Use of a short-chain fatty acid as an anti-dandruff agent

Abstract

Use of a short-chain fatty acid as an anti-dandruff agent. The present invention relates to the cosmetic field, and in particular to the cosmetic uses of at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof, and mixtures thereof, or a conditioned culture medium obtained from at least one microorganism capable of producing this / these short-chain fatty acid(s), as an anti-dandruff agent, to prevent and / or treat desquamative skin disorders associated with the excessive proliferation of yeasts of the genus Malassezia on the skin and to maintain and / or restore the skin's ecoflora to a normal level, in particular by preventing excessive colonization of the skin by the genus Malassezia and / or by mediating the growth of Cutibacterium acnes. Figure for the abstract: 1

Description

Title of the invention: Use of a short-chain fatty acid as an anti-dandruff agent

[0001] The present invention relates to the cosmetic field, and in particular to the cosmetic uses of at least one short-chain fatty acid chosen from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or of a conditioned culture medium obtained from at least one microorganism, capable of producing this / these short-chain fatty acid(s), as an anti-dandruff agent, for preventing and / or treating desquamative skin disorders associated with the excessive proliferation of yeasts of the genus Malassezia on the skin and for maintaining and / or restoring the ecoflora of the skin to a normal level, in particular by preventing excessive colonization of the skin by yeasts of the genus Malassezia and / or by mediating the growth of Cutibacterium acnes.

[0002] Desquamative skin disorders, such as dandruff or seborrheic dermatitis, affect up to 50% of the world's population. They affect both men and women and are perceived to have a very negative psychosocial impact. The appearance of dandruff is unpleasant both aesthetically and because of the discomfort it causes (including tingling or itching), and this is why many people facing this problem want to eliminate it effectively and permanently.

[0003] These disorders correspond to excessive and visible desquamation of the skin resulting from too rapid multiplication of the cells of the epidermis and their abnormal maturation. This phenomenon can be caused in particular by overly aggressive treatments of the skin or hair, extreme climatic conditions, stress, diet, fatigue and pollution. Dandruff and seborrheic dermatitis conditions generally result from a disorder of the skin microflora and more particularly from excessive colonization by a fungus which belongs to the family of yeasts of the genus Malassezia, in particular the species Malassezia restricta, and from a lower abundance of Cutibacterium acnes, compared to a healthy scalp.

[0004] Many treatments have been developed with the primary objective of eradicating Malassezia yeasts from the skin. Thus, the activity of currently used active agents, such as zinc pyrithione, piroctone olamine or selenium disulfide, is based primarily on their fungicidal property. However, it is well known that many of these conventional agents extend their antimicrobial effect to at least one of the other bacteria and are therefore not selective for yeasts of the genus Malassezia , and in particular of the species Malassezia restricta, and can therefore kill or alter the beneficial commensal microflora of the skin.

[0005] Thus, solutions for finding new active agents that have selective growth inhibition activity against yeasts of the genus Malassezia (known to be responsible for desquamative skin disorders), and in particular the species Malassezia restricta, have become a major challenge for maintaining and / or restoring healthy skin microflora and thus meeting consumer needs.

[0006] An aim of the present invention is to provide an active agent effective in inhibiting the growth of yeasts of the genus Malassezia (responsible for desquamative skin disorders), in particular the species Malassezia restricta, without extending its antimicrobial effect to other bacteria, in particular Staphylococcus epidermidis, and / or Staphylococcus capitis, and / or Cutibacterium acnes, which together constitute a large portion of the skin microbiome.

[0007] Another aim of the invention is to provide an active agent which can maintain and / or restore to a normal level, the ecoflora of the skin and in particular by preventing excessive colonization of the skin by yeasts of the genus Malassezia and / or by mediating the growth of Cutibacterium acnes.

[0008] The applicant has surprisingly discovered that the cosmetic use of at least one short-chain fatty acid having a chain length of not more than 5 carbon atoms selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, has made it possible to effectively treat dandruff and / or seborrheic dermatitis conditions associated with the proliferation of yeasts of the genus Malassezia without having an antimicrobial effect on Staphylococcus epidermidis and Cutibacterium acnes unlike medium-chain fatty acids having a chain length of more than 6 carbon atoms such as caproic acid, caprylic acid, ethylcaproate, glyceryl monocaprylate, propylene glycol monocaprylate, and a metal salt of a short-chain fatty acid such as zinc propionate shown in Example 3 of the present application.

[0009] In addition to the selectivity on the genus Malassezia, said short-chain fatty acids mediate the growth of Cutibacterium acnes, a commensal skin bacterium, which is reduced in dandruff and seborrheic dermatitis conditions.

