Novel cosmetic use of N-methylglycine to increase the diversity of the skin microbiome.

Abstract

This invention provides a novel cosmetic use of N-methylglycine to increase the diversity of the skin microbiome. [Solution] The present invention relates to the cosmetic use of N-methylglycine as a skin prebiotic for increasing the diversity of the skin microbiome, for preventing and / or reducing the loss of skin appendages, particularly hair loss, and / or for preventing and / or reducing the appearance of pityriasis scalpi. Another subject relates to a cosmetic care process including topical application of N-methylglycine or a composition containing the same for increasing the diversity of the skin microbiome, for reducing the loss of skin appendages, and / or for preventing and / or reducing the appearance of pityriasis scalpi. Another subject further relates to a pharmaceutical composition containing N-methylglycine for use in reducing skin itching and / or irritation, and / or for preventing and / or reducing scalp sensitivity.

Description

[Technical Field]

[0001] The present invention relates to a novel use of N-methylglycine to advantageously increase the diversity of the scalp and skin microbiome. [Background technology]

[0002] Just like the face and body, the skull has its own skin, or scalp. Often overlooked because it is not easily visible, the scalp is a site of discomfort that can manifest as pityriasis capitis, accompanied by itching and irritation. Scalp sensitivity can also occur, though not necessarily related to factors causing pityriasis capitis. Scalp sensitivity is characterized by a tingling sensation (which may or may not be painful) on the scalp following exposure to various chemical or thermal stimuli. The scalp can also suffer from biological disturbances that result in excessive or premature hair loss. Various biological mechanisms are involved in these discomforts, particularly those correlated with the disruption of the scalp's skin microbiome.

[0003] In particular, with regard to pityriasis capitis, it can affect various types of scalps (dry, oily, juvenile, or adult subjects). Since scalps exhibiting pityriasis capitis show a higher proportion of Staphylococcus bacteria, the origin of pityriasis capitis lies in an imbalance in the scalp's microbiome.

[0004] On the other hand, unpleasant discomforts of the stinging, itching, pain, and burning type have been significantly correlated with the presence of certain bacteria belonging to the genera Bacteroides, Propionibacterium, and Chryseobacterium. In addition, exotoxins derived from Staphylococcus aureus and other staphylococci may trigger the expression of mediators involved in itchy scalp.

[0005] Regarding sensitive scalps, increased sebum production is correlated with an increase in the genus Propionibacterium and a decrease in bacterial diversity. Finally, hair loss has been positively correlated with scalp sensitivity. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] CTFA Cosmetic Ingredient Handbook,Second Edition(1992) [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, in the cosmetics field, there is always a need for active ingredients that can address not only pityriasis capitis but also the irritation and itching that often accompany it. [Means for solving the problem]

[0008] To our great surprise, the applicant has discovered that N-methylglycine (also known as sarcosine) has the ability to increase the diversity of the skin microbiome, thereby preventing and / or reducing hair loss, and / or preventing and / or reducing the appearance of pityriasis capitis, and / or reducing itching and / or irritation of the skin, particularly the scalp. [Modes for carrying out the invention]

[0009] N-methylglycine is a methylated derivative of glycine (CAS number 107-97-1), has the empirical formula C3H7NO2, a molar mass of 89.09 g / mol, and its formula is: [ka] It has the following properties. N-methylglycine is marketed by the applicant under the name MAT-XS(trademark) for use in reducing sebum production, reducing defects associated with hyperseborrhea, and reducing the visibility of skin pores.

[0010] N-methylglycine derivatives are known to be used in scalp cosmetic compositions, particularly as anionic detergents in anti-dandruff cosmetic compositions.

[0011] However, to the best of the applicant's knowledge, the prior art does not disclose or propose any cosmetic use of N-methylglycine that is effective in preventing and / or reducing hair loss, and / or preventing and / or reducing the appearance of pityriasis scalpi, and / or reducing itching and / or irritation of the skin, especially the scalp, especially in preventing and / or reducing scalp skin sensitivity, especially in increasing the diversity of the scalp microbiome.

[0012] The advantage of this molecule is that it is known to be easily formulated into cosmetic compositions, particularly scalp compositions, without the risk of local allergies. Furthermore, it is readily available as a commercially produced product.

