Cosmetic use of an extract of at least one bacterium of the species staphylococcus epidermidis to prevent the decrease of and / or reinforce the barrier function of the skin

Abstract

The present invention relates to the non-therapeutic cosmetic use of an extract of at least one bacterium of the species Staphylococcus epidermidis obtained by at least one step of culturing at least one bacterium of the species Staphylococcus epidermidis, in the presence of a culture medium comprising i) at least one monosaccharide, ii) at least one peptone of vegetable origin and / or at least one yeast extract, and optionally iii) at least one microelement, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration. The present invention also relates to the non-therapeutic cosmetic use of a biomass extract of at least one bacterial strain of the species Staphylococcus epidermidis selected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695 to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration, and also to a method for cosmetic treatment of the skin using said extract within a composition.

Description

Cosmetic use of an extract of at least one bacterium of the speciesStaphylococcus epidermidisto prevent the decrease of and / or reinforce the barrier function of the skin

[0001] The present invention relates to the field of skincare, more particularly to prevention of the decrease of and / or to reinforcement of the barrier function of the skin.

[0002] The present invention relates to the non-therapeutic cosmetic use of an extract of at least one bacterium of the speciesStaphylococcus epidermidisto prevent the decrease of and / or reinforce the barrier function of the skin, obtainable according to a particular process. The present invention relates to the non-therapeutic cosmetic use of an extract of at least one specific bacterial strain of the speciesStaphylococcus epidermidisto prevent the decrease of and / or reinforce the barrier function of the skin. The present invention also relates to a method for cosmetic treatment of the skin, using said extract within a composition, to prevent the decrease of and / or reinforce the barrier function of the skin.Prior art

[0003] The skin is the primary barrier for protecting the body from the external environment. Human skin consists of three compartments, namely a superficial compartment, which is the epidermis, the dermis, and a deep compartment, which is the hypodermis.

[0004] The human epidermis is composed mainly of three types of cells, these being keratinocytes, which form the vast majority (~80%), melanocytes, and Langerhans cells. Each of these cell types contributes, by virtue of its intrinsic functions, to the essential role played in the body by the skin, notably the role of protecting the body from external attacking factors and from loss of water, and so exerts a barrier function with respect to the external environment.

[0005] The epidermis is conventionally divided into a basal layer of keratinocytes constituting the germinative layer of the epidermis, a “spinous” layer consisting of several layers of polyhedral cells positioned on the germinative layers, one to three “granular” layers, and finally the cornified layer (orstratum corneum), consisting of a set of layers of keratinocytes at the terminal stage of their differentiation, known as corneocytes. Corneocytes are anuclear cells mainly composed of a fibrous matrix containing cytokeratins, surrounded by a very strong structure 15 nm thick, known as the cornified envelope. Stacking of these corneocytes constitutes the cornified layer, which is responsible for the physical barrier function of the epidermis.

[0006] The cornified layer constitutes a veritable protective barrier against exogenous factors and prevents endogenous water loss. Its effective renewal and also the quality of its structure are essential for providing an effective barrier against the external environment and for limiting water losses, which are the cause of dehydration and the appearance of dry skin (Velarde M.C., J. Invest. Dermatol., 2017, 137, 1206). Active entities involved in effective regulation of the stratum corneum include filaggrin (FLG).

[0007] Indeed, filaggrin is a major structural protein involved in the surface barrier of the skin. Mutations in the gene encoding filaggrin are the most significant risk factors for skin barrier disorders. Approximately 50% of patients suffering from atopic dermatitis carry loss-of-function mutations in filaggrin. Esparza-Gordillo et al. (Curr Opin Allergy Clin Immunol. 2010 Oct;10(5):418-26) indicated that 10% to 20% of people in industrialized countries suffer from atopic dermatitis, with a strong predisposition in children when the mother carries an FLG mutation. Mutation in the FLG gene is also associated with ichthyosis vulgaris, which is a common skin manifestation characterized by dry and squamous skin, with a prevalence of at least one case per 250 people.

[0008] Reinforcing the quality of the epidermis by favoring the effective regulation of epidermal differentiation, in particular the production of filaggrin, which is a key protein for the maturation of the stratum corneum – indeed, the progressive degradation of filaggrin during differentiation, leads to the stiffening of keratin filaments and to the production of natural hydration factors, thus contributing to the maintenance of functions of the epidermis and in particular its barrier quality, and also to effective hydration of the skin.

[0009] Accordingly, there is a need to identify new active agents which allow the barrier function of the skin to be reinforced.

[0010] In addition, there is a need to identify new active agents making it possible to prevent and / or treat dry skin and / or prevent and / or treat cosmetic signs associated with dry skin and / or promote skin hydration.

[0011] In parallel, the formulation of environmentally friendly cosmetic products, i.e., products whose design and development take account of environmental issues, is becoming a major preoccupation for contributing to meeting the challenges facing the planet. It is therefore proving essential to propose ingredients that make it possible to respond to these environmental issues.

[0012] In this context, it is important to develop new ingredients and / or active agents that are environmentally conscious and are especially of natural origin, in particular biobased, and / or that are derived from sustainable sources that are not obtained from petrochemistry and / or that are biodegradable and / or the process for the extraction of which requires a low consumption of energy and water in order to provide compositions that enable a reduction in the environmental impact of the products.Disclosure of the invention

[0013] It is an object of the present invention to provide a cosmetic composition meeting all of these requirements.

[0014] Indeed, the inventors have made the surprising discovery that an extract of a bacterium of the speciesStaphylococcus epidermidis,in particular a bacterial extract in the form of a lysate of a bacterial strain CNCM-I 5691 of the speciesStaphylococcus epidermidisor a bacterial extract in the form of a supernatant of a bacterial strain CNCM-I 5691 of the speciesStaphylococcus epidermidis,promotes the increase of expression of the protein filaggrin within anin vitroequivalent of human epidermis, and has a hydrating effect close to that of glycerine after application to anin vitroequivalent of human stratum corneum, and are therefore useful to prevent the decrease of and / or reinforce the barrier function of the skin, and promote the hydration of the skin.Summary of the invention

[0015] A first subject of the present invention is the non-therapeutic cosmetic use of an extract of at least one bacterium of the speciesStaphylococcus epidermidisobtainable, obtained or directly obtained by at least one step of culturing at least one bacterium of the speciesStaphylococcus epidermidis, preferably at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695, in the presence of a culture medium comprising i) at least one monosaccharide, ii) at least one peptone of vegetable origin and / or at least one yeast extract, and optionally iii) at least one microelement, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0016] Another of its subjects is the non-therapeutic cosmetic use of a biomass extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695 to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0017] The present invention also relates to a method for non-therapeutic cosmetic treatment of the skin, comprising topical application to the skin of a composition comprising in a physiologically acceptable medium an extract according to the invention, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0018] Other features, aspects and advantages of the invention will become apparent on reading the detailed description that follows.Definitions

[0019] The term "skin" is understood to mean all of the skin of the body and the scalp of a human being, and preferably the skin of the face, neckline, neck, arms and forearms, legs and hands, and even more preferably still the skin of the face (in particular of the forehead, nose, cheeks, lips and chin), neckline and neck.

