Process for treating keratin fibres, using one or more ortho- dihydroxy- l ,2-diphenylethylene derivatives, additional polyphenols and (hydrogen) carbonates The present invention relates to a process for treating keratin fibres, in particular human keratin fibres such as hair, comprising the application o f one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives in combination with one or more manganese and/or zinc derivatives, one or more (hydrogen) carbonates and one or more polypheno ls other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives.

Many people have sought for a long time to modify the co lour of their hair and in particular to mask their grey hair. Essentially two types of dyeing have been developed for this purpose.

The first type o f dyeing is "permanent" or oxidation dyeing, which uses dye compositions containing oxidation dye precursors, generally referred to as oxidation bases. These oxidation bases are co lourless or weakly coloured compounds, which, when combined with oxidizing products, may give rise to coloured compounds via a process of oxidative condensation.

It is also known that the shades obtained with these oxidation bases may be varied by combining them with couplers or colour modifiers. The variety o f mo lecules used in the oxidation bases and couplers allows a wide range of colours to be obtained.

Most of these permanent dyeing processes provide a good level of coverage o f grey hair. However, they require the presence o f an oxidizing agent in a strongly alkaline medium (pH generally of greater than 10) and these conditions are all the harsher, the greater the desired degree of coverage of the grey hairs on the head.

The second type of dyeing is " semi-permanent" dyeing or direct dyeing, which consists in applying direct dyes to the keratin fibres, the said dyes being co loured and co louring molecules that have an affinity for the fibres, and then leaving them to take, to allow the mo lecules to penetrate by diffusion to the interior of the fibre, and then rinsing the fibres.

In order to perform these co lourings, the direct dyes generally used are chosen from nitrobenzene, anthraquinone, nitropyridine, azo , xanthene, acridine, azine and triarylmethane direct dyes . The direct dyes may also be natural dyes .

However, the co lourings resulting therefrom are particularly chromatic co lourings, but are, however, only temporary or semipermanent since the nature of the interactions that bind the direct dyes to the keratin fibre and their desorption from the surface and/or the core of the fibre are responsible for their weak dyeing power and their poor persistence with respect to washing.

Given these drawbacks, consumers are increasingly seeking dyeing processes other than the conventional oxidation dyeing and direct dyeing processes. Consumers are especially seeking processes which use natural dyes, the use o f which is not aggressive for the keratin fibres, and especially which do not require the use of oxidizing agents, and which are more environmentally friendly. Consumers are in particular seeking dyeing methods which are well to lerated and which lead to as natural an appearance as possible.

In traditional Chinese medicine, which is in large part an oral tradition based on the ancestral use of natural products, the use o f plant extracts such as Black Shou Wu (hereinafter "B SW") is known, which is an extract of the roots of Radix Poligoni Multiflori and is used in particular to prevent hair loss and promote hair growth, as a conditioning agent and as an anti-dandruff agent.

Moreover, the use o f Poligonum Multiflorum extract has been mentioned for obtaining blonde co louring, especially in patent application DE 197 16 074.

There is a real need to develop novel processes for dyeing keratin fibres, making it possible to obtain co louring o f the hair while overcoming the abovementioned drawbacks. These processes must especially make it possible to cover grey hair. There is also a need to obtain gradual colouring of grey hair, to avoid an abrupt change in the user's appearance. Gradual co lourings must have a natural effect. They must also make it possible to uniformly cover the head of hair.

These processes must also be easy to apply.

The Applicant has discovered, surprisingly, that the use o f one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives and of one or more polypheno ls other than the ortho-dihydroxy- 1 ,2- diphenylethylenes in a medium comprising salts or oxides o f manganese and/or zinc, and (hydrogen) carbonates, made it possible to achieve the aims set out above.

A subj ect of the present invention is therefore a process for treating keratin fibres, in particular human keratin fibres such as the hair, comprising the application, to said fibres, of one or more ortho- dihydroxy- 1 ,2-diphenylethylene derivatives, o f one or more additional polypheno ls other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives, of one or more manganese and/or zinc derivatives, chosen from manganese salts or oxides and zinc salts or oxides, and of one or more (hydrogen) carbonate(s) .

The process of the invention advantageously comprises :

a) application, to the fibres, of a composition (A) comprising the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s), the additional polypheno l(s) other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives and the manganese and/or zinc derivative(s), and

b) application, to the fibres, of a composition (B) comprising the (hydrogen) carbonates.

The process of the invention also relates to a multicompartment device comprising at least two compartments containing the respective compositions (A) and (B) above.

The treatment process according to the invention is a dyeing process which makes it possible to obtain a (re)pigmentation of the keratin fibres, which is both gradual and visible from the first application. Unlike conventional dyeing processes, the process of the invention makes it possible to produce a real pigmentation or a re- pigmentation of the keratin fibres by returning to the original co lour or by providing shades thereto, or else by changing the co lour. In the case o f grey hair, the process makes it possible to gradually re- pigment the hair, depending on the number o f applications. It also makes it possible to prevent or delay the appearance of grey hair.

The process o f the invention differs from oxidation dyeing processes because it does not employ the condensation of dye precursors in the presence o f an oxidizing agent. It also does not correspond to a direct dyeing process because it does not emplo y co loured mo lecules. In particular, the ortho-dihydroxy- 1 ,2- diphenylethylene derivatives used in the present invention are not co loured mo lecules, unlike direct dyes .

The process according to the invention may be repeated, which makes it possible to gradually obtain a natural dark, or even black, co louring effect. The process o f the invention especially makes it possible to obtain an excellent level o f dark pigmentation and good coverage of grey hair from three applications. The repeated applications may take place one after the other or be separated by several hours or even several days .

