USE OF WATER-SOLUBLE LIGNIN AS A UV FILTER

Abstract

USE OF WATER-SOLUBLE LIGNIN AS A UV FILTER The present invention relates to the use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as a UV filter. It also relates to a cosmetic composition comprising such lignin. Figure for the abstract: none

Description

Title of the invention: USE OF WATER-SOLUBLE LIGNIN AS A UV FILTER

[0001] The present invention relates to the use of a water-soluble lignin obtained by enzymatic treatment, in particular with at least one bilirubin oxidase enzyme, as a UV filter. It also relates to a cosmetic composition comprising such a lignin.

[0002] Sun protection is a major issue in the cosmetics field. In particular, among the various chemical or organic filters used, the stability of these products is an imperative to respect in order to preserve their effectiveness and safety.

[0003] By way of illustration, a very recent study published in Chemical Research in Toxicology (Downs et al., Benzophenone Accumulates over Time from the Degradation of Octocrylene in Commercial Sunscreen Products, 2021, 34, 4, 1046-1054) suggests a harmful effect of octocrylene during its aging, which had not been highlighted until now. This study shows that over time, octocrylene transforms into benzophenone, a compound which the authors explain is genotoxic, carcinogenic, and an endocrine disruptor.

[0004] There is therefore a real need to replace this type of chemical anti-UV filters, or at least to reduce their quantity in cosmetic products.

[0005] Lignin is a natural polymer available in large quantities, particularly from pulp and paper mills. Unlike polysaccharides, this phenolic polymer has seen little industrial development outside of lignosulfonate applications and energy recovery. However, lignin has numerous potential applications. Commercially available lignins are primarily soluble in organic solvents or highly concentrated alkaline aqueous solutions (pH >10). Some lignins are chemically modified and functionalized to produce lignosulfonates that are soluble in aqueous solvents with neutral, acidic, or slightly basic pH, but they still contain numerous impurities.

[0006] US patent 10,729,624 describes the use of mixed microcapsules based on lignins soluble in organic solvents and chemical filters as UV filters. The lignin present in a solvent is dissolved in an aqueous solution with a pH of 12, then adjusted to a pH of 7-10. The fact that this lignin is soluble only in an organic medium (lipid-soluble) severely limits the amount that can be incorporated into sunscreens and makes their formulation more difficult. Indeed, the vast majority of sun protection products are direct oil-in-water emulsions. (H / E) in which the dispersed phase (oily phase) is in the minority.

[0007] However, there is no usable lignin as such, soluble in an aqueous medium of neutral pH, which is effective in protecting surfaces (for example keratinous materials such as skin but also surface coating supports) from UV, in particular UVA and / or UVB.

[0008] The present invention addresses this problem.

[0009] Surprisingly, as shown in the examples, the inventors demonstrate that the water-soluble lignin according to the invention, soluble in water at a pH between 5 and 10, and solubilized in the continuous aqueous phase, clearly improves UV protection performance compared to a commercially available, fat-soluble lignin: this water-soluble lignin offers greater UVB protection (SPF) and also greater UVA absorbance. Furthermore, its water-soluble nature allows for the use of this lignin in larger quantities without compromising the stability of the formula. The UV-protective agents are then better distributed on the keratinous materials after they have been spread. Finally, this lignin is bio-based and offers a distinct advantage over conventional petroleum-based chemical UV filters.

[0010] The present invention therefore relates to the use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as a UV filter. Preferably, the enzymatic treatment is carried out with at least one bilirubin oxidase enzyme.

[0011] Water-soluble lignin obtained by enzymatic treatment, preferably with less an enzyme bilirubin oxidase, is referred to as "lignin according to the invention" or "water-soluble lignin according to the invention" in the present application.

[0012]

[0013] The present invention also relates to a cosmetic composition comprising:

[0014] an aqueous phase comprising at least one water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, and

[0015] an oily phase and / or at least one hydrophilic thickening polymer selected from cellulose and its derivatives, natural gums, scleroglucans, chitin and chitosan derivatives, carrageenans and gellans.