[0020] The term "physiologically acceptable medium" is understood to denote a medium which is particularly suitable for the application of a composition of the invention to keratin materials, in particular the skin.

[0021] As used herein, the terms “treat” and “treatment” are intended to denote the alleviation of the symptoms associated with a disorder or a specific condition and / or the elimination of said symptoms and also the complete disappearance of the disorder or condition in question.

[0022] In the context of the present invention, the terms “prevent” and “prevention” denote the reduction, to a lesser degree, of the risk or probability of occurrence of a given phenomenon.

[0023] Within the meaning of the present invention, the term "reinforce" or "promote" refers to an increase in the effects of the phenomenon. For example, the promotion of skin hydration may lead to greater skin hydration than in the absence of the use of the extract according to the invention.

[0024] Within the meaning of the present invention, the term "dry skin" is understood to mean skin associated with a drop in the level of cutaneous hydration associated with a modification of the maturation process of the stratum corneum. Clinically, dry skin is skin that can be characterized by a low corneometry (level of hydration of the stratum corneum) of ≤ 40 UA (Corneometer®, Courage - Khazaka) and / or a dryness score of ≥ 2 (ODS scale (0-4)) and / or a roughness score of ≥ 4 Dermascore scale (0-7)).

[0025] The term "cosmetic signs associated with dry skin" is understood to refer, within the meaning of the present invention, to the roughness of the skin, the scales, the squamae, and the marked microrelief of the skin, a reduction in the elasticity of the skin, the dull complexion, the tightness of the skin, the sensations of discomfort, the itching.

[0026] The term "topical use or application" is understood to mean the use or application at the surface of the keratin materials in question, preferably at the surface of the skin in question.

[0027] Staphylococcus epidermidis, or white staphylococcus, is a human commensal bacterium and part of the mucocutaneous flora of virtually the whole of the human population.

[0028] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5688 (I-5688) is the strain deposited by L’Oréal with the CNCM on June 3, 2021 under accession number CNCM I-5688 (I-5688).

[0029] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5689 is the strain deposited by L’Oréal with the CNCM on June 3, 2021 under accession number CNCM I-5689 (I-5689).

[0030] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5904 is the strain deposited by L’Oréal with the CNCM on September 21, 2022 under accession number CNCM I-5904 (I-5904).

[0031] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5691 is the strain deposited by L’Oréal with the CNCM on June 3, 2021 under accession number CNCM I-5691 (I-5691).

[0032] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5692 is the strain deposited by L’Oréal with the CNCM on June 3, 2021 under accession number CNCM I-5692 (I-5692).

[0033] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5693 is the strain deposited by L’Oréal with the CNCM on June 3, 2021 under accession number CNCM I-5693 (I-5693).

[0034] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5694 is the strain deposited by L’Oréal with the CNCM on June 7, 2021 under accession number CNCM I-5694 (I-5694).

[0035] Staphylococcus epidermidis(S. epidermidis) strain CNCM I-5695 is the strain deposited by L’Oréal with the CNCM on June 7, 2021 under accession number CNCM I-5695 (I-5695).

[0036] Within the meaning of the present invention, the term "extract of at least one bacterium" refers equally to the culture supernatant of said bacteria, the biomass obtained after culturing said bacteria or else the extracts of the biomass that are obtained by treating this biomass.

[0037] The bacterial extract according to the invention may be in a living, semi-active or inactivated, dead, form; the bacterial extract according to the invention is preferably in an inactivated or dead form.

[0038] Advantageously, said extract is distinct from the culture supernatant of said bacteria.

[0039] Advantageously, said extract of at least one bacterium of the speciesStaphylococcus epidermidisis a lysate of at least one bacterium of the speciesStaphylococcus epidermidis.

[0040] Within the meaning of the present invention, the term "lysate" means a material obtained after the alteration of bacterial cells, such as the destruction or breakage of bacterial cells, in particular of the cell walls and / or membranes, by a phenomenon known as cell lysis, thus causing the release of intracellular biological constituents naturally contained in the cells of the microorganism in question.

[0041] Within the meaning of the present invention, the term “lysate” is used without prejudice to denote the entirety of the lysate obtained by lysis of the microorganism in question, or only a fraction thereof.

[0042] The lysate used is thus formed totally or partially from the intracellular biological constituents and constituents of the cell walls and membranes.

[0043] More specifically, it contains the cellular cytoplasmic fraction containing enzymes such as lactic acid dehydrogenase, phosphatases, phosphoketolases, transaldolases and metabolites. For illustrative purposes, the constituents of the cell walls are especially peptidoglycan, murein or mucopeptide and teichoic acid, and the constituents of the cell membranes are composed of glycerophospholipids.

[0044] This cell lysis can be accomplished by various technologies well known to those skilled in the art, such as osmotic shock, thermal shock, ultrasound or centrifugation, preferably thermal shock such as freezing followed by thawing.Detailed description

[0045] A first subject of the present invention is the non-therapeutic cosmetic use of an extract of at least one bacterium of the speciesStaphylococcus epidermidisobtainable, obtained or directly obtained by at least one step of culturing at least one bacterium of the speciesStaphylococcus epidermidis, preferably an extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695, in the presence of a culture medium comprising i) at least one monosaccharide, ii) at least one peptone of vegetable origin and / or at least one yeast extract, and optionally iii) at least one microelement, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0046] The extract of at least one bacterium of the speciesStaphylococcus epidermidisaccording to the invention is preferably chosen from i) the culture supernatant of said bacterium, ii) the biomass obtained after culturing said bacterium and iii) the biomass obtained after culturing said bacterium which has undergone a chemical or physical treatment such as a cell lysis treatment and / or a stabilization treatment. Said biomass iii) being preferably in the form of a lysate.

[0047] Preferably, said chemical or physical treatment is chosen from osmotic shock, thermal shock, ultrasound, centrifugation, autoclaving, ultra-high temperature (UHT technique), high-pressure sterilization, freeze drying, gamma radiation, and freezing.