The process thus makes it possible to obtain good colouring intensity, especially good coverage of grey hair over the whole head of hair, and also good colour homogeneity along the keratin fibres .

Finally, the co lourings obtained in this way are not aggressive and are well tolerated by the keratin fibres. The process according to the invention does not damage the keratin fibres and provides them with a good level o f conditioning, especially in terms o f manageability, softness, smoothness and disentangling.

Other subj ects, characteristics, aspects and advantages o f the invention will emerge even more clearly on reading the description and the examples that follow. In the text hereinbelow, unless otherwise indicated, the limits of a range of values are included in that range, especially in the expressions "between" and "ranging from ... to

Moreover, the expressions "at least one" and "at least" used in the present description are equivalent to the expressions "one or more" and "greater than or equal to", respectively.

The term "substituted" or "optionally substituted" is intended to mean conventional substituents of the chemical radicals in question, such as alkyl, amino, amino alkyl, hydroxyl, hydroxyalkyl, halogenated substituents, etc.

Ortho-dihydroxy- 1 ,2-diphenylethylene derivatives

The present invention employs one or more ortho-dihydroxy- 1 ,2-diphenylethylene derivatives, preferably present in the composition (A) .

"Ortho-dihydroxy- 1 ,2-diphenylethylene derivatives" denotes compounds comprising at least one ortho-dihydroxy- 1 ,2- diphenylethylene group in their chemical structure. They preferably comprise one ortho-dihydroxy- 1 ,2-diphenylethylene group or two ortho-dihydroxy- 1 ,2-diphenylethylene groups (especially in the case of ortho-dihydroxy- 1 ,2-diphenylethylene dimers) in their structure. These compounds may be compounds, the hydroxyl groups o f which are protected, such as, for example, corresponding glyco sylated derivatives.

The ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) used according to the present invention may be of natural or synthetic origin.

These compounds are preferentially chosen from:

glyco sylated derivatives, such as 2,3 ,5 ,4'-tetrahydroxystilbene 2- Ο-β-D-glucoside; trans-3'-P-glucopyranosyl-4 ,5 '-dihydroxy-3 - methoxystilbene; trans-3'-P-glucopyranosyl-3 ,4 ,5 '-trihydroxystilbene; and piceatannol 3 -glucoside;

non-glycosylated derivatives, such as trans-3 -methoxy-3 ',4 ,5 '- trihydroxystilbene; piceatannol (trans-3 ,3 ' ,4,5 '-tetrahydroxystilbene) ; 5-[(lE)-2-phenylethenyl]-l,2,3-benzenetriol; 4-[(1Ζ)-2-(3,5- dihydroxyphenyl)ethenyl]-l ,2-benzenediol; 5-[(lE)-2-(4- hydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 5-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-l ,2,3-benzenetriol; 4-[(lE)-2-(2,4- dihydroxyphenyl)ethenyl]-l ,2-benzenediol; α-[[(2Ε)-3-[2-[(1Ε)-2-(3,4- dihydroxyphenyl)ethenyl]-3 ,4-dihydroxyphenyl]- 1 -oxo-2-propen- 1 - yl]oxy]-3,4-dihydroxybenzenepropanoic acid; ethyl 2-[(lE)-2-(3,4- dihydroxyphenyl)ethenyl]-6-hydroxybenzoate and 4-[(lE)-2-(3,5- dimethoxyphenyl)ethenyl]- 1 ,2-benzenediol; and

- the optical and/or geometric isomers, the salts and/or solvates and the mixtures of such derivatives.

The ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) of use according to the present invention may also be in dimer form, such as those described in the Journal of Chemical Research (2004), (5), 339- 340, such as andalasin B, extracted from the roots of Morus macroura.

Mention may also be made of condensed tannins of ortho- dihydroxy- 1 ,2-diphenylethylene, such as those described in Tetrahedron Letters (1983), 24(38), 4147-50.

More preferentially, the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are chosen from glycosylated derivatives, and better still, the composition (A) comprises 2,3,5,4'-tetrahydroxystilbene 2-Ο-β-ϋ- glucoside.

According to a particularly preferred embodiment of the present invention, the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) are of natural origin. In this embodiment, the composition (A) comprises one or more extracts of plants which may be chosen, for example, from Polygonum multiflorum, Radix Poligoni Multiflori, Fallopia multiflora, Smilax china, Morus australis Poir, Cistanche tubulosa, Millettia erythrocalyx, Artocarpus lakoocha, Cissus assamica, Veratrum maackii, Vitis vinifera, Vitis labrusca, Smilax stans, Picea abies, and Guibourtia coleosperma, said extracts containing the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s).

The ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) used in the present invention may be extracted from the plants mentioned above, according, for example, to the protocol described in patent application CN 1034055 16.

The total amount of the ortho-dihydroxy- 1 ,2-diphenylethylene derivative(s) present in the composition (A) preferably ranges from 0.001 % to 10% by weight and more preferentially from 0.01 % to 5 % by weight relative to the total weight of the composition (A) .

When these compounds are used in the form o f plant extract, a content of extract ranging from 0. 1 % to 50% by weight and preferably from 0.5 % to 30% by weight relative to the total weight of the composition (A) is typically used.

Manganese and/or zinc derivatives

The process o f the invention also comprises the application o f one or more manganese (Mn) and/or zinc (Zn) derivatives, chosen from the salts or the oxides.

These manganese and/or zinc derivative(s) are preferably contained in the composition (A) .

For the purposes of the present invention, "salts" are intended to mean actual salts in the ionized form. These salts may be so lvated, in particular hydrated.