[0010] Thus, these effects contribute to a rebalancing effect of the skin's ecoflora.

[0011] An object of the present invention is therefore the cosmetic use i) of at least a short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, as an anti-dandruff agent.

[0012] Another object of the present invention is a cosmetic use of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, for preventing and / or treating desquamative skin disorders associated with the proliferation of yeasts of the genus Malassezia, more particularly of the species Malassezia restricta, such as dandruff and / or seborrheic dermatitis.

[0013] The invention also relates to a cosmetic use of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, for maintaining and / or restoring to a normal level the ecoflora of the skin and in particular by preventing excessive colonization of the skin by yeasts of the genus Malassezia, more particularly the species Malassezia restricta, and / or by mediating the growth of Cutibacterium acnes.

[0014] Another subject of the present invention is a cosmetic process for preventing and / or treating desquamative skin disorders associated with the proliferation of yeasts of the genus Malassezia, more particularly of the species Malassezia restricta, such as dandruff and / or seborrheic dermatitis, comprising the application, to the hair and / or the skin, of a cosmetic composition comprising an effective amount of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof. these..

[0015] Another object of the present invention is a cosmetic process intended to maintain and / or restore to a normal level, the ecoflora of the skin and in particular by preventing excessive colonization of the skin by yeasts of the genus Malassezia, more particularly the species Malassezia restricta, and / or by mediating the growth of Cutibacterium acnes, comprising the application, to the hair and / or the skin, of a cosmetic composition comprising an effective amount of i) at least one short-chain fatty acid chosen from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid chosen from propionic acid, butyric acid, valeric acid, non-metallic salts thereof,esters thereof and mixtures thereof. Definitions,

[0016] In this document, the term "treatment" or "treatment" means any action aimed at improving the comfort or well-being of an individual. This term therefore covers the alleviation, relief or suppression of the symptoms of dandruff or seborrheic dermatitis, but is limited to a cosmetic treatment.

[0017] For the purposes of the present invention, the term "non-metallic salts" means salts which do not comprise metal ion(s) such as zinc ion, aluminum ion, copper ion, iron ion, and mixtures thereof.

[0018] For the purposes of the present invention, the term "skin" means the skin of the entire body, including the scalp, preferably the skin of the scalp and the skin of the face such as the forehead, nose, cheeks, chin, chest, neck.

[0019] In the context of the present invention, the term “skin ecoflora” designates the microbial flora naturally present on healthy skin, in particular commensal microorganisms of the skin, such as for example Staphylococcus epidermidis, and / or Staphylococcus capitis, and / or Cutibacterium acnes.

[0020] For the purposes of the present invention, the terms "prevent" mean reducing the risk of manifestation of a phenomenon, in particular in the context of the invention dandruff and seborrheic dermatitis.

[0021] For the purposes of the present invention, the terms “effective amount” mean an amount sufficient to obtain the expected effect.

[0022] For the purposes of the present invention, the terms “cosmetic composition” designate a composition suitable for application to the skin, in particular a composition which comprises a physiologically acceptable medium.

[0023] By "physiologically acceptable medium" is meant a medium suitable for the topical administration of a composition, i.e. compatible with the skin of the face, body and scalp.

[0024] For the purposes of the present invention, the terms "short-chain fatty acid" denote a carboxylic acid with an aliphatic chain comprising 3 to 5 carbon atoms, preferably a carboxylic acid with an aliphatic chain having 3 carbon atoms. Detailed description of the invention

[0025] Short-chain fatty acids (SCFAs)

[0026] As indicated above, an object of the present invention is the cosmetic use of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, as an anti-dandruff agent.

[0027] The present invention also relates to the cosmetic use of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, for preventing and / or treating desquamative skin disorders associated with the proliferation of yeasts of the genus Malassezia, more particularly of the species Malassezia restricta, such as dandruff and / or seborrheic dermatitis.

[0028] The present invention also relates to the cosmetic use of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, for maintaining and / or restoring the ecoflora of the skin to a normal level and in particular by preventing excessive colonization of the skin. by yeasts of the genus Malassezia, more particularly the species Malassezia restricta and / or by mediating the growth of Cutibacterium acnes.

[0029] The non-metallic salts of short chain fatty acids according to the invention are particularly preferred and may be any safe and effective non-metallic salt of such an acid. For illustration, some preferred salts may include calcium salts, sodium salts, magnesium salts and potassium salts, with the most preferred being the sodium salts.

[0030] By way of further illustration, amino acid salts may be used. For example, a carnitine or lysine salt of short chain fatty acids according to the invention may be used. Those skilled in the art will recognize that various other amino acids may also be used.

