Nail polish comprising a lipid extract of the brown algae thallus of the species undaria pinnatifida; its use in cosmetics and pharmaceuticals

Abstract

A composition in the form of a nail varnish consisting of: a nail varnish base and a lipid extract of the gametes of the brown alga Undaria pinnatifida, present in a mass proportion of 0.1% to 2% of the mass of the nail varnish base, wherein the constitutive solvent of the lipid extract is a mixture of fatty acid triglycerides whose acyl chains contain eight to ten carbon atoms; its use in cosmetics and pharmaceuticals.

Description

[0001] Technical Field of the Invention

[0002] This invention belongs to the fields of cosmetics and pharmaceutical industry. The subject of this invention is a novel nail polish and its use in protecting nails from exposure-induced damage.

[0003] Biological and environmental background

[0004] Fingernails are basically composed of hard, flat, rectangular plate-like structures that are tightly connected to the nail bed. During nail plate formation, keratinocytes in the germinal matrix flatten due to the disintegration of their nuclei and the condensation of their cytoplasm, forming flattened keratinized cells with defined cell boundaries (unlike hair).

[0005] Nail health depends not only on internal factors, such as age, genetics, or nutrition, which affect the characteristics of nails as they grow from the germinal matrix, but also on external factors, such as environmental stress, which affect the structure and visual appearance of nails.

[0006] At the molecular level, the differentiation of keratinocytes into corneocytes causes intermediate keratin filaments to aggregate, forming a complex scaffold. This scaffold accumulates in the cytoplasm of terminally differentiated corneocytes and fills the entire interior of the cell, primarily providing the mechanical strength of the nail. The aggregated keratin filaments are structurally organized into superimposed layers through a cross-linking process, which provides a high level of cohesion to the overall structure of the nail plate. The cross-linking of keratin filaments affects characteristic properties of the nail plate, such as stability and strength.

[0007] Previous proteomic analyses of nails and hair have described a group of proteins, some of which are found only in the nail plate (keratin K5, K6A, K14, and K17, as well as connexins DSG1 and EP-PC1). Keratin is a fundamental component of nails and is capable of self-assembling into filaments.

[0008] External factors that damage nails are associated with unsightly changes in their visual appearance. These changes are caused by alterations in physical and chemical structure, leading to weakening, brittleness, discoloration, and the formation of stripes.

[0009] Approximately 20% of the French population suffers from brittle nails. This brittleness is characterized by cracks and various forms of peeling on the nails. As a result, the nails soften and lose their elasticity.

[0010] Nail keratins are designated targets for harmful modifications such as carbonylation due to their high exposure to external or internal environments (UV radiation, pollution, chemical reagents), which may partially explain the molecular basis of physicochemical modifications that make nails brittle and fragile.

[0011] Therefore, OxiProteomics developed an in vitro model of nail experiments, allowing for the analysis of these modifications. A decrease in nail mechanical strength was indeed observed after stress was applied via the exposome. Using proteomics methods combined with image analysis, carbonylation of keratin could be identified and measured. For example, chemical and physical stress induce oxidative damage to keratinocyte structural proteins.

[0012] A significant increase in protein oxidation (carbonylation) was observed in nail keratin primarily after exposure to UVA and chemical agents. Since nails cannot be repaired when damaged, protecting the main nail proteins from carbonylation could be an effective way to protect nails from oxidative stress induced by the exposure group. The concept of the exposure group refers to the cumulative effect of exposure to environmental (non-genetic) factors, particularly to the nails, and complements the genomic effect.

[0013] Existing technology

[0014] Numerous publications disclose methods for strengthening or hardening weakened nails.

[0015] British patent application GB 2 196 978 A discloses a nail polish containing glyoxal.

[0016] European patent application publication number EP 1 408 917 A1 discloses a nail polish containing citral, which is described as a nail hardener.

[0017] International application WO 2021 / 234270 A1 discloses a cosmetic composition for nail care, comprising a chestnut aqueous extract as a cosmetic active ingredient. The composition is described as improving the surface finish of nails.