The derivatives are preferably salts .

Particularly, the derivatives o f the invention are in oxidation state II, such as Mn(II) and Zn(II) .

The manganese and/or zinc salt(s) are advantageously chosen from chlorides, fluorides, iodides, bromides, sulfates, phosphates, nitrates, perchlorates, carbonates, carboxylates, and mixtures thereof.

The carboxylates o f use in the invention also include carboxylic acid salts comprising one or more hydroxyl radicals such as gluconates .

By way o f example o f carboxylates, mention may be made, for example, o f acetate, tartrate, lysinate, glutamate, lactate, glycinate, aspartate, stearate, acetylacetate.

The manganese and zinc derivatives can be introduced in the so lid form into the compositions or else can be introduced in the form of an aqueous so lution, such as a natural, mineral or spring water which is rich in these ions or else o f seawater (Dead Sea water, especially). They can also originate from mineral compounds, such as earths, ochres, such as clays (for example green clay), or even from plant extracts containing them (cf. , for example, the document FR 2 8 14 943) .

Among the manganese salts, preference is given to manganese chloride, manganese carbonate, manganese difluoride, manganese acetate tetrahydrate, manganese lactate trihydrate, manganese phosphate, manganese iodide, manganese nitrate trihydrate, manganese bromide, manganese perchlorate tetrahydrate, manganese sulfate monohydrate, manganese gluconate and mixtures thereof.

Among the zinc salts, preference is given to zinc sulfate, zinc gluconate, zinc chloride, zinc lactate, zinc acetate, zinc glycinate, zinc aspartate and mixtures thereof.

Preferably, the process of the invention employs one or more manganese salts, in particular Mn(II) metal salts.

Even more preferentially, the manganese salt(s) are chosen from manganese carboxylates, especially manganese gluconate, and manganese halides, such as manganese chloride, and mixtures thereof.

Better still, the manganese salt(s) are chosen from manganese chloride, manganese gluconate and mixtures thereof.

When the composition (A) comprises one or more manganese derivatives, the total concentration of said derivative(s) in the composition (A) preferably ranges from 10 ^"3 to 10 ^{" 1} mmo l. l ^{" 1} , and more preferentially from 10 ^"2 to 1 0 ^{" 1} mmo l. l ^{" 1} .

When the composition (A) comprises one or more zinc derivatives, the total concentration of said derivative(s) in the composition (A) ranges from 5. 10 ^"2 to 10 mmo l. l ^{" 1} , and more preferentially from 5. 10 ^{" 1} to 1 mmol. l ^{" 1} .

The polyphenols other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives The process o f the invention comprises the application, to the keratin fibres, o f one or more additional polypheno l(s) other than the ortho-dihydroxy- 1 ,2-diphenylethylene derivatives.

These additional polyphenols are preferably chosen from ortho- diphenols, that is to say compounds comprising one or more aromatic rings, preferably benzene rings, comprising at least two hydroxyl groups (OH) borne by two adj acent carbon atoms of the same aromatic ring. The ortho-dipheno l(s) o f use in the invention are in particular not auto-oxidizable derivatives, especially auto-oxidizable derivatives with an indo le unit. More particularly, they are not 5 ,6- dihydroxyindole.

The aromatic ring may more particularly be a fused aryl or fused heteroaromatic ring, i. e. optionally comprising one or more heteroatoms, such as benzene, naphthalene, tetrahydronaphthalene, indane, indene, anthracene, phenanthrene, isoindo le, indo line, isoindo line, benzo furan, dihydrobenzofuran, chroman, isochroman, chromene, isochromene, quino line, tetrahydroquinoline and isoquino line, said aromatic ring comprising at least two hydroxyl groups borne by two adjacent carbon atoms of the aromatic ring. Preferentially, the aromatic ring of the ortho-dipheno l derivatives according to the invention is a benzene ring.

"Fused ring" is intended to mean that at least two saturated or unsaturated and heterocyclic or non-heterocyclic rings have a common bond, that is to say that at least one ring is placed side-by-side with another ring.

The additional ortho-dipheno ls may or may not be salified. They may also be in the aglycone form (without bonded sugar) or in the form of glycosylated compounds .

According to a particularly preferred embodiment, the composition (A) comprises one or more ortho-dipheno l(s) o f formula (I) below, or an oligomer thereof, in salified or non-salified form: formula (I) , in which the substituents Ri to R ₄ , which are identical or different, represent :

a hydro gen atom,

a halo gen atom,

a hydro xyl radical,

a carboxyl radical,

an alkyl carboxylate or alkoxycarbonyl radical,

an optionally substituted amino radical,

an optionally substituted and linear or branched alkyl radical, an optionally sub stituted and linear or branched alkenyl radical, an optionally substituted cyclo alkyl radical,

an alkoxy radical,

an alkoxyalkyl radical,

- an alkoxyaryl radical, it being possib le for the aryl group to be optionally substituted,

an aryl radical,

a substituted aryl radical,

a saturated or unsaturated hetero cyclic radical carrying or not carrying a cationic or anionic charge, optionally sub stituted and/or optionally fused with an aromatic ring, preferably a benzene ring, the said aromatic ring being optionally sub stituted, in particular with one or more hydro xyl or glyco syloxy group s,

a radical containing one or more silicon atoms,

or two o f the sub stituents borne by two adj acent carbon atoms (namely Ri and R ₂ , R ₂ and R3 or R3 and R ₄ ) form, together with the carbon atoms bearing them, a saturated or unsaturated and aromatic or non- aromatic ring, optionally containing one or more heteroatoms and optionally fused with one or more saturated or unsaturated rings optionally containing one or more heteroatoms.