[0016] Preferably, the composition according to the invention is substantially free of microcapsules. By "substantially free" is meant that the composition comprises less than 1% by weight relative to the total weight of the composition, preferably less than 0.5% by weight, preferably less than 0.3% by weight, preferably less than 0.1% by weight of microcapsules. Preferably, the composition according to the invention is completely free of microcapsules.

[0017] The present invention also relates to a non-therapeutic cosmetic process for the care of keratinous materials, preferably the skin, comprising the application to said keratinous materials, preferably the skin, of a cosmetic composition as described above. WATER-SOLUBLE LIGNIN ACCORDING TO THE INVENTION

[0018] The water-soluble lignin according to the invention is obtained by enzymatic treatment. This enzymatic modification is specific. Indeed, the lignin obtained differs from soluble lignin obtained chemically by the low presence or absence of impurities from chemical synthesis and, in particular, the absence of sulfate or sulfonate groups. Preferably, the enzymatic treatment is carried out with at least one bilirubin oxidase enzyme.

[0019] The lignin according to the invention is water-soluble. By "water-soluble," it is understood that the lignin according to the invention is soluble in an aqueous solution, preferably in water, at a concentration of up to 90% by weight relative to the total weight of the solution. The solubility of the lignin is assessed at room temperature, preferably in an aqueous solution, typically water, by microscopy and by spontaneous redissolution of the lyophilized lignin in an aqueous solvent. No precipitate is observed.

[0020] Furthermore, the water-soluble lignin according to the invention is soluble in water at a pH between 5 and 10, preferably between 6 and 8.

[0021] Preferably, the water-soluble lignin according to the invention is obtained by a process comprising the following steps:

[0022] a- mixture of lignin with water preferably comprising a buffering agent,

[0023] b- preferably, ultrasonic treatment of the mixture obtained at the end of step a,

[0024] c- enzymatic treatment of the lignin obtained in a or b, with at least one bilirubin oxidase enzyme, in the presence or absence of a redox mediator, to obtain a lignin soluble in aqueous medium with a pH greater than or equal to 5 and less than or equal to 10, preferably between 6 and 8, and

[0025] d- separation of water-soluble lignin from the salts of the mixture and any insoluble compounds obtained in c, preferably by dialysis or centrifugation.

[0026] Typically, a process for obtaining water-soluble lignin according to the invention comprises the solubilization of lignin in a solution comprising water, and preferably also a buffering agent (step a). According to a preferred embodiment, the solubilization of lignin takes place in water as the sole solvent, and preferably with a buffering agent.

[0027] According to one embodiment, the lignin is of the kraft type (or alkaline lignin). Kraft lignin is referred to as lignin obtained by a kraft process (also known as "kraft pulping" or sulfate process), which is a process of converting wood into Paper pulp. The kraft process involves treating wood chips with a hot mixture of water, sodium hydroxide, and sodium sulfide, breaking down the wood fibers and separating the lignin and hemicellulose from the cellulose. This technique includes mechanical and chemical steps, notably impregnation and heating.

[0028] According to one embodiment, the lignin is of the organosolv type.

[0029] For example, a buffering agent is chosen from a borate buffer, a sodium phosphate buffer or any other buffer that allows a neutral to basic pH to be maintained.

[0030] The lignin dispersed in the solution preferably undergoes ultrasonic treatment (step b), so as to fragment the material into small particles which can react better with the enzymes.

[0031] Next, the enzymatic treatment of the lignin is carried out (step c). This enzymatic treatment of the lignin according to the invention comprises contacting the aqueous solution of dispersed lignin with at least one bilirubin oxidase (BOD) enzyme, in the presence or absence of a redox mediator, and obtaining lignin soluble in a medium with a pH greater than or equal to 6, preferably greater than or equal to 7. Indeed, enzymes of the bilirubin oxidase type, which are stable and active in acidic media as well as in neutral and basic media, make it possible to modify the lignin so as to render it soluble at neutral or basic pH (i.e., pH 5 to 10). Moreover, these bilirubin oxidases are more active and more stable than laccases at higher temperatures (up to 70°C).

