FR3143370A1 - Metschnikowia rubicola extract and its cosmetic uses - Google Patents

Abstract

The present invention relates to a cosmetic active ingredient obtained from a yeast of the Metschnikowia rubicola species and its cosmetic uses, in particular to improve the barrier function and skin hydration.

Description

Metschnikowiarubicola Extract and its Cosmetic Uses

The invention relates to a cosmetic active ingredient obtained from a yeast of the species Metschnikowia rubicola and its cosmetic uses, in particular for improving the barrier function and skin hydration.

State of the art

Since the health crisis, consumers have been looking for cosmetic products that reflect their aspirations for a healthy lifestyle as well as their environmental and ethical concerns. Thus, nearly 2/3 of consumers are more attentive to the information mentioned on the packaging of the products they consume and are interested in products that are more respectful of the environment and health. These include natural, organic, certified vegan, environmentally friendly products, etc. In particular, products based on natural ingredients that respect the environment are a strong expectation on the part of consumers.

As such, there is a need for new cosmetic products based on natural ingredients, which can improve the barrier function and skin hydration.

To meet this need, the inventor was interested in natural and original raw materials to develop such active ingredients, taken from cultivated plants of the Rosaceae family.

As part of his work, the inventor was particularly interested in yeasts present on cultivated plants of the Rosaceae family. The inventor identified a specific yeast belonging to the species Metschnikowia rubicola on these cultivated plants of the Rosaceae family.

Metschnikowia rubicola yeast has never been used in cosmetics, and surprisingly, according to the invention, an extract from this yeast improves the barrier function and therefore skin hydration.

Thus, the invention proposes a new cosmetic active ingredient obtained from a yeast of the species Metschnikowia rubicola .

The yeast Metschnikowia rubicola was collected in France from cultivated plants of the Rosaceae family, in compliance with current APA regulations.

Thus, the invention relates to a cosmetic active ingredient comprising at least one extract from the biomass of the yeast of the species Metschnikowia rubicola , in particular said extract is a hydrolyzate of Metschnikowia rubicola . Preferably the hydrolyzate of Metschnikowia rubicola is an enzymatic hydrolyzate.

The hydrolysate of Metschnikowia rubicola can be obtained by at least one hydrolysis, preferably at least one enzymatic hydrolysis. According to a particularly preferred object, the hydrolysate is obtained by two enzymatic hydrolyses, in particular the two hydrolyses are simultaneous.

According to another preferred subject of the invention, the extract comprises saccharides.

The saccharide fraction represents at least 15% by weight of dry matter of the extract, according to the DUBOIS method ((Dubois M. et al ., Analytical chemistry , 28, 3, 350-356, 1956), preferably between 28 and 75% by weight of dry matter of the extract.

The saccharide fraction present in the extract according to the invention mainly comprises oligosaccharides with a molecular mass of less than 3600 Da consisting of glucose and mannose.

The extract according to the invention may also comprise peptides. The peptide fraction represents at least 20% by weight of dry matter of the extract. Preferably, the peptide fraction represents less than 50% by weight of dry matter of the extract.

The invention also relates to a method for preparing the active ingredient according to the invention, comprising in particular a culture of the biomass of Metschnikowia rubicola in a suitable culture medium, followed by a solubilization of the biomass of Metschnikowia rubicola in water, at least one hydrolysis, preferably enzymatic, a thermal inactivation, a separation of the soluble and insoluble phase. After recovery of the soluble phase, a molecular sorting is carried out, and optionally a deodorization or decolorization, and/or a filtration of the extract followed by a sterilizing filtration.

The active ingredient according to the invention is a cosmetic ingredient derived from natural materials according to the definition of the internationally recognized ISO 16128 standard. It advantageously has a moisturizing effect and improves the barrier function of the skin, thus making it possible to respond to the problems of the cosmetic market. Also, it can be used for cosmetic applications and be integrated into a cosmetic composition in a form suitable for topical application.

The invention therefore also relates to a cosmetic use of the active ingredient according to the invention or of a composition comprising at least 0.5% by weight of the active ingredient according to the invention, in particular to improve the barrier function and the hydration of the skin.

