FR3027516A1 - USE OF POLYOL ESTERS AND N-ACYL DERIVATIVES OF AMINO ACIDS AS A PROPAGATING AGENT OF THE HUMAN SKIN OF HAIR AND HAIR. - Google Patents

Abstract

On behalf of: Company Operating Products Chemical Industries-SEPPIC Inventors Laetitia CATTUZZATO, Sandy DUMONT, Jerome GUILBOT Abstract: Use of a compound of formula (I): R'-O-CH2-CH (OH) - [CH2-O-CH2] s- [CH (OH)] p -CH2-OR "(I) wherein (I) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R 'and R ", which may be identical or different, represent either a hydrogen atom or a monovalent radical of formula (II): formula (II) in which the group R1-C (= O) - represents a radical ω- undecylenoyl or cocoyl, or (C1) comprising for 100% of its mass: from 99% by weight to 20% by weight of at least one compound of formula (Ia): R'-O-CH 2 -CH (OH) - [ CH 2 -O-CH 2] s- [CH (OH)] p -CH 2 -OH (la) and - From 1 wt% to 80 wt% of at least one compound of formula (lb): RO-CH 2 -CH ( OH) - [CH2-O-CH2] s- [CH (OH)] p-CH2-OR (lb) For browning and / or tanning human skin or maintaining the natural pigmentation of hair. New composition, cosmetic process and drug implementing them.

Description

The present invention relates to the use of esters of N-acylated amino acid derivatives as a dyeing agent for the skin of human hair and body hair, as well as non-therapeutic treatment methods intended for tanning and / or browning the skin of the human body employing cosmetic compositions for topical use comprising said esters of N-acyl derivatives of amino acids. Human skin is the first image offered in the eyes of others, and therefore, the improvement of its appearance is a subject of constant concern for human beings. The skin is a reflection of a state of well-being, often associated with youth, and a contrario a state of fatigue and / or aging. Thus, a tanned complexion and tanned skin are signs of good health and people are attaching more and more importance to this appearance of "good looks". The color of the skin results from the combination of two biological components: the vascularization and the pigmentation of the skin; said pigmentation of the skin being the resultant of the quantities of melanins and carotenes present in human skin. Melanins are produced by specific epidermal cells: melanocytes. These are found at the level of the basal layer of the epidermis or in the hair follicles. Melanins are large cells with many long extensions called dendrites. These dendrites come into contact with the surrounding keratinocytes, which may be up to two superior cell bases, to transmit the melanin grouped in melanosomes. Epidermal Unit of Melanization (EMU), the group of melanocytes and keratinocytes, interacting together to give color to the skin. An EMU comprises in particular a melanocyte and forty keratinocytes. The process of melanogenesis itself includes melanin synthesis by melanocytes, their transfer and distribution to neighboring keratinocytes. The color of the hair and hair is determined by the presence in proportions and in variable quantity of two types of melanins: the pheomelanines (red and yellow pigments) and the eumelanines (brown and black pigments). The pigmentation of the hair requires the presence of melanocytes in the bulb of the hair follicle which, being active, synthesize melanins. It is known in the literature that natural hair whitening, or canitie, is associated with decreased melanin in the hair follicle hair shaft. It has been proposed that the cause of this decrease could be related to a decrease in melanogenic activity in analogy to the skin pigmentation mechanism, but also to a melanin transfer deficiency or a decrease in the proportion of melanocytes in the skin. the bulb (3). The synthesis of melanins occurs in melanocytes, and more particularly in specialized organelles, melanosomes. This synthesis is made from tyrosine and involves several enzymes, including tyrosinase which is the first enzyme to intervene in the reaction chain. There are two main groups of melanins: eumelanins (brown or black) and phaeomelanines (yellow-orange). The maturation of melanosomes goes through four stages in order to be mature and able to be transferred to keratinocytes. During their maturation, melanosomes migrate to the end of the dendrites through a system of microtubules and microfilaments. The transfer between melanocytes and keratinocytes is done by a more or less detailed system of phagocytosis / endocytosis / pinocytosis, via in particular a PAR-2 membrane receptor.

The pigmentation of the skin can either be constitutive or induced. The constitutive pigmentation is based on the genetic heritage of the individual, hormonal factors and age. The induced pigmentation results mainly from ultraviolet radiation exposures. It appears between 48 hours and 72 hours after exposure of the skin to ultraviolet radiation and disappears quickly after the exposure has stopped. This induction of pigmentation results in particular from an activation of tyrosinase, an increase in the size and number of melanocytes and an increase in the transfer of melanosomes to keratinocytes. An indirect action on keratinocytes also comes into play to promote the process of melanogenesis by the secretion of soluble factors.

An increase in the synthesis and / or activity of melanogenic enzymes allowing an increase in the amount of melanins produced by melanocytes, and more generally in the biogenesis of melanosomes, their transport and transfer to keratinocytes, will lead to their visible manifestation. know the coloring and / or natural browning of human skin. Natural tanning is not always recommended because it requires prolonged exposure to the sun's radiation, and more particularly to ultraviolet radiation from the sun, and more particularly to UV-A and UV-B radiation from the sun, which causes browning of the sun. human skin, but which also cause unwanted reactions and alteration of human skin, especially for sensitive skin. Among these reactions and alterations, mention may be made of erythema, burning, external signs of aging of the skin such as, for example, alteration or loss of elasticity, lack of tone, lack of firmness, appearance or the digging of wrinkles or fine lines of human skin. The Ministry of Health and Social Protection, in collaboration with INPES and the Health Insurance, under the cancer plan, recently drafted recommendations on these exposures in order to limit the risk of developing skin cancers. To combine tanned skin and unaltered skin, there are products for tanning and / or artificial browning of the skin, such as carbonyl-containing chemical substances which, by interaction with the amino acids of human skin, allow the formation of colored products on the surface of the skin. Mention may be made, for example, of mono- or polycarbonyl compounds such as dihydroxyacetone (DHA), erythrulose, mesotartaric aldehyde, glutaraldehyde, glyceraldehyde, alloxane and ninhydrin. DHA is the most commonly used self-tanning agent for the preparation of cosmetic compositions intended to brown and / or artificially tan human skin as it provides an external tanning or browning effect of human skin similar to the one that can result from exposure to sunlight. However, the DHA has disadvantages: its effectiveness is not universal, the color generated by its application to the skin depends on the type of skin, and the consumer may encounter problems of unevenness in the coloring obtained on the skin. DHA has the disadvantage of degrading over time, depending on the cosmetic medium in which it is formulated, partially oxidizing during storage, which manifests itself in the eventual appearance of a color yellowish or even orange of the cosmetic composition comprising it.

To overcome the disadvantages of DHA as a self-tanning agent for human skin, the cosmetic industry has deployed over the last twenty years many solutions, including combining DHA with other cosmetically acceptable ingredients. European Patent Publication No. EP 0 425 324 B1 discloses the combination of DHA with an indole derivative for coloring human skin in an intense and rapid manner over time. In addition, academic studies have highlighted the possibility of long-term genotoxicity of DHA (1). To achieve a tanned skin, there are also specific technologies for exposure to ultraviolet radiation, such as cabins called "UV cabins", which are enclosed spaces in which the subject is subjected for a variable duration to UV-radiation. A (320-400 nm). Their regular use is, however, harmful to human health. There are also chemical substances and compositions, more particularly extracts of plants or bacteria, which are disclosed as a coloring agent for human skin. There may be mentioned the French patent application published under the number FR 2 973 697 A1 which discloses the use of a hydroglycolic extract of Tribulus terrestris and of chaulmoogra oil in cosmetic compositions for pigmenting the skin. The use of plant extracts, bacteria, however, has the disadvantage of showing unreliable and non-repetitive performance over time due to the variability of the content of the raw materials used to obtain them. There are also synthetic active principles, for example peptides and polypeptides, which are described as coloring agents for human skin. The French patent application published under the number FR 2 970 968 A1 discloses the increase of the amount of melanin in biopsies of human skin, treated with peptide compounds. The French patent published under the number FR 2 913 685 B1 discloses the use, as agents for treating disorders of skin pigmentation, of unsaturated fatty amino acid derivatives of formula (A): NH 2 -CH 2 [CH (Rn)] - CH2 = CH (R1) -COOR (A) The French patent application published under the number FR 2 827 511 A1 discloses self-tanning compositions comprising self-tanning agents and N-acyl esters of amino acids of general formula (B): R'1- (C = O) -N (R'2) -CH (R'3) (CH2) n (C = O) OR'4 (B) French patent application published under the number FR 2 827 511 A1 specifically discloses self-tanning compositions comprising self-tanning agents and isopropyl N-lauroyl sarcosinate, and the use of the compounds of formula (B) to improve the stability and coloration of compositions comprising a self-tanning agent. Japanese Patent Application No. 2000-229121 describes the use of N-acylamino acid polyol esters as high performance surfactants (paragraph [00003] of said application). International Publication VVO 201/0034917 discloses the mono-esters and polyol diesters of N- (w-undecylenoyl) phenylalanine, and more particularly the monoesters and diesters resulting from the reaction of glycerol and N - (w-undecylenoyl) phenylalanine, and their uses as lightening agents of human skin. As part of their search for new active agents for coloring and / or browning the skin of the human body and for maintaining the pigmentation of human hair and body hair, the inventors have endeavored to develop a new technical solution consisting of the use of products resulting from the esterification reaction between a polyol and N-acylated amino acid derivatives for coloring and / or browning the skin of the human body, and a cosmetic process for tanning and / or browning the skin of the body human by the application on said skin of a cosmetic formulation for topical use comprising said products resulting from the esterification reaction between said polyol and N-acylated derivatives of amino acids. Therefore, according to a first aspect, the subject of the invention is the use of a compound of formula (I): R'-O-CH 2 -CH (OH) - [CH 2 -O-CH 2 L -CH (OH)] - CH 2 -O-R "(I) formula (I) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R 'and R", which are identical or different , represent either a hydrogen atom or a monovalent radical of formula (II): ## STR2 ## wherein R1-C (= O) - represents a chosen acyl radical among the w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl radicals, and R2 represents the isobutyl radical, it being understood that at least one of the radicals R ' or R "does not represent a hydrogen atom and when none of the radicals R 'and R" represents a hydrogen atom, R' and R "are identical, or a mixture of compounds of formula (I), said use being for the purpose of browning and / or tanning human skin and / or maintaining the natural pigmentation of hair and / or hair, and / or limiting and / or stopping the development of canities in humans, and said use being in a cosmetic composition. By "browning and / or tanning of human skin" is meant, in the sense of the invention, a modification of the external appearance of the skin resulting in the appearance and development of a brown color, more or less intense, from the surface of human skin.

According to a first particular aspect, the subject of the invention is the use as defined above, of a composition (CI) comprising for 100% of its mass: from 99% by weight to 20% by weight, more particularly from 99% by weight at 50% by mass, and even more particularly at 95% by mass at 75% by weight of at least one compound of formula (Ia): R'-O-Cl-12-Cl (01-1) 4 Cl -12-0-C1-12], - [C1-1 (01-1)] - C1-12-0-1-1 (la) wherein s is 0 or 1 and p is 0 , 1, 2 or 3 and R 'represents either a monovalent radical of formula (II): ## STR2 ## wherein R 1 -C (= O) -represent represents a radical acyl selected from w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, and R2 represents isobutyl radical, - from 1 wt% to 80 wt% , 1% by mass at 80% by weight, more particularly by 1% mass at 50% by weight, and even more particularly from 5% by mass to 25% by weight of at least one compound of formula (Ib): RO-CH 2 -CH (OH) - [CH 2 -O-CH 2], - [CH (OH)] - CH 2 -O-R (Ib) wherein (Ib) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R is either a monovalent radical of formula (II) Embedded image wherein R 1 -C (= O) is an acyl radical selected from the group consisting of w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, and R2 represents the isobutyl radical. According to another particular aspect, the subject of the invention is the use as defined above, for which, in the formulas (I), (la) or (Ib), s is equal to 0. According to this particular aspect, when p is 0, the compounds of formulas (I), (Ia) and (Ib) are glycerol esters; when p is 1, the compounds of formulas (I), (Ia) and (Ib) are esters of erythritol; when p is equal to 2, the compounds of formulas (I), (Ia) and (Ib) are xylitol esters and when p represents an integer equal to 3, the compounds of formulas (I), (la) and ( lb) are esters of sorbitol. According to a more particular aspect, the subject of the invention is the use as defined above for which, in the formulas (I), (Ia) or (Ib), s and p are equal to 0.