[0018] Technical issues

[0019] As part of their research aimed at reducing nail damage caused by exposure, the inventors developed a novel composition in the form of nail polish.

[0020] Invention Description

[0021] According to a first aspect, the subject of the present invention is a composition comprising the following: A) Nail polish base, and B) Brown algae, wakame ( Undaria pinnatifida A lipid extract of the gamete, wherein the lipid extract is present in a mass ratio of 0.1% to 2% of the nail polish matrix, wherein the constitutive solvent of the lipid extract is a mixture of fatty acid triglycerides whose acyl chains contain eight to ten carbon atoms.

[0022] According to one particular aspect of the invention, the lipid extract of the brown algae Undaria gametophyte is present in the composition as defined above at a mass ratio of 0.5% to 1% of the nail polish matrix.

[0023] According to another specific aspect of the invention, the constituent solvent of the brown algae Undaria gametophyte lipid extract present in the composition as defined above is a mixture of glyceryl tridecanoate and glyceryl tricaprylate.

[0024] According to another specific aspect of the invention, in the composition as defined above, the nail polish base comprises, by weight 100%,: A1) 10% to 35% by weight of a film-forming agent or a mixture of film-forming agents. A2) 5% to 15% by weight of plasticizer or mixture of plasticizers, and A3) 50% to 80% by weight of an organic solvent or a mixture of organic solvents.

[0025] More specifically, the nail polish base, by weight of 100%, further comprises: A4) 0.1% to 2% by mass of an auxiliary agent or a mixture of auxiliary agents, said auxiliary agent being selected from colorants and compounds that absorb ultraviolet light.

[0026] In the context of this invention, the components present in the constituent nail polish matrix of the compositions as defined above are suitable for topical application to the nails.

[0027] According to a particular aspect of the invention, A1) One or more film-forming agents present in the nail polish base are selected from: polyurethane, acrylic polymers, vinyl polymers such as polyvinyl butyral, (adipic acid / neopentyl glycol / trimethicone) copolymers, and cellulose polymers such as nitrocellulose, carboxymethyl cellulose, hydroxycellulose, hydroxypropyl cellulose, cellulose acetate butyrate, or cellulose acetate propionate. A2) One or more plasticizers present in the nail polish base are selected from: glyceryl carbonate, dilaurate carbonate, diammonium carbonate, dibutyl phthalate, tributyl acetyl citrate, camphor, trimethylpentanediol dibenzoate, glyceryl benzoate, and diol esters such as neopentanediol ester or propylene glycol ester. A3) One or more organic solvents present in the nail polish base are selected from: ketones that are liquid at room temperature, such as methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, isophorone, cyclohexanone, or acetone; alcohols that are liquid at room temperature, such as ethanol, isopropanol, or cyclohexanol; diols that are liquid at room temperature, such as ethylene glycol, propylene glycol, or pentanediol; glycerol; and carboxylic acid esters such as ethyl acetate, methyl acetate, butyl acetate, or isoamyl acetate.

[0028] According to a particular aspect of the invention, the lipid extract of the gametophyte of the brown algae Undaria pinnatifida present in the composition as defined above is obtained directly by a method comprising the following sequential steps: a) Step a) The aqueous-alcohol suspension of gametophyte cells of the brown algae Undaria pinnatifida is prepared by mixing an aqueous suspension of biomass composed of gametophyte cells of the brown algae Undaria pinnatifida with an alcohol or a mixture of alcohols at a ratio of five to thirty liters of alcohol per kilogram of biomass, wherein the alcohol is selected from ethanol, propanol, isopropanol, butanol, and isobutanol. b) Step b) ,Will Step a) The aqueous-alcohol suspension of the brown algae Undaria gametophyte cells obtained at the end is mixed with a mixture of fatty acid triglycerides with acyl chains containing eight to ten carbon atoms, such that the mass ratio of the brown algae Undaria gametophyte cells to the mass ratio of the fatty acid triglyceride mixture with acyl chains containing eight to ten carbon atoms is greater than or equal to 2 and less than or equal to 10, to obtain a multiphase mixture. c) Step c) ,Towards Step b) Water is added to the multiphase mixture obtained at the end, such that the mass ratio of the gametophyte cells of the brown algae Undaria pinnatifida to the mass of water is greater than or equal to 0.5% by mass and less than or equal to 2% by mass; d) Step d) The filtrate is obtained by filtration and then centrifugation. Step c) The mixture obtained separates the lipid extracts from the gametophytes of the brown algae Undaria pinnatifida; and, if necessary... e) Step e) ,dry When step d) ends The lipid extract obtained from the gametophyte of the brown algae Undaria pinnatifida.