[0013] Therefore, the first subject of the present invention is the non-therapeutic cosmetic use of N-methylglycine, advantageously for increasing the diversity of the skin microbiome, particularly of the scalp. The second subject is the cosmetic use of N-methylglycine in a cosmetic composition comprising at least one cosmetically acceptable excipient. The third subject relates to a cosmetic care process comprising topical application of N-methylglycine or a composition containing the same to all or part of the scalp and / or skin appendages. The final subject relates to a pharmaceutical, advantageously for skin, composition containing N-methylglycine, advantageously for use in reducing skin itching and / or irritation, advantageously of the scalp.

[0014] Therefore, the first subject concerns the non-therapeutic cosmetic use of N-methylglycine to advantageously increase the diversity of the scalp's skin microbiome.

[0015] The term "cosmetic use" is intended to mean a use that is neither therapeutic, pharmaceutical nor dermatological, i.e., a use that does not require medical treatment and is directed to healthy skin. The term "healthy skin" is intended to mean skin that is described as non-pathological by dermatologists, experts in the field, i.e., skin that does not exhibit any infections, scars, skin diseases or skin conditions, such as candidiasis, impetigo, psoriasis, eczema, acne or dermatitis, wounds or injuries, and / or other skin disorders and / or androgenetic alopecia.

[0016] The subject of the present invention is also the non-therapeutic cosmetic use of N-methylglycine as a skin prebiotic. In fact, N-methylglycine can increase the growth and / or activity of skin microbiota, in particular strains selected from those of the following genera. - Genus Streptococcus, in particular those selected from Streptococcus salivarius, Streptococcus australis, Streptococcus parasanguinis, and Streptococcus infantis, - Genus Staphylococcus, in particular S. pasteuri and S. warneri, - Genus Rothia, in particular Rothia aeria, - Genus Actinomyces, in particular A. odontolyticus, - Genus Veillonella, in particular V. parvula.

[0017] For the purposes of the present invention, the term "skin probiotic" is intended to mean any substance that increases the growth and / or activity of bacteria of the skin microbiota, preferably the strains mentioned above, preferably S. salivarius, S. pasteuri, S. parasanguinis, V. parvula, S. australis, S. warneri, Rothia aeria, S. infantis, Actinomyces odontoliticus. Such growth and / or activity of bacteria of the skin microbiota can be measured by conventional methods in the art.

[0018] Several methods can be used to measure the growth of microbial strains on the skin and / or mucosa, including an increase in the number of counted colonies present on the skin or mucosa or a significant increase in in vitro measurements by optical density of suspended strains or in measurements by PCR. Advantageously, the microbial content is measured in vitro by optical density after recovery of the sample containing the strain.

[0019] Alternatively, the change in the relative content of bacteria can also be measured in situ, particularly by the method described in Example 2a, in the presence of N-methylglycine.

[0020] The activity of microbial strains can be measured according to conventional methods by a person skilled in the art, for example, by examining the metabolites of the skin microbiota, particularly the production of organic acids such as lactic acid and acetic acid by bacteria.

[0021] N-methylglycine is a locally acceptable component. The term "locally acceptable" is intended to mean a component that is suitable for topical application, non-toxic and non-irritating to the skin, does not induce an allergic reaction, and is not chemically unstable.

[0022] This molecule can be used orally or topically. It is advantageous to use it topically. The term “topical” is intended to mean direct topical application and / or spray application of the ingredient onto the surface of the skin.

[0023] The ingredients can be applied topically to all or part of the body (preferably selected from the legs, feet, armpits, hands, thighs, stomach, nape of the neck, neck, arms, torso, back, face (including forehead, cheeks, nose, temples, T-zone (forehead, nose, and chin)), and / or scalp, more preferably the scalp).

[0024] For the purposes of this invention, skin includes the scalp.

[0025] The term "skin appendages" is intended to mean body hair, hair, nails, and, more specifically, hair.