According to a particular aspect, the subject of the invention is the use as described above for which the compound of formula (I) is 2,3-dihydroxypropyl N-octanoyl leucinate or N- (w-undecylenoyl) 2,3-dihydroxypropyl leucinate or for which the mixture of compound of formula (I) is 2,3-dihydroxypropyl N-cocoyl leucinate or for which the composition (Cl) comprises for 100% of its mass from 99% by weight to 20% by weight, more particularly from 99% by weight to 50% by mass, and even more particularly from 95% by weight to 75% by weight of 2,3-dihydroxypropyl N-octanoyl leucinate and 1% by mass. at 80% by weight, more particularly from 1% by mass to 50% by mass, and even more particularly from 5% by weight to 25% by weight of bis (N-octanoyl leucinate) of 2-hydroxy-1,3-propanediyl, or for which the composition (Cl) comprises for 100% of its mass from 99% by weight to 20% by weight, more particularly from 99% to 50% by mass. mass, and even more particularly from 95% by weight to 75% by weight of (2,3-dihydroxy) propyl N-cocoyl leucinate and from 1% by weight to 80% by weight, more particularly from 1% to 50% by mass, and still more particularly from 5% by weight to 25% by weight of bis (N-cocoyl leucinate) of 2-hydroxy-1,3-propanediyl or comprises, for 100% of its mass, from 99% by weight to 20% by weight, more particularly by 99% by weight. mass at 50% by weight, and even more particularly from 95% by weight to 75% by weight of 2,3-dihydroxypropyl N- (w-undecylenoyl) leucinate and from 1% by weight to 80% by weight, more particularly by 1% by weight. mass at 50% by weight, and even more particularly from 5% by weight to 25% by weight of bis [N- (--undecylenoyl) leucinate) of 2-hydroxy-1,3-propanediyl. By N-cocoyl leucinate of (2,3-dihydroxy) propyl, is meant in the definitions of the compounds of formula (I) and (la) a mixture comprising for 100 mol%: - 5 mol% to 15 mol% of N (2, 3-dihydroxy) propyl octanoyl leucinate, - from 5 mol% to 10 mol% of (2,3-dihydroxy) propyl N-decanoyl leucinate, - from 45 mol% to 55 mol% of N-dodecanoyl (2,3-dihydroxy) propyl leucinate; - from 10 mol% to 20 mol% of (2,3-dihydroxy) propyl N-tetradecanoyl leucinate; - from 5 mol% to 15 mol% of N-hexadecanoyl leucinate; (2,3-hydroxy) propyl, and - from 5 mol% to 10 mol% of a mixture of N- (9-octadecenoyl) leucinate N- (9-octadecenoyl) leucinate N-octadecanoyl leucinate (2,3-dihydroxy); 3-dihydroxy) propyl and (2,3-dihydroxy) propyl N (octadeca-9,12-dienoyl) leucinate. By bis (N-cocoyl leucinate) 2-hydroxy 1,3-propanediyl, is meant in the definitions of the compounds of formula (I) and (Ib) a mixture comprising 100 mol%: - 5 mol% to 15% molar ratio of 2-hydroxy-1,3-propanediyl bis (N-octanoyl leucinate), - 5 mol% to 10 mol% of bis (N-decanoyl leucinate) of 2-hydroxy-1,3-propanediyl, - 45% molar to 55% 2-hydroxy 1,3-propanediyl bis (N-dodecanoyl leucinate) molar, - 10% molar to 20% molar bis (N-tetradecanoyl leucinate) 2-hydroxy 1,3-propanediyl, - 5% 15% molar molar of 2-hydroxy-1,3-propanediyl bis (N-hexadecanoyl leucinate), and - From 5 mol% to 10 mol% of a mixture of bis (N-octadecanoyl leucinate) of 2-hydroxy-1 3-propanediyl, bis [N- (9-octadecenoyl) leucinate] 2-hydroxy-1,3-propanediyl, and bis [N- (octadeca-9,12-dienoyl) leucinate] 2-hydroxy 1, 3- propanediyl.

The compound of formula (I) as defined above may be prepared according to a preparation process comprising: - a step a) of esterification of a compound of formula (IVa): ## STR3 ## wherein R1 -C (= O) - and R2 are as defined in formula (IIa), with a compound of formula (V): H-O-A-O-H (V), in which A represents a divalent radical of formula (III) as defined above, to obtain either the compound of formula (Ia), the compound of formula (Ib), or a mixture (M) of the compound of formula (Ia) and the compound of formula (Ib) ); and if necessary or if desired, - a step b) of separating the compounds of formula (Ia) and formula (Ib), from said mixture (M) obtained in step (a). The compounds of formulas (IVa) are known or are synthesizable by N-acylation of the corresponding α-amino acids according to methods known to those skilled in the art. In the process as defined above, the compound molar ratio of formula (IVa) on compound of formula (V) is generally between 3/1 and 1/5, more particularly between 1/1 and 1/5, and even more particularly between 1/1 and 1/3.

In the process as defined above, the step b) of separating the compounds of formula (Ia) and of formula (Ib) is carried out by the conventional separation methods known to those skilled in the art. The compound of formula (I) as defined above may also be prepared according to a preparation method comprising: - a step a1) of esterification of a compound of formula (IVa) ## STR2 ## wherein R1-C (= O) - and R2 are as defined in formula (IIa), with an alcohol of formula (VI): R5-OH (VI), wherein R5 represents a linear aliphatic radical having from 1 to 4 carbon atoms, to form a compound of formula (VIla): R2 (Vila), wherein R1-C (= O) -, R2 and R5 are as previously defined; - a step a2) of trans-esterification of the compound of formula (VIla) obtained in step a1), by reaction with the compound of formula (V), to obtain either the compound of formula (Ia) or the compound of formula (Ib), or a mixture (M) the compound of formula (Ia) and the compound of formula (Ib); and if necessary or if desired, - The implementation of step b). In the process as described above, step a1) is generally carried out at a temperature of about 60 ° C to 120 ° C, under an inert gas, and in the presence of an acidic catalyst system. By acidic catalytic system are meant strong acids such as sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, hypophosphorous acid, methanesulfonic acid, para-toluene sulfonic acid, trifluoromethanesulfonic acid, or acidic ion exchange resins. In step a1) of the variant of the process as described above, the molar ratio of compound of formula (IVa) to alcohol of formula (VI) is generally between 1: 1 and 1: 10, more particularly between 1: / 1 and 1/8, and even more particularly between 1/2 and 1/8. In the variant of the process for preparing the compounds of formula (I) as described above, step a2) of transesterification of the ester of formula (Vila) obtained in step a1) is generally carried out at a temperature of approximately between 80 ° C and 180 ° C, more particularly between 100 ° C and 150 ° C, even more particularly between 120 ° C and 150 ° C, under inert gas, and in the presence of a system catalytic acid as described above, and with vacuum distillation of the alcohol of formula (VI) formed insitu.Dans step a2) of this variant of the process for preparing the compounds of formula (I) as described above , the compound molar ratio of formula (VI la) on the compound of formula (V) is between 3/1 and 1/5, more particularly between 1/1 and 1/5, and even more particularly between 1/1 and 1/3. The composition (C1) whose use as defined above is the subject of the invention may be prepared by various routes. A first route of preparation of the composition (C1) consists in mixing, in the desired mass proportions, the compound of formula (la) as defined above or the mixture of compounds of formula (Ia) with the compound of formula ( lb) as defined above, or the mixture of compounds of formula (Ib). A second route of preparation of the composition (C1) consists of carrying out the process for preparing the compound of formula (I) as described above, by reacting in the desired proportions, the compound of formula (V) with the compound of formula (IVa) or a mixture of compounds of formula (IVa). A third route of preparation of the composition (C1) consists in carrying out the variant of the process for the preparation of the compound of formula (I) as described above, by reacting in the desired proportions the compound of formula (V) with the compound of formula (VIla) or a mixture of compounds of formula (VIla). The subject of the invention is also a composition (C'1) comprising for 100% of its mass: from 99% by weight to 20% by weight, more particularly from 99% by weight to 50% by weight, and even more particularly by 95% by weight. mass at 75% by weight of at least one compound of formula (a): R'-O-CH 2 -CH (OH) - [CH 2 -O-CH 2], - [CH (OH)] - CH 2 -O -H (a) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R 'is either a monovalent radical of formula (II "): ## STR2 ## wherein formula (II ') in which the group R 1 -C (= O) represents an acyl radical selected from octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12- dienoyl, and R2 represents the isobutyl radical, - from 1 wt% to 80 wt%, more particularly from 1 wt% to 50 wt%, and even more particularly from 5 wt% to 25 wt% of at least one compound of formula ( the ID): RO-C1-12-C1-1 (01- 1) 4C1-12-0-C1-12HCI-1 (01-1)] - C1-12-0-R wherein s is 0 or 1 and p is 0, 1, 2 or 3 and R represents either a monovalent radical of formula (I a): ## STR2 ## in which R1-C (= O) - represents a chosen acyl radical among the radicals, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, and R2 represents the isobutyl radical. said composition (C'1) being obtained by the process comprising the following steps: a step A of acylation of leucine with a mixture of acid chlorides comprising for 100 mol%, from 40 mol% to 60 mol% of dodecanoyl chloride, from 10 mol% to 20 mol% tetradecanoyl chloride, from 5 mol% to 15 mol% decanoyl chloride, and from 5 mol% to 15 mol% octanoyl chloride, and optionally up to at a concentration of 100 mol%, hexadecanoyl chloride and / or octadecanoyl chloride and / or 9-octadecenoyl chloride and / or octadeca-9,12-dienoyl chloride, to obtain a mixture of compounds of formula (IV'a): ## STR2 ## An esterification step B of the mixture of compounds of formula (IV'a) obtained in stage A, with the polyol of formula (V ') ): HO-CH 2 -CH (OH) - [CH 2 -O-CH 2], - [CH (OH)] - CH 2 -O-H (V) in which s is 0 or 1 and p is equal to 0, 1, 2 or 3 and R represents In prop appropriate molar injections. The subject of the invention is also the composition (C'1) as defined above, obtained by a variant of the process comprising: - an esterification step A1, of the mixture of compounds of formula (IV'a) obtained at step A, with an alcohol of formula (VI): R 5 -OH (VI), in which R 5 represents a linear aliphatic radical containing from 1 to 4 carbon atoms, to form a mixture of compounds of formula (VII ') ## STR2 ## and a transesterification stage B 1 of the mixture of compounds of formula (VII ') obtained in stage Al), with the polyol of formula (V) in the proportions appropriate.

According to a particular aspect, the subject of the invention is a composition (C'1) as defined above, for which the mixture of acid chloride used in step A of the process for obtaining it comprises for 100 mol%, 45 mol% to 55 mol% of dodecanoyl chloride, 10 mol% to 20 mol% of tetradecanoyl chloride, 5 mol% to 10 mol% of decanoyl chloride, and 5 mol% to 15 mol% of octanoyl chloride, from 5 mol% to 10 mol% of hexadecanoyl chloride and from 5 mol% to 10 mol% of octadecanoyl chloride and / or 9-octadecenoyl chloride and / or chloride of octadeca-9,12-diènoyle. According to another particular aspect, the subject of the invention is the composition (C'1) as previously defined, for which, in formulas (a) or (ID), s and p are equal to 0. The subject of the invention is also a process for preparing the composition (C'1), as defined above, comprising the following steps: a step A of acylation of leucine with a mixture of acid chlorides comprising 100 mol%, 40 mol% to 60 mol% dodecanoyl chloride, 10 mol% to 20 mol% tetradecanoyl chloride, 5 mol% to 15 mol% decanoyl chloride, and 5 mol% to 15 mol%. mole% octanoyl chloride, and optionally and up to 100% molar, hexadecanoyl chloride and / or octadecanoyl chloride and / or 9-octadecenoyl chloride and / or octadecah chloride -9,12-dienoyl, to obtain a mixture of compounds of formula (IV'a): ## STR1 ## cation of the mixture of compounds of formula (IV'a) obtained in step A, with the polyol of formula (V): HO-CH 2 -CH (OH) - [CH 2 -O-CH 2], - [CH (OH) )] - CH2-0-H (V) wherein s is 0 or 1 and p is 0, 1, 2 or 3 and R is In the appropriate molar proportions, to obtain said composition (C'1 ); as well as a variant of the preparation process as defined above, comprising: an esterification step A1, of the mixture of compounds of formula (IV'a) obtained in step A, with an alcohol of formula ( VI): R 5 -OH (VI), wherein R 3 represents a linear aliphatic radical having from 1 to 4 carbon atoms, to form a mixture of compounds of formula (VII '): ## STR1 ## and a step B1 of trans-esterification of the mixture of compounds of formula (VII) obtained in step A1), with the polyol of formula (V) in the appropriate proportions, to obtain said composition (C'1 ). The compound of formula (I), the composition (C1) and the composition (C'1) as defined above can be administered orally, topically or parenterally, and more particularly topically.