[0029] In the context of this invention, the water-alcohol suspension of *Undaria pinnatifida* gametophyte cells used in step a) of the method as defined above can be prepared by the method described in International Publication WO 2016 / 135400.

[0030] A method for obtaining the lipid extract of the gametophyte of the brown algae Undaria pinnatifida, based on a specific aspect of the composition as defined above. Step a) The alcohol used is ethanol.

[0031] According to another specific aspect of the composition as defined above, Step b) The ratio of the mass of the brown algae *Undaria pinnatifida* gametophyte cells used to the mass of the mixture of fatty acid triglycerides whose acyl chains contain eight to ten carbon atoms is greater than or equal to 5 and less than or equal to 10, and preferably about 6.

[0032] According to a more specific aspect of the invention, the constituent nail polish base of the composition as defined above comprises, by weight, 10% to 35% of a film-forming agent mixture, said film-forming agent mixture comprising, by weight, 100% of: - 65% to 75% nitrocellulose by weight (CAS No. = 9004-70-0), - 25% to 35% by weight of adipic acid / neopentyl glycol / trimeric anhydride copolymer (CAS No. = 28407-73-0), and - Optionally up to 0.35% by weight of polyvinyl butyral (CAS No. = 63148-65-2).

[0033] According to another more specific aspect of the invention, the constituent nail polish base of the composition as defined above comprises, by weight 5% to 10% of acetylthiol tributyl citrate (CAS No. = 77-90-7) or 5% to 10% of a plasticizer mixture, said plasticizer mixture comprising, by weight 100% of: - 98% to 99.9% by weight of acetylthiose tributyl citrate, and - 0.1% to 2% by weight of trimethylpentanediol dibenzoate (CAS No. = 68052-23-3).

[0034] According to another more specific aspect of the invention, the constituent nail polish base of the composition as defined above comprises, by weight 100%, 60% to 80% of a solvent mixture, said solvent mixture comprising, by weight 100%, 60% to 80% of a solvent mixture. - 5% to 15% by weight of isopropanol (CAS No. = 67-63-0), - 10% to 75% by weight of butyl acetate (CAS No. = 123-86-4), and - 10% to 75% by mass of ethyl acetate (CAS No. = 141-78-6).

[0035] According to a very specific aspect of the invention, the constituent nail polish base of the composition as defined above comprises, by weight 100%, the following: - 25% to 45% by mass of ethyl acetate (CAS No. = 141-78-6), - 15% to 25% by weight of butyl acetate (CAS No. = 123-86-4), - 5% to 10% by weight of (adipic acid / neopentyl glycol / trimethicone) copolymer (CAS No. = 28407-73-0), - 10% to 20% nitrocellulose by weight (CAS No. = 9004-70-0), - 5% to 10% by weight of acetylated tributyl citrate (CAS No. = 77-90-7), - 5% to 10% by weight of isopropanol (CAS No. = 67-63-0), - 0.1% to 1% by weight of etocrylene (CAS No. = 5232-99-5), - Optionally up to 0.1% by weight of polyvinyl butyral (CAS No. = 63148-65-2).

[0036] The subject of this invention also lies in the use of a lipid extract from the gametophyte of the brown algae Undaria pinnatifida for reducing the unsightly effects induced in human nails by exposure.

[0037] In the context of this invention, the term "exposure group" refers to all environmental stresses that can induce nail keratin oxidation.