Other features and advantages will emerge from the detailed description of the invention and the examples which follow.

Detailed description of the invention

Definition

For the purposes of the invention, the term “ Metschnikowia rubicola ” means any yeast of the Metschnikowiaceae family, of the Metschnikowia genus and of the Metschnikowia rubicola species. Preferably, a strain of the Metschnikowia rubicola yeast has been registered in a yeast collection (CIRM), under the number 2141. This Metschnikowia rubicola yeast has been isolated from plants of the Rosaceae family.

By “cosmetic active ingredient” within the meaning of the invention, we mean an extract comprising at least one set of molecules having a cosmetic effect on the skin. Preferably, the effect is a moisturizing effect and the active ingredient improves the barrier function of the skin.

For the purposes of the invention, the term " Metschnikowia rubicola extract" means an extract comprising at least one set of molecules, preferably an extract of the biomass of the yeast Metschnikowia rubicola , said extract being a hydrolysate, preferably comprising at least sugars representing at least 15% by weight of the total weight of the extract. Said extract constituting an ingredient derived from natural materials, according to the definition of the ISO 16128 standard.

By "cosmetic ingredient derived from natural materials" within the meaning of the invention, we mean a cosmetic ingredient obtained by defined chemical and/or biological processes aimed at chemically modifying it. These chemical modifications are intentional, associated with the process carried out, the structures and ratios of the molecules obtained are no longer identical to what the person skilled in the art knows to be naturally present in yeast.

For the purposes of the invention, the term “ Metschnikowia rubicola hydrolysate” means any extract from the yeast Metschnikowia rubicola , obtained by a process comprising at least one hydrolysis step, preferably at least one enzymatic hydrolysis step.

Active ingredient

The present invention therefore relates to a cosmetic active ingredient comprising at least one extract of Metschnikowia rubicola , said extract is a hydrolysate of Metschnikowia rubicola yeast .

The extract according to the invention can be obtained by any type of process for extracting or transforming yeast molecules comprising at least one hydrolysis step. Also, the extract is a hydrolysate, that is to say it is obtained by hydrolysis of the yeast. It is preferably obtained by at least one enzymatic hydrolysis. Thus, the extract according to the invention is preferably an enzymatic hydrolysate. Particularly advantageously, the extract is obtained by two simultaneous enzymatic hydrolyses.

The extract according to the invention comprises sugars, these representing at least 15% by weight of dry matter of the extract, more preferably between 28% and 75% by weight of dry matter of the extract. The sugar content in the extract can be determined by the DUBOIS method (Dubois M. et al ., Analytical chemistry , 28, 3, 350-356, 1956).

Preferably, the sugars present in the extract according to the invention are mainly oligosaccharides with molar masses of less than 3600 Da and polysaccharides with molar masses of less than 306 kDa. The sugars present mainly in the extract are oligosaccharides with molar masses of between 180 and 3600 Da.

Preferably the oligosaccharides and polysaccharides of the extract are composed of glucose and mannose.

Metschnikowia rubicola extract may also include peptides.

Preferably, the Metschnikowia rubicola extract comprises peptides having a molecular weight of less than 10 kDa, preferably less than 3500 Da, very preferably less than 2000 Da. The distribution and quantity of the protein fraction can be determined by the determination of total nitrogen according to the KJELDHAL method (reference: Official method of analysis of the AOC, 12th ed. W Horwitz, ED, New York, 15-60, 1975).

Preferably, the peptides having a molecular weight of less than 3500 Da represent at least 90% by weight of the protein fraction of the extract, even more preferably the peptides having a molecular weight of less than 2000 Da represent at least 75% by weight of the protein fraction of the extract, according to the KJELDHAL method.

In the extract, the peptide fraction represents at least 20% by weight of dry matter of the extract, preferably between 20 and 60%.

The inventor also determined the ash content of the extract according to the invention. The ash content is preferably between 10 and 40% by weight of dry matter of the extract. The raw ash content can be determined by weighing the residues resulting from the incineration of the samples of the extract according to the invention at 550°C in an electric muffle furnace.