Preferably, the additional ortho-diphenol derivatives o f formula (I) are chosen from those in which two adjacent substituents Ri - P 2 , P 2 - P 3 or P 3 - P 4 cannot form, with the carbon atoms which bear them, a cyclic radical, in particular a pyrrolyl radical. More particularly, R ₂ and R ₃ cannot form a pyrro lyl radical fused to the benzene ring bearing the two hydroxyls .

For the purposes o f the present invention and unless otherwise indicated:

The saturated or unsaturated and optionally fused rings may also be optionally substituted.

- The alkyl radicals are saturated and linear or branched hydrocarbon radicals, generally C 1 - C20 hydrocarbon radicals, particularly C 1 - C 10 hydrocarbon radicals, preferably C i -C ₆ alkyl radicals such as methyl, ethyl, propyl, butyl, pentyl and hexyl.

The alkenyl radicals are unsaturated and linear or branched C2 - C20 hydrocarbon radicals, preferably comprising at least one double bond, such as ethylene, propylene, butylene, pentylene, 2- methylpropylene and decylene.

The aryl radicals are monocyclic or fused or non-fused polycyclic carbon-based radicals, preferentially comprising from 6 to 30 carbon atoms, at least one ring o f which is aromatic; the choice is preferentially made, from the aryl radical, o f a phenyl, biphenyl, naphthyl, indenyl, anthracenyl and tetrahydronaphthyl.

The alkoxy radicals are alkyloxy radicals with alkyl as defined above, preferably C 1 - C 10 alkyloxy radicals, such as methoxy, ethoxy, propoxy and butoxy.

The alkoxyalkyl radicals are preferably ( C 1 - C20) alkoxy (C 1 - C20) alkyl radicals, such as methoxymethyl, ethoxymethyl, methoxyethyl, ethoxyethyl, etc. The cycloalkyl radicals are generally C 4 - C 8 cycloalkyl radicals, preferably the cyclopentyl and cyclohexyl radicals. The cyclo alkyl radicals can be substituted cycloalkyl radicals, in particular substituted with alkyl, alkoxy, carboxylic acid, hydroxyl, amine and ketone groups .

The additional ortho-dipheno ls o f use in the process o f the invention may be natural or synthetic. The natural ortho-dipheno ls include the compounds which may be present in nature and which are reproduced by chemical (semi)synthesis.

According to a particular embodiment of the invention, the process comprises the application o f one or more additional synthetic ortho-dipheno l(s) that do not exist in nature.

According to another preferred embodiment of the invention, the additional ortho-diphenols are natural ortho-dipheno ls.

More particularly, the additional natural ortho-dipheno ls of use in the process o f the invention are chosen from:

- flavano ls, such as catechin and epicatechin gallate,

- flavono ls, such as quercetin,

- anthocyanidins, such as cyanidin, delphinidin, petunidin or pelargonidin,

- anthocyanins or anthocyans such as delphinidin 3 -0- glucoside, also referred to as myrtillin,

ortho-hydroxybenzoates, for example gallic acid derivatives, and in particular gallates, for example propylgallate,

- flavones, such as luteolin,

- 3 ,4-dihydroxyphenylalanine and the derivatives thereo f, such as L-3 ,4-dihydroxyphenylalanine methyl ester hydrochloride,

- 2,3 -dihydroxyphenylalanine and the derivatives thereof,

- 4,5 -dihydroxyphenylalanine and the derivatives thereof,

- dihydroxycinnamates, such as caffeic acid and chlorogenic acid,

- ortho-polyhydroxycoumarins,

- ortho-polyhydroxyisocoumarins,

- ortho-polyhydroxycoumarones,

- ortho-polyhydroxyisocoumarones, - ortho-polyhydroxychalcones,

- ortho-polyhydroxychromones,

- quinones,

- hydroxyxanthones,

- 1 ,2-dihydroxybenzene and the derivatives thereof,

- 1 ,2,4-trihydroxybenzene and the derivatives thereof,

- 1 ,2,3 -trihydroxybenzene and the derivatives thereof,

- 2,4,5 -trihydroxyto luene and the derivatives thereof,

-proanthocyanidins and especially the proanthocyanidins A l ,

A2, B l , B2, B3 and C I ,

- proanthocyanins,

- tannic acid,

- ellagic acid,

- and mixtures of the preceding compounds,

and more particularly from catechin, quercetin, brazilin (CAS 474-07-7), haematein, haematoxylin, chlorogenic, caffeic and gallic acids, catechol, L DOPA, pelargonidin, cyanidin, (-)-epicatechin, (-)- epigallo catechin, (-)-epigallocatchine 3 -gallate (EGCG), (+)-catechin, isoquercetin, pomiferin, esculetin, 6,7-dihydroxy-3 -(3 -hydroxy-2,4- dimethoxyphenyl)coumarin, santalin AC, mangiferin, butein, maritimetin, sulfuretin, robtein, betanidin, pericampylinone A. , theaflavin, proanthocyanidin A2, proanthocyanidin B2, proanthocyanidin C I , procyanidins DP 4-8 , tannic acid, purpurogallin, 5 ,6-dihydroxy-2-methyl- l ,4-naphthoquinone, alizarin, wedelo lactone, variegatic acid, gomphidic acid, xerocomic acid, carnoso l, and the natural extracts containing same.

Preferentially, the additional ortho-diphenol(s) according to the invention are chosen from flavano ls, flavono ls, ortho- hydroxybenzoates, iso flavones and neoflavones .