[0038] Examples of environmental stress include ultraviolet (UVA and / or UVB) radiation, pollution from fine particulate matter, ozone, polycyclic aromatic hydrocarbons, chemical reagents, or cigarette smoke.

[0039] In the context of this invention, the unsightly effects induced by the exposure group on human nails are selected from yellowing, roughness, brittleness, and fragility.

[0040] According to a particular aspect of the invention, the subject matter of the invention is the use as defined above for reducing the unsightly effects of solar radiation, and more particularly ultraviolet A (UVA) irradiation, on human nails.

[0041] The subject of this invention also lies in a non-treatment method for reducing the unsightly effects induced by exposure to human nails, comprising the step of applying a composition as defined above to said nails, and more particularly in a non-treatment method for reducing the unsightly effects induced by solar radiation, more particularly by ultraviolet A (UVA) irradiation on human nails.

[0042] Finally, the subject of this invention is the composition as defined above, which is used to reduce damage to the keratin structure of human nails caused by solar radiation, and more particularly by ultraviolet A (UVA) ray irradiation.

[0043] According to a particular aspect of the invention, the damage to the structure of human nail keratin caused by solar radiation can be selected from the oxidation reaction of nail proteins, particularly the oxidation reaction of nail keratin, and more particularly the carbonylation of nail proteins, especially the carbonylation of nail keratin.

[0044] Exemplary embodiments of the present invention

[0045] Effects of Wakame extract incorporated into nail polish base on in vitro UVA-induced keratin oxidation (carbonylation)

[0046] Will wakame seaweed A lipid extract (in which the constituent solvent of the lipid extract is a mixture of equal masses of glyceryl tricaprylate and glyceryl tridecanoate) is mixed with a nail polish base, the nail polish base being composed of the following components: - 25% to 45% by mass of ethyl acetate (CAS No. = 141-78-6), - 15% to 25% by weight of butyl acetate (CAS No. = 123-86-4), - 10% to 20% nitrocellulose by weight (CAS No. = 9004-70-0), - 5% to 10% by weight of acetylated tributyl citrate (CAS No. = 77-90-7), - 5% to 10% by weight of (adipic acid / neopentyl glycol / trimethicone) copolymer (CAS No. = 28407-73-0), - 5% to 10% by weight of isopropanol (CAS No. = 67-63-0), - 0.1% to 1% by weight of Etolith (CAS No. = 5232-99-5), - Up to 0.1% by weight of polyvinyl butyral (CAS No. = 63148-65-2), - Up to 0.1% by mass of trimethylpentanediol dibenzoate (CAS No. = 68052-23-3), and - Purple coloring agent (CI 60725) (CAS No.=81-48-1).

[0047] Two types of nail polish were thus prepared: - Product A, containing the aforementioned wakame seaweed A lipid extract of the gamete, in a mass ratio equal to 0.5% of the nail polish base; - Product B contains a lipid extract of the wakame gametophyte in a mass ratio equal to 1.0% of the nail polish matrix.

[0048] Evaluation Principles : Assess the effects of UVA exposure on clipped nails

[0049] plan On Day 0, the product was applied to clipped nails and left in contact until dry. A second application of the product was then made, leaving the product in contact with the nails for five days. On Day 5, the product was removed from the nails using a mild nail polish remover (commercially available), and the clipped nails were then transferred to petri dishes to dry. Finally, they were (or not) exposed to UV-A irradiation (6.8 J / cm², 2.365 nm, LED light source) in an OxiProteomics™ chamber. The “untreated control” and “stress control” groups were also treated with a mild nail polish remover solution. After treatment, the nails were prepared, sampled, and stored at -80°C until OxiProteome Score™ analysis was performed.