[0048] Preferably, said bacterium of the speciesStaphylococcus epidermidiscultured is a bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under the serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695, preferably a bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5691, I-5904, I-5692, I-5693, I-5694 and I-5695, even more preferably a bacterial strain of the speciesStaphylococcus epidermidisdeposited at the CNCM under the serial number I-5691.

[0049] Advantageously, said culture medium is free of peptone of animal origin, and preferably said culture medium is free of peptone casein.

[0050] Advantageously, said culture medium comprises less than 4 g / L of sodium chloride, preferably less than 1 g / L by weight of sodium chloride, better still less than 0.5 g / L of sodium chloride, or even is free (0 g / L) of sodium chloride.

[0051] Advantageously, said culture medium is distinct from TSB (tryptic soy broth) medium.

[0052] Within the meaning of the present invention, the term "peptone" is understood to mean a product of a hydrolysis reaction of protein-rich food products. This hydrolysis can be chemical or enzymatic. There are three distinct types of protein raw materials for the manufacture of peptones: peptones of animal origin such as acid casein and whey; peptones of vegetable origin such as soybean, cotton, corn, bean and wheat; and peptones of mycelial origin. Besides the origin of the proteins, peptones can be separated according to their type of hydrolysis: chemical hydrolysis typically by hydrochloric acid, then neutralized by sodium hydroxide; enzymatic hydrolysis, using proteolytic enzymes, digestive enzymes such as pepsin, trypsin and pancreatin, or not, such as papain.

[0053] According to the present invention, the peptone used is a peptone of vegetable origin, preferably a peptone of vegetable origin chosen from soybean, cotton, corn, bean or wheat peptones.

[0054] Advantageously, the peptone used is a peptone obtained by enzymatic hydrolysis, preferably using proteolytic enzymes, more preferably using papain.

[0055] According to one preferred embodiment, the peptone used is a soybean papain peptone.

[0056] Preferably, said culture medium comprises in water, preferably in distilled water:

[0057] i. at least one monosaccharide present in the culture medium in an amount ranging from 0.5 to 30 g / L, and

[0058] ii. at least one peptone of vegetable origin present in the culture medium in an amount ranging from 0.5 to 15 g / L, and / or at least one yeast extract present in the culture medium in an amount ranging from 0.5 to 15 g / L, and

[0059] iii. optionally at least one microelement present in the culture medium in an amount ranging from 0.05 to 6 mg / L, and

[0060] iv. optionally at least one calcium salt present in the culture medium in an amount ranging from 0.01 to 1 g / L.

[0061] Preferentially, said culture medium comprises in water, preferably in distilled water:

[0062] i. at least one monosaccharide present in the culture medium in an amount ranging from 0.5 to 7 g / L, and

[0063] ii. at least one peptone of vegetable origin present in the culture medium in an amount ranging from 0.5 to 5 g / L, and / or at least one yeast extract present in the culture medium in an amount ranging from 0.5 to 5 g / L, and

[0064] iii. optionally at least one microelement present in the culture medium in an amount ranging from 0.5 to 6 mg / L, and

[0065] iv. optionally at least one calcium salt present in the culture medium in an amount ranging from 0.01 to 0.1 g / L.

[0066] More preferentially, said culture medium comprises in water, preferably in distilled water:

[0067] i. at least one monosaccharide present in the culture medium in an amount ranging from 0.5 to 7 g / L, said monosaccharide being chosen from glucose, sucrose, and mixtures thereof, and

[0068] ii. at least one peptone of vegetable origin present in the culture medium in an amount ranging from 0.5 to 5 g / L, said peptone being soybean papain peptone, and at least one yeast extract present in the culture medium in an amount ranging from 0.5 to 5 g / L, said yeast extract being an autolytic yeast extract, and

[0069] iii. at least one microelement present in the culture medium in an amount ranging from 0.5 to 6 mg / L, the one or more microelements being chosen from Heller microelements, and

[0070] iv. at least one calcium salt present in the culture medium in an amount ranging from 0.01 to 0.1 g / L, said calcium salt being calcium chloride.

[0071] Even more preferentially, said culture medium comprises in water, preferably in distilled water:

[0072] i. at least one monosaccharide present in the culture medium in an amount ranging from 0.5 to 7 g / L, said monosaccharide being glucose, and

[0073] ii. at least one peptone of vegetable origin present in the culture medium in an amount ranging from 0.5 to 5 g / L, said peptone being soybean papain peptone, and at least one yeast extract present in the culture medium in an amount ranging from 0.5 to 5 g / L, said yeast extract being an autolytic yeast extract, and

[0074] iii. at least one microelement present in the culture medium in an amount ranging from 0.5 to 6 mg / L, the one or more microelements being chosen from Heller microelements, and

[0075] iv. at least one calcium salt present in the culture medium in an amount ranging from 0.01 to 0.1 g / L, said calcium salt being calcium chloride.

[0076] The Heller microelements, whose composition is given below, were described by Heller, Ann Sci. Nat. Biol. Veg. 14:1 223 (1953). They are mixtures of various mineral elements which were recommended by Heller, not for culturing bacteria, but for the nutrition of plant tissues cultivated in vitro. It should be noted here that no attempt has been made to determine whether the Heller microelements are all indispensable or useful for culturing said bacterium. However, it has been found that the Heller microelements used together in combination with the other abovementioned constituents effectively allow the bacteria in question to be cultured.

[0077] The composition of the Heller microelements, per liter of distilled water, is as follows:

[0078] ZnSO4·7 H2O1 gMnSO4·H2O0.076 gCuSO4·5H2O0.003 gKI0.010 gAlCl3.6H2O0.050 gNiCl2.6H2O0.030 g

[0079] The culturing step may be performed at the appropriate temperature suitable for the bacterial species cultured. Generally, this temperature is between 18 and 40°C. The pH of the culture medium is preferably between 5 and 8.

[0080] When the bacterial culture has reached a terminal stage, that is to say in general when the biomass is at the end of exponential growth, said biomass can be separated from the culture medium. Thus, preferably, after the culturing step, a step of separating the bacteria, also called biomass, from the culture medium is carried out. This separation step can be obtained by any conventional technique, preferably by centrifugation, filtration, or coagulation, in particular with an alcohol such as ethanol, isopropanol, isobutanol, and mixtures thereof. More preferably, the separation step is a separation of the bacteria (or biomass) from the culture medium by centrifugation.