[0031] As examples of esters of propionic acid, butyric acid, or valeric acid, any safe and effective ester of that acid may be used. For example, when the SCFA is an ester of propionic acid, the component may be represented as follows: O RI --, R 2

[0032] where RI = CH3 and R2 is the ester chain or the ester of propionic acid.

[0033] For example, the ester chain of the selected acid may be a straight or branched chain of carbon atoms and typically contains about 8 or fewer carbon atoms. This ester chain more preferably contains from 1 to about 5 carbon atoms and, again, may be a straight (e.g., n-propyl) or branched (e.g., iso-propyl) chain. Highly preferred ester chains include those that form methyl esters (i.e., R2 is -CH3), ethyl esters, n-propyl esters, iso-propyl esters, n-butyl esters, iso-butyl esters, and mixtures thereof. For illustration, methyl propionate, ethyl propionate, n-propyl propionate, iso-propyl propionate, n-butyl propionate, iso-butyl propionate are examples of propionic acid esters that may be used herein. Such esters of propionic, butyric or valeric acid may also be chosen.

[0034] Examples of short-chain fatty acids include sodium propionate (Ref. P188O); sodium butyrate (Ref. 303410); valeric acid (Ref. 75054) sold by Sigma.

[0035] In a particular embodiment, the short-chain fatty acids are obtained from at least one microorganism capable of producing one or more short-chain fatty acids. Said at least one microorganism which is capable of producing one or more short-chain fatty acids may be selected from the group Lactobacillus spp, Bifidobacterium spp, Ruminococcus spp, Roseburia spp, Akkermansia muciniphila, Faecalibacterium spp, Eubacterium rectale, and Cutibacterium acnes, preferably Lactobacillus spp, Bifidobacterium spp, and Cutibacterium acnes, more preferably Cutibacterium acnes, such as the strain Cutibacterium acnes ATCC 6919.

[0036] In another embodiment, the short-chain fatty acids according to the invention are contained in a conditioned culture medium (or supernatant) of at least one microorganism which is capable of producing one or more short-chain fatty acids.

[0037] Said at least one microorganism which is capable of producing one or more short-chain fatty acids may be selected from the group Lactobacillus spp, Bifidobacterium spp, Ruminococcus spp, Roseburia spp, Akkermansia muciniphila, Faecalibacterium spp, Eubacterium rectale, and Cutibacterium acnes, preferably Lactobacillus spp, Bifidobacterium spp, and Cutibacterium acnes, more preferably Cutibacterium acnes, such as the strain Cutibacterium acnes ATCC 6919.

[0038] A “culture supernatant” also called “conditioned culture medium” is typically obtained by culturing the microorganism concerned in a medium suitable for the survival and / or growth of the microorganism, then by separating the medium and the microorganism so as to collect the medium brought into contact with the microorganism. Preferably, the culture is carried out for a period and under conditions likely to allow the microorganism to release into the medium the active agents having the desired anti-dandruff properties, in particular the short-chain fatty acids according to the invention.

[0039] The environment suitable for the survival and / or growth of the microorganism will be any nutrient medium suitable for the survival and / or cultivation of the microorganism. It generally contains a source of carbon and nitrogen, such as, for example, amino acids, sugars, proteins, fatty acids, phosphates, sulfates, minerals and growth factors and vitamins in adequate amounts.

[0040] In the context of the present application, the terms “conditioned culture medium” or “culture supernatant” are used interchangeably to designate the entire culture supernatant obtained after culturing the microorganism in question, or any fraction or sub-compound of the supernatant obtained by dialysis, fractionation, separation phase, filtration chromatography, affinity chromatography, precipitation, concentration, lyophilization, etc.

[0041] In the context of the present invention, the conditioned culture medium of at least one microorganism which is capable of producing one or more short-chain fatty acids according to the invention is obtained by the method comprising the following steps:

[0042] i) culturing at least one microorganism capable of producing one or more short-chain fatty acids, preferably a microorganism of the species Cutibacterium acnes, such as Cutibacterium acnes ATCC 6919;

[0043] ii) separation, in particular by centrifugation, of the culture supernatant from the biomass;

[0044] iii) recovery of the culture supernatant; and

[0045] iv) optional stabilization of the culture supernatant, for example by filtration and / or autoclaving.

[0046] As used herein, the term "biomass" refers to Cutibacterium acnes cells obtained after performing step i).

[0047] Preferably, the filtration is carried out with a syringe filter whose pore size is between 0.2 μm and 0.45 μm.

