(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2016/097248 Al 23 June 2016 (23.06.2016) W P O P C T

(51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every A61Q 5/06 (2006.01) A61K 36/00 (2006.01) kind of national protection available): AE, AG, AL, AM, A61K 8/97 (2006.01) AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, (21) Number: International Application DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, PCT/EP20 15/080403 HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR, (22) International Filing Date: KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, 18 December 2015 (18. 12.2015) MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, (25) Filing Language: English SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, (26) Publication Language: English TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: (84) Designated States (unless otherwise indicated, for every 1462873 19 December 2014 (19. 12.2014) FR kind of regional protection available): ARIPO (BW, GH, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, (71) Applicant: L'OREAL [FR/FR]; 14, rue Royale, 75008 TZ, UG, ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, RU, Paris (FR). TJ, TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, (72) Inventors: CHOISY, Patrick; 6, quai Albert Baillet, LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK, 37270 Montlouis-sur-Loire (FR). GUENAULT, Emilie; 1, SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, rue de la Baratterie, 37390 Saint-Roch (FR). GABANT, GW, KM, ML, MR, NE, SN, TD, TG). Marion; 1, ave Eugene Schueller, BP 22, 93601 Aul- nay-sous-Bois (FR). Published: (74) Agent: KUHLMANN, Sonia; L'Oreal, D.I.P.I., 25-29, — with international search report (Art. 21(3)) quai Aulagnier, 92665 Asnieres-sur-Seine Cedex (FR).

00 l © (54) Title: PROCESS FOR DYEING KERATIN FIBRES USING PRE-HYDROLYSED AND DECONTAMINATED HENNA ¾ (57) Abstract: The subject of the invention is i) a process for preparing an aqueous composition comprising pre-hydrolysed and de - contaminated henna, ii) the aqueous composition prepared according to the process, iii) a process for dyeing keratin fibres, in partic - ular human keratin fibres, such as the hair, which uses the composition comprising pre-hydrolysed and decontaminated henna op - tionally extemporaneously with indigo, and iv) the use of the composition comprising the pre-hydrolysed and decontaminated henna, for dyeing keratin fibres. PROCESS FOR DYEING KERATIN FIBRES USING PRE-HYDROLYSED AND DECONTAMINATED HENNA

The subject of the invention is i) a process for preparing an aqueous composition comprising pre-hydrolysed and decontaminated henna, ii) the aqueous composition prepared according to the process, iii) a process for dyeing keratin fibres, in particular human keratin fibres, such as the hair, which uses the composition comprising pre-hydrolysed and decontaminated henna optionally extemporaneously with indigo, iv) the use of the composition comprising the prehydrolysed and decontaminated henna and optionally indigo prepared extemporaneously, for dyeing keratin fibres in a single action.