As part of his characterization work, the inventor also determined the dry matter content of the extract. This can be determined by weighing the residues resulting from drying the extract according to the invention at 105°C in an oven until a constant weight is obtained. Preferably, the extract according to the invention in liquid form has a dry matter content of: 15 g/L to 38 g/L, even more preferably 20 g/L to 32 g/L.

The active ingredient according to the invention may also comprise other ingredients added by a person skilled in the art, in particular excipients. Also, the active ingredient according to the invention preferably comprises at least one excipient chosen from a preservative, an antioxidant, a stabilizer, an atomization support, and their combination. Such excipients make it possible to stabilize, preserve, and prevent the degradation of the extract, in particular of the molecules included in the extract responsible for the moisturizing effect of said cosmetic active ingredient.

The cosmetic active ingredient according to the invention can be presented in different forms, preferably in liquid form or in solid form.

When it is in liquid form, the active ingredient according to the invention consists exclusively of the extract of Metschnikowia rubicola accompanied by excipients, preferably a stabilizer and/or preservative, and/or an antioxidant.

The extract in liquid form is preferably in the form of a clear liquid, light yellow in color and with a weak odor. It may, however, be more colored and/or be decolorized by any process known to those skilled in the art. The active ingredient may also be combined with stabilizing agents or preservatives.

When it is in solid form, the active ingredient according to the invention is preferably constituted by the extract of Metschnikowia rubicola as previously described and by at least one excipient such as a carrier chosen from maltodextrin, gum arabic or soya lecithin. According to a particularly suitable embodiment, the extract represents at least 10% by weight of the active ingredient and the carrier at most 90% by weight of the active ingredient.

In the case of a solid form in which the active ingredient is associated with a carrier, the protein, sugar and ash contents in the active ingredient are modified, the carrier generally being mainly made up of sugars.

The active ingredient according to the invention may optionally be integrated into a cosmetic composition, in particular a composition comprising at least 0.5% by weight of said active ingredient. The active ingredient according to the invention is in fact preferentially used in compositions, in particular compositions comprising a cosmetically acceptable medium. These may be compositions in different galenic forms, suitable for topical application.

These compositions may be presented in particular in the form of oil-in-water emulsions, water-in-oil emulsions, multiple emulsions (Water/Oil/Water or Oil/Water/Oil) which may possibly be microemulsions or nanoemulsions, or in the form of solutions, suspensions, hydrodispersions, or aqueous gels. They may be more or less fluid and have the appearance of lotion, cream, or mousse.

These may be compositions comprising at least 0.5% by weight of the active ingredient according to the invention. These compositions comprise, in addition to the active ingredient, a physiologically acceptable and preferably cosmetically acceptable medium, i.e. which does not cause unacceptable feelings of discomfort for the user such as redness, tightness or tingling.

• les huiles, qui peuvent être choisies notamment parmi les huiles de silicone, linéaires ou cycliques, volatiles ou non volatiles ;
• les cires, telles que l’ozokérite, la cire de polyéthylène, la cire d’abeille ou la cire de carnauba,
• les élastomères de silicone,
• les tensioactifs, de préférence émulsionnants, qu’ils soient non ioniques, anioniques, cationiques ou amphotères,
• les co-tensioactifs, tels que les alcools gras linéaires,
• les épaississants et/ou gélifiants,
• les humectants, tels que les polyols comme la glycérine,
• les colorants, les conservateurs, les charges,
• les tenseurs,
• les séquestrants,
• les parfums,
• et leurs mélanges, sans que cette liste soit limitative.

The compositions according to the invention may contain as adjuvant at least one compound chosen from:

• oils, which may be chosen in particular from silicone oils, linear or cyclic, volatile or non-volatile;
• waxes, such as ozokerite, polyethylene wax, beeswax or carnauba wax,
• silicone elastomers,
• surfactants, preferably emulsifying surfactants, whether nonionic, anionic, cationic or amphoteric,
• co-surfactants, such as linear fatty alcohols,
• thickeners and/or gelling agents,
• humectants, such as polyols like glycerin,
• colorants, preservatives, fillers,
• tensors,
• sequestrants,
• perfumes,
• and their mixtures, without this list being exhaustive.

Examples of such adjuvants are cited in particular in the International Cosmetic Ingredient Dictionary and Handbook published by the Personal Care Product Council .