[0050] OxiProteome Score™ Analysis Trimmed fingernails were used for protein extraction in an aqueous buffer using the proprietary OxiProteomics™ method (optimized for fingernail proteins). Total protein was quantified using the Bradford method. Extracted proteins were aliquoted for each sample for the following analyses. Oxidized (carbonylated) proteins were labeled with specific fluorescent probes and then separated by high-resolution electrophoresis (SDS-PAGE - 4%–20%). After migration, total protein was stained on the gel with SyproRuby™ fluorescent reagent (Life Technologies, USA). Digital images of carbonylated proteins and total protein were acquired using the iBright system (Thermofisher). Image processing and density analysis were performed using ImageJ software. The carbonylated protein value (carbonyl fraction) was obtained by normalizing the specific fluorescence signal to the total protein content.

[0051] The carbonyl fraction of sample X is equal to Fluorescence value of oxidized protein in the sample The ratio of fluorescence value to the total protein fluorescence value of the same sample.

[0052] The obtained carbonyl fractions were compared and statistical analysis was performed according to the Student t-test (with p<0.05 as the significance threshold) to determine the significance of the results.

[0053] Results obtained: The results obtained are recorded in Table 1 below.

[0054] Table 1

[0055] These results highlight the following: - The carbonyl fraction of untreated nail samples increased by 61.8% after UVA irradiation compared to untreated nail samples; therefore, UVA irradiation has a harmful oxidizing effect on nail keratin. - Treating nails with nail polish base alone reduced the effects of UVA irradiation, but did not prevent keratin oxidation; the carbonyl fraction was still much higher than the untreated control (+37.0%). - Product A has a positive effect on nail treatment because it reduces the carbonyl fraction (-15.2%) compared to nails treated with nail polish base alone; - Product B treatment completely suppressed the effects of irradiation, resulting in a reduction of the carbonyl fraction (-52.4%).

[0056] Therefore, the lipid extract of the brown algae Undaria gametophyte present in nail polish in the required protected proportions offers a technical advantage that cannot be readily derived from the prior art.

Claims

1. A composition comprising the following: - Nail polish base, and - A lipid extract of the gametophyte of the brown algae Undaria pinnatifida, the lipid extract being present in a mass ratio of 0.1% to 2% of the nail polish matrix, wherein the constituent solvent of the lipid extract is a mixture of glyceryl tridecanoate and glyceryl tricaprylate.

2. The composition according to claim 1, wherein the lipid extract of the brown algae Undaria gametophyte is present therein at a mass ratio of 0.5% to 1% of the nail polish matrix.

3. The composition according to any one of claims 1 and 2, wherein the nail polish base comprises, by weight, 100% of: A1) 10% to 35% by weight of a film-forming agent or a mixture of film-forming agents. A2) 5% to 15% by weight of plasticizer or mixture of plasticizers, and A3) 50% to 80% by weight of an organic solvent or a mixture of organic solvents.

4. The composition of claim 3, wherein the nail polish base comprises, by weight, 100% A4) 0.1% to 2% by mass of an auxiliary agent or a mixture of auxiliary agents, said auxiliary agent being selected from colorants and compounds that absorb ultraviolet light.

5. The composition according to any one of claims 1 to 4, wherein the lipid extract of the brown algae *Undaria pinnatifida* gametophyte is obtained directly by a method comprising the following sequential steps: - Step a) Prepare an aqueous-alcohol suspension of gametophyte cells of the brown algae Undaria pinnatifida by mixing an aqueous suspension of biomass composed of gametophyte cells of the brown algae Undaria pinnatifida with an alcohol or a mixture of alcohols at a ratio of five to thirty liters of alcohol per kilogram of biomass; wherein the alcohol is selected from ethanol, propanol, isopropanol, butanol or isobutanol. - Step b) Mix the aqueous-alcohol suspension of the brown algae Undaria gametophyte cells obtained at the end of step a) with a mixture of fatty acid triglycerides with acyl chains containing eight to ten carbon atoms, such that the mass ratio of the brown algae Undaria gametophyte cells to the mass ratio of the fatty acid triglyceride mixture with acyl chains containing eight to ten carbon atoms is greater than or equal to 2 and less than or equal to 10, to obtain a multiphase mixture. - Step c) Add water to the multiphase mixture obtained at the end of step b) such that the mass ratio of the brown algae Undaria gametophyte cells to the mass of water is greater than or equal to 0.5% by mass and less than or equal to 2% by mass; - Step d) Separate the lipid extract of the brown algae Undaria gametophyte from the mixture obtained in step c) by filtering and then centrifuging the filtrate; And when necessary; - Step e) Drying the lipid extract of the gametophyte of the brown algae Undaria pinnatifida obtained at the end of step d).