[0032] According to one embodiment, bilirubin oxidase (BOD) is of fungal origin. In one embodiment, the BOD used in the context of the present invention is a BOD described in international application WO 2012 / 160517 (BOD EC 1.3.3.5. of Magnaporthe oryzae origin).

[0033] According to another variant, the BOD is of bacterial origin. According to one embodiment, the BOD used in the context of the present invention is a BOD described in international application WO 2011 / 117839 (BOD EC 1.3.3.5. of Bacillus pumilus origin).

[0034] Typically, bilirubin oxidase is added to an aqueous solution (preferably with a buffering agent) containing lignin, in the presence or absence of a redox mediator, and then placed under conditions that allow its enzymatic action on the lignin to solubilize it. Typically, bilirubin oxidase is incubated between 20°C and 80°C, preferably with stirring and oxygenation. Typically, the enzymatic action takes place over 2 to 48 hours, preferably over 10 to 24 hours.

[0035] Examples of redox mediators include 2,2-azino-bis-[3-ethylbenzthiazoline-6-sulfonic acid] (ABTS) and 2,6-dimethoxyphenol (2,6-DMP), Syringaldazine, conjugated or unconjugated bilirubin, or osmium compounds.

[0036] The lignin obtained after enzymatic treatment in aqueous solvent is separated from the salts and any insoluble compounds, for example by dialysis or centrifugation (step d).

[0037] According to a preferred embodiment, the insolubles are separated from the water-soluble lignin, for example by centrifugation. The water-soluble lignin is present in the supernatant when centrifugation is used.

[0038] According to one embodiment, the water-soluble lignin is lyophilized.

[0039] The water-soluble lignin according to the invention is soluble in water at a pH greater than or equal to 5, preferably greater than or equal to 6, preferably greater than or equal to 7, and less than 10, preferably less than 9, preferably less than 8.

[0040] Preferably, lignin is soluble over a pH range of 6 to 8.

[0041] According to a preferred embodiment, the water-soluble lignin according to the present invention comprises no or few sulfonate groups. By "few sulfonate groups" is meant a maximum mass content of 1% by weight of sulfonate groups relative to the total weight of lignin. USE OF LIGNIN AS A UV FILTER

[0042] The present invention relates to the use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as a UV filter. The present invention also relates to the use of a composition comprising an aqueous phase, said aqueous phase comprising a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as a UV filter. Preferably, the enzymatic treatment is carried out with at least one bilirubin oxidase enzyme.

[0043] Indeed, preferably, the water-soluble lignin according to the invention is solubilized in the aqueous phase of a composition.

[0044] This use is applicable in the cosmetics field, particularly for formulating sunscreens but also makeup or skincare compositions; and in other fields. For example, the lignin according to the invention can be used in various materials, in a paint or varnish composition, in a pesticide composition, in textiles, in concrete or cement compositions, in food films, or various coatings or substrates. Indeed, when incorporated into a composition, material, coating, or substrate, it provides, after application or use, anti-UV properties to said composition, material, coating, or substrate.

[0045] Preferably, the present invention relates to the use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as an anti-UV filter in cosmetic compositions, for example makeup or skincare compositions.

[0046] Preferably, the present invention also relates to the use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as an anti-UV filter in a paint or varnish composition, in a pesticide composition, in textiles, in concrete or cement compositions, in food films or in various coatings or substrates. COSMETIC COMPOSITION

[0047] The cosmetic composition according to the invention comprises at least one aqueous phase comprising at least one water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10. Preferably, the enzymatic treatment is carried out with at least one bilirubin oxidase enzyme.

[0048] Preferably, this composition comprises an aqueous phase in which the water-soluble lignin according to the invention is solubilized, and an oily phase.

[0049] In this case, typically, the composition according to the invention is an emulsion. Preferably, the oily phase is dispersed in the aqueous phase, resulting in a direct emulsion (oil-in-water or O / W). The aqueous phase can also be dispersed in the oily phase, resulting in a reverse emulsion (water-in-oil or W / O).

[0050] The cosmetic composition according to the invention may also include a thickening polymer, to obtain a gelled composition, for example a gel. Aqueous phase

[0051] The aqueous phase according to the invention comprises at least water and the water-soluble lignin according to the invention. The water-soluble lignin according to the invention is solubilized in water.