Of course, the person skilled in the art will take care to choose any additional compounds, active or non-active, and their quantity, such that the advantageous properties of the mixture are not, or not significantly, altered by the envisaged addition.

The compositions comprising an active ingredient according to the invention are in particular intended to be used to improve the barrier function and hydration of the skin.

Extraction process

The extract constituting or contained in the active ingredient according to the invention can be obtained by any process comprising at least one step of extracting the biomass of the yeast of Metschnikowia rubicola and at least one step of hydrolysis. According to the present invention, the extraction of the biomass of the yeast does not consist of the recovery of the supernatant of the yeast culture.

Prior to the process for obtaining the extract as such, it is appropriate to produce the biomass of Metschnikowia rubicola . This step is carried out according to the method of culturing the yeasts in a medium adapted to their development, for example a suitable culture medium, in a conventional manner for those skilled in the art. From the biomass, an extraction of the active molecules, preferably sugars, is carried out. The extraction is carried out by at least one hydrolysis, according to any means known to those skilled in the art, preferably by enzymatic hydrolysis.

1. Culture de la biomasse deMetschnikowia rubicoladans un milieu de culture adapté à leur développement,
2. Solubilisation à raison d’au moins 80 g/L de la biomasse deMetschnikowia rubicoladans l’eau,
3. Au moins une hydrolyse enzymatique, préférentiellement au moins deux hydrolyses enzymatiques simultanées,
4. Traitement permettant l’inactivation des activités enzymatiques, par exemple par traitement thermique de l'hydrolysat,
5. Séparation de la phase soluble et insoluble, et récupération de la phase soluble,
6. Tri moléculaire des molécules de la phase soluble, par tout moyen permettant le tri moléculaire, par exemple par ultrafiltration ou chromatographie ionique,
7. Éventuellement, désodorisation ou décoloration, et
8. Eventuellement, filtration et filtration stérilisante.

According to a particularly suitable embodiment, the active ingredient according to the invention is obtained by implementing the following steps:

1. Cultivation of Metschnikowia rubicola biomass in a culture medium adapted to their development,
2. Solubilization at a rate of at least 80 g/L of Metschnikowia rubicola biomass in water,
3. At least one enzymatic hydrolysis, preferably at least two simultaneous enzymatic hydrolyses,
4. Treatment allowing the inactivation of enzymatic activities, for example by heat treatment of the hydrolysate,
5. Separation of the soluble and insoluble phase, and recovery of the soluble phase,
6. Molecular sorting of the molecules of the soluble phase, by any means allowing molecular sorting, for example by ultrafiltration or ion chromatography,
7. Possibly, deodorization or discoloration, and
8. Optionally, filtration and sterilizing filtration.

A hydrolysis step, preferably at least one enzymatic hydrolysis, and even more preferably at least two simultaneous enzymatic hydrolyses can be envisaged in the process for preparing the active ingredient according to the invention.

The process may optionally include a step of heat treatment of the extract, in particular to eliminate residual enzymatic activities.

The separation of the soluble and insoluble phases is carried out by any means known to those skilled in the art, for example by centrifugation, filtration or decantation. Preferably, the separation of the soluble and insoluble phases is carried out to recover the soluble phase containing, among other things, soluble sugars, such as oligosaccharides and polysaccharides and the peptide fraction.

The process includes a filtration step, preferably by suitable molecular sorting, for example by ultrafiltration or ion chromatography.

Bleaching or deodorizing steps can also be added.

The product obtained at this stage may optionally be further concentrated and/or purified, preferably by successive ultrafiltration steps through filters of different porosity, retaining the filtrates at each step and/or by a chromatographic type method.

The product obtained after filtration, before or after concentration and sterilizing filtration, is an extract of Metschnikowia rubicola , and constitutes a first form of the active ingredient according to the invention, and is then presented in liquid form.

• un support d’atomisation, de préférence la maltodextrine, est ajouté dans l’extrait deMetschnikowia rubicola, d’au plus 90% (en masse/volume) ;
• cette solution est ensuite concentrée sous vide ;
• une élimination des bactéries éventuellement présentes est réalisée par traitement thermique ;
• l’atomisation permet d’obtenir une poudre.

