Novel cosmetic use of a myrtus communis extract

Abstract

The present invention relates to the non-therapeutic cosmetic use of an aqueous extract of Myrtus communis to maintain and / or improve the evenness of the skin tone, in particular by maintaining and / or improving the proteostasis and barrier function of the skin, in particular of healthy skin. The present invention also relates to the non-therapeutic cosmetic use of an aqueous extract of Myrtus communis to maintain and / or improve the proteostasis and barrier function of the skin, in particular of healthy skin.

Description

[0001] New cosmetic use of a Myrtus communis extract

[0002] The present invention relates to the non-therapeutic cosmetic use of an aqueous extract of Myrtus communis to maintain and / or improve skin tone evenness, in particular by maintaining and / or improving proteostasis and the skin barrier function, especially in healthy skin. The present invention also relates to the non-therapeutic cosmetic use of an aqueous extract of Myrtus communis to maintain and / or improve proteostasis and the skin barrier function, especially in healthy skin.

[0003] Proteins perform a wide variety of functions. They can have structural functions, as in the case of actin, keratin, or tubulin; enzymatic functions, as in matrix proteases or transglutaminase; transport functions, as in the case of aquaporins; or defense functions. Since all of these vital functions are ensured by protein activity, maintaining their homeostasis is crucial for preserving all cellular and tissue functions.

[0004] Protein homeostasis, or proteostasis, describes the work of a complex network of pathways essential for cell function and viability, controlling the biogenesis, folding, trafficking, and degradation of proteins both inside and outside the cell. It ensures the correct concentration, proper folding, and interactions of proteins from synthesis to degradation. Proteostasis is crucial for successful development, healthy aging, resistance to environmental stresses, and minimizing disruptions to tissue homeostasis.

[0005] The integrity of skin tissue encompasses its barrier function, its cohesive structure, and its capacity for regeneration and hydration.

[0006] Keratinization is an epidermal process based on the maturation of keratinocytes. Originating in the basal layer from skin stem cells, these cells gradually migrate towards the surface, undergoing a series of transformations. As the keratinocytes progress, they accumulate keratin, making them more resistant and impermeable. This accumulation leads to the formation of the stratum corneum, the skin's protective barrier. The keratinization process is crucial for skin health because it enables the formation and maintenance of this protective barrier (stratum corneum) and regulates hydration by retaining water in the deeper layers of the skin. Combined with the cell renewal of keratinocytes, it helps maintain smooth, radiant, and even skin by preventing the accumulation of dead cells and regenerating the skin after external aggressors.An active ingredient that can maintain or even improve proteostasis and the skin's barrier function could therefore provide benefits in cosmetic care, promoting healthy, even-toned skin.

[0007] The inventors of the present invention have made a surprising discovery: that an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% water by weight relative to the total weight of solvent maintains and / or improves proteostasis and the skin barrier function, particularly in healthy skin. This extract also maintains and / or improves the evenness of skin tone, particularly in healthy skin.

[0008] The mechanisms by which proteostasis is maintained include regulated protein translation, assisted folding of chaperone proteins, and protein degradation pathways. It is essential to adjust each of these mechanisms to the protein demand so that all cellular functions rely on a properly folded proteome. Loss of proteostasis, in particular, leads to the accumulation of defective or unnecessary proteins.

[0009] The machinery of cellular proteostasis consists of several major elements including the chaperone protein sorting system, autophagy, and the ubiquitin-proteasome degradation system (UPS), which aims to control misassembled polypeptides.

[0010] The chaperone protein sorting system is primarily carried out by heat shock proteins (HSPs), notably HSP70, which are capable of recognizing misfolded or damaged polypeptides, correcting their structure or, for non-correctable structures, directing them towards ubiquitination and proteasomal degradation (UPS system).