[0052] Preferably, the composition according to the invention comprises at least 50% by weight of water relative to the total weight of composition, preferably at least 60% by weight, preferably at least 70% by weight.

[0053] Preferably, the composition according to the invention comprises from 50% to 99% by weight of water relative to the total weight of composition, preferably from 65% to 95% by weight, preferably from 70% to 90% by weight.

[0054] The aqueous phase may also include at least one additive selected from preservatives and humectants. Typically, the preservative may be selected from parabens and benzyl alcohol. Typically, the humectant may be selected from polyols, preferably glycerin or sorbitol.

[0055] Preferably, the composition according to the invention comprises from 55% to 95% by weight of aqueous phase relative to the total weight of composition, preferably from 65% to 90% by weight, preferably from 75% to 90% by weight.

[0056] Preferably, if the composition according to the invention is in the form of an inverse emulsion, it comprises from 1% to 50% by weight of water relative to the total weight of the composition, preferably from 5% to 45% by weight. Water-soluble lignin according to the invention

[0057] The aqueous phase comprises at least one water-soluble lignin according to the invention.

[0058] The water-soluble lignin according to the invention is as defined above.

[0059] Preferably, the composition according to the invention comprises at least 1% by weight of water-soluble lignin according to the invention relative to the total weight of composition, preferably at least 1.5% by weight, preferably at least 2% by weight.

[0060] Preferably, the composition according to the invention comprises from 1% to 30% by weight of water-soluble lignin according to the invention relative to the total weight of the composition, preferably from 1.5% to 25% by weight, preferably from 2% to 20% by weight. Hydrophilic thickening polymer

[0061] The aqueous phase according to the invention may comprise at least one hydrophilic thickening polymer selected from cellulose and its derivatives, natural gums, scleroglucans, chitin and chitosan derivatives, carrageenans and gellans.

[0062] By hydrophilic thickening polymer, we mean a thickening polymer that is soluble or dispersible in water.

[0063] Said hydrophilic thickening polymer is preferably selected from:

[0064] - cellulose and its derivatives, such as carboxymethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose or hydroxypropylmethylcellulose;

[0065] - natural gums, such as xanthan gum, guar gum, the gum arabic or carob gum;

[0066] - scleroglucans;

[0067] - chitin and chitosan derivatives;

[0068] - carrageenans; and

[0069] - the gellanes.

[0070] As an additional feature, the composition according to the invention may include, in addition to the above thickener, an additional carbomer-type thickener.

[0071] Preferably, the composition according to the invention comprises an aqueous phase in which the water-soluble lignin according to the invention is solubilized, and at least one hydrophilic thickening polymer selected from cellulose and its derivatives, natural gums, scleroglucans, chitin and chitosan derivatives, carrageenans and gellans.

[0072] Such a composition is an aqueous gel.

[0073] Preferably, the hydrophilic thickening polymer is present in an amount ranging from 0.1% to 5% by weight relative to the total weight of composition, preferably from 0.2% to 3% by weight. Oily phase

[0074] The composition according to the invention may include an oily phase. The oily phase comprises at least one lipophilic compound (i.e., not soluble in water), preferably selected from oils, waxes, butters and mixtures thereof.

[0075] By "oil" is meant a lipophilic compound that is liquid at room temperature.

[0076] By "wax" is meant a lipophilic compound that is solid at room temperature.

[0077] By "butter" is meant a semi-liquid or semi-solid lipophilic compound at ambient temperature.

[0078] Oils, waxes and butters are well known from the prior art. By way of non-limiting examples, one may mention in particular vegetable oils, lanolin, dicaprylyl carbonate, butters of vegetable origin such as shea butter or cocoa butter, or waxes of vegetable or animal origin, such as for example beeswax.

[0079] Preferably, the composition according to the invention comprises from 5% to 50% by weight of oily phase relative to the total weight of composition, preferably from 10% to 40% by weight, preferably from 15% to 30% by weight.

[0080] Preferably, if the composition according to the invention is in the form of an inverse emulsion, it comprises from 50% to 95% by weight of oily phase relative to the total weight of composition.