As will be shown in the experimental part of the present patent application, the compound of formula (I), the composition (C1) and the composition (C'1) as defined above make it possible to increase the production of melanin by melanocytes. This is why the invention also relates to a method for the purpose of browning and / or tanning the human skin and / or to maintain the natural pigmentation of the hair and / or the hair, and / or to limit and / or or to stop the development of canitia in humans, comprising at least one step A of application to human skin or hair or hair, a cosmetic formulation for topical use comprising at least one cosmetically acceptable excipient and an effective amount of at least one compound of formula (I) or a composition (C1) or a composition (C'1) as defined above. The expression "for topical use" used in the definition of the cosmetic formulation used in step A) of the cosmetic process that is the subject of the present invention means that said formulation is implemented by application to the skin, that it is a direct application in the case of a cosmetic formulation or an indirect application when the cosmetic formulation according to the invention is impregnated on a support intended to be placed in contact with the skin (paper, wipe, textile, transdermal device, etc ...). The expression "cosmetically acceptable" used in the definition of the cosmetic formulation for topical use, used in step A) of the cosmetic process that is the subject of the present invention, means according to the directive of the Council of the European Economic Community No. 76/768 / EEC of 27 July 1976 as amended by Directive 93/35 / EEC of 14 June 1993, that the said formulation for topical use includes any substance or preparation intended to be placed in contact with the various parts of the human body ( epidermis, hair and hair system, nails, lips and genitals) or with oral teeth and mucous membranes with a view, exclusively and principally, to clean them, to perfume them, to modify their appearance and / or to correct body odor and / or protect or maintain it in good condition. By effective amount of the compound of formula (I), of the composition (Cl) or of the composition (C'1) as defined above, is meant for 100% of the mass of said cosmetic formulation for topical use, the quantity included between 0.1% and 5% by weight, more particularly between 0.1% and 3% by weight, and even more particularly between 0.5% and 2% by weight of compound of formula (I), of composition (Cl) or of composition (C'1). According to a particular aspect, the method as defined above further comprises a step B of exposure to sunlight or ultraviolet radiation generated by an artificial light device, said human skin or said hair or hair having undergone said step A .. Among artificial light devices capable of generating ultraviolet radiation and can be used in step B) of the non-therapeutic method of tanning or browning the human skin that is the subject of this invention, for example, ultraviolet lamps, consisting of one or more fluorescent lamp emitting ultraviolet radiation, 95% of which are constituted by ultraviolet-A radiation (wavelength of 400 to 315 nanometers ) and 5% are ultraviolet-B radiation (wavelength 315 to 280 nanometers) (with an error margin of ± 3%).

Advantageously, the cosmetic process as defined above makes it possible to obtain a tan or browning of the skin treated after a short period, characterized by a greater intensity of the coloration and a prolonged duration of persistence after the end of step B), and by a protective effect against histological alterations characteristic of sunburn or against the consequences of abusive exposures to ultraviolet radiation. Cosmetic processes of the canitie intended to maintain the natural pigmentation of the hair and / or hair as described above, may consist of an application of the cosmetic formulations used on the surface to be treated followed by a rinsing step with water. 'water. These methods may also consist of the application of the cosmetic formulations used on the surfaces to be treated, followed by storage on the treated surface overnight and then followed by a rinsing step in the morning. These methods may also consist of a preliminary step of washing the zones to be treated by a separate cleaning formulation of the surface to be treated (such as, for example, a shampoo), followed by an application step on said surface to be treated with a formulation. topical application comprising an effective amount of at least one compound of formula (I) of a composition of formula (Cl) or of formula (C'1), as defined above, followed by a rinsing step. The cosmetic formulations for topical use used in stage A) of the cosmetic process which is the subject of the present invention are generally in the form of aqueous or hydro-alcoholic or hydro-glycolic solutions, in the form of a suspension, of an emulsion, a microemulsion or a nanoemulsion, whether of the water-in-oil, oil-in-water, water-in-oil-in-water or oil-in-water-in-oil type or in the form of a powder.

The topical cosmetic formulations used in the cosmetic process which is the subject of the present invention may be packaged in a bottle, in a device of the pump "bottle" type, in pressurized form in an aerosol device, in a device provided with a perforated wall such as a grid or in a device provided with a ball applicator (called "roll-on").

In general, the compound of formula (I) or the composition (Cl), present in topical cosmetic formulations used in the cosmetic process that is the subject of the present invention, is associated with chemical additives usually used. in the field of formulations for topical use, such as foaming and / or detergent surfactants, thickening and / or gelling surfactants, thickening and / or gelling agents, stabilizing agents, film-forming compounds, solvents and co-solvents, hydrotropic agents, thermal or mineral waters, plasticizers, emulsifiers and co-emulsifiers, opacifying agents, pearlescent agents, superfatting agents, sequestering agents, chelating agents, oils, waxes, antioxidants, fragrances, essential oils, preservatives, conditioners, deodorants, bleaching agents for the fading of hair and skin, the active ingredients intended to provide a treating and / or protective action with respect to the skin or the hair, sunscreens, mineral fillers or pigments, the particles providing an effect visual or for the encapsulation of active, exfoliating particles, texture agents, optical brighteners, repellents for insects. Examples of foaming and / or detergent surfactants which can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process which is the subject of the present invention may be mentioned foaming surfactants and / or anionic, cationic, amphoteric or nonionic detergents. Among the foaming and / or detergent anionic surfactants that can be combined with the compound of formula (I) or with the compositions (Cl) or (C'1) in cosmetic formulations for topical use implemented in the cosmetic process which is the subject of the present invention may be mentioned alkali metal salts, alkaline earth metal salts, ammonium salts, amines, or amino alcohols of alkyl ether sulphates, alkyl sulphates, alkyl amido ether sulphates, alkyl aryl polyether sulphates, monoglyceride sulphates. , alpha-olefin sulfonates, paraffin sulfonates, alkyl phosphates, alkyl ether phosphates, alkyl sulfonates, alkyl amide sulfonates, alkylarylsulfonates, alkylcarboxylates, alkylsulfosuccinates, alkylethersulfosuccinates, alkylamidesulfosuccinates, alkylsulfoacetates, alkylsarcosinates, acylisethionates, N-acyltaurates, acyllactylates, N-acyl derivatives of amino acids, N-acyl derivatives of peptides, N-acyl derivatives of proteins, N-acyl derivatives of fatty acids.

Among the foaming and / or detergent amphoteric surfactants which can be combined with the compound of formula (I) or with the compositions (Cl) or (C'1) in the topical cosmetic formulations used in the cosmetic process which is the subject of the present invention includes alkylbetaines, alkylamidobetaines, sultaines, alkylamidoalkylsulfobetaines, imidazoline derivatives, phosphobetaines, amphopolyacetates and amphopropionates. Among the foaming and / or detergent cationic surfactants that can be combined with the compound of formula (I) or with the compositions (Cl) or (C'1) in cosmetic formulations for topical use implemented in the cosmetic process object of the present invention, there may be mentioned particularly quaternary ammonium derivatives. Among the foaming and / or detergent nonionic surfactants that can be combined with the compound of formula (I) or with the compositions (Cl) or (C'1) in cosmetic formulations for topical use used in the cosmetic process object of the present invention, there may be mentioned more particularly alkylpolyglycosides comprising a linear or branched, saturated or unsaturated aliphatic radical containing from 8 to 16 carbon atoms, such as octylpolyglucoside, decylpolyglucoside, undecylenylpolyglucoside, dodecylpolyglucoside, tetradecyl polyglucoside, hexadecyl polyglucoside, 1-12 dodecanediyl polyglucoside; ethoxylated hydrogenated castor oil derivatives such as the product marketed under the INCI name "Peg-40 hydrogenated castor oil"; polysorbates such as Polysorbate 20, Polysorbate 40, Polysorbate 60, Polysorbate 70, Polysorbate 80, Polysorbate 85; coconut amides; N-alkylamines. Examples of thickening and / or gelling surfactants that can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process which is the subject of the present invention may include fatty esters of alkylpolyglycosides optionally alkoxylated, such as ethoxylated methylpolyglucoside esters such as PEG 120 methyl glucose trioleate and PEG 120 methyl glucose dioleate respectively marketed under the names GLUCAMATETm LT and GLUMATETm DOE120; alkoxylated fatty esters such as PEG 150 pentaerythrityl tetrastearate sold under the name CROTHIX ™ DS53, PEG 55 propylene glycol oleate sold under the name ANTIL ™ 141; fatty chain polyalkylene glycol carbamates such as PPG-14 laureth isophoryl dicarbamate marketed under the name ELFACOSTM T211, PPG-14 palmeth-60 hexyl dicarbamate sold under the name ELFACOSTM GT2125. Examples of thickening and / or gelling agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention, mention may be made of polyelectrolytes polymers, linear or branched or crosslinked, such as homopolymer of partially or totally salified acrylic acid, homopolymer of partially or totally salified methacrylic acid, homopolymer partially or completely salified 2-methyl-[(1-oxo-2-propenyl) amino] -1-propanesulfonic acid (AMPS), copolymers of acrylic acid and AMPS, copolymers of acrylamide and AMPS, copolymers of vinylpyrrolidone and AMPS, copolymers of AMPS and (2-hydroxyethyl) acrylate, copolymers of AMPS and methacrylate of hydroxyethyl), copolymers of AMPS and hydroxyethylacryl ylamide, copolymers of AMPS and N, N-dimethylacrylamide, copolymers of AMPS and tris (hydroxy-methyhacrylamido methane (TL-1), copolymers of acrylic or methacrylic acid and (2-hydroxyethyl) acrylate, copolymers of acrylic or methacrylic acid and (2-hydroxyethyl) methacrylate, copolymers of acrylic or methacrylic acid and hydroxyethylacrylamide, copolymers of acrylic or methacrylic acid and THAM, copolymers of acrylic or methacrylic acid and N, N-dimethyl acrylamide, terpolymers of acrylic or methacrylic acid, AMPS and (2-hydroxy acrylate) ethyl), terpolymers of acrylic or methacrylic acid, AMPS and (2-hydroxyethyl) methacrylate, terpolymers of acrylic or methacrylic acid, AMPS and THAM, terpolymers of Acrylic or methacrylic acid, AMPS and N, N-dimethyl acrylamide, terp polymers of acrylic or methacrylic acid, AMPS and acrylamide, copolymers of acrylic acid or methacrylic acid and alkyl acrylates having a carbon chain of between four and thirty carbon atoms, carbon and more particularly between ten and thirty carbon atoms, the copolymers of the AMPS and of alkyl acrylates whose carbon chain comprises between four and thirty carbon atoms and more particularly between ten and thirty carbon atoms, the terpolymers linear, branched or crosslinked at least one monomer having a strong acid function, free, partially salified or fully salified, with at least one neutral monomer, and at least one monomer of formula (VIII): CH2 = C (R7) - C (= O) - [CH2-CH2-OH-R8 (VIII) in which R7 represents a hydrogen atom or a methyl radical, R8 represents a linear or branched alkyl radical containing from eight to thirty carbon atoms and n represents a higher number equal to one and less than or equal to fifty. Polymers of polyelectrolytic type, linear or branched or crosslinked that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process The subject of the present invention may be in the form of a solution, an aqueous suspension, a water-in-oil emulsion, an oil-in-water emulsion or a powder. Polymers of polyelectrolytic type, linear or branched or crosslinked that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process The object of the present invention can be selected from the products sold under the names SIMULGELTm EG, SIMULGELTmEPG, SEPIGELTM 305, SIMULGELTm 600, SIMULGELTm NS, SIMULGELTm INS 100, SIMULGELTm FL, SIMULGELTm A, SIMULGELTm SMS 88, SEPINOVTmEMT 10, SEPIPLUSTm400, SEPI PLUSTm265, SEPI PLUS TmS, SEPIMAXTMZEN, ARISTOFLEXTMAVC, ARISTOFLEXTMAVS, NOVEMERTMEC-1, NOVEMERTMEC 2, ARISTOFLEXTMHMB, COSMEDIATMSP, FLOCARETM AND 25, FLOCARETM AND 75, FLOCARETM AND 26, FLOCARETMET 30, FLOCARETMET 58, FLOCARETMPSD 30, VISCOLAMTMAT 64, VISCOLAMTMAT 100. As examples of thickening and / or gelling agents that can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in cosm formulations for use in the cosmetic process that is the subject of the present invention, mention may be made of polysaccharides consisting solely of monosaccharides, such as glucans or homopolymers of glucose, glucomannoglucans, xyloglycans, galactomannans whose degree of substitution ( DS) units of D-galactose on the main D-mannose chain are between 0 and 1, and more particularly between 1 and 0.25, such as galactomannans originating from cassia gum (DS = 1/5), locust bean gum (DS = 1/4), tara gum (DS = 1/3), guar gum (DS = 1/2), fenugreek gum (DS = 1). Examples of thickening and / or gelling agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention, mention may be made of polysaccharides consisting of monosaccharides, such as sulphated galactans and more particularly carrageenans and agar, uronans and more particularly alginines, alginates and pectins, heteropolymers of monosaccharides. and uronic acids and more particularly xanthan gum, gellan gum, exudates of arabic gum and karaya gum, glucosaminoglycans. Examples of thickening and / or gelling agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention include cellulose, cellulose derivatives such as methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, silicates, starch, hydrophilic derivatives of starch, polyurethanes. As examples of stabilizing agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention mention may be made of microcrystalline waxes, and more particularly ozokerite, mineral salts such as sodium chloride or magnesium chloride, and silicone polymers such as polysiloxane polyalkyl polyether copolymers. As examples of solvents which can be combined with the compound of formula (I) or with the compositions (Cl) or (C'1) in the topical cosmetic formulations used in the cosmetic process which is the subject of the present invention, it is possible to mention may be made of water, organic solvents such as glycerol, diglycerol, glycerol oligomers, ethylene glycol, propylene glycol, butylene glycol, 1,3-propanediol, 1,2-propanediol, hexylene glycol, diethylene glycol, xylitol, erythritol, sorbitol, water-soluble alcohols such as ethanol, isopropanol or butanol, water mixtures and said organic solvents. Examples of thermal or mineral waters that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the the present invention, there may be mentioned thermal or mineral waters having a mineralization of at least 300 mg / l, in particular Avene water, Vittel water, Vichy basin water, water from Uriage, the water of the Roche Posay, the water of the Bourboule, the water of Enghien-lesbains, the water of Saint-Gervais-the baths, the water of Néris-les-bains, the water Allevard-les-bains, Digne water, Maizieres water, Neyrac-les-bains water, Lons le Saunier water, Rochefort water, Saint Christau water , the water of the Fumades and the water of Tercis-the-baths. As examples of hydrotropic agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention there may be mentioned xylenesulfonates, cumenesulfonates, hexylpolyglucoside, 2-ethylhexylpolyglucoside, n-heptylpolyglucoside. As examples of emulsifying surfactants that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process which is the subject of the present invention the invention includes nonionic surfactants, anionic surfactants, cationic surfactants. Examples of emulsifying nonionic surfactants that can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process which is the subject of the the present invention include esters of fatty acids and sorbitol, such as the products marketed under the names MONTANETm40, MONTANETm60, MONTANETm70, MONTANETm80 and MONTANETm85; compositions comprising glycerol stearate and ethoxylated stearic acid between 5 moles and 150 moles of ethylene oxide, such as the composition comprising stearic acid ethoxylated with 135 moles of ethylene oxide and glycerol stearate. sold under the name SIMULSOL ™ 165; mannitan esters; ethoxylated mannitan esters; sucrose esters; methylglucoside esters; alkylpolyglycosides having a linear or branched, saturated or unsaturated aliphatic radical containing from 14 to 36 carbon atoms, such as tetradecyl polyglucoside, hexadecyl polyglucoside, octadecylpolyglucoside, hexadecylpolyxyloside, octadecylpolyxyloside and eicosyl; polyglucoside, dodecosyl polyglucoside, 2-octyldodecyl polyxyloside, 12-hydroxystearyl polyglucoside; linear or branched fatty alcohol compositions, saturated or unsaturated, and comprising from 14 to 36 carbon atoms, and alkylpolyglycosides as described previously, such as, for example, the compositions sold under the tradename MONTANOVTm68, MONTANOVTm82, MONTANOVTm14, MONTANOVTm202, MONTANOVTmS, MONTANOVTmVVO 18, FLUIDANOVTm2OX and EASYNOVTM. As examples of anionic surfactants that can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process that is the subject of the present invention, mention may be made of glyceryl stearate citrate, cetearyl sulphate, soaps such as sodium stearate or triethanolammonium stearate, N-acyl derivatives of salified amino acids, for example stearoyl glutamate. Examples of emulsifying cationic surfactants that can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process forming the subject of the present invention mention may be made of the aminoxides, quaternium-82 and the surfactants described in the international application published under the number VVO 96/00719 and mainly those whose fatty chain comprises at least 16 carbon atoms.