[0026] The term "skin microbiome" is intended to mean beneficial mutually beneficial commensal strains of bacteria and / or yeasts and / or fungi, and / or pathogenic opportunistic strains, in particular beneficial mutually beneficial commensal strains selected from the following: - Bacteria of the family Corynebacteriaceae, especially the genus Corynebacterium; bacteria of the family Micrococcaceae, especially the genus Micrococcus and / or the genus Kocuria; bacteria of the family Propionibacteriaceae, including the genera Propionibacterium or Cutibacterium; bacteria of the phylum Actinobacteria, especially the genus Brevibacterium, - Bacteria of the Proteobacteria phylum, including bacteria of the Rhodobacteriaceae family, especially those of the genera Paracoccus and / or Amaricoccus; bacteria of the Acetobacteraceae family, especially those of the genera Roseomonas; bacteria of the Caulobacteraceae family, especially those of the genera Brevundimonas; and bacteria of the Moraxellaceae family, especially those of the genera Enhydrobacter and / or Acinetobacter. - Bacteria of the Staphylococcus family, particularly those belonging to the genus Staphylococcus, especially Staphylococcus hominis, S. warneri, S. capitis, S. epidermidis, S. pasteuri, S. saprophyticus, and preferably S. epidermidis; and the genus Streptococcus, particularly Streptococcus salivarius. Bacteria of the family Streptococcus (including *salivarius* and *australis*), bacteria of the family Bacilliaceae (including *Bacillus*), bacteria of the genus Veillonella, and bacteria of the phylum Firmicutes, which includes bacteria of the family Lactobacilliaceae, particularly *Lactobacillus*.

[0027] In preference, beneficial commensal skin bacteria include the genera Corynebacterium, Micrococcus, Kocuria, Propionibacterium, Brevibacterium, Paracoccus, Amaricoccus, Roseomonas, Brevundimonas, and Enhydrobacter. The species are selected from the following genera: Acinetobacter, S. hominis, S. warneri, S. capitis, S. epidermidis, S. pasteuri, S. saprophyticus, preferably S. epidermidis, Lactobacillus, Lactobacillus, and mixtures thereof.

[0028] Pathogenic opportunistic skin strains are selected from the following: - Strains of the genus Pantoea, particularly of the family Enterobacteriaceae, within the phylum Proteobacteria, and / or strains of the genus Pseudomonas, particularly of the family Pseudomonaceae. - Strains of the phylum Firmicutes, which includes the family Staphylococcusae, especially the genus Staphylococcus, especially Staphylococcus aureus, and the family Streptococcusae, especially Streptococcus pyogenes. - Strains of the Actinobacteria phylum, particularly the Propionibacteriaceae family, including Propionibacterium acnes (Cutibacterium acnes).

[0029] Preferably, pathogenic opportunistic skin strains are selected from the genera Pantoea, Pseudomonas, S. aureus, S. pyogenes, and P. acnes. According to one preferred embodiment, the pathogenic opportunistic skin strain is S. aureus and / or P. acnes.

[0030] Therefore, for the purposes of the present invention, the skin microbiota of the scalp, in particular, includes species of the genus Malassezia, and preferably yeasts including the species M. restricta.

[0031] The expression "increased diversity of the skin microbiome" is intended to mean the promotion of the emergence of new bacteria and / or bacterial strains that constitute the skin microbiome. In one advantageous embodiment of the present invention, this includes the emergence of at least 10%, and preferably at least 20%, of new strains 28 days after application of a formulation containing N-methylglycine, compared to the population of strains detected 28 days after application of the same formulation without N-methylglycine, as described in Example 2. In one particularly advantageous embodiment, this is beneficial to commensal strains, more advantageously to Streptococcus salivarius, Staphylococcus pasteuri, Rothia mucilaginosa, Streptococcus parasanguinis, Staphylococcus saprophyticus, Veillonella parvula, Streptococcus australis, Haemophilus parainfluenzae, Staphylococcus warneri, and Rothia aeria. aeria), Streptococcus thermophilus, Acinetobacter ursingii, Propionibacterium phage_P14_4, Veillonella dispar, Streptococcus infantis, Streptococcus cristatus, Staphylococcus pettenkoferi, Actinomyces odontolyticus, and mixtures thereof, preferably S. pasteuri (S.This includes the emergence of at least 10% new strains, and favorably at least 20% new strains, selected from S. pasteuri, S. saprophyticus, S. warneri, S. pettenkoferi, and mixtures thereof, more preferably S. pasteuri, S. warneri, and mixtures thereof (very preferably S. warneri).

[0032] In one embodiment of the present invention, the use of N-methylglycine is intended to increase the diversity of the skin microbiome for the purpose of reducing and / or preventing the loss of skin appendages, preferably hair loss.