6. The composition according to claim 5, wherein Step a) The alcohol used is ethanol.

7. The composition according to any one of claims 5 and 6, wherein Step b) The ratio of the mass of the brown algae *Undaria pinnatifida* gametophyte cells used to the mass of the mixture of fatty acid triglycerides whose acyl chains contain eight to ten carbon atoms is greater than or equal to 5 and less than or equal to 10, and preferably about 6.

8. The composition according to any one of claims 3 to 7, wherein the nail polish base comprises 10% to 35% by weight of a film-forming agent mixture, said film-forming agent mixture comprising, by weight: - 65% to 75% nitrocellulose by weight (CAS No. = 9004-70-0), - A copolymer of adipic acid, neopentyl glycol, and trimellitic anhydride (CAS No. = 28407-73-0) at 25% to 35% by weight. Optionally up to 0.35% by mass of polyvinyl butyral (CAS No. = 63148-65-2).

9. The composition according to any one of claims 3 to 8, wherein the nail polish base comprises, by weight, 5% to 10% of acetylthiol tributyl citrate (CAS No. = 77-90-7) or 5% to 10% of a plasticizer mixture, wherein the plasticizer mixture comprises, by weight, 5% to 10% of: - 98% to 99.9% by weight of acetylthiose tributyl citrate, and - 0.1% to 2% by weight of trimethylpentanediol dibenzoate (CAS No. = 68052-23-3).

10. The composition according to any one of claims 3 to 9, wherein the nail polish base comprises 60% to 80% by weight of a solvent mixture, said solvent mixture comprising, by weight, 60% to 80% by weight of the nail polish base. - 5% to 15% by weight of isopropanol (CAS No. = 67-63-0), - 10% to 75% by weight of butyl acetate (CAS No. = 123-86-4), and - 10% to 75% by mass of ethyl acetate (CAS No. = 141-78-6).

11. The composition according to any one of claims 3 to 10, wherein the nail polish base comprises, by weight 100%,: - 25% to 45% by mass of ethyl acetate (CAS No. = 141-78-6), - 15% to 25% by weight of butyl acetate (CAS No. = 123-86-4), - 10% to 20% nitrocellulose by weight (CAS No. = 9004-70-0), - 5% to 10% by weight of acetylated tributyl citrate (CAS No. = 77-90-7), - 5% to 10% by weight of (adipic acid / neopentyl glycol / trimethicone) copolymer (CAS No. = 28407-73-0), - 5% to 10% by weight of isopropanol (CAS No. = 67-63-0), - 0.1% to 1% by weight of Etolith (CAS No. = 5232-99-5), - Optionally up to 0.1% by weight of polyvinyl butyral (CAS No. = 63148-65-2), - Optionally up to 0.1% by weight of trimethylpentanediol benzoate (CAS No. = 68052-23-3), and - Optional colorant.

12. Non-therapeutic use of topical application of lipid extracts from the gametophytes of the brown algae Undaria pinnatifida to reduce the unsightly effects induced in human nails in the exposed group.

13. The use according to claim 12, for reducing the unsightly effects of solar radiation, and more particularly ultraviolet A (UVA) ray irradiation, on human nails.

14. A non-treatment method for reducing the unsightly effects induced by exposure on human nails, comprising the step of applying a composition as defined in any one of claims 1 to 11 to the nails.

15. The non-treatment method according to claim 14, which is used to reduce the unsightly effects of solar radiation, and more particularly ultraviolet A (UVA) ray irradiation, on human nails.

16. The composition according to any one of claims 1 to 11, which is used to reduce damage to the keratin structure of human nails caused by solar radiation, more particularly by ultraviolet A (UVA) radiation.

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