Examples of opacifying and / or nacrating agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention, mention may be made of sodium palmitate, sodium stearate, sodium hydroxystearate, magnesium palmitate, magnesium stearate, magnesium hydroxystearate, ethylene glycol monostearate, sodium distearate and the like. ethylene glycol, polyethylene glycol monostearate, polyethylene glycol distearate, fatty alcohols having from 12 to 22 carbon atoms. As examples of texture agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in cosmetic formulations for topical use implemented in the cosmetic process object of this and N-acylated amino acid derivatives, such as lauroyl lysine marketed under the name AMINOHOPETmLL, octenyl starch succinate sold under the trade name DRYFLOTM, myristyl polyglucoside sold under the name MONTANOVTm 14, cellulose fibers, cotton fibers, chitosan fibers, talc, sericite, mica. As examples of deodorant agents that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention there may be mentioned alkali silicates, zinc salts such as zinc sulfate, zinc gluconate, zinc chloride, zinc lactate; quaternary ammonium salts such as cetyltrimethylammonium salts, cetylpyridinium salts; glycerol derivatives such as glycerol caprate, glycerol caprylate, polyglycerol caprate; 1,2 decanediol; 1,3 propanediol; salicylic acid; sodium bicarbonate; cyclodextrins; metallic zeolites; TRICLOSANTm; aluminum bromohydrate, aluminum chlorohydrates, aluminum chloride, aluminum sulphate, aluminum and zirconium hydrochlorides, aluminum and zirconium trihydrochloride, aluminum zirconium tetrachlorohydrate , aluminum and zirconium pentachlorohydrate, aluminum and zirconium octochlorhydrate, aluminum sulphate, sodium and aluminum lactate, aluminum and glycol hydrochloride complexes, as well as propylene glycol aluminum dihydrochloride complex, aluminum and propylene glycol sesquichlorohydrate complex, polyethylene glycol aluminum aluminum and polyethylene glycol, the complex of aluminum sesquichlorohydrate and polyethylene glycol. As examples of oils which can be combined with the compound of formula (I) or with compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process which is the subject of the present invention, mention may be made of mineral oils such as paraffin oil, liquid petrolatum, isoparaffins or mineral white oils; oils of animal origin, such as squalene or squalane, vegetable oils, such as phytosqualane, sweet almond oil, coconut oil, castor oil, jojoba oil, olive oil, rapeseed oil, peanut oil, sunflower oil, wheat germ oil, corn germ oil, soybean oil, cottonseed oil, alfalfa oil, poppy oil, pumpkin oil, evening primrose oil, millet oil, barley oil, rye oil, Safflower oil, bancoulier oil, passionflower oil, hazelnut oil, palm oil, shea butter, apricot kernel oil, calophyllum oil, sysymbrium oil, avocado oil, calendula oil, oils derived from flowers or vegetables ethoxylated vegetable oils; synthetic oils such as fatty acid esters such as butyl myristate, propyl myristate, isopropyl myristate, cetyl myristate, isopropyl palmitate, octyl palmitate, butyl stearate, hexadecyl stearate, isopropyl stearate, octyl stearate, isocetyl stearate, dodecyl oleate, hexyl laurate, propylene glycol dicaprylate, lanolic acid derived esters, such as isopropyl lanolate, isocetyl lanolate, monoglycerides, diglycerides and triglycerides of fatty acids such as glycerol triheptanoate, alkylbenzoates, hydrogenated oils, poly (alpha-olefin), polyolefins such as polyisobutane ) synthetic isoalkanes such as isohexadecane, isododecane, perfluorinated oils; silicone oils such as dimethylpolysiloxanes, methylphenylpolysiloxanes, amine-modified silicones, fatty acid-modified silicones, alcohols-modified silicones, alcohol-modified silicones and fatty acids, modified silicones, polyether groups, modified epoxy silicones, silicones modified with fluorinated groups, cyclic silicones and silicones modified with alkyl groups. By "oils" is meant herein the compounds and / or the mixtures of water-insoluble compounds having a liquid appearance at a temperature of 25 ° C. As examples of waxes that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process that is the subject of the present invention, may include beeswax, carnauba wax, candelilla wax, ouricoury wax, Japan wax, cork fiber wax, sugar cane wax, paraffin waxes, waxes lignite, microcrystalline waxes, lanolin wax; ozokerite; polyethylene wax; silicone waxes; vegetable waxes; fatty alcohols and solid fatty acids at room temperature; glycerides solid at room temperature. By "waxes" is meant in the present application the compounds and / or mixtures of compounds insoluble in water, having a solid appearance at a temperature greater than or equal to 45 ° C. As examples of active principles that can be associated with the compound of formula (I) or compositions (Cl) or (C'1) in cosmetic formulations for topical use implemented in the cosmetic process object of the present invention, mention may be made of vitamins and their derivatives, in particular their esters, such as retinol (vitamin A) and its esters (retinyl palmitate, for example), ascorbic acid (vitamin C) and its esters, sugar derivatives of ascorbic acid (such as ascorbyl glucoside), tocopherol (vitamin E) and its esters (such as tocopherol acetate), vitamins B3 or B10 (niacinamide and its derivatives); compounds showing a lightening or depigmenting action of the skin, such as w-undecelynoyl phenylalanine marketed under the name SEPIVVHITETmMSH, SEPICALMTmVG, the mono ester and / or the glycerol diester of w-undecelynoyl phenylalanine, the w-undecelynoyl dipeptides, l arbutin, kojic acid, hydroquinone; the compounds showing a soothing action, especially SEPICALM ™ S, allantoin and bisabolol; anti-inflammatory agents; compounds showing a moisturizing action such as urea, hydroxyureas, glycerol, polyglycerols, glycerolglucoside, diglycerolglucoside, polyglycerylglucosides, xylitylplucoside; plant extracts rich in polyphenols such as grape extracts, pine extracts, wine extracts, olive extracts; compounds showing a slimming or lipolytic action such as caffeine or its derivatives, ADIPOSLIM ™, ADIPOLES ™, fucoxanthin; N-acylated proteins; N-acylated peptides such as MATRIXIL ™; N-acyl amino acids; partial hydrolysates of N-acyl proteins; amino acids; peptides; total hydrolysts of protein; soy extracts, for example Raffermine TM; wheat extracts, for example TENSINETm or GLIADINETM; plant extracts, such as tannin-rich plant extracts, plant extracts rich in isoflavones or plant extracts rich in terpenes; freshwater or marine algae extracts; marine plant extracts; marine extracts in general such as corals; essential waxes; bacterial extracts; ceramides; phospholipids; compounds showing antimicrobial action or purifying action, such as LIPACIDETM C8G, LIPACIDETM UG, SEPICONTROLTm AS; OCTOPIROXTm or SENSIVATm SC50; compounds showing an energizing or stimulating property such as PHYSIOGENYL ™, panthenol and its derivatives such as SEPICAP ™ MP; anti-aging actives like SEPILIFTTm DPHP, LI PACI TM PVB, SEPIVINOLTM, SEPIVITALTm, MANOLIVATM, PHYTO-AGETm, TIMECODETm; SURVICODETM; anti-aging photo active ingredients; the active ingredients protecting the integrity of the dermal-epidermal junction; actives enhancing the synthesis of extracellular matrix components such as collagen, elastins, glycosaminoglycans; assets acting favorably on chemical cellular communication such as cytokines or physical ones such as integrins; active ingredients that create a sensation of "heating" on the skin, such as activators of cutaneous microcirculation (such as nicotinic acid derivatives) or products that create a sensation of "freshness" on the skin (such as menthol and derivatives) ; the active agents improving cutaneous microcirculation, for example the venotonic ones; draining assets; decongestant active ingredients such as extracts of ginko biloba, ivy, horse chestnut, bamboo, ruscus, holly, centalla asiatica, fucus, rosemary, willow; agents for tanning or browning the skin, such as, for example, dihydroxyacetone (DHA), erythrulose, mesotartaric aldehyde, glutaraldehyde, glyceraldehyde, alloxane, ninhydrin, plant extracts, for example extracts red woods of the genus Pterocarpus and of the genus Baphia such as Pteropcarpus santalinus, Pterocarpus osun, Pterocarpus soyauxii, Pterocarpus erinaceus, Pterocarpus indicus or Baphia nitida as those described in the European patent application EP 0 971 683; ; the agents known for their action of facilitating and / or accelerating the tanning and / or browning of human skin, and / or for their action of coloring human skin, such as, for example, caratenoids (and more particularly beta carotene and gamma carotene), the product marketed under the tradename "Carrot oil" (INCI name: Daucus Carota, helianthus annuus sunflower oil) by Provital, which contains carotenoids, vitamin E and vitamin K ; tyrosine and / or its derivatives, known for their effect on the tanning acceleration of human skin in association with exposure to ultraviolet radiation, such as for example the product marketed under the brand name "SunTan AcceleratorTM" by the Provital company which contains tyrosine and riboflavins (vitamin B), tyrosine complex and tyrosinase sold under the brand name "Zymo Tan Complex" by the company Zymo Line, the product marketed under the brand name MelanoBronzeTM (name INCI: Acetyl Tyrosine, Monk's pepper extract (Vitex Agnus castus)) by the company Mibelle which contains acetyl tyrosine, product sold under the brand name Unipertan VEG-24/242/2002 (INCI name: butylene glycol and acetyl) Tyrosine and Hydrolyzed Vegetable Protein and Adenosine Triphosphate) by the company UNIPEX, the product sold under the brand name "Try-ExcellTm" (INCI name: Oleoyl Tyrosine and Luffa Cylindric a (Seed) Oil and Oleic acid) by the company Sederma which contains extracts of pumpkin seed (or Loofah oil), the product marketed under the trademark "Actibronze TM" (INCI name: hydrolyzed wheat protein and acetyl tyrosine and copper gluconate) by Alban Muller, the product sold under the trade name TyrostanTm (INCI name: potassium caproyl tyrosine) by Synerga, the product sold under the trade name Tyrosinol (INCI name: Sorbitan Isostearate, glyceryl oleate , caproyl Tyrosine) by Synerga, the product sold under the brand name lnstaBronzeTM (INCI name: Dihydroxyacetone and acetyl tyrosine and copper gluconate) marketed by Alban Muller, the product sold under the trade name Tyrosilane (INCI name: methylsilanol and acetyl tyrosine) by Exymol; peptides known for their effect of activating melanogenesis, for example the product marketed under the brand name Bronzing SF Peptide powder (INCI name: Dextran and Octapeptide-5) by the company Infinitec Activos, the product sold under the name Melitane brand (INCI name: Glycerin and Aqua and Dextran and Acetyl hexapeptide1) including acetyl hexapeptide-1 known for its alpha-MSH agonist action, the product marketed under the brand name Melatimes SolutionsTM (INCI name: Butylene glycol , Palmitoyl Tripeptide-40) by LIPOTEC, sugars and sugar derivatives such as for example the product sold under the brand name TanositolTm (INCI name: inositol) by Provital, the product sold under the brand name Thalitan TM (or Phycosaccharide TM AG) by CODIF International (INCI name: Aqua and hydrolyzed algin (Laminaria Digitata) and magnesium sulfate and manganese sulfate) containing n oligosaccharide of marine origin (guluronic acid and mannuronic acid chelates with magnesium and manganese ions), the product sold under the brand name MelactivaTM (INCI name: Maltodextrin, Mucuna Pruriens Seed extract) by Alban Muller, the rich compounds in flavonoids such as for example the product sold under the brand name "Biotanning" (INCI name: Hydrolyzed citrus Aurantium dulcis fruit extract) by the company Silab and known to be rich in flavonoids of lemon (hesperidin type). Examples of antioxidants that can be combined with the compound of formula (I) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention mention may be made of EDTA and its salts, citric acid, tartaric acid, oxalic acid, BHA (butylhydroxyanisole), BHT (butylhydroxytoluene), tocopheryl derivatives, such as tocopherol acetate, mixtures of antioxidant compounds such as DISSOLVINETM GL 47S marketed by Akzo Nobel under the name INCI: Tetrasodium Glutamate Diacetate.

