at 1% in water. The legends are as follows:

[0137] [Fig.9] MH20 = Aqueous extract of Garcinia mangostana; N35 = Niacinamide at 35% in water; N35_MH2O = sum of the % inhibition of the aqueous extract of Garcinia mangostana and niacinamide at 35% in water; MN35 = Aqueous extract of Garcinia mangostana obtained using 35% niacinamide;

[0138] [Fig. 10] MH20 = Aqueous extract of Garcinia mangostana; D35 = Dimethylisosorbide at 35% in water; D35_MH2O = sum of the % inhibition of the aqueous extract of Garcinia mangostana and of dimethylisosorbide at 35% in water; MD35= Aqueous extract of Garcinia mangostana obtained using 35% dimethylisosorbide; [Fig.11] MH20 = Aqueous extract of Garcinia mangostana; P35 = Pantolactone at 35% in water; P35_MH2O = sum of the % inhibition of the aqueous extract of Garcinia mangostana and of pantolactone at 35% in water; MP35= Aqueous extract of Garcinia mangostana obtained using 35% pantolactone.

[0139] 2.3 / Roots of Alkanna tinctoria Liquid extracts of dried Alkanna tinctoria roots obtained with 35% niacinamide, 35% dimethylisosorbide or 35% pantolactone have a synergistic and significant positive effect on the inhibition of xanthine oxidase (*observed in-tubo) compared to the aqueous extract of Alkanna tinctoria.

[0140] The results are presented in [Fig. 12], [Fig. 13], and [Fig. 14] as a graph representing the measurement of the inhibitory effect of xanthine oxidase by liquid extracts of Alkanna tinctoria at 1% in water. The following are the key symbols:

[0141] [Fig. 12] AH 20 = Aqueous extract of Alkanna tinctoria; N35 = Niacinamide at 35% in water; N35_AH2O = sum of the % inhibition of the aqueous extract of Alkanna tinctoria and of niacinamide at 35% in water; AN35 = Aqueous extract of Alkanna tinctoria obtained using 35% niacinamide;

[0142] [Fig. 13] AH 20 = Aqueous extract of Alkanna tinctoria. D35 = Dimethylisosorbide at 35% in water; D35_AH2O= sum of the % inhibition of the aqueous extract of Alkanna tinctoria and dimethylisosorbide at 35% in water; AD35= Aqueous extract of Alkanna tinctoria obtained using 35% dimethylisosorbide;

[0143] [Fig. 14] AH 20 = Aqueous extract of Alkanna tinctoria; P35 = Pantolactone at 35% in water; P35_AH2O= sum of the % inhibition of the aqueous extract of Alkanna tinctoria and pantolactone at 35% in water; AP35 = Aqueous extract of Alkanna tinctoria obtained using 35% pantolactone

[0144] 3. Conclusion: Extracts prepared with cosmetic ingredients at a concentration sufficient to exert a hydrotropic effect resulted in significantly greater inhibition of xanthine oxidase compared to their respective aqueous extracts. Furthermore, a notable synergistic effect between the cosmetic ingredient used and the resulting extract was observed, surpassing the sum of the effects observed with the aqueous extract and an aqueous solution containing 35% by mass of the cosmetic ingredient.

Claims

Demands

1. A plant extraction process in aqueous medium of at least one metabolite contained in a plant selected from plants of the genera Vitis sp., Alkanna sp. and Garcinia sp., said process comprising: i) a step of preparing an extraction solution comprising or being essentially composed of water and at least one cosmetic ingredient in a concentration selected to exert a hydrotropic function, ii) a step of introducing at least a part of the plant into the extraction solution, iii) a step of extracting the metabolite, iv) a step of recovering an aqueous solution containing the metabolite and the cosmetic ingredient.

2. Aqueous extraction process according to claim 1, characterized in that the cosmetic ingredient is selected from pantolactone and niacinamide.

3. Aqueous extraction process according to claim 1 or 2, characterized in that the plant is selected from the species Vitis vinifera and Alkanna tinctoria.

4. Aqueous extraction process according to any one of the preceding claims, characterized in that the extraction step is carried out by maceration at a temperature between 20°C and 40°C and for a duration between 30 minutes and 3 hours.

5. A plant extraction process in aqueous medium of at least one metabolite selected from stilbenoids, xanthones and hydroxynaphthoquinones, said process comprising: i) a step of preparing an extraction solution comprising or being substantially composed of water and at least one cosmetic ingredient in a concentration selected to exert a hydrotropic function, ii) a step of introducing at least a part of the plant into the extraction solution, iii) a step of extracting the metabolite, and iv) a step of recovering an aqueous solution containing the metabolite and the cosmetic ingredient.

6. Aqueous extraction process according to claim 5, characterized in that the metabolite is selected from resveratrol, epsilon-viniferine, coelonine, methoxycoelonine, gigantol, mangostine, acetylshikonin and deoxyshikonin.

7. Aqueous extraction process according to claim 5 or 6, characterized in that the cosmetic ingredient is selected from pantolactone and dimethylisosorbide.

8. Use of pantolactone as a co-solvent in a plant extraction process in aqueous medium.

9. Use of niacinamide as a co-solvent in an aqueous plant extraction process of a metabolite selected from xanthones and hydroxynaphthoquinones.

10. Use of dimethylisosorbide as a co-solvent in an aqueous plant extraction process of a metabolite selected from stilbenoids, xanthones and hydroxynaphthoquinones.

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