The extract obtained can then be dried and associated or not with a support, to be presented in solid form. This phase can be carried out by implementing the following steps:

• an atomization carrier, preferably maltodextrin, is added into the Metschnikowia rubicola extract, at most 90% (mass/volume);
• this solution is then concentrated under vacuum;
• any bacteria present is eliminated by heat treatment;
• atomization produces a powder.

The steps of the processes described above, taken individually, are common in the field of extraction of active ingredients from natural raw materials and those skilled in the art are able to adjust the reaction parameters on the basis of their general knowledge.

Cosmetic use

The active ingredient according to the invention is of particular interest for strengthening/improving the barrier function of the skin and for improving skin hydration.

The invention thus aims at a cosmetic, non-therapeutic use of the active ingredient according to the invention for its cosmetic effects, alone or in a composition, in particular for at least one moisturizing cosmetic effect and to improve the skin barrier function.

For the purposes of the invention, non-therapeutic use means cosmetic use of the active ingredient according to the invention or of a cosmetic composition comprising it, intended for healthy, non-sick people, in particular people with healthy skin.

Preferably, the active ingredient according to the invention, alone or in a composition, aims to be used for a cosmetic treatment in topical application to the skin. Also, the cosmetic use according to the invention also aims at the use of a composition comprising the active ingredient according to the invention.

The invention is now illustrated by non-limiting examples of compositions according to the invention and by results.

Examples

Example 1 – Active ingredient according to the invention

1. Culture deMetschnikowia rubicoladans un milieu de culture adapté
2. Solubilisation de la biomasse de la levureMetschnikowia rubicoladans l’eau, à raison de 80g/l,
3. Au moins deux hydrolyses enzymatiques simultanées par des carbohydrases,
4. Inactivation enzymatique par traitement thermique,
5. Séparation des phases soluble et insoluble par décantation et récupération de la phase soluble,
6. Purification par tri moléculaire, en particulier par ultrafiltration,
7. Filtration, et filtration stérilisante.

The active ingredient of Example 1 is obtained from a Metschnikowia rubicola yeast. The active ingredient of Example 1 is obtained by the following process:

1. Cultivation of Metschnikowia rubicola in a suitable culture medium
2. Solubilization of Metschnikowia rubicola yeast biomass in water, at a rate of 80g/l,
3. At least two simultaneous enzymatic hydrolyses by carbohydrases,
4. Enzymatic inactivation by heat treatment,
5. Separation of soluble and insoluble phases by decantation and recovery of the soluble phase,
6. Purification by molecular sorting, in particular by ultrafiltration,
7. Filtration, and sterilizing filtration.

• Teneur en Matières Sèches = 32 g/L
• Teneur en Sucres Totaux (selon la méthode de Dubois) = 15,4 g/L (48%, en poids par rapport à la matière sèche)
• Teneur en peptides (selon la méthode KJELDHAL) = 11,3 g/L (35,3%, en poids par rapport à la matière sèche)
• Liquide limpide, jaune clair, il présente une odeur faible.

The active ingredient obtained has the following characteristics:

• Dry Matter Content = 32 g/L
• Total Sugar Content (according to the Dubois method) = 15.4 g/L (48%, by weight relative to dry matter)
• Peptide content (according to the KJELDHAL method) = 11.3 g/L (35.3%, by weight relative to dry matter)
• Clear, light yellow liquid, it has a weak odor.

The saccharide fraction of the active ingredient according to example 1 is composed of glucose and at least 20% mannose.

Example 2 – Active ingredient according to the invention

1. Culture deMetschnikowia rubicoladans un milieu de culture adapté
2. Solubilisation de la biomasse de la levureMetschnikowia rubicoladans l’eau, à raison de 90g/l,
3. Hydrolyse enzymatique des protéines,
4. Inactivation enzymatique,
5. Séparation des phases soluble et insoluble par décantation et récupération de la phase soluble,
6. Tri moléculaire, en particulier par ultrafiltration,
7. Filtration, et filtration stérilisante.