[0033] Advantageously, the term “reduction in hair loss” is intended to mean a reduction in resting or shedding hair density of at most 2%, preferably at most 1%, and more preferably at most 0.5%. Measurement of resting and growing hair density can be performed in vivo using phototrichogram technology in the presence of N-methylglycine or a composition containing it, particularly in formulations in the form of shampoo, compared to resting and growing hair density measured without the use of N-methylglycine or a composition containing it.

[0034] In another embodiment, the use of N-methylglycine is intended to increase the diversity of the skin microbiome, advantageously of the scalp, for the prevention and / or reduction of pityriasis capitis. Therefore, N-methylglycine is considered to be an effective amount for the prevention and / or reduction of pityriasis capitis when the concentration ratio of Staphylococcus (any species) / P. acnes strain is at most half, and advantageously at most one-third, of the ratio measured after application of the same formulation without N-methylglycine after application of the formulation containing N-methylglycine. Advantageously, this is the measurement of the concentration ratio of Staphylococcus (any species) / P. acnes strain 28 days after application of a hair formulation containing 1% by weight of the N-methylglycine-containing preparation prepared according to Example 1b) under the conditions described in Example 2.

[0035] Therefore, N-methylglycine is an ingredient that induces a feeling of peeling of the skin, especially the scalp.

[0036] N-methylglycine is commercially available in powder form and is solubilizable in any solvent or solvent mixture, preferably aqueous solvents, preferably water, alcohol, glycol, polyol, or a 99 / 1 to 1 / 99 (w / w) water / alcohol, water / glycol, or water / polyol mixture (e.g., water mixed with ethanol, glycerol and / or butylene glycol and / or other glycols, such as xylitol and / or propanediol), preferably in water as the sole solvent.

[0037] Specifically, an N-methylglycine solution is an aqueous solution. The term "aqueous solution of N-methylglycine" is intended to mean any aqueous solution that contains more than 60% by weight, preferably at least 70% by weight, specifically at least 80% by weight, more specifically at least 90% by weight, and especially at least 95% by weight of water based on the total weight of the aqueous solution, and more preferably does not contain glycol, specifically does not contain alcohol, and more specifically contains only water.

[0038] When used alone in the form of a cosmetic ingredient, N-methylglycine is advantageously solubilized in an aqueous solvent containing glycerin and is advantageously present at a concentration of 60% to 90%, more advantageously 70% to 85%, and very advantageously 82% by weight, based on the total weight of the aqueous solution.

[0039] Alternatively, N-methylglycine is solubilized and / or diluted in a solvent, specifically a polar solvent, for example, water, alcohol, polyol, glycol, for example, pentylene glycol and / or butylene glycol and / or hexylene glycol and / or caprylyl glycol or mixtures thereof, preferably an aqueous glycolic mixture, more preferably an aqueous glycolic mixture containing a glycol selected from hexylene glycol, caprylyl glycol and mixtures thereof, or glycerol. Advantageously, N-methylglycine is diluted and / or dissolved in an aqueous solution containing hexylene glycol, specifically 0.1% to 10% by weight of hexylene glycol, preferably 0.5% to 5% by weight of hexylene glycol, based on the total weight of the cosmetic components. Advantageously, N-methylglycine is diluted and / or dissolved in an aqueous solution containing caprylyl glycol, specifically 0.01% to 5% by weight of caprylyl glycol, preferably 0.1% to 1% by weight of caprylyl glycol, based on the total weight of the aqueous solution.

[0040] In a first embodiment of the present invention, N-methylglycine in powder form is solubilized in water as the sole solvent at a final weight concentration of 7% based on the total weight of the solution, as described in Example 1a).

[0041] In the second embodiment, N-methylglycine in powder form is solubilized in an aqueous solution of glycerin (82% w / w) at a weight concentration of 7% based on the total weight of the final solution. The solution is then filtered (0.45 μm) as described in Example 1b).

[0042] Another subject of the present invention relates to the use of N-methylglycine in cosmetic compositions comprising at least one cosmetically acceptable excipient for the advantage of increasing the diversity of the scalp's skin microbiome, for the loss of skin appendages, preferably for reducing and / or preventing hair loss, and / or for preventing and / or reducing the appearance of pityriasis scalpi.

[0043] The term "acceptable" is intended to mean a cosmetic excipient that is non-irritating to the skin, does not induce allergic reactions, and is chemically stable.