[0081] The supernatant fraction of this biomass can also be filtered in a sterile container to remove suspended particles, using for example a 0.2 µm filter, and / or stabilized, preferably by heat treatment, by autoclaving for example between 115°C and 121°C for 15 to 40 minutes. This supernatant fraction may also be transferred aseptically into a sterile container. According to one particular embodiment of the invention, the supernatant fraction thus obtained is used as an active agent to prevent the decrease of and / or reinforce the barrier function of the skin and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0082] Preferably, after the step of separating the bacteria (or biomass), a cell lysis step is performed. This cell lysis step can be obtained by any conventional technique well known to those skilled in the art, preferably by osmotic shock, thermal shock, ultrasound, or centrifugation, preferably by thermal shock such as freezing followed by thawing.

[0083] Preferably, after the step of separating the bacteria (or biomass) from the culture medium, a step of stabilizing the bacteria (or biomass) is carried out.

[0084] Preferably, after the cell lysis step, a step of stabilizing the lysate obtained at the end of the cell lysis step is carried out.

[0085] This stabilization step can then be carried out by any method well known to those skilled in the art, preferably by autoclaving, ultra-high temperature (UHT technique), high-pressure sterilization, freeze drying, gamma radiation or freezing, preferentially by autoclaving, even more preferentially by autoclaving carried out at a temperature of between 115°C and 121°C and / or for a time of between 15 and 40 minutes.

[0086] In one preferred embodiment, the stabilization step is carried out by autoclaving carried out at a temperature of between 115°C and 121°C and / or for a time of between 15 and 40 minutes.

[0087] In another preferred embodiment, the stabilization step is carried out by freeze drying.

[0088] A preparation example for an extract which can be used according to the invention is also given in the examples.

[0089] The present invention also relates to the non-therapeutic cosmetic use of a biomass extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695 as an active agent to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0090] Advantageously, said extract is a lysate of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695.

[0091] Advantageously, said extract is an extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5691, I-5904, I-5692, I-5693, I-5694 and I-5695.

[0092] Advantageously, said extract is a lysate of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5691, I-5904, I-5692, I-5693, I-5694 and I-5695.

[0093] More preferably, said extract is an extract of at least one bacterial strain of the speciesStaphylococcus epidermidisdeposited at the CNCM under the serial number I-5691.

[0094] Even more preferably, said extract is a lysate of at least one bacterial strain of the speciesStaphylococcus epidermidisdeposited at the CNCM under the serial number I-5691.

[0095] Advantageously, said extract comprises amino acids; preferably, said amino acids are present in an amount ranging from 20% to 50% by weight relative to the total weight of the dry extract; more preferably, said amino acids are present in an amount ranging from 25% to 45% by weight relative to the total weight of the dry extract.

[0096] The amino acids can be chosen from aspartic acid, threonine, serine, glutamic acid, proline, valine, alanine, cystine, glycine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, arginine, histidine, and mixtures thereof.

[0097] For the purposes of the present invention, the term "amino acids" is understood to mean both free amino acids and those contained in proteins.

[0098] Advantageously, said extract comprises lipids; preferably, said lipids are present in an amount ranging from 1% to 10% by weight relative to the weight of the dry extract; more preferably, said lipids are present in an amount ranging from 3% to 7% by weight relative to the weight of the dry extract.

[0099] Advantageously, said extract comprises sugars; preferably, said sugars are present in an amount ranging from 1% to 10% by weight relative to the weight of the dry extract; more preferably, said sugars are present in an amount ranging from 3% to 7% by weight relative to the weight of the dry extract.

[0100] Advantageously, said extract comprises mineral matter; preferably, said mineral matter is present in an amount ranging from 10% to 30% by weight relative to the weight of the dry extract; more preferably, said mineral matter is present in an amount ranging from 15% to 25% by weight relative to the weight of the dry extract.

[0101] According to one preferred embodiment, the said extract comprises:

[0102] - from 20% to 50% by weight of amino acids relative to the total weight of the dry extract, more preferably from 25% to 45% by weight of amino acids relative to the total weight of the dry extract, and

[0103] - from 1% to 10% by weight of lipids relative to the weight of the dry extract, more preferably from 3% to 7% by weight of lipids relative to the weight of the dry extract, and

[0104] - from 1% to 10% by weight of sugars relative to the weight of the dry extract, more preferably from 3% to 7% by weight of sugars relative to the weight of the dry extract, and

[0105] - from 10% to 30% by weight of mineral matter relative to the weight of the dry extract, more preferably from 15% to 25% by weight of mineral matter relative to the weight of the dry extract.

[0106] The extract according to the invention can be used pure or in a composition, in particular a cosmetic composition, more particularly for caring for keratin materials, also comprising a physiologically acceptable medium.

[0107] Advantageously, said extract is present in said composition in an amount ranging from 0.0001% to 20% by weight of dry matter relative to the total weight of the composition, preferably in an amount ranging from 0.001% to 10% by weight of dry matter, more preferably in an amount ranging from 0.01% to 5% by weight of dry matter, and better still in an amount ranging from 0.1% to 1% by weight of dry matter, relative to the total weight of the composition.

[0108] Of course, said composition may comprise an extract of a single type of bacterial strain as indicated above or a mixture of extracts of at least two or more bacterial strains as listed above.

[0109] Said composition is preferably devoid of an extract of any strain other than a strain as listed above.

[0110] The physiologically acceptable medium is generally suited to the nature of the support onto which the composition has to be applied, and also to the appearance under which the composition has to be packaged.

[0111] The physiologically acceptable medium may comprise water and optionally one or more water-miscible solvents.

[0112] According to one preferred embodiment, said composition comprises at least 20% by weight of water, in particular at least 40% by weight of water, relative to the total weight of said composition. Preferentially, said composition has a water content ranging from 20% to 95% by weight, better still from 40% to 90% by weight, relative to the total weight of the composition.

[0113] The water-miscible (at room temperature such as 25°C) organic solvents include lower monoalcohols having from 1 to 5 carbon atoms such as ethanol and isopropanol, glycols having from 2 to 8 carbon atoms such as ethylene glycol, hexylene glycol, propylene glycol, 1,3-butylene glycol, pentylene glycol and dipropylene glycol, and glycerol.

[0114] The water-miscible organic solvent(s) may be present in a concentration of from 0.01% to 30% by weight, preferably from 0.1% to 20% by weight and more preferably from 1% to 15% by weight, relative to the total weight of the composition.

[0115] According to one particular embodiment, the pH of the composition according to the invention is between 4 and 7.5, notably between 4.5 and 7, and in particular between 4.7 and 6.5.