As examples of sunscreens that can be combined with the compound of formula (1) or compositions (Cl) or (C'1) in topical cosmetic formulations used in the cosmetic process object of the present invention, we can cite all those appearing in the cosmetic directive 76/768 / CEE modified annex VII. Among the organic solar filters which can be combined with the compound of formula (1) or with the compositions (Cl) or (C'1) in the topical cosmetic formulations used in the cosmetic process which is the subject of the present invention, mention may be made of the family of benzoic acid derivatives such as para-aminobenzoic acids (PABA), in particular the monoglycerol esters of PABA, the ethyl esters of N, N-propoxy PABA and the ethyl esters of N, N-diethoxy; PABA, the ethyl esters of N, N-dimethyl PABA, the methyl esters of N, N-dimethyl PABA, the butyl esters of N, N-dimethyl PABA; the family of anthranilic acid derivatives such as homomenthyl-N-acetyl anthranilate; the family of salicylic acid derivatives such as amyl salicylate, homomenthyl salicylate, ethylhexyl salicylate, phenyl salicylate, benzyl salicylate, p-isopropanolphenyl salicylate; the family of cinnamic acid derivatives such as ethylhexyl cinnamate, ethyl-4-isopropyl cinnamate, methyl-2,5-diisopropyl cinnamate, p-methoxypropyl cinnamate and p-methoxyisopropyl cinnamate; p-methoxyisoamyl cinnamate, pmethoxyoctyl cinnamate (p-methoxy-2-ethylhexyl cinnamate), p-methoxy-2-ethoxyethyl cinnamate, p-methoxycyclohexyl cinnamate, ethyl-a-cyano cinnamate Phenyl, 2-ethylhexyl-ia-cyano-6-phenyl cinnamate, glyceryl diparamethoxy mono-2-ethylhexanoyl cinnamate; the family of benzophenone derivatives such as 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4'-methylbenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonate, 4-phenylbenzophenone, 2-ethylhexyl-4'-phenylbenzophenone-2-carboxylate, 2-hydroxy-2-hydroxybenzophenone, 4-n-octyloxybenzophenone, 4-hydroxy-3-carboxybenzophenone; 3- (4'-methylbenzylidene) -d, 1-camphor, 3- (benzylidene) -d, 1-camphor, benzalkonium methosulfate camphor; urocanic acid, ethyl urocanate; the family of sulfonic acid derivatives such as sulfonic acid 2-phenylbenzimidazole-5 and its salts; the family of triazine derivatives such as hydroxyphenyl triazine, ethylhexyloxyhydroxyphenyl-4-methoxyphenyltriazine, 2,4,6-trianillino- (p-carbo-2'-ethylhexyl-1-oxy) -1,3, 5-triazine, 4,4 - ((6 - (((1,1-dimethylethyl) amino) carbonyl) phenyl) amino) -1,3,5-triazine-2,4-diyl diimino) bis- (2) benzoic acid ester, 2-phenyl-5-methylbenzoxazole, 2,2'-hydroxy-5-methylphenylbenzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole; dibenzazine; dianisoylmethane, 4-methoxy-4-tert-butylbenzoylmethane, 5- (3,3-dimethyl-2-norbornylidene) -3-pentan-2-one, the family of diphenylacrylate derivatives such as 2-ethylhexyl-2-yl; cyano-3,3-diphenyl-2-propenoate, ethyl-2-cyano-3,3-diphenyl-2-propenoate, the family of polysiloxanes such as benzylidene malonate siloxane, among the inorganic solar filters, also called inorganic screens ", which can be combined with the compound of formula (1) or with the compositions (Cl) or (C'1) in the topical cosmetic formulations used in the cosmetic process which is the subject of the present invention, mention may be made of titanium oxides, zinc oxides, cerium oxide, zirconium oxide, yellow, red or black iron oxides, chromium oxides These inorganic screens may or may not be micronised, having undergone or not surface treatments and may be presented in the form of aqueous or oily pre-dispersions.

The subject of the invention is also the compound of formula, the composition (Cl) or the composition (C'1) as defined above, for their use in a therapeutic treatment method intended to stimulate the production of melanins to prevent and / or or treat diseases of human skin and / or hair or hair. The following examples illustrate the invention without limiting it.

EXAMPLE 1 Preparation of a Composition (C18) According to the Invention 554.7 grams of leucine, ie one molar equivalent, are introduced into a hydroalcoholic mixture consisting of 2000 grams of water and 220 grams of isopropanol, at a concentration of temperature of 20 ° C. The pH of the medium is adjusted to pH 10 by adding a 30% sodium hydroxide solution. 551.2 grams of octanoyl chloride, ie 0.8 molar equivalents, are then gradually added to the mixture maintained between 20 ° C. and 40 ° C., and at a pH of between 10 and 10.5. The reaction medium is then stirred for two hours and then heated to 70 ° C, then added 687.7 grams of a 75% phosphoric acid acid solution to gradually reach a pH value of about 2.0. The aqueous phase of the medium is decanted and withdrawn and the organic phase remaining in the reactor is washed several times with brine at room temperature with stirring. After washing and then drying by vacuum distillation of the residual water, the organic phase comprising 756.7 grams of desired N-octanoyl leucine is obtained. 62.1 grams of glycerol, ie a molar equivalent of glycerol, are introduced into the reactor comprising 174.0 grams of the dried reaction medium obtained in the preceding step. The temperature is raised to 120 ° C. 0.51 grams of 98% sulfuric acid and 0.52 grams of 50% hypophosphorous acid are then added and the resulting mixture is heated to 125 ° C under partial vacuum with a nitrogen sparge. The reaction mixture is then maintained for 10 hours with stirring at this temperature, then neutralized by addition of a 30% sodium hydroxide solution so as to obtain a pH of the composition (C1A), diluted to 5% in water, between 3.0 and 6.0.

The analytical characteristics of the composition (C1A) obtained are as follows: acid number (according to NFT 60-204) = 13.7 pH 5% of the composition (C1A) in water (according to the method NFT 73-206) = 5.5 Hydroxyl number (according to US Pharmacopeia XXI NF XVI 01/011985) = 316.9 Ester number (calculated as the difference between the saponification number measured according to the method NFT 60-110 and the index d acid measured according to the method NFT 60-204) = 164.9 Saponification number (according to NFT 60-206) = 178.6 mg KOH / g Exem the 2nd aration of a composition CIB according to the invention The mode The procedure described in Example 1 is carried out by replacing the 0.8 molar equivalent of octanoyl chloride with 0.8 molar equivalents of w-undecylenoyl chloride, to obtain the composition (C1B) whose characteristics Analyzes are: Acid value (according to NFT 60-204) = 14.6 pH 5% of the composition (C1B) in water (according to the NFT 73-206 method) = 5.3 Index d Hydroxyl (according to US Pharmacopeia XXI NF XVI 01/011985) = 295.2 Ester number (calculated as the difference between the saponification number measured according to the method NFT 60-110 and the acid number measured according to the method NFT 60-204) = 147.3 Saponification number (according to NFT 60-206) = 161.9 mg KOH / g Exem. 3: e aration of a composition C1c according to the invention. The procedure is as in Example 1, replacing the 0.8 molar equivalent of octanoyl chloride with 0.8 equivalents (542.3 grams) of cocoyl chloride, comprising for 100% of its mass 8% by weight of chloride of octanoyl, 8% by weight of decanoyl chloride, 50% by weight of lauroyl chloride, 17% by weight of myristoyl chloride, 8% by weight of palmitoyl chloride, 3% by weight of stearoyl chloride, 4% by weight of oleoyl chloride (9-octadecenoyl) and 2% by weight of linoleoyl chloride (octadeca-9,12-dienoyl).