[0048] The short-chain fatty acids or the conditioned culture medium according to the present invention are used in an amount representing from 0.01% to 5% by weight relative to the total weight of the composition, preferably in an amount representing from 0.3% to 1.0% by weight relative to the total weight of the composition.

[0049] Another subject of the present invention is a cosmetic process for preventing and / or treating desquamative skin disorders associated with the proliferation of yeasts of the genus Malassezia, more particularly of the species Malassezia restricta, such as dandruff and / or seborrheic dermatitis, comprising the application, to the hair and / or the skin, of a cosmetic composition comprising an effective amount of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, these..

[0050] Another object of the present invention is a cosmetic process intended to maintain and / or restore to a normal level, the ecoflora of the skin and in particular by preventing excessive colonization of the skin by yeasts of the genus Malassezia, more particularly the species Malassezia restricta, and / or by mediating the growth of Cutibacterium acnes, comprising the application, to the hair and / or the skin, of a cosmetic composition comprising an effective amount of i) at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof, or ii) a conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof.

[0051] Preferably, said cosmetic composition comprises a cosmetically acceptable medium, that is to say a medium compatible with topical application to keratinous materials, in particular the skin.

[0052] Preferably, the pH of said cosmetic composition is between 6 and 8, in particular between 6.5 and 7.5, and in particular at a neutral pH of 7.0.

[0053] Advantageously, the short-chain fatty acid or the conditioned culture medium according to the present invention is present in an amount representing from 0.01% to 5% by weight relative to the total weight of the composition, preferably in an amount representing from 0.3% to 1% by weight relative to the total weight of the composition.

[0054] In a first preferred embodiment, said cosmetic composition is a composition for the scalp, which may be a rinse-off or leave-on composition. The composition is preferably in the form of a shampoo, a cream, a mousse (aerosol or not), a paste, a gel, an emulsion, a lotion or a stick. Preferably, the composition for the hair is a shampoo, a gel or a lotion.

[0055] In a second preferred embodiment, said cosmetic composition is a skin composition which may be more or less fluid and may have the appearance of a white or colored cream, an ointment, a milk, a lotion, a serum, a paste or a mousse. They may optionally be applied to the skin in the form of an aerosol. They may also be in solid form, for example in the form of a stick or a compact powder. In particular, said cosmetic composition may be in the form of an aftershave gel or lotion, a body hygiene composition such as a shower gel, a solid composition such as a soap or a cleansing bar, a skin care or cleansing composition.

[0056] The cosmetic composition preferably comprises water and / or one or more water-miscible organic solvents which may be chosen from linear or branched C1-C6 monoalcohols, such as ethanol, isopropanol, tert-butanol or n-butanol; polyols, such as glycerol, propylene glycol, hexylene glycol (or 2-methyl-2,4- pentanediol) and polyethylene glycols; polyol ethers, such as dipropylene glycol monomethyl ether; and mixtures thereof.

[0057] Preferably, the cosmetic composition comprises water in an amount ranging from 30 to 98% by weight, in particular from 40 to 95% by weight, better still from 50 to 90% by weight, relative to the total weight of the composition.

[0058] Preferably, the cosmetic composition comprises the organic solvent(s) in an amount ranging from 0.05 to 60%, preferably from 0.5 to 50% and better still from 1 to 40% by weight, relative to the total weight of the cosmetic composition.

[0059] Said cosmetic composition according to the invention may also comprise at least one usual cosmetic ingredient, in particular chosen from vegetable, mineral, animal or synthetic oils; liquid fatty alcohols; liquid fatty esters; solid fatty bodies and in particular waxes, solid fatty esters, solid alcohols; anionic, cationic, amphoteric and non-ionic surfactants; anionic, non-ionic, amphoteric and cationic polymers; anti-dandruff agents other than short-chain fatty acids or the culture medium conditioned according to the present invention; antioxidants; agents for combating hair loss; silicones; perfumes; polymeric or non-polymeric thickeners, and in particular associative polymers; optionally preservatives; chelators; colorants. The composition may, of course, comprise several cosmetic ingredients appearing in the list above.A person skilled in the art will take care to select the ingredients making up the composition, as well as their quantities, in such a way that the advantageous properties of the composition according to the invention are not, or not significantly, altered by the envisaged addition.

[0060] The application of said short-chain fatty acid or of the conditioned culture medium or of the composition to the hair and / or the skin may or may not be followed by a rinsing step, for example with water.

[0061] Throughout the description, including the claims, the expression "comprising a" should be understood as being synonymous with "comprising at least one", unless otherwise indicated.

[0062] Furthermore, the expression "at least one" should be understood as being synonymous with "one or more", unless otherwise indicated.