[0044] In one embodiment of the present invention, N-methylglycine is 1 × 10 -6 M~1×10 -1 M, 1x10 preferred -5 M~1×10 -2 At the final concentration of M, 7 × 10 is highly preferred. -3 It is present in the cosmetic composition at concentration M.

[0045] Alternatively, N-methylglycine may be present in a cosmetic composition containing at least one cosmetically acceptable excipient at a final weight concentration of 1% based on the total weight of the composition.

[0046] Excipients may be selected from surfactants and / or emulsifiers, preservatives, buffers, chelating agents, modifiers, opacifiers, pH adjusters, reducing agents, stabilizers, thickeners, gelling agents, film-forming polymers, fillers, matting agents, glossing agents, pigments, dyes, fragrances, and mixtures thereof. Non-patent document 1 describes various cosmetic excipients suitable for use in the present invention.

[0047] Advantageously, the excipients include polyglycerols, esters, cellulose polymers and derivatives, lanolin derivatives, phospholipids, lactoferrin, lactoperoxidase, sucrose-based stabilizers, vitamin E and its derivatives, xanthan gum, natural and synthetic waxes, vegetable oils, triglycerides, unsaponifiable substances, phytosterols, silicones, protein hydrolysates, betaine, amine oxides, plant extracts, sucrose esters, titanium dioxide, glycine, and parabens, more preferably steareth-2, steareth-21, glycol-15 stearyl ether, cetearyl alcohol, phenoxyethanol, methylparaben, ethylparaben, propylparaben, butylparaben, butylene glycol, caprylyl glycol, natural tocopherol, glycerin, dihydroxycetyl sodium phosphate, isopropyl hydroxycetyl ether, glycol stearate, triisononanoin, Selected from the group consisting of octyl cocoate, polyacrylamide, isoparaffin, laureth-7, carbomer, propylene glycol, hexylene glycol, glycerol, bisabolol, dimethicone, sodium hydroxide, PEG-30 dipolyhydroxystearate, caprylic / capric triglyceride, cetearyl octanoate, dibutyl adipate, grape seed oil, jojoba oil, magnesium sulfate, EDTA, cyclomethicone, xanthan gum, citric acid, sodium lauryl sulfate, mineral waxes and oils, isostearyl isostearate, propylene glycol diperargonate, propylene glycol isostearate, PEG-8, beeswax, glycerides from hydrogenated palm kernel oil, lanolin oil, sesame oil, cetyl lactate, lanolin alcohol, castor oil, titanium dioxide, lactose, sucrose, low-density polyethylene, isotonic saline solution, and mixtures thereof.

[0048] The cosmetic composition according to the present invention may be selected from aqueous or oily solutions, creamy gels or aqueous or oily gels, particularly shower gels, shampoos and conditioners, milks, emulsions, microemulsions, or nanoemulsions (particularly oil-in-water, water-in-oil, composite, or silicone types), masks, serums, lotions, liquid soaps, skin bars, ointments, foams, patches, and anhydrous substances (preferably in liquid, paste, or solid form, such as makeup powder, rod, or stick form). Advantageously, it may be a cream or serum.

[0049] Cosmetic compositions may also contain other cosmetic active ingredients. Many cosmetic active ingredients for improving skin health and / or physical appearance are known to those skilled in the art. Furthermore, the compounds described in the present invention may have synergistic effects when combined with each other. Such combinations are also covered by the present invention. Non-patent document 1 describes various cosmetic and pharmaceutical ingredients commonly used in the cosmetic and pharmaceutical industries, which are particularly suitable for topical use. Examples of components in this class include, but are not limited to, the following compounds: abrasives, absorbents, compounds for aesthetic purposes, e.g., fragrances, pigments, dyes, essential oils, astringents, e.g., clove oil, menthol, camphor, eucalyptus oil, eugenol, menthyl lactate, witch hazel distillate, anti-acne agents, antiflocular agents, antifoaming agents, antimicrobial agents (e.g., iodopropyl butylcarbamate), antioxidants, binders, biological additives, buffers, leavening agents, chelating agents, additives, biocides, denaturants, thickeners, and vitamins, as well as their derivatives or equivalents, film-forming materials, polymers, opacifiers, pH adjusters, reducing agents, depigments or diluting agents (e.g., hydroquinone, kojic acid, ascorbic acid, magnesium ascorbyl phosphate, ascorbyl glucosamine), and conditioning agents (e.g., humectants).