The active ingredient of Example 2 is obtained from a yeast of Metschnikowia rubicola . The active ingredient of Example 2 is obtained by the following process:

1. Cultivation of Metschnikowia rubicola in a suitable culture medium
2. Solubilization of Metschnikowia rubicola yeast biomass in water, at a rate of 90g/l,
3. Enzymatic hydrolysis of proteins,
4. Enzyme inactivation,
5. Separation of soluble and insoluble phases by decantation and recovery of the soluble phase,
6. Molecular sorting, in particular by ultrafiltration,
7. Filtration, and sterilizing filtration.

• Teneur en Matières Sèches = 24,6 g/L
• Teneur en Sucres Totaux = 6,1 g/L (24,8%, en poids par rapport à la matière sèche)
• Teneur en peptides (selon la méthode KJELDHAL) = 10,2 g/L (41,5%, en poids par rapport à la matière sèche)
• Teneur en cendres minérales = 8,3 g/L (33,7%, en poids par rapport à la matière sèche)

La fraction saccharidique du principe selon l’exemple 2 est composé à 100% de glucose.The active ingredient obtained has the following characteristics:

• Dry Matter Content = 24.6 g/L
• Total Sugar Content = 6.1 g/L (24.8%, by weight relative to dry matter)
• Peptide content (according to the KJELDHAL method) = 10.2 g/L (41.5%, by weight relative to dry matter)
• Mineral ash content = 8.3 g/L (33.7%, by weight relative to dry matter)

The saccharide fraction of the principle according to example 2 is composed of 100% glucose.

Example 3 – Composition according to the invention

An example of a formulation comprising the active ingredient according to the invention in the form of a day gel is presented in Table 1 below.

Ingredient % HAS Water qsp 100% Conservative 1% Glycerol 2% B DUB 1632 3% DUB MM 1.5% DUB STGAE30 3% DUB ININ 2% Sophiderm 4% Easynov 4% C Active ingredient according to the invention 2.5%

The composition comes in the form of a fluid, white, odorless, shiny emulsion, with easy application, smooth and gliding spread.

1. Mélanger A. Chauffer au bain-marie à 80°C sous agitation magnétique.
2. Mélanger B. Chauffer au bain-marie à 80°C sous agitation magnétique.
3. A 80°C, émulsionner A dans B sous rotor stator à 1800 tr/min.
4. A 30°C additionner C.
5. Laisser sous agitation jusqu’à complet refroidissement.

The composition can be obtained as follows:

1. Mix A. Heat in a bain-marie to 80°C with magnetic stirring.
2. Mix B. Heat in a bain-marie to 80°C with magnetic stirring.
3. At 80°C, emulsify A in B under rotor stator at 1800 rpm.
4. At 30°C add C.
5. Leave to stir until completely cooled.

Tests – Effectiveness of the active ingredient according to the invention on the barrier function and hydration

The in vitro study was carried out on normal human keratinocytes, epidermal cells, in monolayer culture with or without treatment with the active ingredients according to example 1 or example 2 for 24 hours. An analysis of the transcriptomic profile by quantitative real-time PCR of the genes involved in epidermal metabolism, in particular in relation to the barrier function and hydration, was conducted.

The statistically significant variations in transcriptional activity of the genes described below between the untreated control normal human keratinocytes and the normal human keratinocytes treated with the active ingredient according to Example 1 or Example 2 are presented in Tables 2 and 3 below. Only gene expression variation values significantly greater than 1.5 (overexpression of the gene) or significantly less than 0.75 (underexpression of the gene) are reported. If no significant variation in gene expression is measured, then no value is reported in the tables (/).