The analytical characteristics of the composition (C1c) are the following: acid number (according to NFT 60-204) = 16.5 pH 5% of the composition (C1c) in water (according to the method NFT 73-206) = 5 , 7 Hydroxyl number (according to US Pharmacopeia XXI NF XVI 01/011985) = 202.6 Ester number (calculated as the difference between the saponification number measured according to the NFT method 60-110 and the index of acid measured according to the method NFT 60-204) = 143.3 Saponification number (according to NFT 60-206) = 159.8 mg KOH / g Example 4 (comparative): preparation of a composition F comprising Noctanoyl isoleucinate ( 2,3-dihydroxy) propyl and bis (N-octanoyl isoleucinate) 2-hydroxy 1,3-propanediyl The procedure is as in Example 1, replacing the equivalent of leucine with a molar equivalent of isoleucine, to obtain Composition F whose analytical characteristics are as follows: Acid value (according to NFT 60-204) = 44.8 pH 5% of the composition F in water (according to the NFT method 73-206) = 5.1 Hydroxyl number (according to US Pharmacopeia XXI NF XVI 01/011985) = 364.7 Ester number (calculated as the difference between the saponification number measured according to the NFT 60-110 method) and the acid number measured according to the method NFT 60-204) = 142.9 Saponification number (according to NFT 60-206) = 187.7 mg KOH / g Example 5 (Comparative): Preparation of a Composition G comprising (2,3-dihydroxy) propyl Nhexadecanoyl phenylalaninate and 1,3-propanedidyl bis (N-hexadecanoyl phenylalaninate).

The procedure is as in Example 1, replacing the equivalent of leucine with one molar equivalent of phenylalanine, and the 0.8 equivalent of octanoyl chloride with 0.8 molar equivalent of hexadecanoyl chloride to obtain the Composition G of which the analytical characteristics are as follows: Acid value (according to NFT 60-204) = 12.4 pH 5% of composition G in water (according to the NFT 73-206 method) = 6.0 Hydroxyl number (according to US Pharmacopeia XXI NF XVI 01/011985) = 230.1 Ester number (calculated as the difference between the saponification number measured according to the method NFT 60-110 and the acid number measured according to the NFT method 60- 204) = 112.9 Saponification number (according to NFT 60-206) = 125.3 mg KOH / g Demonstration of the human skin coloring activity of the compounds and compositions according to the invention by a study of the production of melanin on a veil of murine melanocytes B16 / F1 The highlighting of the activity of coloratio It was carried out by the implementation of a study model of the production of melanin on a line of murine B16 / F1 melanocytes. This test is commonly used in the cosmetics and pharmaceutical sector. Protocol: B16F1 murine melanocytes were amplified in T75 culture flask, then seeded at 5000 cells / well in 96-well culture plates in a specific culture medium, at 37 ° C. in a humid atmosphere containing 5% CO 2. After 24 hours of plaque amplification, the cells were treated with the compositions according to the invention, or culture medium alone (control) and then incubated for 72 hours at 37 ° C. under 5% CO 2. Each condition has been realized in triplicate. Evaluation of the effects: After the incubation, the supernatants were recovered and the melanin secreted by the cells in the (extracellular) culture medium was quantified by spectrophotometric measurement at 450 nm of these culture supernatants, against a standard range of melanin. The results were expressed in μg of melanin / ml of culture medium. The cell mats were lysed in PBS using a sonication rod and 2 evaluations were performed on these: Evaluation of the amount of melanin by spectrophotometric measurement at 450 nm of the lysates against a standard range of melanin; Evaluation of the amount of protein by assay according to the method of Bradford. The results of melanin production by (intracellular) cells were expressed relative to the amount of protein present in the carpets. Thus the final result is given as pg melanin per mg protein. Statistical analysis using the Student's test was performed to compare each condition with the control condition. Tests were conducted during a first experimental series with the composition (C1B) according to the invention, compared to the control culture. The results obtained are recorded in the following Table 1: Table 1 Products tested Intracellular extranellular melanin Intracellular melanin (pg / ml) (pg / mg of proteins) Culture control 119 ± 4 101 ± 5 Composition (C1b) (10 μg / ml) 130 ± 2 114 ± 6 Tests were conducted in a second experimental series with compositions (C1A) and (C10), compared to the culture control and compositions F and G. The results obtained are shown in Table 2 Table 2 Products Tested Extracellular Melanin Intracellular Melanin (μg / mL) (μg / mg Protein) Culture Control 135 ± 4 88 ± 3 Composition (C1A) (10 μg / mL) 144 ± 6 114 ± 14 Composition (C1c) (10 μg / ml) 154 ± 2,107 ± 4 Composition F (10 μg / ml) 134 ± 6,103 ± 13 Composition G (10 μg / ml) 138 ± 7,887 ± 4 The results shown in Tables 1 and 2 demonstrate an increase in the production of extracellular melanin and / or intracellular melanin for the compositions (C1A) (C1B) and (C10) according to the invention. The comparative composition G is characterized by a quasi-stagnation of extracellular melanin production (not significant) and a decrease in the production of intracellular melanin. The comparative composition F is characterized by a stagnation of extracellular melanin production and a non-significant evolution of intracellular melanin production since the standard deviation measured is ± 12.6% relative to the average value. taken from the measurements. Demonstration of the human skin coloring activity of the compounds and compositions according to the invention by a clinical study The demonstration of the human skin coloring activity of the compositions according to the invention, the speed of said staining and its persistence over time, was carried out by the implementation of a clinical study for a panel of volunteers. Protocol: The study was conducted on a panel of 20 female volunteers, aged 18 to 40 years (mean age: 29 years, minimum age: 20 years and maximum age: 37 years), Caucasian skin, phototype III . The formulations for topical use comprising the compositions according to the invention and the reference products to be tested were applied daily to the skin of the thighs at a frequency of twice a day.

Conduct of the study: The study is carried out in three phases: Phase a): period of application of the evaluated products of a duration of 15 days. Measurements made during the period of phase a) make it possible to evaluate the coloration of the skin without exposure of said skin to UV-A radiation. The end of this phase a) is noted J15. Phase b): period following the period of phase a), consisting of exposure to ultraviolet radiation of an ultraviolet lamp of the skin treated with the tested products. For each subject, this exposure is performed every 2/3 days for a total of 6 exposures corresponding to 1 MPD (Minimal Pigmenting Dose - 16J / cm2 on average) each, and is followed by an application of the tested products. Phase b) lasts 12 days, and the end of phase b) is noted as J27. Phase c): period following the period of phase b), consisting of an observation of the evolution of the coloration of the treated skin according to the provisions of the previous phases. Phase c) does not include application of the formulations comprising the tested products, nor exposure to ultraviolet radiation A as described in phase b). Phase c) lasts 13 days, and the end of the period of phase c) is noted J40. In the context of this clinical study, the formulations, comprising the compositions according to the invention, applied to the skin of panel members contain for 100% of their mass: 99% by weight of water, 1% by weight of the composition According to the invention to be evaluated Thus, the formulation (F0) comprises, for 100% of its mass, 1% by weight of the Composition (C10) according to the invention, and 99% by weight of water. In the context of this clinical study, the formulation (FO) comprising a reference compound known for its skin-coloring activity, applied to the skin of panel members, contains for 100% of its mass: 99% by mass of 1% by weight water of acetyl tyrosine (AT). Evaluation of the effects: The coloration of the surfaces of the skin treated with the formulations (FO) and (Fa), as well as an area of the untreated skin and close to the area of the treated skin, is evaluated by measuring the angle Individual Typological (or ATI) which represents the degree of pigmentation of the skin; the lower the ATI, the darker the skin. Its detection was carried out by spectrocolorimetry according to the standards of the International Commission on Illumination (CIE), by measuring the parameters L * and b *, then by calculating the Individual Typological Angle as follows: ITA = [ArcTangent ( (L * -50) / b *)] x (180 / rr)). L * being the parameter characterizing the brightness and b * the parameter which determines the blue axis towards yellow. The measurements are made: the first day of phase a) of the protocol, before the first application of the formulation (JO) - The last day of phase a) of the protocol (J15) 30 - After the first exposure to UV radiation from Phase b) of the protocol (J17) - After the second exposure to UV radiation of phase b) of the protocol (J19) - After the third exposure to UV radiation of phase b) of the protocol (J22) - After two days following the third exposure to UV radiation (J24) - Four days after the third exposure to UV radiation (J26) - The last day of phase b) of the protocol (J27) - At half the duration of phase c) of protocol (J33) - The last day of phase c) of the protocol (noted J40). For the same treated surface, a decrease of the ITA over time will mean an increase in the coloration of said surface of the treated skin. The results obtained are shown in Table 3 below: Table 3 ATI at OJ ATI at D15 ATI at D17 ATI at D19 DTI at D22 Untreated skin 36.6 +/- 8.2 37.2 +/- 7, 8 37.2 +/- 8.1 36.8 +/- 8.1 36.3 +/- 8.4 Skin treated with (Fo) 36.9 +/- 8.8 36.9 +/- 8 , 7 ° 36.3 +/- 8.9 ° 35.9 +/- 9.1 ° 36.3 +/- 9.5 Skin treated with (Fa) 38.2 +/- 7 ° 38.2 +/- 8.2 ° 38.2 +/- 8.3 ° 368 +/- 8.0 * 0 35.6 +/- 8.5 * 0 # Table 3 (continued) ATI to J24 ATI to J26 ATI to J27 ATI to J33 ATI to J40 Untreated skin 36.0 +/- 8.5 35.1 +/- 8.6 35.3 +/- 7.6 33.1 +/- 7.6 * 34.2 +/- 7.4 Skin treated with (Fo) 36.4+ / -9,4 35.7 +/- 9.8 35.2 +/- 8.9 32.2 +/- 8.6 * 33.2 +/- 8.9 * 0 Skin treated with (Fa) 35.1 +/- 8.5 * 0 # 34.4 +/- 8.5 * 0 # 32.9 +/- 8.5 * 0 # 33.2 +/- 8.3 * 33.1 +/- 8.2 ° *: Statistically significant difference with respect to the OJ value (p <0.05) °: Statistically significant difference with respect to to the untreated area (p <0.05) #: Statistically significant difference from the result with Fo (p <0.05) Between OJ and J15, as part of the phas e a) of the protocol, a non-statistical decrease of the ITA is only observed for the skin treated with the formulation (F0) according to the invention (decrease of the ITA of 0.11%). Furthermore, at the end of phase a) (at D15), the value of the ITA remains unchanged for the skin treated with the formulation (Fo) and the zone of untreated skin tends to become lighter (increase non-statistical ITA of 2.27% at J15 compared to OJ). When an inter-group statistical analysis is conducted for phase a), for the values obtained at OJ and J15, a statistically significant difference is obtained between the zone of untreated skin and zone of skin treated with the formulation (F0). according to the invention, as well as between the untreated skin zone and the skin zone treated with the formulation (Fo). The formulation (F0) according to the invention thus makes it possible to induce a coloration of the skin without prior exposure to ultraviolet radiation.

During phase b) of the protocol, the decrease in ITA is faster, stronger and statistically significant for the only skin treated with the formulation (FD) according to the invention, as soon as the second exposure to ultraviolet radiation ( J19) and during the entire period of exposure to said radiation. Inter-group statistical analysis made it possible to demonstrate a statistically significant difference between the measurements obtained for the area of the skin treated with the formulation (FD) according to the invention and for the zone not treated from the second exposure. UV (J19), and between the measurements obtained for the area of the skin treated with the formulation (FD) according to the invention and for the area treated with the formulation (Fo) from the third exposure to UV (J22) . These elements show an effect of acceleration of tanning by the implementation of the formulation (FD) according to the invention: the tanning of the treated skin is obtained more rapidly and with a higher intensity of coloration. In phase c) of the protocol, the skin zone treated with the formulation (Fa) according to the invention is characterized by a stability of the value of the ITA at D33 and D40.