[0050] The cosmetic composition may also include other cosmetic agents or cosmetic agents having complementary effects that have the same properties as the extract according to the present invention and induce a synergistic effect.

[0051] Examples of anti-hair loss agents include combinations of sulfopeptides, amino acids, amino sugars, B vitamins, zinc, and extracts of Panax ginseng and Arctium majus sold by the applicant under the name Trichogen® LS8960; hair protectants, such as extracts of Litchi chinensis fruit peel sold by the applicant under the name Litchiderm®; or sedative and antipruritic agents, such as rapeseed phytosterol sold by the applicant under the name Phytosoothe® LS9766. Combinations with scalp protectants such as Purisoft® and Puricare® are also possible.

[0052] Examples of activators used to reduce scalp sensitivity include Elestab® HP100, PatcH2O®, and Sanicapyl®.

[0053] Finally, N-methylglycine can be combined with surfactants that regulate sebum production by the skin and scalp (for example, Asebiol®, Betapur®, and Sebaryl®).

[0054] Other types of activators, such as Cassia alata leaf extract sold as DN-Age(trademark) as an antioxidant activator for hair care, a combination of Salvia miltiorhizza extract and niacinamide, specifically sold as CollRepair(trademark) as a deglycerating agent, or activators that promote skin tightening, such as synthetic tetrapeptide sold as Dermican(trademark), Hibiscus abelmoschus extract sold as Linefactor(trademark), purified pea extract sold as Proteasyl(trademark), Manilkara multinervis extract sold as Elestan(trademark), and Khaya senegalensis sold as Collalift(trademark)18. The composition may contain extracts of *Schizandra chinensis*, argan pulp sold by the applicant under the name Argassential®, schizandra chinensis sold under the name Sqisandryl®, eperua falcata sold under the name Eperuline®, and orthosiphon stamineus, a commercially available product sold by the applicant under the name MAT-XS® Bright. Such combinations of activators can strengthen hair follicles and reduce hair loss.

[0055] In one advantageous embodiment, the cosmetic composition is applied to the scalp and / or skin appendages, preferably all or part of the scalp.

[0056] Another subject also relates to a cosmetic care process that includes topical or oral administration, or more favorably topical application, of N-methylglycine or compositions containing the same, for the advantage of increasing the diversity of the skin microbiome, of the scalp. In one embodiment, the process includes topical application of N-methylglycine or compositions containing the same to the scalp and / or skin appendages, or more favorably, to all or part of the scalp.

[0057] Therefore, advantageously, the cosmetic care process according to the present invention aims to reduce and / or prevent loss of skin appendages, preferably hair loss, and / or prevent and / or reduce the appearance of pityriasis scalpi, by topical application of N-methylglycine or a composition containing the same.

[0058] The subject of the present invention is also a cosmetic treatment method, comprising the following steps, for reducing and / or preventing the loss of skin appendages, preferably hair loss, and / or preventing and / or reducing the appearance of pityriasis scalpi in individuals who require and / or desire it. - Identification on an individual of areas of skin and / or skin appendages where loss of skin appendages, preferably reduction and / or prevention of hair loss, and / or prevention and / or reduction of the appearance of pityriasis capitis, - Topical application of a cosmetic composition containing an effective amount of N-methylglycine to such areas of the skin and / or skin appendages for the purpose of reducing and / or preventing loss of skin appendages, preferably hair loss, and / or preventing and / or reducing the appearance of pityriasis scalpi.

[0059] The final subject of the present invention relates to pharmaceuticals, advantageously for skin, and compositions containing N-methylglycine for use in reducing skin itching and / or irritation, advantageously scalp irritation, and / or skin sensitivity, advantageously scalp sensitivity. The term “skin sensitivity” is intended herein to mean skin tightness and / or pain on contact and / or burning sensation (distinguishable from itching and irritation) caused similarly by an imbalance in the skin microbiome.

[0060] The term "reduction of itching and / or irritation" is intended to mean a reduction in the adhesion of S. aureus to the skin, particularly the scalp. Thus, N-methylglycine is considered to be in an effective amount for reducing itching and / or irritation of the skin when the adhesion of S. aureus to the skin surface is reduced by at least 30%, preferably at least 44%, more preferably at least 60% in the presence of N-methylglycine compared to the percent adhesion measured without using N-methylglycine. More preferably, it includes a reduction in the adhesion of S. aureus to the surface of the scalp.