[0063] The expressions “more than”, “between ... and ...” and “ranging from ... to ...” must be understood with the limits included, unless otherwise indicated.

[0064] The following examples and figures are presented for the purpose of illustration and without limitation of the invention.

[0065] The compounds are, as the case may be, cited by chemical name or by CTFA name (International Cosmetic Ingredient Dictionary and Handbook).

[0066] The invention is illustrated in more detail in the following examples. Figures

[0067] [Fig.l]: Effect of AGCCs on the growth of Malassezia restricta.

[0068] [Fig.2]: Effect of SCFAs on the growth of Cutibacterium acnes.

[0069] [Fig.3]: Effect of SCFAs on the growth of Sta p hylococcus epidermidis.

[0070] [Fig.4]: Effect of fatty acids (50 mM) on the growth of Malassezia restricta, quantified using fluorescence staining.

[0071] [Fig.5]: Effect of fatty acid esters and metal salts (50 mM) on the growth of Malassezia restricta, quantified by ATP measurement.

[0072] [Fig.6]: Effect of fatty acids, esters and metal salts on the growth of Cutibacterium acnes.

[0073] [Fig.7]: Effect of fatty acids, esters and metal salts on the growth of Staphylococcus epidermidis.

[0074] [Fig.8]: Effect of SCFAs on the growth of Cutibacterium acnes when Cutibacterium acnes is grown in co-culture with Sta p hylococcus epidermidis under aerobic conditions. Examples

[0075] Example 1 - Evaluation of the selective inhibition of the growth of Malassezia restricta by sodium propionate, sodium butyrate and sodium valerate (according to the invention). A) Materials and processes Organisms and growing conditions

[0076] M. restricta ATCC MYA-4611, S. epidermidis ATCC 12228, and C. acnes ATCC 6919 were purchased from ATCC. M. restricta was routinely cultured in Dixon's (MD) modified medium (pH 6), composed of 36 g malt extract (Sigma 70167), 20 g desiccated oxbile (Sigma 70168), 6 g Bacto™ Peptone (BD 211677), 1% (v / v) Tween 40 (Sigma P1504), 0.2% (v / v) oleic acid (Fluka 75096), and 0.2% (v / v) glycerol (Promega H5433) in 1 liter of dH2O. C. acnes and S. epidermidis were grown in modified brain heart infusion (MBHI) medium (pH 7), containing 37 g of BHI base (Accumedia 7116B), 0.4% (v / v) Tween-40 (Sigma P1504), 0.2% (v / v) oleic acid (Fluka 75096), and 0.2% (v / v) glycerol (Promega H5433) in 1 liter of dH2O. M. restricta and S. epidermidis were routinely grown aerobically, shaking at 200 rpm, and C. acnes was grown anaerobically. All organisms were grown at 33 °C.Whenever necessary, the media were supplemented with: sodium acetate (CH3COOH, Sigma Ref. 32319), sodium propionate (CH3CH2COOH, Sigma Ref. P188O), sodium butyrate (CH3(CH2)2COOH, Sigma Ref. 303410), valeric acid (CH3(CH2)3COOH, Fluka Ref. 75054). For . valeric acid, the pH of the modified cell medium was neutralized with NaOH (sodium hydroxide, Sigma 283060).

[0077] Quantification of total cell number by SYTO9

[0078] M. restricta cells from 1 ml of the culture were harvested by centrifugation at 10,000 xg for 5 minutes at room temperature. The cells were washed once, pelleted, and resuspended in 0.9% NaCl solution. Equal volumes of the above cell suspension and SYTO 9 working stock (3 μl of the SYTO 9 component of the Live / Dead BacLight Bacterial Viability Kit, ThermoFisher Scientific, L7012, diluted in 1 ml of 0.9% NaCl solution) were mixed well, incubated in the dark for 10 minutes, and the fluorescence intensity pattern was measured in a Tecan microplate reader with excitation / emission wavelengths of 485 / 530 nm. A standard for the correlation of fluorescence units and concentration was prepared using a fluorimeter and a hemocytometer under a light microscope. This standard curve was used to calculate the total cell number. Growth tests

[0079] M. restricta cells stored as glycerol stocks (30% glycerol in MD medium) were reactivated by plating them on MD agar plates and incubated for 2-3 days at 33°C. A pre-culture was made from the cell lawn grown on the agar plate. The cells from % of the plate were scraped, homogenized after suspension in 70 ml of MD medium in a 250 ml baffled Erlenmeyer flask and incubated for 24 hours at 33°C at 200 rpm. For experiments, 107 cells / ml were inoculated into fresh MD medium with or without short-chain fatty acids. Growth was monitored by measuring cell density with SYTO 9 for 24 hours or 96 hours. C. acnes and S. epidermidis were inoculated into MBHI medium at a starting cell density D0600 of 0.05 and 0.25, respectively.Bacterial growth was measured by plating serially diluted cultures onto brain heart infusion agar plates at different time points and colonies were counted after 72 hours for C. acnes and 24 hours for S. epidermidis.