[0116] Said composition may also comprise any water-soluble or water-dispersible compound, such as gelling agents, film-forming polymers, thickeners, surfactants, and mixtures thereof.

[0117] Said composition may also comprise at least one fatty substance, such as one or more oils.

[0118] According to one embodiment, the composition may comprise from 5% to 80% by weight of fatty substance, preferably of oil(s), and preferably from 10% to 60% of fatty substance, preferably of oil(s), by weight relative to the total weight of said composition.

[0119] The term “oil” refers to any fatty substance that is in liquid form at ambient temperature (20-25°C) and at atmospheric pressure. These oils may be of plant, mineral or synthetic origin.

[0120] Oils that can be used in said composition include, for example:

[0121] - hydrocarbon oils of plant origin;

[0122] - synthetic esters and ethers, notably of fatty acids, for instance oils of formulae R1COOR2 and R1OR2 in which R1 represents the residue of a fatty acid comprising from 8 to 29 carbon atoms, and R2 represents a branched or unbranched hydrocarbon chain containing from 3 to 30 carbon atoms;

[0123] - linear or branched hydrocarbons, of mineral or synthetic origin;

[0124] - fatty alcohols having from 8 to 26 carbon atoms;

[0125] - fluoro oils which are partially hydrocarbon-based and / or silicon-based;

[0126] - silicone oils;

[0127] - mixtures thereof.

[0128] In the list of oils mentioned above, a hydrocarbon oil means any oil mainly comprising carbon and hydrogen atoms, and optionally ester, ether, fluoro, carboxylic acid and / or alcohol groups.

[0129] According to a preferred embodiment of the invention, the composition used in the context of the invention is a water-in-oil (W / O) or oil-in-water (O / W) emulsion, preferably an oil-in-water (O / W) emulsion. The proportion of fatty substance in the emulsion may range from 5% to 80% by weight and preferably from 10% to 60% by weight relative to the total weight of the composition.

[0130] The composition may comprise at least one emulsifier. The emulsions generally contain at least one emulsifier chosen from amphoteric, anionic, cationic and non-ionic emulsifiers, used alone or as a mixture, and optionally a coemulsifier. The emulsifiers are appropriately chosen according to the emulsion to be obtained (W / O or O / W).

[0131] The emulsifier and the coemulsifier are generally present in the composition in a proportion ranging from 0.3% to 20% by weight, and preferably from 0.5% to 10% by weight, relative to the total weight of the composition.

[0132] Preferably, said composition may comprise at least one additional ingredient selected from the group consisting of thickeners, fragrances, preservatives, cosmetic active agents other than the extract according to the invention, such as active agents promoting the barrier function of the skin and moisturizing active agents other than the extract according to the invention, emollients, fillers and mixtures thereof.

[0133] Such an additional ingredient may represent from 0.0001% to 20%, preferably from 0.01% to 10% and better still from 0.1% to 5% by weight, relative to the total weight of the composition.

[0134] Of course, a person skilled in the art will take care to select these one or more additional ingredients, and / or the amount thereof, such that the advantageous properties of the strains according to the invention are not, or are not substantially, adversely affected by the envisioned addition.

[0135] Said composition may be in any presentation form normally used in the cosmetics field.

[0136] It may notably be in the form of an aqueous or aqueous-alcoholic solution, which may be gelled, a dispersion of the lotion type, which may be a two-phase dispersion, an oil-in-water or water-in-oil emulsion or a multiple emulsion, an aqueous gel, or else a dispersion of oils in an aqueous phase, notably using spherules, it being possible for these spherules to be polymeric particles or, better still, lipid vesicles of ionic and / or nonionic type. It may be of more or less fluid liquid consistency.

[0137] Preferentially, a composition according to the invention differs from compositions having an essentially detergent purpose with regard to the skin, hair and / or mucous membranes, such as soaps, shampoos and shower gels for washing and / or cleansing.

[0138] Said composition is preferentially suitable for topical administration.

[0139] Thus said composition may comprise any constituents usually employed in the envisaged topical application and administration.

[0140] Said composition may advantageously be in the form of an emulsion, particularly obtained by dispersion of an aqueous phase in a fatty phase (W / O) or of a fatty phase in an aqueous phase (O / W), of liquid or semi-liquid consistency of the milk type, or of soft consistency, or even of a multiple emulsion (W / O / W or O / W / O). These compositions are prepared according to the usual known methods.

[0141] More particularly, said composition may be intended for topical application and may preferably be in the form of an emulsion, preferably an oil-in-water emulsion. Preferably, such an emulsion is not intended to be rinsed off after application.

[0142] Said composition is preferably intended to be applied to keratin materials, preferably the skin.

[0143] Said composition according to the invention may be manufactured via any known method generally used in the cosmetics field.

[0144] The ingredients are mixed before shaping, in the order and under conditions readily determined by a person skilled in the art.

[0145] According to one particular mode of the invention, other agents intended to enhance the appearance and / or texture of the skin may also be added to said composition.

[0146] The present invention also relates to a method for non-therapeutic cosmetic treatment of the skin, comprising topical application to the skin of a composition comprising in a physiologically acceptable medium an extract according to the invention, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.

[0147] The cosmetic uses and processes considered according to the invention are non-therapeutic.

[0148] The cosmetic uses and methods of the invention are preferentially performed by topically administering an extract according to the invention or a composition according to the invention.

[0149] By way of illustration, the cosmetic use or method according to the invention may be implemented by topical application, daily for example, of at least one composition according to the invention, which may be formulated, for example, in the form of a cream, gel, serum, lotion, emulsion, or makeup-removing milk, preferably in the form of an emulsion.

[0150] The application may be repeated, for example, once to twice daily for one or more days and generally over an extended period of at least 4 weeks, or even 4 to 15 weeks, with, where appropriate, one or more periods of stoppage.

[0151] According to one embodiment, the application is daily (once a day) and generally over a prolonged period of at least 4 weeks, or even 4 to 15 weeks, with, where appropriate, one or more periods of stoppage.

[0152] According to one embodiment, the cosmetic treatment method according to the invention may comprise a single application.

[0153] Another subject of the present invention is a method for preparing an extract of at least one bacterium of the speciesStaphylococcus epidermidiscomprising at least one step of culturing at least one bacterium of the speciesStaphylococcus epidermidisin the presence of a culture medium comprising i) at least one monosaccharide, ii) at least one peptone of vegetable origin and / or at least one yeast extract, and optionally iii) at least one microelement.

[0154] The present invention also relates to an extract of at least one bacterium of the speciesStaphylococcus epidermidis, preferably an extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under the serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695, obtainable, obtained or directly obtained by the abovementioned preparation method.