[0061] In an advantageous embodiment of the invention, the measurement of the percent adhesion of S. aureus is carried out at the level of human keratinocytes, under the conditions described in Example 3, in the presence of two distinguishable concentrations of N-methylglycine.

[0062] In one embodiment of the invention, a pharmaceutical, preferably a dermatological, composition comprises at least one dermatologically acceptable excipient. Preferably, N-methylglycine is present in the composition at a concentration of 1×10 -6 M to 1×10 -1 M, preferentially at a concentration of 1×10 -5 M to 1×10 -2 M, very preferentially at a concentration of 7×10 -3 M. Alternatively, N-methylglycine is present in a pharmaceutical, preferably a dermatological, composition at a final weight concentration of 1% based on the total weight of the composition.

[0063] Examples are presented below with reference to the description. These examples are given for illustrative purposes and are not intended to limit the scope of the invention in any way. Each example has a general scope. The examples form an essential part of the invention, and any novel features that appear with respect to any prior art from the description written in its entirety, including the examples, form an essential part of the invention.

[0064] Unless otherwise specified, temperature is expressed in degrees Celsius (°C), the abbreviation "w" represents weight, and the abbreviation "v" represents volume. [Examples]

[0065] Example 1: Preparation of N-methylglycine solution Example 1a): Commercially available N-methylglycine powder (Sigma-Aldrich) was dissolved in water as the sole solvent at a weight concentration of 7% based on the total weight of the final solution. The solution was filtered (0.45 μm).

[0066] Example 1b): Commercially available N-methylglycine powder (Sigma-Aldrich) was solubilized in an aqueous solution of glycerin (82% w / w) at a weight concentration of 7% based on the total weight of the final solution. The solution was filtered (0.45 μm).

[0067] Example 2: Increased microbial diversity of the scalp in the presence of N-methylglycine protocol: A clinical trial was conducted on a group of 29 subjects (males and females) aged 23 to 66 years with oily scalps. In a group of 17 volunteers, a composition containing 1% by weight of an N-methylglycine preparation prepared according to Example 1b) based on the total weight of the composition was applied to the entire scalp in the form of a mask three times a week for four weeks, followed by the application of a neutral shampoo. The other 12 volunteers were treated with a composition that did not contain the substance according to the present invention (control).

[0068] The amount of sebum on the scalp was evaluated 2 and 4 weeks after application.

[0069] At the start of the study (T0) and at the end of the study (4 weeks after application of the N-methylglycine-containing formulation, T28), the scalp microbiome was sampled using swab technology (cotton swab). After enzymatic lysation, microbial DNA was extracted, purified on a silicone membrane, and quantified by fluorescence. All DNA contained in the sample was analyzed by complete metasequencing of the whole genome. The results are shown in Table 1 for the overall increase in microbial diversity and in Table 2 for the qualitative analysis of the detected strains.

[0070] result: 2a) Increase in microbial diversity of the scalp

[0071] [Table 1]

[0072] Conclusion: In the presence of N-methylglycine, scalp microbial diversity increased by 21.7% after 28 days.

[0073] 2a)a Qualitative analysis of microbial diversity of the scalp A negative value indicates that the strain statistically represents the microbial population at the start of the experiment (T0). A positive value indicates that the strain statistically represents the microbial population at the end of the experiment (T28).

[0074] Therefore, it is a measure of the change in the relative bacterial content in the presence of the tested formulation (control formulation or N-methylglycine-containing formulation) (i.e., reasonably explainable across the total population tested).

[0075] [Table 2A] [Table 2B]

[0076] 2b) Reduction and stabilization of the total amount of Staphylococcus strains.

[0077] [Table 3]

[0078] Conclusion:Within 28 days of applying a shampoo containing N-methylglycine, the overall population of Staphylococcus strains (all species) was significantly reduced compared to application of a shampoo without N-methylglycine. Therefore, N-methylglycine can stabilize populations of Staphylococcus strains.

[0079] 2c) Effects of reducing and stabilizing the Staphylococcus / P. acnes ratio and reducing pityriasis capitis.

[0080] [Table 4]

[0081] Conclusion: The appearance of pityriasis capitis was shown to correlate with an increase in the Staphylococcus population, particularly an increase in the Staphylococcus / P. acnes ratio. However, the presence of a final concentration of 0.07% (w / w) N-methylglycine in the cosmetic formulation delayed the increase in the ratio of Staphylococcus (any species) to P. acnes, demonstrating N-methylglycine's ability to reduce pityriasis capitis.