[0080] Quantification of colony-forming units (CFU)

[0081] Bacterial growth was quantified by plating the serially diluted cultures onto brain heart broth agar plates at different time points and colonies were counted after 72 hours for C. acnes and 24 hours for Staphylococcus sp. B) Results

[0082] Sodium propionate, sodium butyrate and sodium valerate completely inhibit the growth of Malassezia restricta at a concentration of 30 mM. No effect of acetate was observed at the same concentration ([Fig.l]).

[0083] Sodium propionate, sodium butyrate and sodium valerate do not affect the growth of C. acnes and S. epidermidis at concentrations where complete inhibition of Malassezia restricta was observed (30 mM) ([Fig.2] and 3).

[0084] Conclusion: Sodium propionate, sodium butyrate and sodium valerate selectively inhibit Malassezia restricta and do not affect the growth of other major commensal skin microbes such as C. acnes and S. epidermidis.

[0085] Example 2 - Evaluation of the promotion of the growth of Cutibacterium acnes by sodium propionate (according to the invention) A) Materials and methods Organisms and growth conditions

[0086] S. epidermidis ATCC 12228, and C. acnes ATCC 6919 were purchased from ATCC. C. acnes and S. epidermidis were cultured in modified brain heart infusion (MBHI) medium (pH 7), containing 37 g of BHI base (Accumedia 7116B), 0.4% (v / v) Tween-40 (Sigma P1504), 0.2% (v / v) oleic acid (Fluka 75096), and 0.2% (v / v) glycerol (Promega H5433) in 1 liter of dH2O. S. epidermidis was routinely cultured under aerobic conditions, shaken at 200 rpm, and C. acnes was cultured under anaerobic conditions. All organisms were grown at 33°C. Whenever necessary, the medium was supplemented with: sodium propionate (CH3CH2COOH, Sigma Ref. P188O), Growth assays

[0087] C. acnes and S. epidermidis were inoculated into MBHI medium at a starting cell density DOfflo of 0.05 and 0.25, respectively. Bacterial growth was measured by plating the serially diluted cultures onto brain heart broth agar plates at different time points, and colonies were counted after 72 hours for C. acnes and 24 hours for S. epidermidis. Co-culture assays

[0088] For co-cultures, equal volumes of exponentially growing cells of both species were mixed at a cell density of 105 cells per ml in 24-well glass-bottom plates. The growth of each species in the co-cultures was quantified by plating the culture suspension onto an agar medium. For selective quantification of each bacterium in the co-culture, the agar plates were either grown aerobically to promote selective growth of S. epidermidis or grown anaerobically to selectively enumerate C. acnés with furazolidone, which kills only S. epidermidis.

[0089] Quantification of colony forming units (CFU)

[0090] Bacterial growth was quantified by plating the serially diluted cultures onto brain heart broth agar plates at different time points and colonies were counted after 72 hours for C. acnes and 24 hours for Staphylococcus Sp. B) Results

[0091] S. epidermidis was grown to biofilm formation for 24 hours to maximize its growth, and then C. acnes cells were added in fresh oxygen-saturated medium with or without propionate. C. acnes growth will be minimal unless propionate is metabolized by the S. epidermidis layer, which would create favorable conditions for C. acnes growth.

[0092] The growth of C. acnes and S. epidermidis was monitored for 24, 48 and 72 hours, and it was found that the growth of C. acnes was increased in the presence of propionate ([Fig.8]). The significantly higher growth of C. acnes under aerobic conditions in the presence of propionate demonstrates that propionate is capable of modulating the community dynamics of the skin microbiome by promoting the growth of C. acnes in the presence of Staphylococcus Sp.