Effect on barrier function

• TGM1 (Transglutaminase 1) : code pour l’enzyme impliquée dans la formation de l'enveloppe cornée, une structure protéique rigide et insoluble qui entoure les kératinocytes en différenciation terminale et contribue à former une barrière protectrice entre le corps et son environnement.
• SPRR1B (Small Proline-Rich Protein 1B ) ou Cornifin : code pour une protéine qui est réticulée aux protéines de la membrane des kératinocytes et participe ainsi à la formation de l’enveloppe cornée.
• ZNF750 (Zinc Finger Protein 750) ou Epigenin : code pour un facteur de transcription impliqué dans l’activation des gènes de différenciation épidermique terminale.
• DSG1 (Desmoglein) : code pour une protéine impliquée dans la formation des desmosomes, des jonctions inter-kératinocytaires qui confèrent aux kératinocytes leur résistance et leur extensibilité. Ces jonctions jouent un rôle clef dans la cohésion de l’épiderme et sa fonction barrière physique.
• OCLN (Occludin) et CLDN1 (Claudin-1) : codent pour des protéines constitutives des jonctions serrées, qui assurent la cohésion entre les kératinocytes au niveau de la couche granuleuse et participent à la fonction barrière mécanique épidermique. Les jonctions serrées assurent aussi l’étanchéité de l’épiderme et préviennent la perte en eau.
• FABP5 (Fatty Acid Binding Protein 5) : code pour une protéine impliquée dans le métabolisme des lipides épidermiques, lipides qui jouent un rôle important dans la formation de la fonction barrière cutanée.
• PI3 (Peptidase Inhibitor 3) ou Elafin ou SKALP (Sin-derived anti-leukoproteinase) : code pour une protéine inhibitrice des protéinases, elle participe à la formation de l’enveloppe cornée. Elle est décrite également pour son une activité bactéricide et participe ainsi à la fonction barrière épidermique antimicrobienne.
• BIRC5 (baculoviral IAP repeat containing 5) ou Survivin : code pour une protéine régulatrice du cycle cellulaire, exprimée particulièrement dans les cellules souches kératinocytaires, elle participe au renouvellement de l’épiderme.
• TLR2 (Toll-like receptor 2) : code pour un récepteur transmembranaire qui permet aux kératinocytes de discriminer la présence de microorganismes commensaux des microorganismes transitoires et d’activer des voies de signalisation distinctes pour induire une réponse immune innée spécifique et adaptée, notamment antimicrobienne.

The inventor analyzed the expression of genes involved in strengthening the skin barrier function, namely:

• TGM1 (Transglutaminase 1): encodes the enzyme involved in the formation of the horny envelope, a rigid, insoluble protein structure that surrounds terminally differentiating keratinocytes and helps form a protective barrier between the body and its environment.
• SPRR1B (Small Proline-Rich Protein 1B) or Cornifin: encodes a protein that is cross-linked to keratinocyte membrane proteins and thus participates in the formation of the horny envelope.
• ZNF750 (Zinc Finger Protein 750) or Epigenin: encodes a transcription factor involved in the activation of terminal epidermal differentiation genes.
• DSG1 (Desmoglein): encodes a protein involved in the formation of desmosomes, inter-keratinocyte junctions that give keratinocytes their strength and extensibility. These junctions play a key role in the cohesion of the epidermis and its physical barrier function.
• OCLN (Occludin) and CLDN1 (Claudin-1): encode proteins that constitute tight junctions, which ensure cohesion between keratinocytes at the level of the granular layer and participate in the epidermal mechanical barrier function. Tight junctions also ensure the sealing of the epidermis and prevent water loss.
• FABP5 (Fatty Acid Binding Protein 5): encodes a protein involved in the metabolism of epidermal lipids, lipids which play an important role in the formation of the skin barrier function.
• PI3 (Peptidase Inhibitor 3) or Elafin or SKALP (Sin-derived anti-leukoproteinase): codes for a proteinase inhibitor protein, it participates in the formation of the horny envelope. It is also described for its bactericidal activity and thus participates in the antimicrobial epidermal barrier function.
• BIRC5 (baculoviral IAP repeat containing 5) or Survivin: codes for a cell cycle regulatory protein, expressed particularly in keratinocyte stem cells, it participates in the renewal of the epidermis.
• TLR2 (Toll-like receptor 2): encodes a transmembrane receptor that allows keratinocytes to discriminate the presence of commensal microorganisms from transient microorganisms and to activate distinct signaling pathways to induce a specific and adapted innate immune response, particularly antimicrobial.

The results of the gene expression described above are shown in Table 2 below.