[0082] Example 3: Reduction in adhesion of S. aureus and reduction in skin itching and irritation. protocol: Based on the final volume of the solution, 3 × 10 -2 and 6×10 -2To a final w / v N-methylglycine solution, S. aureus pre-labeled with CFSE (carboxyfluorescein succinimimidyl ester) was added at a rate of 1.108–1.109 CFU / ml. After addition, the solutions were homogenized, and each mixture was incubated at 37°C for 1 hour and then brought into contact with the keratinocyte layer. The entire mixture was incubated at 37°C for 1 hour. The cells were rinsed, and fluorescence was then measured at excitation (max) = 492 nm and emission (max) = 517 nm.

[0083] result:

[0084] [Table 5]

[0085] Conclusion: N-methylglycine demonstrated effectiveness in reducing scalp itching and irritation by decreasing the adhesion of S. aureus to keratinocytes.

[0086] Example 4: Example of a cosmetic ingredient containing N-methylglycine Percentages are expressed in weight based on the final volume of the component.

[0087] [Table 6]

[0088] Example 5: Example of a cosmetic formulation in the form of a mask

[0089] [Table 7]

Claims

1. Use of N-methylglycine as a cutaneous prebiotic.

2. The non-therapeutic cosmetic use of N-methylglycine according to claim 1 is advantageous for increasing the diversity of the scalp's skin microbiome.

3. The use according to claim 1 or claim 2 for the loss of skin appendages, preferably for reducing and / or preventing hair loss, and / or for preventing and / or reducing the appearance of pityriasis capitis.

4. The use according to any one of claims 1 to 3, characterized in that it is for local use.

5. The N-methylglycine is contained in a cosmetic composition comprising at least one cosmetically acceptable excipient, wherein the N-methylglycine is 1 × 10 －６ M~1 x 10 －１ M, 1x10 －５ M~1 x 10 －２ At the final concentration of M, 7 × 10 is highly preferred. －３ The use according to any one of claims 1 to 4, characterized in that it exists at a concentration of M.

6. The use according to any one of claims 1 to 4, characterized in that the N-methylglycine is present in a cosmetic composition comprising at least one cosmetically acceptable excipient at a final weight concentration of 1% based on the total weight of the composition.

7. The use according to claim 5 or 6, characterized in that the composition is applied to the scalp and / or skin appendages, preferably all or part of the scalp.

8. Streptococcus salivarius, Staphylococcus pasteuri, Rotia mucilaginosa, Streptococcus parasanguinis, Staphylococcus saprophyticus, Veillonella parvula, Streptococcus australis australis), Haemophilus parainfluenzae, Staphylococcus warneri, Rotia aeria, Streptococcus thermophilus, Acinetobacter ursingii, Propionibacterium phage P14, Veillonella dispal Selected from S. dispar), Streptococcus infantis, Streptococcus cristatus, Staphylococcus pettenkoferi, Actinomyces odontolitisus, and mixtures thereof, more preferably S. pasteuri, S. saprophyticus, S. warneri, S. pettenkoferi, and mixtures thereof, more preferably S. Use according to any one of claims 1 to 7 for promoting the emergence of beneficial commensal strains selected from S. pasteuri, S. warneri, and mixtures thereof, with very preference being S. warneri.

9. A cosmetic care process that includes topical or oral administration, or topical application, of N-methylglycine or a composition containing the same, for the benefit of increasing the diversity of the scalp and skin microbiome.

10. A cosmetic care process according to claim 9, for the loss of skin appendages, preferably for reducing and / or preventing hair loss, and / or for preventing and / or reducing the appearance of pityriasis capitis.

11. A pharmaceutical, preferably for skin use, or a composition containing N-methylglycine, for use in reducing itching and / or irritation of the skin, preferably scalp irritation, and / or preventing and / or reducing skin sensitivity, preferably scalp sensitivity.

12. 1×10 －６ M to 1×10 －１ M, preferably 1×10 －５ M to 1×10 －２ At a concentration of M, very preferably 7×10 －３ N-methylglycine for use according to claim 11, characterized in that it is present in the pharmaceutical composition at a concentration of M.

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