[0011] Autophagy is a highly regulated process and essential for maintaining cellular homeostasis, as this physiological mechanism allows the recycling of various cellular components such as misfolded proteins. This mechanism relies on cellular organelles involved in enzymatic digestion, the lysosomes, and manifests in different systems depending on the component to be digested and how it is processed. Chaperone-mediated autophagy (CMA) is one such lysosomal degradation system that utilizes Hsc70-type chaperone proteins and the lysosomal surface receptor LAMP2A. The former recognize a specific peptide sequence, which then targets the latter, ultimately enabling the degradation of the target protein within the lysosomal lumen.

[0012] The ubiquitin-proteasome system (UPS) is another major protein degradation pathway, involving the ubiquitination of proteins to be degraded (conjugation of ubiquitin to proteins) via successive enzymatic reactions. Ubiquitinated proteins are recognized and degraded by the 26S proteasome, itself formed by the association of the 20S proteasome, the latter being its catalytic core, with the 19S regulatory complex. The applicant discovered that a myrtle extract obtained by extraction with a solvent containing more than 90% water by weight relative to the total weight of solvent had the ability to increase the expression of Lamp2A, HSP70, and the 20S proteasome. It therefore has an effect on proteostasis mechanisms.It helps regulate and / or enhance proteostasis, particularly protein degradation pathways such as chaperone-mediated autophagy (CMA), the ubiquitin-proteasome degradation system (UPS), and the chaperone protein sorting system, including HSPs. The use of myrtle extract obtained by extraction with a solvent containing more than 90% water by weight relative to the total solvent weight promotes protein folding, especially by HSPs, protein ubiquitination and proteasome degradation, as well as the degradation of polypeptides and proteins by autophagy.

[0013] Involucrin is a protein whose synthesis is activated by an increase in intracellular calcium. Synthesized in the cytoplasm of keratinocytes in the stratum granulosum, it participates in the initiation of the formation of the stratum corneum, notably by associating with envoplakin and peripakin dimers via transglutaminase 1. It therefore constitutes a marker of the terminal differentiation of keratinocytes, plays a major role in the skin barrier function, and limits water loss from the skin, thus preventing dehydration.

[0014] Collagen XVII (Col-XVI I), also known as 180-kDa bullous pemphigoid antigen (BP180), is a transmembrane protein located at the dermo-epidermal junction, specifically at the hemidesmosomes. This protein acts as a crucial anchoring protein, connecting intracellular and extracellular hemidesmosomal proteins. It binds to other hemidesmosomal components such as P4 integrins, plectin, and laminin 332. In the skin, collagen XVII stabilizes the adhesion of epidermal cells to the dermo-epidermal junction and is involved in regulating keratinocyte migration. It thus plays a role in the skin barrier function.

[0015] The plaintiff made a surprising discovery: a myrtle extract obtained by extraction with a solvent containing more than 90% water by weight relative to the total solvent also had the ability to increase the expression of involucrin and collagen XVII. This extract therefore has a beneficial effect on the skin's barrier function, particularly cell differentiation and the cohesion of the dermo-epidermal junctions. It helps maintain, and even strengthen, the skin's barrier function, specifically by maintaining a functional and hydrated skin barrier, strengthening the cohesion of the dermo-epidermal junction, and promoting cell differentiation in the skin.

[0016] Summary of the invention

[0017] Thus, the present invention relates to the non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the homogeneity of skin tone, in particular by maintaining and / or improving proteostasis and the skin barrier function, in particular of healthy skin.

[0018] It also relates to the non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent to maintain and / or improve the proteostasis and barrier function of the skin, in particular of healthy skin.

[0019] It also relates to a non-therapeutic cosmetic treatment and / or care process characterized in that it includes the topical application to at least one area of ​​skin of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, or of a cosmetic composition comprising it, to maintain and / or improve the homogeneity of skin tone, in particular via the maintenance and / or improvement of proteostasis and the skin barrier function, in particular of healthy skin.

[0020] It also relates to a non-therapeutic cosmetic treatment and / or care process characterized in that it includes the topical application to at least one area of ​​skin of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the proteostasis and barrier function of the skin, in particular of healthy skin.

[0021] Detailed description

[0022] As mentioned above, the present invention relates to the non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the homogeneity of skin tone, in particular by maintaining and / or improving the proteostasis and barrier function of the skin.