[0081] Such an emulsion composition may also comprise at least one surfactant, at least one lipophilic UV filter, and / or at least one colorant. Surfactant

[0082] The composition according to the invention may comprise at least one surfactant. Preferably, the surfactant is chosen from anionic surfactants, non-ionic surfactants, amphoteric surfactants and mixtures thereof.

[0083] Preferably, the composition according to the invention comprises at least one non-ionic surfactant. Lipophilic UV filter

[0084] The composition according to the invention may include at least one lipophilic UV filter. Said filter is solubilized in the oil phase.

[0085] Preferably, said UV filter is chosen from mineral UV filters, organic UV filters and mixtures thereof.

[0086] Examples of mineral UV filters include titanium dioxide (TiO2), zinc oxide, or mixtures thereof. The mineral UV filter can be functionalized by surface treatment, for example with a surfactant or a metal oxide (particularly silica or alumina), to give it different properties.

[0087] As an organic UV filter, any authorized organic UV filter may be cited. Preferably, the organic UV filters usable according to the present invention are chosen from among benzylidene camphor derivatives, benzophenone derivatives, para-aminobenzoic acid and its derivatives, triazine derivatives, dibenzoylmethane derivatives, salicylic derivatives, cinnamic derivatives, [3,[3-diphenylacrylate] derivatives, phenyl benzimidazole derivatives, phenyl ben-zotriazole derivatives and benzalmalonate derivatives.

[0088] Preferably, the organic UV filter is selected from camphor benzalkonium methosulfate, ethylhexyl methoxycinnamate, homosalate, para-aminobenzoic acid, isoamyl p-methoxycinnamate, PEG-25 PABA, ethylhexyl dimethyl PABA (or padimate O), octocrylene, anisotriazine, polysilicone-15, drometrizole trisiloxane, oxybenzone (or benzophenone-3), terephthalylidene diacmphre sulfonic acid (or ecamsule), benzylidene diacmphre sulfonic acid, polyacrylamidomethyl benzylidene diacmphre, octyl triazone (or ethylhexyl triazone), butyl methoxydibenzoylmethane (BMDBM or avobenzone), 4-methylbenzylidene camphor, diethylhexyl butamido triazone, diethylamino hydroxybenzoyl hexyl benzoate, phenyl salicylate, ethylhexyl salicylate, disodium phenyl dibenzimidazole tetrasulfonate, methylene bis-benzotriazolyl tetramethylbutylphenol, phenylbenzimidazole sulfonic acid (or ensulizole),benzophenone-4 or 5 and bis-ethylhexyloxyphenol methoxyphenyl triazine. ,

[0089] Preferably, the composition according to the invention comprises at least one lipophilic UV filter selected from organic UV filters. Preferably, the composition according to the invention comprises at least one lipophilic UV filter selected from mineral UV filters, preferably TiO2.

[0090] Without wishing to be bound by any theory, as shown in examples, the water-soluble lignin according to the invention presents a synergistic effect with a mineral anti-UV filter of the TiO2 type.

[0091] Preferably, regardless of the nature of the composition, the UV filter(s) is / are present in an amount ranging from 1% to 20% by weight relative to the total weight of the composition, preferably from 2% to 15% by weight, preferably from 5% to 12% by weight. Coloring agent

[0092] The composition according to the invention may include at least one coloring material.

[0093] Preferably, the colouring material is chosen from pigments, nacres and liposoluble dyes.

[0094] The pigments are preferably chosen from zirconium or cerium oxides, iron or chromium oxides, in particular red iron oxide, yellow iron oxide, brown iron oxide, black iron oxide, manganese violet, ultramarine blue, curcumin, beta-carotene, chlorophyll, chromium hydrate and ferric blue, and mixtures thereof.

[0095] The nacres are preferably chosen from borosilicates or mica, natural or synthetic, and optionally coated with titanium oxide (TiO2), iron oxide (Fe2O3) (red, yellow or black), chromium oxide (Cr2O3) or a mixture of these oxides.