Two major methods for dyeing human keratin fibres, and in particular the hair, are known. The first, known as oxidation dyeing or permanent dyeing, consists in using one or more oxidation dye precursors, more particularly one or more oxidation bases optionally combined with one or more couplers. Oxidation bases are usually chosen from ortho- or para-phenylenediamines, ortho- or para-aminophenols, and heterocyclic compounds. These oxidation bases are colourless or weakly coloured compounds, which, when combined with oxidizing products, can give rise via a process of oxidative condensation to coloured species, which remain trapped within the fibre. The shades obtained with these oxidation bases are often varied by combining them with one or more couplers, these couplers being chosen in particular from aromatic meta- diamines, meta-aminophenols, meta-diphenols and certain heterocyclic compounds, such as indole compounds. The variety of the molecules used as oxidation bases and couplers allows a wide range of colours to be obtained. The second dyeing method, known as direct dyeing or semi-permanent dyeing, comprises the application of direct dyes, which are coloured and colouring molecules that have affinity for fibres. Given the nature of the molecules used, they tend rather to remain on the surface of the fibre and penetrate relatively little into the fibre, when compared with the small molecules of oxidation dye precursors. The main advantages of this type of dyeing are that it does not require any oxidizing agent, which limits the degradation of the fibres, and that it does not use any dyes that have particular reactivity, resulting in limitation of the intolerance risks. The first hair dyes were semi-permanent. One of the most well known natural dyes is that derived from the henna plant. Henna continues to be used in feminine beauty enhancement for colouring the hair or the nails, or for dyeing leather, silk and wool, etc. It is also used traditionally for various important events, celebrations and beliefs. Red henna is constituted of leaves of shrubs of the genus Lawsonia from the family Lythraceae, which is based on the principle of dyeing with the active agent lawsone: 2- hydroxy-1 ,4-naphthoquinone. Lawsone [83-72-7] (CI Natural Orange 6 ; C I 75420), also known as isojuglone, may be found in henna shrubs (Lawsonia alba, Lawsonia inermis) ("Dyes, Natural", Kirk-Othmer Encyclopedia of Chemical Technology, "Henna " Encyclopedia Britannica). This dye affords an orange-red colouration on grey hair, and a "warm" i.e. coppery to red colour on chestnut-brown hair. The dyeing process using henna is difficult to perform. A kind of "paste" (often referred to as a "poultice") is first made from ground or powdered henna leaves, which is then diluted at the time of use with warm water, and said paste is then applied to the keratin fibres. However, this process using said paste has drawbacks. During the preparation and application of the composition to keratin fibres, it is not always possible to obtain satisfactory impregnation due to the poor consistency of the composition obtained from the ground powder. Furthermore, it is very difficult to hope to reproduce the shades exactly, since the lawsone content very often varies from one batch to another and between different ground materials. The henna leaf in reality contains only a very small amount of lawsone, but contains its glycosylated precursor (NGP), enzymes and β-glucosidases. In the presence of water, said enzymes hydrolyse glucose and release a naphthohydroquinone which is rapidly oxidized in atmospheric oxygen to lawsone. Since the amount of β-glucosidases is small, approximately 1.8 U β-glucosidase/g of leaf, the reaction is slow. It is known practice to use exogenous enzymes of β-glucosidase type with henna (DE 1020500); nevertheless, the provision of exogenous enzymes can bring about type I allergies, the effectiveness of said enzymes is also significantly decreased by, in particular, problems of diffusion, added to this is the potential problem of storage of a composition comprising enzymes, and the excess cost generated is considerable.

Moreover, henna powder generally contains between 105 and 106 bacteria per gram of leaves. In point of fact, it is preferable to have a henna powder quality with a very low bacterial content. In order to ensure a suitable microbiological quality, it is necessary to decontaminate, in particular by applying an ionizing treatment to the henna. The problem is that this treatment decreases the amount of β-glucosidases, and subsequently the capacity of the henna to suitably dye the keratin fibres.

Another very well-known natural dye is indigo (see Ullmann's Encyclopedia of Industrial Chemistry, Hair preparation, point 5.2.3, 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim; 10.1002/1 4356007.a 12 57 1.pub2). Indigo continues to be used for feminine beauty enhancement by dyeing the hair or the nails, or for dyeing fabrics (jeans), leather, silk, wool, etc. Indigo [482-89-3] is a natural dye, originating in particular from the indigo plant, and having the empirical formula: C H N and having the structure: 6 0 2O2; Indigo is derived from indican and may be prepared from various plants known as indigo-producing plants such as Indigofera tinctoria, Indigo suffruticosa, Isatis tinctoria, etc. (see Kirk-Othmer Encyclopedia of Chemical Technology, updated on 17/04/2009, DOI: 10.1002/0471238961 .0425051903150618.a01 .pub2). The indigo-producing plants are generally chopped and soaked in hot water, heated, fermented and oxidized in the open air to liberate the purple-blue coloured indigo (see Chem. Rev. 201 1, 1 1 1, 2537-2561 , p. 2537- 2561). Indigo is the result of the fermentation, in the presence of β-glucosidases, and then oxidization of indican (glycosyl precursor). The indigo molecule is insoluble in water. The current colourations with henna and derived from indigo-producing plant(s) are applied in the form of a poultice for a long leave-on time on the hair and are then rinsed out, and the hair is dried, generally in the open air without final shampooing, so as to allow the colouration to become oxidized in the course of the following hours or even days. Depending on the composition used, the oxidation time is more or less long, but is never instantaneous. Besides the leave-on time, which is long with henna or indigo and which may range from a few tens of minutes to a few hours (overnight) depending on the desired intensity, without being able to control the result, the result also varies as a function of the fibres to be dyed and of the indigo or henna raw material used. As much as the colour obtained on chestnut-brown hair has a natural look, grey hair is equally dyed an unaesthetic and unnatural orange colour with henna or blue colour with indigo ("Hair preparations", Kirk-Othmer Encyclopedia of Chemical Technology, John Wiley & Sons, Inc.). Furthermore, the colourations obtained are not uniform between the root and the end or from one fibre to another (The Science of Hair Care, C. Bouillon, J. Wilkinson, 2d Ed., CRC Press, Taylor & Francis Group; Boca Raton, London, pp. 236-241 (2005)). In order to obtain fundamental colours using natural dyes, on keratin fibres, in particular grey or white fibres, it is proposed to combine henna with indigo. Nevertheless, it is best to avoid applying henna and indigo at the same time since the lawsone precursor NPG is an inhibitor of indigo β-glycosidases, thereby greatly reducing the colouring potential of the henna and of the indigo. Conventionally, when henna and indigo are in a mixture together and they are applied at the same time, the colour obtained is very often an unattractive orange on white or grey hair. In order to overcome this problem, use is generally made of a dyeing process in at least two steps; the first consists in dyeing the hair with henna, then removing the henna poultice, rinsing and optionally shampooing, rinsing again and drying, and then in dyeing the hair with indigo, removing the henna poultice and rinsing, and optionally shampooing, rinsing again, and drying. This type of process is not therefore easy to carry out since it comprises several steps to be controlled, and the dyeing results obtained are not always satisfactory, in particular in terms of reproducibility of fundamental colours, strengths, and/or colour uniformity. Added to this are the risks of staining of clothing and the skin with henna or indigo during the preparation of the "paste" and also during its application to the keratin fibres, since the consistency is very irregular.