[0023] It also relates to the non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the proteostasis and barrier function of the skin, in particular of healthy skin.

[0024] The term "cosmetic use" refers to non-therapeutic use, meaning use that is not intended for therapeutic purposes and is applied to a part of the body considered healthy, particularly to an area of ​​skin considered healthy.

[0025] The term "skin" refers to any part of the body and / or face, including the scalp, and advantageously the face, neck and décolletage.

[0026] The term "healthy skin" means an area of ​​skin, tissue or epidermis, on which the extract or composition according to the invention comprising said extract is applied, which is said to be "non-pathological" by a dermatologist, that is to say, not showing any infection, scar, disease or skin condition such as candidiasis, impetigo, psoriasis, eczema, acne or dermatitis, or any sores or injuries.

[0027] Thus, within the framework of the present invention, the use of T'extrait makes it possible to maintain and / or improve the homogeneity of the skin tone.

[0028] The term "maintaining and / or improving the evenness of skin tone" is used in the common sense of the term for a professional in the field. Specifically, it refers to any cosmetic action aimed at giving the skin a more even, uniform, and harmonious appearance. Such improvement may include reducing, mitigating, or preventing uneven skin tone, and / or improving the radiance and luminosity of the complexion, and / or maintaining and / or improving the evenness or uniformity of the skin tone by controlling microrelief or reducing skin roughness.

[0029] The improvement of skin tone uniformity can result, for example, from a decrease in the visibility of existing pigment spots, a reduction in redness, an improvement in skin texture, better diffusion or reflection of light on the skin surface, an improvement in skin hydration, a limitation of the appearance of new color irregularities, or even an optical correction of skin color defects.

[0030] According to one embodiment of the invention, the effect of maintaining and / or improving the uniformity of the complexion is understood to exclude any overall depigmenting or lightening effect on the skin, in particular any effect aimed at generally reducing the amount of melanin present in the skin, directly inhibiting melanogenesis or causing generalized lightening of the skin and / or any anti-aging effect.

[0031] The use of the extract also helps to maintain and / or improve proteostasis, particularly through the protein degradation pathway.

[0032] More specifically, maintaining and / or improving proteostasis includes promoting:

[0033] - the degradation of polypeptides and proteins,

[0034] - the ubiquitination of proteins followed by their degradation,

[0035] - protein folding by chaperone proteins.

[0036] The term “maintaining and / or improving proteostasis” is understood in the common sense for those skilled in the art. As mentioned above, the use of the extract according to the invention allows for the maintenance, promotion, and improvement of protein degradation pathways such as chaperone-mediated autophagy (CM A), the ubiquitin-proteasome degradation system (UPS), and the chaperone protein sorting system, particularly for heat shock proteins (HSPs). The use of the extract according to the invention also promotes protein folding, particularly by HSPs, protein ubiquitination and proteasome degradation, and the degradation of polypeptides and proteins by autophagy. More specifically, the use of the extract according to the invention increases the protein expression of Lamp2A, HSP70, and / or the 20S proteasome.“Improving chaperone-mediated autophagy (CMA)” specifically means increasing the protein expression of Lamp2A.

[0037] More specifically, the use of the extract according to the invention makes it possible to increase the protein expression of Lamp2A by at least 7%.

[0038] By "increasing Lamp2A protein expression by at least 7%", we mean specifically that the protein expression level increases by at least 7% compared to the protein expression level when it is not in the presence of the extract. This expression level can be measured by any method known to those skilled in the art, for example, by specific immunolabeling quantification, Western blot, or ELISA assay, performed on expiants, cell culture models, or reconstructed skin.

[0039] By "at least 7%", we mean, for example, at least 8 or 10%.

[0040] The term “improving the ubiquitin-proteasome degradation system” specifically means increasing 20S proteasome protein expression.