Evaluation of cellular alterations following UV exposure: Protocol: Human skin biopsies (8mm diameter explants) recovered from operating waste were cultured in a defined specific medium. These explants were then treated with 2 mg / cm 2 a placebo formulation (Fp) or with a formulation (F'D) according to the invention, the compositions of which in percentages by weight are given in Table 4 below. Table 4 Components (Fp) (Fp) Components (Fp) (F'0) MONTANOVTm L 1% 1% Composition (CID) 0% 3% SIMULSOLTm165 2% 2% SEPIMAXTm Zen 1.5% 1.5% LANOLTMP 2% 2% SOLAGUM TM AX 0.5% 0.5% TRIGLYCERIDE C8-5% 5% EDTA Disodium 0.10% 0.10% C10 DUB DONPG 8% 8% EUXYL PE9010 1.00% 1.00% DC 200 / 350 1% 1% Sodium Benzoate 0.30% 0.30% Water qs 100% q.s. 100% The explants were then placed in an incubator at 37 ° C under 5% CO2 for 24 hours. At the end of this first incubation, the explants were rinsed and wiped before being exposed to a dose of 1.5 mJ / cm 2 of UVB. At the end of this exposure, the explants were reprocessed in the same way as previously by the same formulations. They were delivered for 24 hours in the incubator at 37 ° C under 5% CO2. At the end of this incubation, the explants were placed in a fixing solution (Excel plus, MM), and then dehydrated by successive baths of alcohol to be able to be embedded in paraffin. Once included in paraffin, sections of 5 .mu.m were made, placed on slides and then rehydrated in order to carry out an HES (Hematoxylin-Eosin-Safran) staining. Photographs of the sections were then taken under the right optical microscope at objective x20 and the Sunburn Cells (SBC) were field-counted, in parallel with the number of total cells present in the epidermis. . The "Sunburn Cells" (SBC) cells are characterized by the presence of a pycnotic nucleus (ie retraction of the nucleus under the effect of condensation of chromatin), these modifications being observable under the microscope after histological staining. The percentage of SBC was then calculated for each of the conditions and the conditions were compared to that of the UV control. The results are shown in the following Table 5: Table 5% Mean SBC (a% effect vs.% effect = standard deviation) to the UV exposed photoprotective control Expierant untreated control and 3.37%; a = 0.66% -62% 100% not subject to UVB Expiant untreated control and 8.96%; a = 0.86% 0% 0% submitted UVB Expiant treated (Fp) and submitted 4.51%; a = 0.20% -50% 80% UVB Expiant treated with (F0) and 4.01%; a = 1, 18% -55% 89% UVB exposure The exposure to UV radiation of the control explants did indeed make it possible to generate "sunburn" cells (+166% increase over the unexposed control), which allows to validate the model. The application of the Formulation (F ',) makes it possible to limit the number of cells "sunburn" when the explants are subjected to UV radiation.

Without being able to be the subject of any theory, the production of cells "sunburn" in smaller amounts when the explants were treated with the formulations according to the invention and by the implementation of the non-therapeutic method tanning and / or browning according to the invention, provides a photo-protection to human skin. Bibliography: (1): Petersen et al., "Dihydroxyacetone, the active browning ingredient in sunless tanning lotions, DNA damage digests, cell-cycle block and apoptosis in cultured HaCaT keratinocytes", 2004, Mutat Res, Jun 13; 560 (2 ): 173-86. (2) Karleskind A., 1992. Manual of fatty substances, Lavoisier, Vol. 1 and 2: 65-78, 115-241, 1072-1089, 1433-1459. (3): Tobin P.J., Paus R. "graying: gerontobiology of the hair follicle pigmentary unit", Exp. Gerontol.

2001 Jan: 36 (1): 29-54. LANOLTM 2681: 3.0% SEPIMAXTmZen: 2.5% Water: q.s. 100% Composition (CI A): 1.0% Perfume: 0.2% SEPICIDETM HB: 0.8% Soda: q.s. pH = 5 Sunless bronzing emulsion LANOLTM 99: 15% MONTANOVTm 68: 5.0% PARSOLTM MCX: 3.0% Water: qsp100 ° / 0 Composition (C1B): 3.0% Monosodium phosphate: 0.2% SEPIMAXTm Zen: 0.5% Perfume: 0.3% SEPICIDETM HB: 0.8% Examples of cosmetic formulations In the following examples the proportions are expressed in percentages by weight. Non-greasy tanning agent for face and body 25 30 Soda: q.s. pH = 5. Pressed powder Earth of sun SIMULGELTmEG: 2,00% LANOLTM 99: 12,00% Composition (C1B) 1,00% Talc: 33,00% MICROPEARLTM M310: 3,00% Iron oxide yellow: 0,80% Oxide of red iron: 0.30% Black iron oxide: 0.05% Mica: qs 100% self-tanning gel SIMULGELTmEG: 5.0% Ethanol: 30% Composition (Clc) Menthol: 0.1% Caffeine: 2.5% Ivry extract: 2% SEPICIDETm HB: 1% Water: q.s. 100% Sunblock and self-tanning gel MONTANOVTm 5: 3.0% Glyceryl triheptanoate: 10.0% LIPACIDETM PVB: 1.05% SIMULGELTmEG: 2.2% Water: q.s. 100% Composition (Clc) 5% Fragrance: 0.1% SEPICIDETM HB: 0.3% SEPICIDETM Cl: 0.1% PARSOLTM MCX: 4.0% Self-bronzing cream with a-hydroxy acids MONTANOVTm 68: 5.0% LIPACIDETM PVB: 1.05% LANOLTM 99: 10.0% Water: qs 100% Gluconic acid: 1.5% Composition (CIA): 3% Triethanolamine: 0.9% SEPIMAXTmZen: 1.5% Perfume: 0.4% SEPICIDETM HB: 0.2% SEPICIDETM Cl: 0.4% Self-tanning cream a-hydroxy acids for sensitive skin Mixture of N-lauroyl amino acids: 0.1% to 5% Magnesium and potassium aspartate: 0.002% to 0.5% MONTANOVTm 68: 5.0% LANOLTM 99: 2.0% Water: qs 100% Lactic Acid: 1.5% Composition (C1c): 3.5% Triethanolamine: 0.9% SIMULGELTmINS 100: 1.5% Perfume: 0.4% SEPICIDETM HB: 0.3% SEPICIDETM Cl: 0.2 % SIMULSOLTm 165 self-tanning moisturizing emulsion: 5.0% LANOLTM 1688: 8.5% Galam butter: 2% Liquid paraffin: 6.5% LANOLTM 14M: 3% LANOLTM S: 0.6% Water: 66, 2% Composition (C1c): 3% MICROPEARLTM M100: 5% SIMULGELTmNS: 3% AQUAXYL TM 5% Vitamin E acetate: 0.20% Sodium pyrolidinonecarboxylate: 0.20% Fragrance: 0.2% SEPICIDETM HB: 0, 5% SEPICIDETM CI: 0.3% Self-tanning moisturizing emulsion A Water Up to 100 ° / 0 Disodium EDTA 0.10% Sodium Benzoate 0.30% Soda (12%) 0.07% B MONTANOVTm L 1.00% SIMULSOLTm 165 2.00% LANOLTM P 2.00 % Caprylic / Capric Triglyceride 5.00% Neopentyl Glycol 8.00% Dimethicone 1.00% Composition (CIA) 1.00% C SEPIMAXTm ZEN 1.50% SOLAGUM TM AX 0.50% D Phenoxyethanol and Ethylhexylglycerin 1.00% Suncare Lotion - SPF15 Aqua / VVater Up to 100% SOLAGUM TM AX 0.50% TriEthanolAmine (99%) 0.40% B SENSANOVTM VVR 3.00% MONTANOVTm S 1.00% C12-15 Alkyl Benzoate 10.00% Ethylhexylmethoxycinnamate and BHT 5.00% Butylmethoxydibenzoylmethane 2.50% C Cyclopentasiloxane and cyclohexasiloxane 2.50% D AQUAXYL TM 3.00% Phenoxyethanol and Ethylhexylglycerin 1.00% Composition (C1B) 1.00% Perfume / Fragrance 0.10% Lactic Acid (25%) 0.09% Sun-activating cream gel with DHA A Aqua / VVater Qs 100% B SIMULGELTm SMS 88 3.00% C12-15 Alkyl Benzoate 10.00% Dimethicone 5.00% C Glycerin 3.00% Monopropylene Glycol 2.00% Phenoxyethanol and Ethylhexylglycerin 1.00% Tocopherol 0.05% D Aqua / VVater 40.00% Dihydroxyacetone 3.00% E Composition (C1B) 1.00% Fragrance / Fragrance 0.10% Citric acid Qs pH Body lotion after solar A Water Up to 100 ° A SEPIMAXTm ZEN 0.50% B AQUAXYL TM 2.00 % SEPICALMTm S VVP 1.00% C Butylene Glycol 3.00% SEPICLEARTM G7 1.30% Perfume / Fragrance 0.03% Phenoxyethanol and Ethylhexylglycerin 0.80% Composition (CI 1.00% Nourishing capillary mask A C12-C15 Alkyl Benzoate 4 4.0% Butyrospermum Parkii 11.0% B 44 1.0% C SEPICIDETmHB SEPINOVTM EMT10 Aqua / VVater 1.5% Qsp 100% ORAMIXTm CG110 0.5% Composition (CI c) 1.0% Triethanolamine 12% 0, 02% Fragrance / Fragrance 0.1% Capillary Mask to rinse A MONTANOVTm82 1.0% SIMULSOLTm165 2, 5% Cetearyl alcohol 1.5% Arginia Spinosa kernel Oil 1.0% Hydrogenated vegetable Oil & Prunus 1.0% Mineral Oil 3, 0% B Dimethicone & Dimethiconol 3, 0% C Water qs 100 ° A Behentrimonium 1, 5% Distearoylethyl Dimonium Chloride & cetearyl alcohol 1, 5% D Hydroxyethylcellulose 1.0% E AQUAXYL TM 1.0% Phenoxyethanol & Ethylhexylglycerin 1.0% Composition (CI c) 1.0% Fragrance 1.0% Frequent Use Shampoo A Sodium Lauryl Ether Sulfate 28% Proteol TM OAT 5% Fragrance 0.3% Water & Methylisothiazolinone & Ethylhexylglycerine 0.12% B Water Qsp100 ° / 0 C MONTALINETmC40 8.0% D Lactic Acid Qs pH = 6.2 Capillary Lotion Composition (CI c) 1.0% Propylene Glycol 20% Ethanol 950 30% Water qs 100% The commercial products used in the examples are defined as follows: LANOLTM 2681 is a caprylate mixture, copra caprate, marketed by the company SEPPIC; SEPIMAXTmZen (INCI name: polyacrylate crosspolymer-6) is a thickening, emulsifying and stabilizing agent - SEPINOVTM EMT10 (Hydroxyethyl Acylate & Sodium Acyloyldimethyl Taurate Copolymer) 10 - ORAMIX ™ CG110 (Capiylic Capric Glucoside) - LANOL ™ 99 is isononanoate isononyl marketed by the company SEPPIC; MONTANOV-68 (cetearyl glucoside), is a self-emulsifiable composition as described in VVO 92/06778, sold by the company SEPPIC; SEPICIDETM HB (INCI name: Phenoxyethanol / Methylparaben / Ethylparaben / Propylparaben / Butylparaben) is a preserving agent marketed by the company SEPPIC; PARSOL ™ MCX is octyl para-methoxy cinnamate; marketed by GIVAUDAN; MICROPEARL ™ M310 is an ultra fine powder with a very soft feel and a mattifying action marketed by MATSUMO; SIMULGELTmEG (INCI name: sodium acryloyldimethyltaurate / sodium acrylate, and isohexadecane and polysorbate 80) is a thickening, emulsifying and stabilizing agent marketed by the company SEPPIC. MONTANOV ™ S is a pearlescent agent marketed by the company SEPPIC, based on a mixture of alkyl polyglucosides such as those described in VVO 95/13863; LIPACIDETM PVB, is a hydrolysate of acyl wheat proteins marketed by the company SEPPIC; SEPICIDETM C1, imidazolidine urea, is a preserving agent marketed by the company SEPPIC; SIMULGELTMINS 100 (INCI name: sodium acryloyldimethyltaurate / hydroxyethyl acrylate, and isohexadecane and polysorbate 60) is a thickening, emulsifying and stabilizing agent marketed by the company SEPPIC. SIMULSOL ™ 165 is self-emulsifiable glycerol stearate marketed by the company SEPPIC; LANOLTM 1688 is an emollient ester with a non-oily effect marketed by the company SEPPIC; - LANOLTM 14M and LANOLTM S are consistency factors marketed by the company SEPPIC; - SIMULGELTmNS (INCI name: sodium acryloyldimethyltaurate / hydroxy ethyl acrylate, and squalane and polysorbate 60) is a thickening, emulsifying and stabilizing agent marketed by the company SEPPIC. AQUAXYLTM (INCI name: Xylitylglucoside and Anhydroxylitol and Xylitol): moisturizing composition marketed by the company SEPPIC; MONTANOVTM L (INCI name: C14-22 Alkyl Alcohol C12-20 Alkyl Glucoside) is an emulsifying composition marketed by the company SEPPIC, - LANOLTM P is an emollient ester of palmitic acid and ethylene glycol - SOLAGUM Tm AX is a mixture of acacia gum and xanthan gum used as an emulsifying agent - SENSANOVTM VVR (INCI name: C20-22 Alkyl phosphate & C20-22 Alcohols) is an anionic surfactant mixture marketed by the company SEPPIC - SIMULGELTm SMS 88 (INCI name : Sodium acrylate / Acryloyldimethyl taurate / Dimethylacrylamide crosspolymer & Isohexadecane & Polysorbate 60) is a thickening and emulsifying agent marketed by the company SEPPIC - SEPICALMTM S VVP (INCI name: Sodium Cocoyl Amino Acids & Sarcosine & Potassium Aspartate & Magnesium) is an agent soothing marketed by the company SEPPIC - SEPICLEARTM G7 (INCI name: heptyl glucoside) is a solubilizing agent marketed by the company SEPPIC - DUB DONPG (Name IN CI: neopentylglycol diethylhexanoate) is an emollient marketed by the company DU BOIS - DC 200/350 (INCI name: Dimethicone) is a silicone oil marketed by Dow Corning.