[0155] The present invention also relates to a biomass extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under the serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695.

[0156] Advantageously, the steps of the method and also the extract are as defined above.

[0157] Throughout the description, including the claims, the terms “between ... and ...”, and “ranging from ... to ...” should be understood as meaning limits included, unless otherwise specified.

[0158] The examples that follow illustrate the present invention without limiting the scope thereof.

[0159] In the examples, unless otherwise specified, the temperature is room temperature (20°C) and is expressed in degrees Celsius, and the pressure is atmospheric pressure.Examples

[0160] Example 1: Preparation of a biomass extract of the Staphylococcus epidermidis strain CNCM-I 5691 according to the invention

[0161] A culture of theStaphylococcus epidermidisstrain CNCM-I 5691 is carried out in its complete culture medium in a 10 effective liter bioreactor in batch or fed batch mode. During this step, the pH is regulated at 6.5 by adding a 1M KOH solution, the temperature is maintained at 32°C and the dissolved oxygen at 40%.

[0162] The composition of the initial culture medium is described in Table 2 below.

[0163] Chemical namesConcentrations by massAutolytic yeast extract5 g / LSoybean papain peptone5 g / LGlucose6.5 g / LKH2PO40.088 g / LCaCl20.050 g / LCuSO4.5H2O60 µg / LMnSO4.1H2O152 µg / LKI20 µg / LZnSO4.7H2O200 µg / LAlCl3.6H2O100 µg / Ldeionized waterqs for 1 L

[0164] As soon as the plateau phase is reached after 20 to 48 hours of culture, the extraction and the separation of the cells are carried out by centrifugation (under laboratory conditions, 10 000 g for 30 min). Then the pellet, also called biomass, containing the cells is recovered, to be subsequently frozen at -20°C and then thawed, allowing the cells to burst and thus a lysate to be obtained. The lysate is then packaged in bags or tubes and finally stabilized by sterilization at 121°C for 30 minutes.

[0165] The lysate obtained at the end of the method as described according to the example contains 5.2% by weight of dry matter, relative to the total weight of the lysate.

[0166] The analysis of the constituents of the dry extract is presented in Table 3 below.

[0167] Compositiong per 100 g of dry extractTotal lipids5.88Total amino acids34.30Total sugars5.29Mineral matter19.01

[0168] Example 2: Preparation of a supernatant extract of the Staphylococcus epidermidis strain CNCM-I 5691 according to the invention

[0169] A culture of theStaphylococcus epidermidisstrain CNCM-I 5691 is carried out in its complete culture medium in a 10 effective liter bioreactor in batch or fed batch mode. During this step, the pH is regulated at 6.5 by adding a 1M KOH solution, the temperature is maintained at 32°C and the dissolved oxygen at 40%.

[0170] The composition of the initial culture medium is described in Table 2 above.

[0171] As soon as the plateau phase is reached after 20 to 48 hours of culture, the extraction and the separation of the cells are carried out by centrifugation (under laboratory conditions, 10 000 g for 30 min). Then the supernatant, i.e., the culture medium freed of cells, is recovered. The supernatant is then stabilized by autoclaving heat treatment for 30 minutes at 121°C.

[0172] Example 3: Evaluation of the impact of the culture medium on the expression of the protein filaggrin (FLG)

[0173] Preparation of a biomass extract ofStaphylococcus epidermidisin a TSB medium (non-invention): a pre-culture is prepared with 1 colony of theStaphylococcus epidermidisstrain CNCM-I 5691 in 5 mL of liquid TSB medium (Sigma Aldrich ref 43592) with the following composition in g / l: casein peptone (pancreatic), 17; dipotassium hydrogen phosphate, 2.5; glucose, 2.5; sodium chloride, 5; soya peptone (papain digest.), 3.

[0174] The pH is adjusted to 7.3±0.2 (25°C), at 37°C and 150 rpm (Innova 4230 incubator).

[0175] The culture is then incubated at 37°C and 150 rpm for 24 h. After cessation of culturing (stationary phase), centrifugation (10 min at 11 000 g; ref. Sigma 6-16K) is carried out to separate the bacteria from the supernatant. The supernatants are filtered to 0.2 μm and a portion (50 µL) is spread onto TSA dishes to verify the absence of viability. On the other hand, the bacteria are washed twice with 1 mL of sterile PBS (Gibco Ref 14190-094) and then resuspended in 1 mL of sterile PBS. One half is placed in a water bath at 65°C for 35 min to be inactivated, while the other half will serve as a positive viability control. 50 µL of each sample are spread onto TSA to verify the absence of viable cells in the inactivated sample compared to the positive viability control, where the number of CFUs is counted.

[0176] The results were carried out on 3 Episkin campaigns from different batches, normalized with respect to the total proteins, and are presented in Table 4 below. *p < 0.1, **p < 0.05, ***p < 0.001.

[0177] Level of expression of filaggrin*Standard deviationStudent testControl1----Extract according to the invention, obtained according to Example 11.90.510.039 (p < 0.05)Extract outside the invention, obtained according to Example 3 in TSB medium0.982.260.455 (p < 0.05)

[0178] The level of expression of filaggrin is measured according to the protocol described in Example 4 below.

[0179] Conclusion: The filaggrin expression of the extract according to the invention obtained according to Example 1 is 1.9 (standard deviation of 0.51, p < 0.05), whereas the extract outside the invention obtained according to Example 3 after culture on TSB culture medium has an activity of 0.98 (standard deviation 2.26), an activity lower than that of the negative control normalized to 1. There is no activity on filaggrin expression of the extract outside the invention obtained after culture on TSB medium.

[0180] Example 4: Evaluation of the expression of the protein filaggrin (FLG) by Western blotting of extracts according to the invention obtained according to Examples 1 and 2

[0181] A.Materials and Method

[0182] Culturing of the Episkin reconstructed skin model

[0183] The model used is an Episkin reconstructed epidermis model (EPISJ6, Episkin, Lyon) 1 cm2in diameter on a plate of 12 units. It is sent into the Episkin agar maintenance medium on D6, i.e., 6 days after the emergence of cells at the air / liquid interface, and received on D7. It is a human epidermis reconstructed in vitro from human keratinocytes cultured on a type I and IV collagen matrix.

[0184] To cultivate these tissues, the maintenance medium and the Episkin differentiation medium (MAIN3- and DIFFWA-, respectively), without antibiotics and without antifungals, were used.