There is thus a real need to develop dyeing processes using natural dyes that can produce powerful colourations using henna of satisfactory microbiological quality, in particular using henna that has previously undergone an ionizing treatment, while at the same time respecting the cosmetic aspect of keratin fibres. In particular, there is a need to provide keratin fibre dyeing processes using natural dyes, without the use of exogenous enzymes, that are quick and easy to use and can in particular produce fundamental colourations that are less aggressive to the hair and at the same time that are resistant to external agents (light, bad weather or shampooing), and that are fast and uniform, while at the same time remaining powerful and chromatic.

This or these objective(s) is (are) achieved by the present invention, a subject of which is a process for preparing an aqueous composition comprising pre-hydrolysed and decontaminated henna, consisting: 1) in mixing i) henna powder with ii) an aqueous medium; then 2) subjecting said mixture to a decontamination treatment. Another subject of the invention relates to an aqueous composition comprising pre- hydrolysed and decontaminated henna, said composition being prepared according to the preparation process as defined previously, preferably packaged under vacuum and/or under argon. In particular, the composition is packaged in a sealed multilayer pouch, more particularly said pouch is constituted of polyethylene terephthalate (PET), polypropylene terephthalate (PPT) and/or polyamide imide (Al).

Another subject of the invention relates to a process for dyeing keratin fibres, in particular human keratin fibres, such as the hair, comprising: 1) a step of applying, to said fibres, the composition as defined previously which contains pre-hydrolysed and decontaminated henna; particularly, said composition is left on said fibres for a period of between 15 minutes and 6 hours, preferably between 30 minutes and 2 hours, particularly at a temperature of between 20°C and 30°C, preferably for 1 hour at 27°C, followed by 2) a step of rinsing said keratin fibres, preferably with water.

The composition according to the invention which comprises pre-hydrolysed and decontaminated henna, prepared according to the process of the invention, has the advantage of having very satisfactory colouring properties even though the henna has been decontaminated. The same is true for the dyeing process using the composition according to the invention which makes it possible to obtain very effective colouring properties, despite the use of decontaminated henna and indigo. The composition of the invention and the process for dyeing keratin fibres, in particular human keratin fibres, using this composition, have the advantage of dyeing said fibres, with powerful, chromatic dyeing results that are resistant to washing, perspiration, sebum and light, and that are moreover long-lasting, without modifying said fibres. Furthermore, the colourations obtained using the composition and the process for dyeing keratin fibres give uniform colours from the root to the end of a fibre (little colouration selectivity). Furthermore, the application of the composition of the invention, in particular the composition A as defined hereinafter, does not give off any raw-material dust (it is "dust- free"). In addition, the composition and the pre-hydrolysed henna active agent remain stable with respect to storage, in particular the composition A as defined hereinafter. The keratin fibres treated have a very pleasant cosmetic aspect, and the integrity thereof is respected after treatment with the composition of the invention, and the dyeing process according to the invention.