[0041] More specifically, the use of the extract according to the invention increases 20S proteasome protein expression by at least 30%. By "increasing 20S proteasome protein expression by at least 30%", it is specifically understood that the protein expression level increases by at least 30% compared to the protein expression level when it is not in the presence of the extract. This expression level can be measured by any method known to those skilled in the art, for example, by specific immunolabeling quantification, Western blotting, or ELISA, performed on expiants, cell culture models, or reconstructed skin.

[0042] By "at least 30%", we mean, for example, at least 32% or 35%.

[0043] The term “improving the chaperone protein sorting system” refers specifically to increasing the protein expression of HSP70.

[0044] More specifically, the use of the extract according to the invention makes it possible to increase the protein expression of HSP70 by at least 40%.

[0045] By "increasing HSP70 protein expression by at least 40%", we mean specifically that the protein expression level increases by at least 40% compared to the protein expression level when it is not in the presence of the extract. This expression level can be measured by any method known to those skilled in the art, for example, by specific immunolabeling quantification, Western blot, or ELISA assay, performed on expiants, cell culture models, or reconstructed skin.

[0046] By "at least 40%", we mean for example at least 42, 45 or 50%.

[0047] Within the framework of the present invention, the use of the extract allows the maintenance and / or improvement of the skin's barrier function.

[0048] The term "maintaining and / or improving the skin's barrier function" is understood by those skilled in the art. Myrtus communis extract, obtained by extraction with a solvent containing more than 90% water by weight relative to the total weight of solvent, can particularly influence the mechanical properties of the skin, such as its suppleness and elasticity, notably by improving and / or maintaining skin hydration.

[0049] In particular, the use of the extract according to the invention promotes keratinocyte cell differentiation and / or the formation of the stratum corneum and / or the regulation of hydration and / or the cohesion of dermo-epidermal junctions. More specifically, the use of the extract according to the invention increases the protein expression of involucrin and / or collagen XVII.

[0050] The term “promoting keratinocyte cell differentiation and / or stratum corneum formation and / or hydration regulation” refers in particular to increasing involucrin protein expression.

[0051] More specifically, the use of the extract according to the invention makes it possible to increase the protein expression of involucrin by at least 5%.

[0052] By "increasing involucrin protein expression by at least 5%", we mean specifically that the level of protein expression increases by at least 5% compared to the level of protein expression when it is not in the presence of the extract. This level of expression can be measured by any method known to those skilled in the art, for example by specific immunolabeling quantification, Western blot, or ELISA assay, performed on expiants, cell culture models, or reconstructed skin.

[0053] By "at least 5%", we mean for example at least 5, 7 or 10%.

[0054] “Promoting the cohesion of dermo-epidermal junctions” means, in particular, increasing the protein expression of collagen XVII.

[0055] More specifically, the use of the extract according to the invention makes it possible to increase the protein expression of collagen XVII by at least 15%.

[0056] By "increasing collagen XVII protein expression by at least 15%", we mean, in particular, that the level of protein expression increases by at least 15% compared to the protein expression level when it is not in the presence of the extract. This level of expression can be measured by any method known to those skilled in the art, for example, by specific immunolabeling quantification, Western blot, or ELISA assay, performed on expiants, cell culture models, or reconstructed skin.

[0057] By "at least 15%", we mean for example at least 17, 20, 30 or 40%.

[0058] The Myrtus communis extract according to the invention may be an extract of any part of the plant, particularly the aerial parts. The aerial parts include the leaves, flowers, fruits, stem, or mixtures thereof. Advantageously, the Myrtus communis extract is an extract of leaves, stem, and flower buds and / or flowers.

[0059] The extract according to the present invention is obtained by any extraction method known to those skilled in the art. In particular, it is chosen from hot decoction, maceration, hot extraction, subcritical extraction, and extraction assisted by ultrasound and / or microwaves. Advantageously, the extract will be obtained by hot extraction.

[0060] Prior to extraction, the plant material of Myrtus communis, especially the aerial parts, can be prepared to reduce its size, in particular by grinding.

[0061] The extraction may be carried out from dry or fresh plant material, advantageously dry, in a quantity of 1% to 90% by weight, advantageously from 5% to 50%, very advantageously from 5% to 10%, by weight of plant material in relation to the total weight of plant material and extraction solvent.