According to one embodiment, the natural ortho-dipheno ls are derived from, or are introduced in the form o f, extracts of animals, bacteria, fungi, algae, plants and fruits, used in their entirety or partially. In particular regarding plants, the extracts are derived from fruits, including citrus fruits, from vegetables, from trees, from shrubs and from lychen. Use may also be made of mixtures o f these extracts rich in ortho-dipheno ls as defined above.

Preferably, the additional ortho-dipheno l(s) are natural ortho- diphenols derived from extracts of plants or plant parts . These extracts of plants or plant parts may be used directly in the process o f the invention.

The extracts are obtained by extraction from various plant parts, such as, for examp le, the root, the wood, the bark, the leaf, the flower, the fruit, the seed, the pod or the peel.

Mention may be made, among the extracts of plants, of extracts of rose or tea leaves .

Mention may be made, among the extracts of fruit, o f extracts of apple, extracts of grape (in particular of grape seed) or extracts of cocoa beans and/or pods .

Mention may be made, among the extracts of vegetables, o f extracts of potato or of onion peel.

Mention may be made, among the extracts of tree wood, of extracts of pine bark and extracts of logwood.

Use may also be made of mixtures of plant extracts .

According to a particular embodiment of the invention, the ortho-dipheno l(s) are natural extracts rich in ortho-diphenols. According to a preferred embodiment, the additional ortho-dipheno l derivative(s) are so lely contained in natural extracts.

Preferentially, the polyphenol(s) used in the process according to the invention are chosen from catechin, quercetin, haematein, haematoxylin, brasilin, gallic acid, and natural extracts containing same, chosen especially from grape marc, pine bark, green tea, onion, cocoa bean, logwood, redwood and gall nut. The extract used is preferably logwood.

More preferentially still, the additional po lypheno l(s) are chosen from catechin, quercetin, gallic acid and hematoxylin.

The natural extracts containing the additional po lypheno ls according to the invention may be in the form of powders or liquids. Preferably, the extracts containing the additional po lypheno ls according to the invention are in the form of powders .

According to the invention, the synthetic or natural polypheno l(s) and/or the natural extract(s) containing same preferably represent(s) from 0.001 % to 20% by weight of the total weight o f composition (A).

As regards the pure polyphenol(s), the content thereo f in the composition (A) is preferably between 0.001 and 5 % by weight relative to the total weight of the composition (A) .

As regards the extracts, the content of extract in the composition (A) is preferably between 0.5 and 20% by weight relative to the total weight of the composition (A) .

According to a particularly preferred embodiment, the process according to the invention does not employ oxidation dyes or direct dyes other than the ortho-dihydroxy- l ,2-diphenylethylene derivatives and the additional po lypheno ls described above.

The (hydrogen) carbonates

The (hydrogen) carbonate(s) used in the process o f the invention are especially chosen from the compounds o f the fo llowing formulae :

R' ⁺ , HCO3 ^" , with R' representing a hydrogen atom, an alkali metal, an ammonium group R ⁿ 4N ⁺ - or a phosphonium group R ⁿ 4P ⁺ - in which the groups R", which are identical or different, represent a hydrogen atom, an optionally substituted (Ci -C ₆ )alkyl group, such as hydroxyethyl; when R' represents a hydrogen atom, the hydrogen carbonate is then referred to as dihydrogen carbonate (CO2 , H ₂ 0); and

Met' ²⁺ (HC03 ^~ )2 , with Met' representing an alkaline earth metal.

More particularly, the (hydrogen) carbonate(s) are chosen from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonate(s), ammonium hydrogen carbonates and the mixtures thereo f; and more preferentially from alkali metal hydrogen carbonates, alkaline earth metal hydrogen carbonates and the mixtures thereo f.

Better still, the hydrogen carbonates are chosen from sodium, potassium, magnesium and calcium hydrogen carbonates and the mixtures thereo f, and in particular sodium hydrogen carbonate and potassium hydrogen carbonate. Even more preferentially, the hydrogen carbonate used in the process o f the invention is sodium hydrogen carbonate.

These (hydrogen) carbonates may originate from a natural water, for examp le spring water from the Vichy basin or from La Roche-Posay or Badoit water (cf. for example, patent document FR 2 8 14 943) . Mention may particularly be made o f sodium carbonate Na ₂ CC" 3 , and sodium hydrogen carbonate or sodium bicarbonate NaHCOs .

These hydrogen carbonates may also be generated in situ by any process making it possible to generate an HC O3 ^" salt.

The composition (B) may contain a total amount of the (hydrogen) carbonate(s) which preferably ranges from 0. 1 % to 15 % by weight and more preferentially from 0.5 % to 1 0% by weight relative to the total weight of the composition (B) .

According to a preferred embodiment, the total mo lar concentration o f (hydrogen) carbonates is greater than the total mo lar concentration o f manganese salts and of zinc salts applied to the keratin fibres.

The metal salts other than the manganese and zinc salts

The process according to the present invention may also comprise the application, to the keratin fibres, of one or more additional divalent or trivalent metal salt(s) other than the manganese salts and zinc salts defined above.

For the purposes of the present invention, "metal salt" is intended to mean actual salts, that is to say in ionized form, o f the metals o f co lumns 3 to 14 of the periodic table o f the elements, other than manganese and zinc. Among these additional metal salts, mention may especially be made o f hydroxides, halides, sulfates, phosphates, nitrates and carboxylates.

The additional metal salt(s) are preferably chosen from iron(II) salts and iron(III) salts .