Moreover, the time devoted to dyeing using a natural product according to the process of the invention is shorter and the process is easier, without the need to keep a composition such as a poultice on the head for a long time (for several hours or even overnight) or to leave the composition (for example the poultice) to stand before application for a long time (several hours or several days), this being the case even though the henna used and optionally the indigo had been decontaminated.

pre-hydrolysed henna

The dyeing process of the invention uses i) henna in powder form, particularly in fine particles. It is understood that the henna powder is different from an extract. Specifically, an extract is a product of maceration in aqueous or organic solvents, whereas the powder according to the invention is a pure natural product originating from henna plants, reduced by grinding or other mechanical means, into fine particles. Preferably, the henna used in the process is in a composition in an amount of at least 10% by weight relative to the total weight of said composition. The henna used in the invention is preferably red henna (Lawsonia inermis, alba). The henna powder may be screened to obtain particles with upper limit sizes corresponding to the orifices or mesh sizes of the screen particularly between 35 and 80 mesh (US). According to one particular mode of the invention, the size of the henna powder particles is fine. According to the invention, a particle size of less than or equal to 500 µ η is more particularly intended. Preferentially, the powder is constituted of fine particles with sizes inclusively between 50 and 300 µ η and more particularly between 10 and 200 µ η . It is understood that said henna particles preferentially have a moisture content of between 0 and 10% by weight, relative to the total weight of the powders. Preferably, said henna particles are derived from henna leaves. In addition, the henna of the invention is pre-hydrolysed. The term"pre-hydrolysed henna" is intended to mean that the henna powder or the henna leaves have been hydrolysed beforehand according to conventional hydrolysis methods known to those skilled in the art.

Process for preparing pre-hydrolysed and decontaminated henna:

The process for preparing the aqueous composition comprising pre-hydrolysed henna consists, according to the invention, in 1) the first step, in mixing i) henna powder with ii) an aqueous medium. According to one embodiment, the pre-hydrolysed henna is prepared by leaving the henna powder i) in an aqueous medium ii) comprising predominantly water; preferably, the water used is demineralized or distilled. Preferentially, the water included in the mixture with the henna is in an amount of between 30% and 95%, more preferentially between 50% and 90%, better still between 60% and 80% by weight relative to the total weight of the mixture. According to one variant, the henna is in an acidic medium at a pH of between 3.5 and 6.5, inclusive. Organic or inorganic acids may be added thereto. According to one preferred embodiment, no acid is added to the henna. According to one particular embodiment of the invention, the henna i) is in the aqueous medium ii) as defined previously in an amount of between 1% and 50%, more particularly of between 10% and 40%, preferably between 20% and 30% by weight relative to the total weight of the mixture. According to one particular embodiment of the process for preparing the composition of the invention, the mixture of step 1) also contains one or more fatty substances as defined hereinafter. According to one particular embodiment of the process for preparing the composition of the invention, the mixture of step 1) also comprises one or more adjuvants as defined hereinafter, preferably chosen from polyols and polyol ethers, for instance 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, hexylene glycol, and glycerol, more particularly glycerol, preferably in an amount of between 0.01% and 20%, preferably between 0.05% and 15%, better still between 2% and 10% by weight relative to the total weight of the mixture of henna and aqueous medium. According to one particular embodiment of the process for preparing the composition of the invention, the mixture of step 1) does not comprise indigo. According to one particular embodiment of the process for preparing the composition of the invention, the mixture of henna i) and aqueous medium ii) of step 1) is left: for a period of between 5 minutes and 48 hours, particularly between 30 minutes and 24 hours, more particularly between 1 hour and 12 hours, preferentially between 2 hours and 6 hours; and at a temperature of between 2°C and 60°C, preferentially between 4°C and 45°C, more particularly between 25°C et 40°C such as at ambient temperature (25°C). According to one particular embodiment of the process for preparing the composition of the invention, the mixture of henna i) and aqueous medium ii) of step 1) is left stirring at a rotational speed of between 1 and 400 revolutions / minute, preferably between 50 and 200 revolutions / minute and more particularly between 70 and 150 revolutions / minute, such as 100 revolutions / minute. Preferably, the stirring is carried out in a mixer-grinder. According to one particular embodiment of the process for preparing the composition of the invention, the mixture of henna i) and aqueous medium ii) of step 1) is left in a deflocculating mixer at a rotational speed of between 200 and 1500 revolutions / minute, particularly between 300 and 1000 revolutions / minute, more particularly between 500 and 950 revolutions / minute, preferentially between 700 and 900 revolutions / minute. Preferably, the deflocculation is carried out in a mixer-grinder. According to one particular embodiment, the mixture of henna and aqueous medium as described previously can subsequently be placed under vacuum, and/or vacuum-packaged, and 2) can undergo decontamination as defined hereinafter in order to produce a composition A comprising henna. The placing under vacuum and/or the vacuum-packaging can be carried out in particular at a pressure of between 5 and 400 mb, more particularly between 10 and 300 mb, preferentially between 20 and 200 mb, for a period of time of particularly between 5 seconds and 5 minutes, more particularly between 30 seconds and 3 minutes, preferentially between 45 seconds and 1 minute. The packaging is preferably carried out in sealed multilayer pouches under vacuum; in particular, the pouches are constituted of polyethylene terephthalate (PET), polypropylene terephthalate (PPT) and/or polyamide imide (Al). Preferably, the preparation process of the invention which comprises pre-hydrolysed and decontaminated henna consists: 1) in mixing i) henna powder with ii) an aqueous medium with or without adjuvants as defined hereinafter, in particular chosen from polyols, fatty substances and care active agents; then bagging the preparation, sealing under an air vacuum or under an inert atmosphere such as argon or nitrogen, then leaving for a period of time required for the pre-hydrolysis of the NGP by the endogenous β-glucosidases; then 2) applying a decontamination treatment as defined previously. According to one particular embodiment, between the vacuum step and step 2), the mixture is left under vacuum and/or under an inert atmosphere such as nitrogen or argon for between 1 hour and 48 hours, in particular between 2 hours and 24 hours, at a temperature of between 4°C and 45°C, preferentially 2 to 6 hours at a temperature between 20 and 40°C, even more preferentially 6 hours at ambient temperature. The pre-hydrolysed henna, in particular the composition A as defined previously and 2) as defined hereinafter, can be stored at ambient temperature (25°C) or in the cold, in particular at a temperature between 4 and 10°C. Preferably, the composition A as defined previously is not packaged with indigo.