[0096] Liposoluble dyes are preferably chosen from quinolines, anthraquinones, triarylmethanes, xanthenes, cyanines, phthalocyanines, nitroso, azo and indigoid dyes.

[0097] The invention is now illustrated by the following examples.

[0098] In the examples, all percentages are given by weight relative to the total weight of composition, unless otherwise stated; the temperature is ambient (20-25°C) and expressed in degrees Celsius unless otherwise stated, the pressure is atmospheric pressure (101325 Pa), unless otherwise stated. Examples

[0099] Example 1 - Preparation of water-soluble lignin according to the invention

[0100] The process is described in application WO2019 / 076893:

[0101] 2g of kraft lignin, purchased from Sigma-Aldrich under reference (370959) are taken up in 100mL of 50mM Borate pH9 buffer (step a).

[0102] 5.2 mg of Bacillus pumilus BOD are then added to this solution, then this The final stage is placed at 60°C under stirring with a magnetic stir bar at 100 rpm and bubbling with compressed air at 0.1 L / min*, for 16 hours (step c). The solution is then dialyzed in a 100 mL dialysis drum of 10 kDa, in three 4 L baths of mQ water, the first for 2 hours, the second for 4 hours, and the third overnight (step d). The solution is centrifuged for 5 minutes at 1500 rpm.

[0103] The supernatant containing the water-soluble lignin according to the invention is lyophilized overnight and stored at room temperature.

[0104] Example 2 - Evaluation of the anti-UV properties of water-soluble lignin according to the invention

[0105] A reference sunscreen (P2) used for calibrating in vivo tests for measuring sun protection factors (SPF) is used here as a formula base to test the effectiveness of lignin (see table 1). Composition of the reference sunscreen P2

[0106] [Tables 1] Ingredients Quantities (%) Aqueous phase Water Sorbitol Triethanolamine Methylparaben Propylparaben Benzyl alcohol Qsp 100 5 1 0.3 0.1 0.5 Oily phase Lanolin Cocoa butter Glyceryl stearate SE Stearic acid Para-aminobenzoic acid Oxybenzone 4.5 2 3 2 7 3

[0107] 2% or 4% by weight of the water-soluble lignin according to the invention, relative to the weight of total composition, are incorporated into the continuous aqueous phase of P2.

[0108] Separately, 2% or 4% by weight of a commercial lipophilic lignin (Kraft Lignin, Sigma Aldrich- ref 370959) are dissolved in the dispersed fatty phase of P2 in order to compare the two processes and the two types of lignin.

[0109] SPF measurements were carried out in vitro on these four creams with commercial lignin (Table 2) and water-soluble lignin of the invention (Table 3).

[0110] The SPF measurement is performed in vitro using molded PMMA substrates with a roughness of Ra~4pm (HelioScreen Labs, HELIOPLATE HD6). The different formulations are then spread onto these polymer supports according to the protocol of ISO 24443 (In vitro determination of UVA photoprotection). 1.3 mg / cm² of the product is deposited as uniform drops, distributed symmetrically on the substrate. Spreading is then carried out by small circular movements with the index finger for less than 30 seconds before horizontal back-and-forth movements. The samples are then placed in the dark and left to dry for 2 hours. Their transmittance is then measured using a spectrophotometer equipped with an integrating sphere. The SPF is finally calculated using the following equation: [YES] [Math.l] onr _ 1) • 7 ( 71 • ^ri vitro - Moo,™ , xzx L.„ £(2) . / (2) .7(2) .dÀ

[0112] with T(X) the transmittance at a wavelength X such that:

[0113] [Math.2] A(V) = -log(T(i))

[0114] with A(X) the absorbance of the sample, / (4) the irradiance of the UV source used in vivo and E( A ) the erythemal action spectrum.