[0185] On reception on D7, the skin units are transferred into 3.5 mL of maintenance medium MAINT3WA- (Episkin, Lyon) and incubated at 37°C, 5% CO2 for 24 h. On D8, the skins are treated topically with the various extracts in triplicate and are replaced in plates containing 3.5 mL of differentiation medium. A renewal of differentiation medium is carried out on D10, and culturing is stopped on D13.

[0186] The culturing of the Episkin skins is stopped under an RNase-free hood. The tissues are rinsed with 500 µL of sterile PBS (Gibco, reference 10010031). The epidermis is detached using a punch and sterile forceps before being inserted into a sterile Eppendorf tube and frozen in liquid nitrogen. The samples are then stored at -80°C. In addition, 200 µL of culture subnatants are recovered on a 96-well microplate in order to quantify the concentration of interleukins-8 (IL-8). Assay thereof makes it possible to determine whether the epithelial cells have undergone inflammation during their culturing.Protein analysisExtraction of proteins

[0187] The epidermises of the samples are thawed and suspended in 300 µL of RIPA extraction buffer (Sigma, reference RO278) supplemented with EDTA-free protease inhibitor (1 tablet per 10 mL, Roche, reference 04693132001) and pepstatin (1 μM, Roche, reference 04693159001). After adding a stainless steel ball (diameter 3 mm, Retsch, reference 224550002), grinding is carried out using the Retsch MM 400 Vibromill, three times for 3 min at 30 Hz. The protein lysate is recovered using 0.45 µm PVDF centrifuge filters (Millipore, reference UFC30HVNB), 10 min at 12 000 rpm and 4°C.Protein assay

[0188] The concentration of total proteins is determined by a Bradford assay (Thermo Fischer Scientific, reference 23209). To do this, a BSA range of initial concentration 2 mg / mL is carried out at a rate of 2. In a 96-well plate, 10 µL of the range or sample are deposited per well. After addition of the reagent of the kit, the plate is protected with a film and agitated at ambient temperature for 5 min. Reading is carried out by a plate reader (Molecular devices, SpectraMax M5e) at 660 nm.Sample adjustment and preparation

[0189] After the absorbance results obtained are averaged, the various samples are adjusted to the same concentration in RIPA buffer. Laemli 4X (Tris-HCl (62.5mM), DTT (200mM), SDS (2%), glycerol (10%) and BBT (bromothymol blue)) are then added to each tube and the samples are incubated in a water bath (95°C) for 5 min and then stored at -20°C until gel deposition takes place.Gel deposition and migration

[0190] An equal quantity of proteins contained in 10 µL is deposited in the wells of TGX Stain-free 8-16% electrophoresis gel (BioRad, reference 4568104) and also the molecular weight marker "Full range rainbow" (Sigma Aldrich, reference 28925341). Protein migration is carried out in a BioRad Power PAC 3000 electrophoresis tank containing Tris / glycine / SDS migration buffer (BioRad, reference 1610732) at 200 V until total migration of the samples. The gels are then visualized on the BioRad ChemiDoc MP imaging system by induced UV detection of tryptophan residues of proteins to verify proper migration.Transfer to nitrocellulose membrane

[0191] The transfer is carried out on 0.2 µm nitrocellulose membranes (BioRad, reference 1704159) using the BioRad Transblot Turbo membrane transfer apparatus at 25 V for 10 min. The membrane is then visualized using the BioRad ChemiDoc MP to verify the transfer of the proteins.Detection by antibodies

[0192] The membranes are blocked with a blocking solution containing 1% milk powder (BioRad, reference 170-6404) in Tris Buffer Saline (TBS, Calbiochem, reference 524753-1EA), with stirring for 15 min. The buffer is discarded and the step is reproduced again. The detection of filaggrin is carried out by a mouse monoclonal primary antibody (Santa Cruz Biotechnologies, reference sc66192), prepared in TBS and incubated at 4°C for 12 h with orbital agitation. After three successive washes of 5 min with the blocking solution, the goat anti-mouse secondary antibody (BioRad, reference 170-6516) is prepared in TBS and incubated at room temperature for 1 h 30 with orbital agitation. The secondary antibody is coupled to HRP (horseradish peroxidase), a molecule that leads to a colorimetric change detected by spectrophotometric methods when oxidized by hydrogen peroxide.Development

[0193] Three washes of 5 min of TBS Tween milk are carried out, followed by 2 washes of 5 min with a solution of water and TBS-Tween. The membranes are then incubated with 4 mL of ECL Prime (GE Healthcare, reference RPN 2236) following the protocol specified by the supplier. The membranes are read using the BioRad Chemidoc MP. The images are then analyzed using the BioRad ImageLab software to determine the pixel intensity of the band correlated with the amount of our protein of interest.Analysis of results and statistics

[0194] Results and graphs are analyzed using the Microsoft Excel software. A biological triplicate (three Episkin units per condition) was performed each time. The averages and standard averaging errors are calculated. The Fischer test is used to determine the type of Student test to be performed for the experiment, depending on the p-value. If p > 0.05, the Student test to be performed will be of order 2, and if p < 0.05, it will be of order 3.

[0195] The Student test is then carried out to compare the samples in pairs and to make it possible to determine whether the difference visualized between two results is decisive or not. The degree of significance, which is represented by the p-value, must at least be less than 0.1 for the difference to be considered significant (p < 0.1).

[0196] B.Results

[0197] The results of the analysis of the protein expression of filaggrin, following topical application to the Episkin reconstructed skin model of the extracts according to the invention obtained according to Examples 1 and 2, are presented in Table 4 below. The results were generated in triplicate on 3 Episkin campaigns from different batches, normalized with respect to the total proteins, and are presented in Table 5 below. *p < 0.1, **p < 0.05, ***p < 0.001.

[0198] Level of expression of filaggrinStandard deviationStudent testControl1----Extract according to the invention, obtained according to Example 14.630.890.08 (p < 0.05)Extract according to the invention, obtained according to Example 21.250.180.002 (p < 0.05)ATCC 122281.770.420.001 (p < 0.05)

[0199] Conclusion:

[0200] The extract according to the invention obtained according to Example 1 increases the expression of filaggrin by a factor of 4.63 (standard deviation = 0.51, Student test 0.039, p < 0.05) compared to the negative control normalized to 1, and the extract of ATCC strain 12228 increases expression only by a factor of 1.77 compared to the negative control.

[0201] The extract according to the invention obtained according to Example 2 increases the expression of filaggrin by a factor of 1.25 (standard deviation = 0.002, Student test 0.002, p < 0.05) relative to the negative control normalized to 1.