More preferentially, the additional metal salt(s) are chosen from iron sulfate, iron fumarate, iron gluconate, iron acetylacetonate, iron oxalate, mixed salts, such as Mohr's salt, and the mixtures thereo f; and better still, iron sulfate.

According to a first preferred embodiment, the additional metal salt(s) are present in the composition (A) .

According to a second preferred embodiment, the additional metal salt(s) are present in a composition (C) separate from the compositions (A) and (B) .

It is also possible to combine these two embodiments, and to use the additional metal salt(s) both in the composition (A) and in a separate composition (C) .

When they are used, the total amount of the additional metal salt(s) preferably ranges from 0.001 % to 5 % by weight and more preferentially from 0.01 % to 4% by weight relative to the total weight of the composition containing same.

Deglycosylation

In the case in which one or more glycosylated derivatives o f ortho-dihydroxy- l ,2-diphenylethylene are used in the process o f the invention, the process also comprises the use o f an enzyme o f β- glucosidase type, in order to promote deglycosylation and therefore to optimize the co louring obtained. Use may also be made of any other means known for deglyco sylating, such as those described, for example, in Kinetics and mechanism of 2, 3, 5, 4 '-tetrahydroxystilbene- 2-0-β-d-glycoside (THSG) degradation in aqueous solutions, J. Pharm. Biomed. Anal. 201 1 Apr 28 ;55 ( 1 ) :21 1 -5. Epub 2010 Dec 3 1 .

It is possible to add the enzyme extemporaneously into the composition (A) comprising the glycosylated dihydroxy- 1 ,2- diphenylethylene, immediately before applying this composition to the fibres.

It is also possible to add the enzyme extemporaneously into the composition (A) comprising the glyco sylated dihydroxy- 1 ,2- diphenylethylene, to add, if required, an aqueous so lution at pH 5 to 9 if the initial composition did not contain water, and to maintain this new composition as is from 10 min to 2 hours, preferably from 15 min to 1 hour before applying to the fibres, said enzyme possibly being eliminated from this composition just before applying to the fibres, by any means known to those skilled in the art.

Preferentially, glucosidases of natural origin are used, such as almond beta glucosidases, such as, in particular, sweet almond glucosidase EC 3.2. 1 .

It is possible to use, for example, the almond β-glucosidase so ld by Aldrich under the name 49290 SIGMA β-Glucosidase from almonds lyophilized, powder, >6 U/mg. This composition may be applied in solution at 1 mg/ml for 30 min to 1 hour.

Preferentially, the composition containing an enzyme o f β- glucosidase type is applied at a temperature of less than 55 °C and more preferentially from 30 to 40°C . The pH of this composition may range from 5 to 9.

Surfactants

The compositions o f use for the invention may optionally comprise one or more surfactants .

The surfactant(s) of use are preferably chosen from nonionic surfactants, anionic surfactants and amphoteric or zwitterionic surfactants .

The total amount of surfactant(s) present in the compositions according to the invention may range from 0. 1 to 30% by weight, and preferably from 0.5 to 20% by weight relative to the total weight o f each composition containing same.

The surfactant(s) are preferably present in the composition (B) . The compositions

The compositions used in the present invention may be in any form which is compatible with an application to keratin fibres, and especially the hair.

In particular, the compositions (A) , (B) and, where appropriate, (C), of use in the invention may be in the form o f liquid or powder compositions. According to a preferred embodiment, the compositions (A), (B) and, where appropriate, (C), are in the form o f liquid compositions such as solutions.

They may be aqueous solutions, in particular aqueous-alcoho lic so lutions. They generally comprise water or a mixture of water and o f one or more so lvents, for example chosen from the lower C i to C ₄ alcoho ls, such as ethano l, isopropanol, tert-butano l or n-butano l; polyo ls such as glycerol, propylene glycol and polyethylene glyco ls ; and the mixtures thereof.

When they are present, the total amount of the so lvent(s) preferably ranges from 0.01 % to 50% by weight and more preferentially from 0.05 % to 30% by weight relative to the weight o f each composition containing same.

When the composition which contains the metal salt(s) is in the form o f a so lution, the latter must not flo cculate. Those skilled in the art will choose the suitable pH to prevent flocculation o f the composition, as a function o f the metal salt.

When it is aqueous, the composition (A) has an acid pH, preferably ranging from 3 to 7. When it is aqueous, the composition (B) has a rather basic pH, preferably between 7. 1 and 9.5. When it is aqueous, the composition (C) has a rather acid pH, ranging from 2 to 7, preferably from 3 to 4. The additives

The compositions of use in the invention may comprise one or more additives, among which mention may be made o f cationic, anionic, nonionic and amphoteric polymers or the mixtures thereo f, thickeners, anti-dandruff agents, antiseborrheic agents, agents for preventing hair lo ss and/or promoting hair regrowth, vitamins and provitamins including pantheno l, sunscreens, sequestrants, plasticizers, so lubilizers, acidifying agents, opacifiers or nacreous agents, hydroxy acids, fragrances, preserving agents, or fillers, preferentially o f natural origin. As fillers, mention may be made o f pigments such as iron oxides derived from ochres, carbon black, chlorophyll or polymerized anthocyanins .

The above additives may be present in an amount, for each o f them, o f between 0 and 20% by weight relative to the total weight of each composition containing same, in the case of a liquid composition.

The above additives may be present in an amount, for each o f them, o f between 0 and 80% by weight relative to the total weight of each composition containing same, in the case of a solid composition. The process

When the process according to the present invention is carried out starting with the compositions (A), (B) and where appropriate (C) described above, the compositions (A) and (B), and also the composition (C) when it is present, are applied to dry or wet keratin fibres and preferably to wet keratin fibres .