[0062] The extraction can be carried out at a temperature ranging from 4°C to 300°C, including ambient temperature, i.e., a temperature of approximately 20°C. In a preferred embodiment of the invention, the extraction will be carried out at a temperature ranging from 20°C to 150°C, preferably from 45°C to 90°C, in particular from 60°C to 90°C.

[0063] The extraction can be conducted over a period of 30 seconds to 24 hours, preferably from 5 minutes to 12 hours, again preferably over a period of 1 hour to 8 hours.

[0064] Thus, the extract according to the invention is, for example, an extract of leaves, stem and flower buds and / or flowers, obtained by hot extraction, for a period of 1 hour to 8 hours, in particular at a temperature of 60°C to 90°C, optionally after grinding said leaves, stem and flower buds and / or flowers.

[0065] The solvent is predominantly water. The solvent may be a mixture comprising water and an organic solvent selected from a glycol, a polyol, or a mixture thereof. In particular, the organic solvent may be glycerin (or glycerol), 1,2-propanediol (or propylene glycol), butane-1,3-diol (or butylene glycol), or a mixture thereof. The mixture comprises more than 90% by weight of water relative to the total weight of solvent, preferably more than 95% by weight of water, and more preferably more than 98% by weight of water.

[0066] According to a preferred method, the extract is obtained by hot extraction in water. Within the framework of the invention, the extract is therefore an aqueous extract.

[0067] The term "aqueous extract" means that the extract is obtained, as described above, by extraction with a solvent consisting mainly of water, within the scope of the invention more than 90% by weight of water relative to the total weight of solvent, preferably more than 95% by weight of water, and more preferably essentially water (traces of organic solvent may remain). Following extraction, the extract may be filtered.

[0068] The extract obtained by extraction with a solvent containing more than 90% water by weight relative to the total weight of solvent may be diluted in water, an organic solvent, or a mixture thereof. This is then referred to as a diluted Myrtus communis extract. In particular, the organic solvent is chosen from a glycol, a polyol, or a mixture thereof. Specifically, the organic solvent may be glycerin (or glycerol), 1,2-propanediol (or propylene glycol), butane-1,3-diol (or butylene glycol), or a mixture thereof. More preferably, the organic solvent is glycerin. Preferably, the extract obtained by extraction with a solvent containing more than 90% water by weight relative to the total weight of solvent is diluted in an organic solvent as described above.

[0069] Dilution helps stabilize the sample in terms of physicochemical properties (preventing crystallization or precipitation) and microbiological properties (bacteriostatic effect). It also allows for control of the dry extract concentration, color, and prevents degradation.

[0070] The Myrtus communis extract described above can therefore be an extract consisting primarily of water as the solvent, or a diluted extract comprising a mixture of water and an organic solvent as mentioned above. Specifically, the diluted Myrtus communis extract may contain a mixture of water and glycerin as the solvent. In other words, the diluted Myrtus communis extract may be a Myrtus communis extract diluted with glycerin.

[0071] Preferably, the diluted Myrtus communis extract may comprise from 10 to 90% by weight of organic solvent relative to the total weight of the diluted extract, more preferably from 25 to 85% by weight, in particular from 50 to 75% by weight of organic solvent, especially glycerin.

[0072] The dry extract of active Myrtus communis may be between 0.01% and 10%, preferably between 0.01% and 1.0%. In particular, the Myrtus communis extract obtained by extraction with a solvent comprising more than 90% water by weight relative to the total weight of solvent is diluted so that the dry extract concentration falls within the ranges mentioned above.

[0073] The extract of Myrtus communis, in particular the diluted extract, may have a total polyphenol content of between 1 and 10 g / L (grams of polyphenols per liter of extract, in particular diluted extract), preferably between 2 and 7 g / L, more preferably between 2.5 and 6 g / L. The total polyphenol content is determined according to the Folin-Ciocalteu method.