[0093] Example 3 - Evaluation of the selectivity of the inhibition of the growth of Malassezia restricta by sodium propionate, sodium butyrate and sodium valerate (according to the invention) compared to medium-chain fatty acids: caproic acid, caprylic acid, ethyl caproate, glyceryl monocaprylate, propylene glycol monocaprylate (not part of the invention) and to the metal salt of short-chain fatty acid: zinc propionate (not part of the invention). A) Materials and processes Organisms and growing conditions

[0094] M. restricta ATCC MYA-4611, S. epidermidis ATCC 12228, and C. acnes ATCC 6919 were purchased from ATCC. M. restricta was routinely cultured in Dixon's (MD) modified medium (pH 6), composed of 36 g malt extract (Sigma 70167), 20 g desiccated oxbile (Sigma 70168), 6 g Bacto™ Peptone (BD 211677), 1% (v / v) Tween 40 (Sigma P1504), 0.2% (v / v) oleic acid (Fluka 75096), and 0.2% (v / v) glycerol (Promega H5433) in 1 liter of dH2O. C. acnes and S. epidermidis were grown in modified brain heart infusion (MBHI) medium (pH 7), containing 37 g of BHI base (Accumedia 7116B), 0.4% (v / v) Tween-40 (Sigma P1504), 0.2% (v / v) oleic acid (Fluka 75096), and 0.2% (v / v) glycerol (Promega H5433) in 1 liter of dH2O. M. restricta and S. epidermidis were routinely grown aerobically, shaking at 200 rpm, and C. acnes was grown anaerobically. All organisms were cultured at 33 °C. Whenever necessary, the medium was supplemented with 50 mM of: sodium propionate (CH3CH2COOH, Sigma Ref. P188O), sodium butyrate (CH3(CH2)2COOH, Sigma Ref. 303410), valeric acid (CH3(CH2)3COOH, Fluka Ref. 75054). For valeric acid, the pH of the modified cell medium was neutralized with NaOH (sodium hydroxide, Sigma 283060).

[0095] Quantification of the total number of M. restricta cells by SYTO9

[0096] M. restricta cells from 1 ml of the culture were harvested by centrifugation at 10,000 xg for 5 minutes at room temperature. The cells were washed once, pelleted, and resuspended in 0.9% NaCl solution. Equal volumes of the above cell suspension and SYTO 9 working stock (3 μl of the SYTO 9 component of the Live / Dead BacLight Bacterial Viability Kit, ThermoFisher Scientific, L7012, diluted in 1 ml of 0.9% NaCl solution) were mixed well, incubated in the dark for 10 minutes, and the fluorescence intensity pattern was measured in a Tecan microplate reader with excitation / emission wavelengths of 485 / 530 nm. A standard for the correlation of fluorescence units and concentration was prepared using a fluorimeter and a hemocytometer under a light microscope. This standard curve was used to calculate the total cell number.Growth tests.

[0097] M. restricta cells stored as glycerol stocks (30% glycerol in MD medium) were reactivated by plating them on MD agar plates and incubated for 2-3 days at 33°C. A pre-culture was made from the cell lawn grown on the agar plate. The cells from % of the plate were scraped, homogenized after suspension in 70 ml of MD medium in a 250 ml baffled Erlenmeyer flask and incubated for 24 hours at 33°C at 200 rpm. For experiments, 107 cells / ml were inoculated into fresh MD medium with or without short-chain fatty acids at a concentration of 50 mM. Growth was monitored by measuring cell density with SYTO 9 or by estimating ATP concentration (see below) for 24 hours or 96 hours. C. acnes and S. epidermidis were inoculated into MBHI medium at a starting cell density DOfl of 0.05 and 0.25, respectively.Bacterial growth was measured by plating serially diluted cultures onto brain heart infusion agar plates at different time points and colonies were counted after 72 hours for C. acnes and 24 hours for S. epidermidis. ATP Estimation

[0098] Cellular ATP was measured using the BacTiterGlo Microbial Cell Viability Kit (Promega) following the manufacturer's protocol. Briefly, the activity of the Luciferase, which uses ATP as a substrate, was estimated as a direct measure of ATP produced by cells. B) Results

[0099] Due to the varying characteristics of different compounds that interfere with the test readings, estimation of M. restricta growth was performed using two different methods:

[0100] - For all fatty acids and caproic acid esters, the total number of cells after 72 hours of incubation was quantified by measuring the fluorescence of cells stained with the fluorescent dye SYTO9 (see methods). The initial cell density of M. restricta was 1 x 107 cells / ml ([Fig.4]).

[0101] - For caprylic acid esters and zinc propionate, cell viability has was quantified by estimating the total amount of ATP in the cell lysate prepared from cells cultured for 24 hours (since these compounds make the medium opaque). ATP measurements were expressed as relative luminescence units (RLU) of the luminescence emitted by the enzyme luciferase in the presence of ATP ([Fig. 5]).

[0102] The growth of C. acnes was quantified by estimating colony forming units (CFU) after 72 hours of growth in media containing fatty acids and their esters ([Fig.6]).