According to a preferred embodiment, the composition (A) then the composition (B) are applied successively.

According to this embodiment, the process more preferentially comprises :

- according to a first variant, the application, to the keratin fibres, of the composition (A), then o f the composition (B), preferably with a time gap between the application of the compositions (A) and (B) which may vary from 30 seconds to 1 hour, preferably from 1 min to 30 min;

- according to a second variant, the application, to the keratin fibres, of the extemporaneous mixture of the composition (A) and o f the composition (B), that is to say that the mixture of the compositions (A) and (B) is immediately applied to the fibres, without intermediate storage; - according to a third variant, the application, to the keratin fibres, of a composition resulting from the mixing o f the composition

(A) with the composition (B), kept, before application to the fibres, in a container which does not contain oxygen.

In the latter two variants, oxygen in the air acts directly on the hair at the moment of application. This embo diment makes it possible to reduce the number of steps to be carried out.

According to the particular embo diment which uses one or more additional metal salts as defined above, present in a composition (C) separate from the compositions (A) and (B), the three compositions (A), (B) and (C) are applied successively to the keratin fibres.

According to this embo diment, the composition (C) is applied after the composition (B) or before the composition (A), preferably with a time gap between the application of the compositions (A) and

(B) , as defined above.

Each of the compositions (A), (B) and optionally (C), or the composition resulting from the mixing of these, is advantageously left in place on the keratin fibres for a duration ranging from 30 seconds to 1 hour, and more preferentially from 30 seconds to 30 minutes .

The process of the present invention may be repeated several times, especially from 2 to 50 times, preferably from 3 to 30 times, depending on the desired degree of co louring. The greater the number of applications, the more intense and the darker is the co louring, thereby improving the repigmentation of grey hair.

Advantageously, the process of the invention is carried out by re-applying the compositions (A), (B) and optionally (C) several times, to obtain, over time, a natural and visible co louring. For example, the compositions according to the invention may be applied after each shampooing operation, or for example once or twice per week.

The process of the invention may also comprise a step o f rinsing after the application of the compositions (A) and (B) or after application o f the compositions (A), (B) and (C) . More preferentially, the process comprises a single final rinsing step . In other words, the keratin fibres are only rinsed after the application o f the final composition. Device

Finally, the present invention relates to a multi-compartment device comprising :

a first compartment containing the composition (A) as defined above; and

- a second compartment containing the composition (B) as defined above.

According to another embodiment of the device, the latter contains a compartment comprising a composition resulting from the mixing o f the composition (A) with the composition (B), this compartment not containing oxygen.

The device according to the present invention may also comprise :

- an additional compartment containing the composition (C) as defined above, and/or

- an additional compartment containing a composition comprising a glucosidase.

The compositions o f the compartments are intended to be applied successively to the keratin fibres according to the process as described above.

The examples that fo llow serve to illustrate the invention without, however, being limiting in nature.

EXAMPLES

In all the examples below, the colour of the locks was evaluated in the CIE L*a*b* system, using a Minolta Spectrophotometer CM2600D colorimeter.

In this L*a*b* system, the three parameters respectively denote the intensity of the colour (L*), the green/red colour axis (a*) and the blue/yellow colour axis (b*). The higher the value of L*, the lighter the colour. The higher the value of a*, the more red the colour and the higher the value of b*, the more yellow the colour.

In the examples that follow, all the amounts are given as percentages by weight relative to the total weight of each composition. Example 1: according to the invention a. Compositions tested

The following compositions Al and B were prepared from ingredients whose contents are indicated in the tables below.

Composition Al :

Black Shou Wu is a natural extract enriched in THSG, prepared according to the preparation process described in patent application CN103405516, and which contains from 15 to 30% by weight of THSG. It contains a total amount of polyphenols including THSG of 25 to 50% by weight. The term THSG denotes 2,3 ,5 ,4'-tetrahydroxystilbene 2-Ο-β-ϋ- glucoside, which is a derivative of ortho-dihydroxy- 1 ,2- diphenylethylene of formula:

Composition B : a. Procedure

The compositions A l and B thus obtained were then applied, according to the protocol below, to locks of Chinese hair ( 100% or 50% grey), washed beforehand.

Protocol for an application:

The composition A l was firstly applied by means of a brush at an amount of 500 μΐ of composition A l on 0.5 g lo cks . The lo cks were then left to take at 22°C for 5 minutes.

An identical amount of composition B was then applied, namely 500 μΐ per 0.5 g lock. The lo cks of hair were rubbed.

After leaving to take for 3 minutes at 22°C , the locks of hair were rinsed in water then left to dry.

The above protocol was repeated once, 3 times or 10 times on the locks . The colour of the locks obtained was evaluated in the CIE L*a*b* system, using a Minolta Spectrophotometer CM2600D colorimeter.

The tables below represent the colouring intensity values evaluated in the L*a*b* system (mean value for 3 locks), obtained from 100% grey hair (table 1) or 50% grey hair (table 2).

Table 1

Table 2

The above results show that the process according to the present invention makes it possible to darken 100% grey hair (table 1) and 50% grey hair (table 2) from the first applications.

Moreover, the colourings are significantly darker and more intense after 10 applications. Example 2: according to the invention a) Compositions tested

The following compositions A2, A2\ A3, A3', A4, A4 ^* , A5, A5' and B were prepared from ingredients whose contents are indicated in the tables below.