[0074] Myrtus communis extract, particularly diluted extract, may have a total flavonoid content of between 0.1 and 1 g / L (grams of flavonoids per liter of extract, particularly diluted extract), preferably between 0.2 and 0.7 g / L. The total flavonoid content is determined using the aluminum chloride method.

[0075] The aqueous extract of Myrtus communis, in particular the diluted extract, may have a total sugar content of between 1 and 5 g / L (grams of sugar per liter of extract, in particular diluted extract), preferably between 1.5 and 4.5 g / L, more preferably between 2 and 4 g / L. The total sugar content is determined according to the DUBOIS method.

[0076] The extract according to the invention, in particular the diluted extract, may have a pH between 3 and 6, preferably between 4 and 5.

[0077] Preferably, the Myrtus communis extract obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, particularly from the process described above, comprises hydrolyzable ellagic and gallic acid tannins, gallic and ellagic acid monomers, glycosylated assemblies of these monomers, eugeniflorin D2, and oenothein B. The extract may also comprise flavonols, particularly glycosylated flavonols such as myricetin-3O-galactoside, myricitrin, or myricetin. In an embodiment according to the present invention, the extract according to the invention is incorporated into a cosmetic composition.

[0078] The term "cosmetic composition" refers to a non-therapeutic composition, that is, one that is not intended for therapeutic use and is applied to an area of ​​healthy skin.

[0079] In particular, the cosmetic composition according to the invention comprises an amount of Myrtus communis extract effective in maintaining and / or improving the homogeneity of skin tone and / or maintaining and / or improving proteostasis and the skin barrier function, more particularly of healthy skin.

[0080] More specifically, Myrtus communis extract may be present in the cosmetic composition at a concentration of 0.5 to 10% by weight relative to the total weight of the cosmetic composition, in particular 1 to 5%.

[0081] In particular, the cosmetic composition according to the invention further comprises at least one cosmetically acceptable excipient.

[0082] According to one embodiment, the extract or composition according to the invention is administered topically to the skin, in particular to healthy skin, more particularly to all or part of the body and / or face.

[0083] The term "topical route" refers to the direct local application and / or spraying of the Myrtus communis extract or the cosmetic composition containing it onto the surface of the skin area to be treated.

[0084] The cosmetic composition may be in the form of a solution, aqueous or oily, rinsed or not, a cream or aqueous gel or an oily gel, including a shower gel, a milk, an emulsion, a microemulsion or a nanoemulsion, including oil-in-water or water-in-oil or multiple or silicone, a mask, a serum, a lotion, a liquid soap, a dermatological bar, an ointment, a mousse, a hair care lotion, a deodorant, a shampoo, a conditioner, a hair mask, a sprayable solution.

[0085] Other advantages and features of the present invention will become apparent from the illustrative examples set forth below.

[0086] EXAMPLES

[0087] Materials and methods

[0088] I. Preparation of an extract according to the invention

[0089] The extract was prepared as follows:

[0090] Grinding of the aerial parts of Myrtus communis,

[0091] Extraction in water at a temperature between 60°C and 90°C for a duration of between 1 and 8 hours,

[0092] Filtrations,- Addition of glycerin to obtain a dry extract concentration of 1% by weight relative to the total extract weight.

[0093] The extract obtained has:

[0094] a total polyphenol content of between 2.5 and 6 g / L (grams of polyphenols per liter of extract),

[0095] a total flavonoid content of between 0.2 and 0.7 g / L (grams of flavonoids per liter of extract),

[0096] a total sugar content of between 2 and 4.5 g / L (grams of sugar per liter of extract),

[0097] a pH between 4 and 5.

[0098] II. Biomarker Study Protocol

[0099] To evaluate the efficacy of the extract in modulating the skin barrier-associated markers Involucrin and Collagen XVII, as well as the proteostasis markers LAMP2A, HSP70, and Proteasome 20S, an aqueous solution containing 1 w% of Myrtus communis extract, as described in Part I, was applied twice daily for three days to the surface of explants obtained from an abdominoplasty of a 31-year-old woman. The treated explants were sectioned, and their marker expression levels were compared to those of control explants. The control treatment consisted of applying water alone to the surface of the explants following the same protocol as the explants treated with the 1% aqueous extract solution. Protein expression levels were determined by image processing analysis of specific immunofluorescent stains (n=3).Each labeling consists of labeling with an antibody specific to the marker being studied and its detection by means of a secondary fluorescent antibody specific to the first antibody.