[0103] The growth of S. epidermidis was quantified by estimating colony forming units (CFU) after 24 hours of growth in media containing fatty acids and their esters ([Fig.7]). The results are presented in Tables 1 and 2 below.

[0104] [Table 1] Table 1 - Compounds tested according to the invention Rep.# Control NaP NaB NaV C. acnes (log10 CFU / ml) #1 8.37 7.82 8.26 8.90 #2 8.16 8.34 8.10 8.03 #3 8.05 8.29 8.34 8.00 S. epidermidis (log10 CFU / ml) #1 9.55 8.82 8.87 9.29 #2 9.64 9.00 8.90 9.08 #3 8.72 9.16 9.15 8.90 M. restricta (log10 of total cell count) #1 8.06 6.95 6.94 6.86 #2 7.98 6.79 6.88 6.92 #3 8.01 6.82 6.88 6.93

[0105] *NaP: sodium propionate, NaB: sodium butyrate, NaV: sodium valerate.

[0106] [Table 2] Table 2 - Compounds tested outside the invention Rep.# Control Cpo EH_Cpo Cpy GM_Cp y PGM_Cpy Zn_Pr o C. acnes (loglOCFU / m 1) #1 8.37 8.29 9.94 0.00 0.00 0.00 0.00 #2 8.16 8.26 8.47 0.00 0.00 0.00 0.00 #3 8.05 8.41 8.00 0.00 0.00 0.00 0.00 S. epidermid is (loglOCFU / m 1) #1 9.55 7.67 5.54 3.03 0.00 4.15 5.05 #2 9.64 7.57 5.66 3.00 0.00 4.11 0.00 #3 8.72 7.64 5.55 3.34 0.00 4.12 5.00 M. restricta (log10 of the total number of units) #1 8.06 6.93 6.80 6.98 #2 7.98 6.95 6.69 6.91 #3 8.01 6.87 6.74 6.84 (Relative luminescence units) #1 543000 16700 -2410 12500 #2 1480000 -1470 -2430 11900 #3 1070000 -2030 -2270 10300

[0107] *Cpo: caproic acid, EH Cpo: ethyl caproate, Cpy: caprylic acid, GM Cpy: glyceryl mono caprylate, PGM Cpy: propylene glycol glyceryl mono caprylate, Zn Pr: zinc propionate.

[0108] Conclusion: Sodium propionate, sodium butyrate and sodium valerate (compounds according to the invention) selectively inhibit M. restricta and do not affect the growth of other major commensal skin microbes such as C. acnes and S. epidermidis, unlike caproic acid, ethyl caproate, caprylic acid, glyceryl monocaprylate, propylene glycol glyceryl monocaprylate, zinc propionate (compounds not within the scope of the invention) which have been shown to inhibit at least one of the commensal skin microbes. Example 3 - Face cream

[0109] The composition described below is prepared.

[0110] [Table 3] Table 3 - Composition of face cream Compounds Concentration (w / w) Sodium propionate 1.0 Sodium methylstearoyltaurate 0.23 Xanthan gum 0.05 carbomer 0.2 water qs 100

[0111] The composition is applied to skin with seborrheic dermatitis.

Claims

Claims

1. Conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, for use as an anti-dandruff agent, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof and said microorganism being Cutibacterium acnes.

2. Conditioned culture medium obtained from at least one microorganism capable of producing one or more short-chain fatty acids, for use in preventing and / or treating desquamative skin disorders associated with the proliferation of yeasts of the genus Malassezia, such as dandruff and / or seborrheic dermatitis, said medium comprising at least one short-chain fatty acid selected from propionic acid, butyric acid, valeric acid, non-metallic salts thereof, esters thereof and mixtures thereof and said microorganism being Cutibacterium acnes.

3. A conditioned culture medium for use according to claim 1 or 2, wherein said short chain fatty acid is selected from sodium propionate, sodium butyrate, sodium valerate, and mixtures thereof.

4. Conditioned culture medium for use according to any one of the preceding claims, wherein said short-chain fatty acid is obtained from at least one microorganism of the strain Cutibacterium acnes ATCC 6919.

5. Conditioned culture medium for use according to claim 1 or 2, wherein said conditioned culture medium is obtained by the method comprising the following steps: i. culturing at least one microorganism capable of producing one or more short-chain fatty acids, said microorganism being a microorganism of the species Cutibacterium acnes, such as Cutibacterium acnes ATCC 6919; ii. separating, in particular by centrifugation, the culture supernatant from the biomass; iii. recovery of culture supernatant; and iv. optional stabilization of the culture supernatant, e.g. by filtration and / or autoclaving.

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