[0202] Example 5: Evaluation of the hydrating effect of an extract according to the invention obtained according to Example 1

[0203] A.Materials and Method

[0204] The Corneometry on Isolated Stratum Corneum (CISC) test was developed to select active humectant agents (hygroscopic molecules, such as glycerol) which penetrate easily and which attract or retain water in the epidermis.

[0205] The principle of the test used is based on measuring the electrical capacitance of isolated human stratum corneum (SC) using a Corneometer™, which is a measuring device that was initially developed in clinical studies for determining the hydrating potential in the upper layers of the skin (~50 µm). This capacitance depends on the mean dielectric permittivity value of the tissue. The dielectric permittivity varies greatly with the amount of water contained in the SC, since the permittivity of water (E = 81) is very different from that of numerous other substances contained in the skin (E < 7°). This enables a fairly selective measurement. The sensor is composed of 2 metal (gold) electrodes in the form of a comb. A thin insulating layer separates the electrodes on the end of the probe in contact with the skin. The electrical circuit power induces an electric field in the SC and an alternating electrical current (f = 1 MHz) between the 2 electrodes. The apparatus measures the corresponding capacitance.

[0206] Measurement with a corneometer involves several advantages. In contrast with impedance measurements, the capacitance measurement is not influenced by the chemical substances or the conductivity of the products applied to the skin (salts). The depth of penetration of the electric field is very low (20-45 µm), so it is only the hydration of the surface of the skin that is measured. The measuring time is very short (1 sec in standard mode).

[0207] This method is therefore applicable to the evaluation of cosmetic products which change the water content in the SC. These are mainly hygroscopic products that are capable of penetrating into the SC so as to attract or retain water inside the SC (e.g., glycerol). The method is not applicable to products which induce hydration via an occlusive effect (e.g., petroleum jelly, oils, etc.).

[0208] In the CISC test, the test product is applied topically to thestratum corneum(SC) in a simple vehicle or in a formula.

[0209] The difference between the capacitance measurements before and after application makes it possible to estimate its hydration potential and to position it relative to the hydration level of the vehicle and positive control (5% glycerol) references.

[0210] In terms of field of application, the CISC test is adapted to the evaluation of active agents with humectant properties.

[0211] This test was used to evaluate the effects of the extract according to the invention obtained according to Example 1.

[0212] The extracts were tested at 5% by weight of dry matter in a neutral vehicle which contains 80% of ultrapure deionized water and 20% of n-propanol. The positive reference corresponds to a 5% glycerol solution.

[0213] B.Results

[0214] The results are expressed as a percentage relative to the moisturizing effect of the positive reference (5% glycerol):

[0215] Relative humectant effect of treatment (%) = [(∆CM(treatment)−∆CM(vehicle)) / (∆CM(glycerol 5%)−∆CM(vehicle))] *100%. Here, ∆CM represents the variation of the corneometer signal obtained on the SC before (t = 0) and after (t = 4h) application of the product (test treatment, reference or vehicle).

[0216] Table 6 below shows the results of the humectant effect relative to glycerol of the extract according to the invention obtained according to Example 1.

[0217] TreatmentHumectant effect relative to glycerol (%)Extract according to the invention, obtained according to Example 1101.7

[0218] Conclusion: the results show a very strong humectant effect of the extract according to the invention obtained according to Example 1, this effect being comparable to that of the positive reference, glycerol, which has a humectant effect equal to 100. Thus the extract according to the invention obtained according to Example 1 improves surface hydration in topical application.

Claims

The non-therapeutic cosmetic use of an extract of at least one bacterium of the speciesStaphylococcus epidermidisobtainable by at least one step of culturing at least one bacterium of the speciesStaphylococcus epidermidis, in the presence of a culture medium comprising i) at least one monosaccharide, ii) at least one peptone of vegetable origin and / or at least one yeast extract, and optionally iii) at least one microelement, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.The use as claimed in claim 1, wherein said culture medium comprises in water:i. at least one monosaccharide present in the culture medium in an amount ranging from 0.5 to 30 g / L, andii. at least one peptone present in the culture medium in an amount ranging from 0.5 to 15 g / L, and / or at least one yeast extract present in the culture medium in an amount ranging from 0.5 to 15 g / L, andiii. optionally at least one microelement present in the culture medium in an amount ranging from 0.05 to 6 mg / L, andiv. optionally at least one calcium salt present in the culture medium in an amount ranging from 0.01 to 0.1 g / L.The use as claimed in claim 1 or 2, wherein said bacterium of the speciesStaphylococcus epidermidiscultured is a bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695, preferably a bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5691, I-5904, I-5692, I-5693, I-5694 and I-5695, even more preferably a bacterial strain of the speciesStaphylococcus epidermidisdeposited at the CNCM under serial number I-5691.The use as claimed in any one of the preceding claims, characterized in that it comprises, after said culturing step, a step of separating the bacteria from the culture medium, preferably by centrifugation, filtration, or coagulation, more preferably by centrifugation.The use as claimed in the preceding claim, characterized in that it comprises, after said separation step, a cell lysis step, preferably by osmotic shock, thermal shock, ultrasound, or centrifugation, more preferably by thermal shock.The use as claimed in the preceding claim, characterized in that it comprises, after said cell lysis step, a stabilization step, preferably by autoclaving, ultra-high temperature, high-pressure sterilization, lyophilization, gamma radiation or freezing, preferably by autoclaving.The non-therapeutic cosmetic use of a biomass extract of at least one bacterial strain of the speciesStaphylococcus epidermidisselected from the group consisting of bacteria deposited at the CNCM under serial numbers I-5688, I-5689, I-5904, I-5691, I-5692, I-5693, I-5694 and I-5695 to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.The use as claimed in any one of the preceding claims, wherein said extract is in the form of a lysate.A method for non-therapeutic cosmetic treatment of keratin materials, preferably the skin, comprising topical application to the keratin materials, preferably the skin, of a composition comprising in a physiologically acceptable medium an extract as defined according to any one of claims 1 to 8, to prevent the decrease of and / or reinforce the barrier function of the skin, and / or to prevent and / or treat dry skin and / or to prevent and / or treat cosmetic signs associated with dry skin and / or to promote skin hydration.The method as claimed in claim 9, wherein said extract is present in the composition in an amount ranging from 0.0001% to 20% by weight of dry matter relative to the total weight of the composition, preferably in an amount ranging from 0.001% to 10% by weight of dry matter, more preferably in an amount ranging from 0.01% to 5% by weight of dry matter, and better still in an amount ranging from 0.1% to 1% by weight of dry matter, relative to the total weight of the composition.