[0100] The quantification was normalized to the control condition (considered to be 100%) to obtain a mean value (denoted as "mean" in the tables) and a standard deviation. Statistical analyses were performed using one-way analysis of variance (one-way ANOVA) and Dunnett's method with a 95% confidence interval.

[0101] Results

[0102] Increased protein expression of the markers LAMP2A, HSP70 and Proteasome 20S in the presence of a Myrtus communis extract

[0103] The results are presented in Table 1:

[0104] [Table 1]

[0105] LAMP2A

[0106] Group Mean Standard deviation Induction p-value

[0107] (% vs Control) (%) (vs Control)

[0108]

[0109] Control 100 2 0% / Myrtus communis extract 110 2 10% <0.001

[0110] HSP70

[0111] Group Mean Standard deviation Induction p-value (vs (% vs Control) (%) Control) Control 100 10 0% /

[0112] Extract Myrtus communis 151 8 51% <0.001

[0113] 20S Proteasome

[0114] Group Mean Standard deviation Induction p-value (vs (% vs Control) (%) Control

[0115] Control 100 1 0% /

[0116]

[0117] Extract Myrtus communis 136 3 36% <0.001

[0118] Increased protein expression of the markers involucrin and Collagen XVII in the presence of Myrtus Communis extract

[0119] The results are presented in Table 2:

[0120] [Table 2]

[0121] Involucrine

[0122] Group Mean Standard deviation Induction p-value

[0123] (% vs Control) (%) (vs Control)

[0124] Control 100 2 0% /

[0125] Extract Myrtus communis 109 4 9% < 0.1

[0126] Collagen XVII

[0127] Group Mean Standard deviation Induction p-value

[0128] (% vs Control) (%) (vs Control)

[0129] Control 100 4 / /

[0130] Extract Myrtus communis 132 12 32% 0.003

[0131]

[0132] III. Effect on insensible water loss

[0133] A face cream comprising 2%m of diluted Myrtus communis extract as described in Part I (active formula) or the associated placebo composition (composition in which the Myrtus communis extract has been replaced by water) is applied to half of the face by a panel of female volunteers aged 59 to 70 years (n = 20) twice a day for 14 days.

[0134] The measurements of insensible water loss are carried out under controlled conditions at JO and J14 using a closed chamber evaporimeter.

[0135] Indeed, transepidermal water loss (TEWL) measures the skin's ability to retain water in its deeper layers and thus maintain an intact and functional skin barrier. It directly reflects the integrity of the stratum corneum: when it is well-structured and cohesive, the diffusion of water to the outside is limited; conversely, an impaired barrier allows more water to escape, resulting in a higher TEWL (transepidermal water loss, equivalent to transepidermal water loss).

[0136] The results are presented in Table 3:

[0137] [Table 31

[0138] Average variation between J0 and J14 of the condition, p-value between J0 and J14 of the condition, the condition

[0139] (% compared to JO)

[0140] Placebo -4.7% < 0.05 Active formula -17.5% < 0.001 Difference in change between

[0141] placebo and active formula <0.01

[0142] after 14 days of application

[0143]

[0144] IV. Effect on complexion brightness

[0145] A face cream comprising 2%m of diluted Myrtus communis extract as described in Part I (active formula) or the associated placebo composition (composition in which the Myrtus communis extract has been replaced by water) is applied to half of the face by a panel of female volunteers aged 59 to 70 years (n = 20) twice a day for 14 days.

[0146] The evaluation of the effect of the active formula and the placebo on the brightness of the complexion is carried out by quantifying the light scattered on the surface and in volume of a defined area on the cheeks of volunteers photographed in % in diffuse light at JO and J14.