TGM1 SPRR1B ZNF750 DSG1 OCLN CLDN1 FABP5 PI3 BIRC5 TLR2 Witness 1 1 1 1 1 1 1 1 1 1 Example 1 - 2.5% 2.279 2,903 3.106 3.656 1,571 1,669 1,697 3,832 1,544 1,548 Example 2 - 2.5% / 2.074 / 1,890 / / / 3,556 / 1,563

The active ingredient according to example 1 significantly increases the expression of the genes TGM1, SPRR1B, ZNF750, DSG1, OCLN, CLDN1, FABP5, PI3, BIRC5 and TLR2, genes essential for strengthening the epidermal mechanical and immune barrier function. In particular, the active ingredient according to example 1 modulates the expression of the genes TGM1, ZNF750, OCLN, CLDN1, FABP5 and BIRC5 that the active ingredient according to example 2 does not modulate.

Effect on hydration

• HAS3 (Hyaluronan Synthase 3) : code pour une enzyme intervenant dans la synthèse de l’acide hyaluronique, une molécule à fort pouvoir hygroscopique qui retient l’eau dans l’épiderme.
• AQP3 (Aquaporin 3) et AQP9 (Aquaporin 9) : codent pour des protéines transmembranaires des kératinocytes impliquées dans le transport sélectif de l’eau, du glycérol ou de l’urée à travers l’épiderme. Ces protéines jouent un rôle majeur dans l’hydratation cutanée.

The inventor continued his work by analyzing the expression of genes involved in skin hydration, namely:

• HAS3 (Hyaluronan Synthase 3): codes for an enzyme involved in the synthesis of hyaluronic acid, a molecule with high hygroscopic power that retains water in the epidermis.
• AQP3 (Aquaporin 3) and AQP9 (Aquaporin 9): encode keratinocyte transmembrane proteins involved in the selective transport of water, glycerol or urea across the epidermis. These proteins play a major role in skin hydration.

The results of the gene expression described above are shown in Table 3 below.

HAS3 AQP3 AQP9 Witness 1 1 1 Example 1 - 2.5% 1,518 1.945 3.050 Example 2 - 2.5% / / 2.380

The active ingredient according to example 1 significantly increases the expression of the HAS3, AQP3 and AQP9 genes and thus improves skin hydration. In particular, the active ingredient according to example 1 significantly increases the expression of the HAS3 and AQP3 genes that the active ingredient according to example 2 does not modulate.

Claims (11)

Cosmetic active ingredient comprising at least one extract of Metschnikowia rubicola characterized in that the extract is a hydrolyzate of Metschnikowia rubicola . Active ingredient according to the preceding claim, characterized in that the extract is an enzymatic hydrolyzate of Metschnikowia rubicola . Active ingredient according to one of the preceding claims, characterized in that the extract is an enzymatic hydrolyzate of Metschnikowia rubicola obtained by at least two enzymatic hydrolyses. Active ingredient according to one of the preceding claims, characterized in that the extract comprises at least sugars. Active ingredient according to the preceding claim, characterized in that the sugars represent at least 15% by weight of dry matter of the extract, according to the DUBOIS method. Active ingredient according to one of claims 4 or 5, characterized in that the sugars represent between 28% and 75% by weight of dry matter of the extract, according to the DUBOIS method. Cosmetic active ingredient according to one of claims 4 to 6, characterized in that the sugars are composed of glucose and mannose. Cosmetic active ingredient according to one of the preceding claims, characterized in that the extract also comprises peptides. Active ingredient according to one of the preceding claims, characterized in that the extract ofMetschnikowia rubicolais likely to be obtained by an extraction process comprising the following steps:

1. Solubilization of Metschnikowia rubicola biomass in water at a rate of at least 80 g/l,
2. At least one enzymatic hydrolysis,
3. Enzyme inactivation,
4. Separation of the soluble and insoluble phases by decantation, and recovery of the soluble phase,
5. Molecular sorting,
6. Possibly, deodorization or discoloration,
7. Possibly, filtration and sterilizing filtration.

Cosmetic composition comprising at least 0.5% of a cosmetic active ingredient according to one of the preceding claims. Use of a cosmetic active ingredient according to one of claims 1 to 11 or of a composition according to claim 12 for a cosmetic treatment in topical application to the skin.