Claims (14)

REVENDICATIONS1. Use of a compound of formula (I): ## STR2 ## is equal to 0 or 1 and p is 0, 1, 2 or 3 and R 'and R ", which are identical or different, represent either a hydrogen atom or a monovalent radical of formula (II): O R2 Wherein R1-C (= O) - represents an acyl radical selected from the group consisting of w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, it being understood that at least one of the radicals R 'or R "does not represent a hydrogen atom and that when none of the radicals R 'and R "represents a hydrogen atom, R' and R" are identical, or a mixture of compounds of formula (I), said use being for the purpose of browning and / or tan the pe to human and / or maintain the natural pigmentation of hair and / or hair, and / or limit and / or stop the development of canities in humans, and said use being in a cosmetic composition. 20 - 2. Use as defined in claim 1, of a composition (Cl) comprising for 100% of its mass: from 99% by weight to 20% by weight of at least one compound of formula (Ia): R'- In which s is 0 or 1 and p is 0, 1, 2 or And R 'represents either a monovalent radical of formula (II): wherein R1-C (= O) -represented represents an acyl radical chosen from w-undecylenoyl, octanoyl radicals decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R 2 is isobutyl and R 3 is hydrogen, - 1 wt.% to 80 wt. at least one compound of formula (Ib): RO-CH 2 -CH (OH) - [CH 2 -O-CH 2 H 4 CH (OH) b -CH 2 -O-R (Ib) formula (Ib) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R is either a monovalent radical Formula (II): wherein R1-C (= O) - represents an acyl radical chosen from the radicals w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom. 3. Use as defined in any one of claims 1 or 2 wherein, in formulas (I), (la) or (lb), s and p are equal to 0. 4. Composition (C'1) comprising for 100% of its mass: from 99% by weight to 20% by weight of at least one compound of formula (a): R'-O-CH 2 -CH (OH) - [CH2-O-CH21s4CH (OH) L-CH2-O-H (a) in which s is 0 or 1 and p is 0, 1, 2 or 3 and R 'represents either a monovalent radical of formula (II "): ## STR2 ## wherein R 1 -C (= O) represents an acyl radical chosen from octanoyl, decanoyl, dodecanoyl and tetradecanoyl radicals. and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, - from 1 wt% to 80 wt% of at least one compound of formula ( In which s is 0 or 1 and p is 0, 1, 2 or 3 and R represents either a monovalent radical of formula (I a): ## STR1 ## wherein R1-C (= O) represents an acyl radical selected from the radicals, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom. said composition (C'1) being obtained by the process comprising the following steps: a step A of acylation of leucine with a mixture of acid chlorides comprising for 100 mol%, from 40 mol% to 60 mol% of dodecanoyl chloride, from 10 mol% to 20 mol% tetradecanoyl chloride, from 5 mol% to 15 mol% decanoyl chloride, and from 5 mol% to 15 mol% octanoyl chloride, and optionally up to at a concentration of 100 mol%, hexadecanoyl chloride and / or octadecanoyl chloride and / or 9-octadecenoyl chloride and / or octadeca-9,12-dienoyl chloride, to obtain a mixture of compounds of formula (IV'a): ## STR2 ## A step B of esterifying the mixture of compounds of formula (IV'a) obtained in step A, with the polyol of formula ( V): HO-CH 2 -CH (OH) - [CH 2 -0-CH 2], - [CH (OH)] - CH 2 -O-H (V) in which s is 0 or 1 and p is equal to at 0, 1, 2 or 3 and R represents In the s appropriate molar proportions. 5. Composition (C'1) as defined in claim 4, obtained by a variant of the process comprising: - an esterification step A1, of the mixture of compounds of formula (IV'a) obtained in step A, with an alcohol of formula (VI): R 5 -OH (VI), in which R 5 represents a linear aliphatic radical containing from 1 to 4 carbon atoms, to form a mixture of compounds of formula (VII '): ## STR2 ## ° R5 o (VIF), and - A transesterification step B1 of the mixture of compounds of formula (VII ') obtained in step A1), with the polyol of formula (V) in the appropriate proportions. 6. Composition (C'1) as defined in any one of claims 4 or 5, for which the mixture of acid chloride used in step A of the process for obtaining it comprises 100 mol% from 45 mol% to 55 mol% of dodecanoyl chloride, from 10 mol% to 20 mol% of tetradecanoyl chloride, from 5 mol% to 10 mol% of decanoyl chloride, and from 5 mol% to 15 mol% of octanoyl chloride, 5 mol% to 10 mol% hexadecanoyl chloride and 5 mol% to 10 mol% octadecanoyl chloride and / or 9-octadecenoyl chloride and / or octadecahloride chloride. 9,12-diènoyle. 7. Composition (C'1) as defined in any one of claims 4 to 6, wherein, in the formulas (a) or (11), s and p are equal to 0. 8. Process for the preparation of the composition (C'1), as defined in any one of Claims 4 to 7, comprising the following steps: a step A of acylation of leucine with a mixture of chlorides of acid comprising per 100 mol%, from 40 mol% to 60 mol% of dodecanoyl chloride, from 10 mol% to 20 mol% of tetradecanoyl chloride, from 5 mol% to 15 mol% of decanoyl chloride, and 5% 15 mol% of octanoyl chloride, and optionally up to 100 mol%, hexadecanoyl chloride and / or octadecanoyl chloride and / or 9-octadecenoyl chloride and / or octadeca-9,12-dienoyl, to obtain a mixture of compounds of formula (IV'a): ## STR2 ## A step B of esterification of the mixture of compounds of formula (INTA) ) obtained in step A, with the polyol of formula (V): HO-CH2-CH (OH) - [CH2-O-CH2] sICH (OH)] - CH2-O-H (V) in which s is 0 or at 1 and p is 0, 1, 2 or 3 and R is In the appropriate molar proportions, to obtain said composition (C'1). 9. A variant of the preparation method as defined in claim 8, comprising: An esterification step A1, of the mixture of compounds of formula (IV'a) obtained in step A, with an alcohol of formula (VI): R5-OH (VI), in which R3 represents an aliphatic radical; linear system having 1 to 4 carbon atoms, to form a mixture of compounds of formula (VII '): ## STR2 ## A step B1 of transesterification of the mixture of compounds of formula (VII) obtained in step A1), with the polyol of formula (V) in the appropriate proportions, to obtain said composition (C'1). 10. Method for the purpose of browning and / or tanning human skin and / or maintaining the natural pigmentation of hair and / or hair, and / or limiting and / or stopping the development of canities in humans, comprising at least one step A for application to human skin or hair or hair, of a topical cosmetic formulation comprising at least one cosmetically acceptable excipient and an effective amount of at least a compound of formula (I): ## STR2 ## equal to 0 or 1 and p is equal to 0, 1, 2 or 3 and R 'and R ", which are identical or different, represent either a hydrogen atom or a monovalent radical of formula (II): 0 R2 R1 Wherein R 1-C (= O) - represents an acyl radical selected from the group consisting of w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, it being understood that at least one of the radicals R 'or R "does not represent a hydrogen atom; and that when none of the R 'and R "radicals represents a hydrogen atom, R' and R" are identical. 11. A method for the purpose of browning and / or tanning human skin and / or maintaining the natural pigmentation of hair and / or hair, and / or limiting and / or stopping the development of canities in the human being, comprising at least one step A of application to said human skin or to said hair or hair, of a cosmetic formulation for topical use comprising at least one cosmetically acceptable excipient and an effective amount of one of a composition (C1) comprising for 100% of its mass - from 99% by weight to 20% by weight of at least one compound of formula (Ia): R'-O-CH 2 -CH (OH) - [CH 2 -0- CH2LICH (OH)] - CH2-0-H (la) wherein s is 0 or 1 and p is 0, 1, 2 or 3 and R 'is either a monovalent radical of formula (11): Wherein R1-C (= O) -represents formula (11a) wherein R1-C (= O) - represents an acyl radical selected from the group consisting of w-undecylenoyl radicals, octa noyle, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R 2 is isobutyl and R 3 is hydrogen; From 1 wt.% To 80 wt.% Of at least one compound of formula (Ib): RO-CH2-CH (OH) - [CH2-O-CH21, - [CH (OH)] - CF-12-0 -R (Ib) Formula (Ib) wherein s is 0 or 1 and p is 0, 1, 2 or 3 and R is either a monovalent radical of Formula (II): O R2 R1 (I R3 0 (II), formula (II) in which the group R 1 -C (= O) - represents an acyl radical chosen from the radicals w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, or a composition (C1) as defined in any one of claims 4 to 7, 12. A method as defined in any one of claims 10 or 11, characterized in that it further comprises a step B of exposure to sunlight or ultraviolet radiation generated by an artificial light device, of said human skin or said hair or hair having undergone said step A .. 13. Compound of formula (I): R'-O-CH2-CH (OH) - [CH2-O-CH2WCH (OH) L-CH2-O-R "(I) formula (I) in which s is equal to at 0 or 1 and p is 0, 1, 2 or 3 and R 'and R ", which may be identical or different, represent either a hydrogen atom or a monovalent radical of formula (II): ## STR2 ## R3 0 (II), formula (II) in which the group R1-C (= O) - represents an acyl radical chosen from the radicals w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl; and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, being understood that at least one of the radicals R 'or R "does not represent a hydrogen atom and that when none of the radicals R 'and R "does not represent a hydrogen atom, R' and R" are identical, for its use in a therapeutic treatment method intended to stimulate the production of melanins to prevent and / or treat Iter diseases of human skin and / or hair or hair. 14. Composition (Cl) comprising for 100% of its mass: from 99% by weight to 20% by weight of at least one compound of formula (Ia): R'-O-CH 2 -CH (OH) - [CH 2 - 0-CH2] s- [CH (OH)] - CH2-O-H (la) wherein s is 0 or 1 and p is 0, 1, 2 or 3 and R 'is either a radical monovalent compound of formula (II): wherein R1-C (= O) -represented represents an acyl radical chosen from the radicals w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12-dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, - from 1% by weight to 80% by weight of at least one compound of formula (Ib): RO-CH2-CH (OH) - [CH2-O-CH21s4CH (OH)] - CH2-0-R (Ib) wherein (Ib) in which s is 0 or 1 and p is equal to 0, 1, 2 or 3 and R represents either a monovalent radical of formula (II): ## STR2 ## (II) in which the group R 1 -C (= O) - represents an acyl radical chosen from the radicals w-undecylenoyl, octanoyl, decanoyl, dodecanoyl, tetradecanoyl and optionally hexadecanoyl, octadecanoyl, 9-octadecenoyl and octadeca-9,12- dienoyl, R2 represents the isobutyl radical and R3 represents a hydrogen atom, or composition (C'1), as defined in one of claims 4 to 7, for their use in a method of therapeutic treatment intended to stimulate the production of demanines to prevent and / or treat diseases of human skin and / or hair or hair.