[0147] The results are presented in Table 4:

[0148] [Table 4]

[0149] Average variation between J0 p-value between J0 and J14 of and J14 of the condition the condition

[0150] (% compared to day 0)

[0151] Placebo -0.3% Not significant Active formula +1.8% <0.001 Difference in change between

[0152] placebo and active formula <0.01

[0153] after 14 days of application

[0154]

[0155] V. Effect on skin roughness

[0156] A face cream comprising 2%m of diluted Myrtus communis extract as described in Part I (active formula) or the associated placebo composition (composition in which the Myrtus communis extract has been replaced by water) is applied to half of the face by a panel of female volunteers aged 30 to 45 years (n = 20) twice a day for 28 days.

[0157] The effect of the active formula and placebo on skin roughness was evaluated using standardized image analysis of hemifaces at day 0 and day 28. High-resolution images were acquired under controlled conditions. Skin texture mapping was then performed on these images. The roughness area, expressed in pixels, was measured. 2 is calculated.

[0158] A reduction in this surface area reflects a smoothing effect on the skin texture, indicating an improvement in the homogeneity of the skin's micro-relief.

[0159] The results are shown in Table 5:

[0160] [Table 5]

[0161] Average variation between J0 and J28 p-value between J0 and J28 of the condition and J28 of the condition

[0162] (% compared to JO)

[0163] Placebo -1.9% Not significant Active formula -8.6% <0.001 Difference in change between

[0164] placebo and active formula <0.0001

[0165] after 28 days of application

[0166]

Claims

DEMANDS 1. Non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the homogeneity of skin tone, in particular by maintaining and / or improving the proteostasis and barrier function of the skin.

2. Non-therapeutic cosmetic use of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, to maintain and / or improve the proteostasis and barrier function of the skin.

3. Use according to claim 1 or 2, wherein the extract maintains and / or enhances skin proteostasis, in particular by the protein degradation pathway.

4. Use according to claim 3, wherein the maintenance and / or improvement of proteostasis includes promoting: - the degradation of polypeptides and proteins, - the ubiquitination of proteins followed by their degradation, - protein folding by chaperone proteins.

5. Use according to claim 1 or 2, wherein the extract maintains and / or improves the skin barrier function.

6. Use according to any of the preceding claims, wherein the extract of Myrtus communis is an extract of the aerial parts of the plant, in particular the leaves, stem, flower buds and / or flowers.

7. Use according to any one of the preceding claims, wherein the extract of Myrtus communis is obtained by hot extraction in water and optionally diluted in water, in an organic solvent or in a mixture thereof.

8. Use according to any one of the preceding claims, wherein the Myrtus communis extract is diluted in an organic solvent, in particular glycerin.

9. Use according to claim 7 or 8, wherein the Myrtus communis extract has a total polyphenol content of between 1 and 10 g / L, preferably between 2 and 7 g / L, more preferably between 2.5 and 6 g / L, and a total sugar content of between 1 and 5 g / L, preferably between 1.5 and 4.5 g / L, more preferably between 2 and 4 g / L.

10. Use according to any one of the preceding claims, wherein the extract of Myrtus communis is incorporated into a cosmetic composition further comprising at least one cosmetically acceptable excipient.

11. Use according to any one of the preceding claims, characterized in that it is a topical use.

12. A non-therapeutic cosmetic treatment and / or care method characterized in that it comprises the topical application to at least one area of ​​skin of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, or of a cosmetic composition comprising it, to maintain and / or improve the homogeneity of skin tone, in particular via the maintenance and / or improvement of proteostasis and the skin barrier function, in particular of healthy skin.

13. A non-therapeutic cosmetic treatment and / or care process characterized in that it comprises the topical application to at least one area of ​​skin of an extract of Myrtus communis obtained by extraction with a solvent comprising more than 90% by weight of water relative to the total weight of solvent, or of a cosmetic composition comprising it, to maintain and / or improve the proteostasis and barrier function of the skin, in particular of healthy skin.

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