Composition A2 A2'

Black Shou Wu (extract identical 5% 5% to that of example 1)

Manganese chloride 0.406% 0.406%

Gallic acid 0.1% 1%

Water qs 100 qs 100

Composition A3 A3 ^*

Black Shou Wu (extract identical 5% 5% to that of example 1)

Manganese chloride 0.406% 0.406%

Catechin 0.1% 1%

Water qs 100 qs 100

Composition A4 A4'

Black Shou Wu (extract identical 5% 5% to that of example 1)

Manganese chloride 0.406% 0.406%

Quercetin 0.1% 1%

Water qs 100 qs 100

Composition A5 A5 ^*

Black Shou Wu (extract identical 5% 5% to that of example 1)

Manganese chloride 0.406% 0.406% Tannic acid 0.1% 1%

Water qs 100 qs 100

Composition B: b.) Procedure

The compositions A2, A2\ A3, A3', A4, A4', A5, A5' and B thus obtained were then applied, according to the protocol below, to locks of Chinese hair (100% grey), washed beforehand.

Protocol for an application:

The composition A was firstly applied by means of a brush at an amount of 500 μΐ to locks each weighing 0.5 g. The locks were then left to take at 22°C for 30 minutes.

An identical amount of composition B was then applied, namely 500 μΐ per 0.5 g lock. After leaving to take for 30 minutes at 22°C, the locks of hair were rinsed in water then left to dry.

The application was carried out once.

The colour of the locks obtained was evaluated in the CIE L*a*b* system, using a Minolta Spectrophotometer CM2600D colorimeter. c) Results

The table below represents the colouring intensity values, evaluated in the L*a*b* system (mean value for 3 locks). L* a* b*

100% grey hair

before 67.2 1.15 20.33 treatment

A2 + B 50.26 5.25 16.84

A2' + B 30.2 4.98 13.6

A3 + B 46.27 6.98 20.09

A3 ^* + B 41.94 5.64 21.05

A4 + B 49.65 6.49 16.5

A4' + B 52.38 5.45 17.77

A5 + B 44.75 3.17 15.91

A5 ^* + B 45.79 4.17 18.67

The above results show that the process according to the present invention makes it possible to obtain varied natural shades for the head of hair, from the first application.

Example 3: according to the invention a) Compositions tested

The following compositions A6, A6', B, CI and CI' were prepared from ingredients whose contents are indicated in the tables below.

Compositions A:

Composition A6 A6 ^*

Black Shou Wu (extract identical 5% 5% to that of example 1)

Manganese chloride 0.406% 0.406%

Haematoxylin (in the form of 0.1% 1% logwood extract containing 25% (0.025% AM) (0.25% AM) haematoxylin)

Water qs 100 qs 100 AM : active material

Composition B : Compositions C : b) Procedure

The compositions A, B and C thus obtained were then applied, according to the protocol below, to locks of Chinese hair ( 1 00% grey), washed beforehand.

Protocol for an application:

The composition A was firstly applied by means o f a brush at an amount of 500 μΐ o f composition A to locks each weighing 0.5 g . The locks were then left to take at 22°C for 30 minutes.

An identical amount of composition B was then applied, namely 500 μΐ per 0.5 g lock.

After leaving to take for 30 minutes at 22°C, 1 ml o f composition C was applied to the locks, then each lo ck was rubbed and left to take for one minute.

The locks were then rinsed with water and then left to dry.

The application was carried out once.

The co lour of the locks thus obtained was evaluated in the CIE L* a*b * system, using a Mino lta Spectrophotometer CM2600D co lorimeter. c) Results

The table below represents the colouring intensity values, evaluated in the L*a*b* system (mean value for 3 locks).

The above results show that the process according to the present invention makes it possible to obtain significant pigmentation of the head of hair from the first application, with dark shades close to HT2 level (two levels of tone depth).

Example 4: comparative tests a. Compositions tested

Compositions A:

Composition A7 A8 A8 ^* A9 A9 ^*

Black Shou Wu

(extract identical 5% - - 5% 5% to that of

example 1)

Manganese 0.406% 0.406% 0.406% 0.406% 0.406% chloride

Haematoxylin

(logwood extract - 0.1% 1% 0.1% 1% containing 25% (0.025% (0.25% (0.025% (0.25% haematoxylin) AM) AM) AM) AM)

Water qs 100 qs 100 qs 100 qs 100 qs 100

AM : active material

Composition B b. Procedure

The compositions A and B thus obtained were then applied, according to the protocol below, to locks of Chinese hair ( 100% grey), washed beforehand.

Protocol for an application:

The composition A was firstly applied by means o f a brush at an amount of 500 μΐ o f composition A to locks each weighing 0.5 g . The locks were then left to take at 22°C for 30 minutes.

An identical amount of composition B was then applied, namely 500 μΐ per 0.5 g lock.

The locks were then rinsed with water and then left to dry.

The co lour of the locks thus obtained was evaluated in the CIE L* a*b * system, using a Mino lta Spectrophotometer CM2600D co lorimeter. c. Results

The table below represents the co louring intensity values, evaluated in the L * a*b * system (mean value for 3 locks), after one application.

Comparative example : A7 + B :

L* a* b*

100% grey hair

67.2 1 . 15 20.33 before treatment

After 1

application 5 1 .45 5.74 16.95

After 3

applications 44.54 8.28 16.66

After 10

applications 45.4 9.53 17.9

Comparative example : A8 or A8' + B :

Example according to the invention: A9 or A9' + B :

The above examples show that the process according to the invention, employing the combination of an ortho-dihydroxy- 1 ,2- diphenylethylene derivative in combination with a po lypheno l, makes it possible to obtain a superior co louring performance, with a black tone having a tone depth comparable to that of natural black hair and which is more intense than the co louring obtained in the comparative processes employing just one of these two compounds .