[0115] Evaluation of the SPF for sunscreen P2 formulated with 2% and 4% by weight of commercial lipophilic lignin, respectively

[0116] [Tables2] P2 P2 with 2% by weight of commercial lignin P2 with 4% by weight of commercial lignin Average final mass (mg) 7.2 7.1 7.6 Average SPF 20.9 + / - 2.9 19.2 + / - 2.2 24.2 + / - 2.3

[0117] Evaluation of the SPF for the P2 sunscreen formulated with 2% and 4% by weight of water-soluble lignin of the invention

[0118] [Tables3] P2 P2 with 2% by weight of water-soluble lignin P2 with 4% by weight of water-soluble lignin Average final mass (mg) 7.2 5.9 8.6 Average SPF 20.9 + / - 4.7 24.3 + / - 2.3 42.2 + / - 4.9

[0119] Table 3 shows that adding 4% by weight of water-soluble lignin according to the invention more than doubles the SPF value (20.9 to 42.2).

[0120] As these results show, the SPF increases more with the use of water-soluble lignin according to the invention in the continuous aqueous phase than with an addition of commercial lipophilic lignin in the dispersed oil phase, which underlines the interest of water-soluble lignin.

[0121] Comparison of transmittance spectra shows more generally the advantage of using water-soluble lignin, whose absorbance is significantly higher. carrying that commercial lignin in UVA.

[0122] Additional formulations of P2, comprising 3% by weight of TiO2 in place of the two organic filters (para-aminobenzoic acid and oxybenzone) of P2 (see Table 1), and 2%, 4%, 6% or 8% by weight of water-soluble lignin in the aqueous phase, have been prepared. They include the mineral filter of titanium dioxide (TiO2).

[0123] These formulations demonstrate the benefit of combining water-soluble lignin with other filters to improve the UV protection properties of sunscreens. The results obtained suggest a synergistic effect between mineral filters and water-soluble lignin. Indeed, a reference cream P2 containing only 3% by weight of TiO2 and 6% by weight of water-soluble lignin as filters achieves an in vitro SPF of over 34.

[0124] The water-soluble lignin according to the invention has several undeniable advantages, particularly compared to commercially available fat-soluble lignin: 1. In equal quantities in the formulas, it always provides a significantly higher SPF than commercial lignin; 2. The absorbance spectra of creams formulated with water-soluble lignin always show a higher absorbance across the entire UVB and UVA spectrum than those of creams formulated with commercial lignin; 3. The absorbance spectra of creams formulated with water-soluble lignin also show a different shape, with a much higher absorbance in the UVA range. The water-soluble lignin of the invention therefore offers better protection in the UVA range; 4. The use of water-soluble lignin facilitates the formulation of sunscreen compositions, as it allows for the incorporation of a higher quantity of lignin. In particular, it is possible to exceed 10% by weight, which seems impossible with commercially available fat-soluble lignin incorporated into the dispersed oil phase (because this leads to stability and texture problems); and 5. Incorporating water-soluble lignin into the continuous aqueous phase allows for better distribution of the filters, once the cream is spread on the skin and the volatile fraction has evaporated.

[0125] Example 3 - Comparison of the transmittance of water-soluble lignin according to the invention with a chemically treated water-soluble lignin

[0126] Composition P2 according to Table 1 of Example 2, without the two organic filters, was mixed with 4% by weight of water-soluble lignin according to the invention relative to the total weight of the composition. Said water-soluble lignin according to the invention was obtained according to Example 1. A composition according to the invention is thus obtained.

[0127] Composition P2 according to Table 1 of Example 2, without the two organic filters, was also mixed with 4% by weight relative to the total weight of water-soluble lignin composition obtained by chemical treatment. Said water-soluble lignin was obtained by a sulfite process. It comprises sulfonate groups. A comparative composition is thus obtained.

[0128] [Fig.1] Fig.1 illustrates the transmittance spectra obtained with composition P2 as such without the two organic filters (“P2 without filter”, comparative), the comparative composition with chemically treated lignin (“P2 without filter + 4% comparative sulfonated lignin”) and the composition according to the invention with enzymatically treated lignin (“P2 without filter + 4% lignin according to the invention”).

[0129] The results show that only the composition according to the invention has the lowest transmittance T and therefore a satisfactory absorbance A (A = -logi0 (T)) in both UVA and UVB.

[0130] Enzymatic treatment, unlike chemical treatment, thus brings unique properties of interest to water-soluble lignin.

Claims

Demands

1. Use of a water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, as a UV filter, the water-soluble lignin not comprising any sulfonate groups or comprising a maximum mass content of 1% by weight of sulfonate groups relative to the total weight of the water-soluble lignin.

2. Cosmetic composition comprising: an aqueous phase comprising at least one water-soluble lignin obtained by enzymatic treatment, said lignin being soluble in water at a pH between 5 and 10, the water-soluble lignin not comprising any sulfonate groups or comprising a maximum mass content of 1% by weight of sulfonate groups relative to the total weight of the water-soluble lignin, and an oily phase and / or at least one hydrophilic thickening polymer selected from cellulose and its derivatives, natural gums, scleroglucans, chitin and chitosan derivatives, carrageenans and gellans.

3. Use according to claim 1 or cosmetic composition according to claim 2, wherein the enzymatic treatment is carried out with at least one bilirubin oxidase enzyme.

4. Use according to claim 1 or 3, or cosmetic composition according to claim 2 or 3, wherein the water-soluble lignin is obtained by a process comprising the following steps: a- mixing of the lignin with water preferably comprising a buffering agent, b- preferably, ultrasonic treatment of the mixture obtained at the end of step a, c- enzymatic treatment of the lignin obtained in a or b, with at least one bilirubin oxidase enzyme, in the presence or absence of a redox mediator, to obtain aqueous-soluble lignin of pH greater than or equal to 5 and less than or equal to 10, preferably between 6 and 8, d- separation of the water-soluble lignin from the salts of the mixture and any insoluble compounds obtained in c, preferably by dialysis or centrifugation.

5. Use according to claim 3 or 4, or cosmetic composition

6.

7.

8.

9. according to claim 3 or 4, wherein the bilirubin oxidase is of fungal origin, preferably is a bilirubin oxidase of Magnaporthe oryzae origin; or the bilirubin oxidase is of bacterial origin, preferably is a bilirubin oxidase of Bacillus pumilus origin. Cosmetic composition according to any one of claims 2 to 5, comprising an aqueous phase in which water-soluble lignin is solubilized, and an oily phase, and in which the oily phase is dispersed in the aqueous phase, or the aqueous phase is dispersed in the oily phase. Cosmetic composition according to claim 6, comprising at least one surfactant, at least one lipophilic UV filter and / or at least one colouring material. A cosmetic composition according to claim 6 or 7, comprising at least one lipophilic UV filter selected from mineral UV filters, organic UV filters and mixtures thereof, preferably from titanium dioxide, zinc oxide, camphor benzylidene derivatives, benzophenone derivatives, para-aminobenzoic acid and its derivatives, triazine derivatives, dibenzoylmethane derivatives, salicylic derivatives, cinnamic derivatives, [3,[3-diphenylacrylate] derivatives, phenylbenzimidazole derivatives, phenylbenzotriazole derivatives and benzalmalonate derivatives, more preferably from titanium dioxide, zinc oxide, camphor benzalkonium methosulfate, ethylhexyl methoxycinnamate, homosalate, para-aminobenzoic acid, isoamyl p-methoxycinnamate, PEG-25 PABA, ethylhexyl dimethyl PABA, octocrylene, anisotriazine, polysilicone-15, drometrizole trisiloxane, oxybenzone,terephthalylidene diamphr sulfonic acid, benzylidene diamphr sulfonic acid, polyacrylamidomethyl benzylidene diamphr, octyl triazone, butyl methoxydibenzoylmethane, 4-methylbenzylidene camphor, diethylhexyl butamido triazone, diethylamino hydroxybenzoyl hexyl benzoate, phenyl salicylate, ethylhexyl salicylate, disodium phenyl dibenzimidazole tetrasulfonate, methylene bis-benzotriazolyl, tetramethylbutylphenol, phenylbenzimidazole sulfonic acid, benzophenone-4 or 5 and bis-ethylhexyloxyphenol methoxyphenyl triazine. A cosmetic composition according to any one of claims 2 to 5, comprising an aqueous phase in which water-soluble lignin is solubilized, and at least one hydrophilic thickening polymer selected from cellulose and its derivatives, natural gums, sclero-glucans, chitin and chitosan derivatives, carrageenans and gellans.

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