Decontamination method:

In the process for preparing the composition according to the invention, the second step which follows the hydrolysis of the henna is 2) the decontamination step. This decontamination can also be applied to the indigo. The term "decontamination" is intended to mean any process known to those skilled in the art which makes it possible to reduce the number of microbes, i.e. by a factor of 102 to 106, that is to say preferably between 99.9 and 99.99999%. The term "microbes" is intended to mean microorganisms and in particular fungi, moulds, spores and bacteria. The number of microorganisms is on average between 105 and 107 microorganisms per gram of powder or of leaves. According to one particular embodiment of the invention, the decontamination is carried out a) by pasteurization or heat-controlled debacterialization. The term pasteurization is intended to mean the method known to those skilled in the art, developed by Louis Pasteur, see for example http://fr.wikipedia.org/wiki/Pasteurisation. More specifically, it is the application, to the mixture of pre-hydrolysed henna and aqueous medium that it is desired to decontaminate, of a temperature which ranges between 60°C and 90°C, more particularly of a temperature of between 62°C and 88°C, inclusive. In particular, this temperature is applied to the mixture of pre-hydrolysed henna and aqueous medium for a period of between 5 seconds and 1 hour, more particularly between 10 seconds and 30 minutes. According to one variant, the process of the invention uses a pasteurization termed "high", i.e. at a temperature which is between 70°C and 75°C, more particularly at 72°C. According to this variant, the mixture of pre-hydrolysed henna and aqueous medium is subjected to a temperature of between 70°C and 75°C, more particularly at 72°C, for a short period of time, preferably of between 10 seconds and 30 seconds, such as 15 seconds (process known as HTST, High Temperature Short Time), and then is left to cool to ambient temperature. According to another variant, the process of the invention uses a pasteurization termed "low", i.e. at a temperature which is between 62°C and 67°C, more particularly at 65°C. According to this variant, the mixture of pre-hydrolysed henna and aqueous medium is subjected to a temperature of between 62°C and 67°C, more particularly at 65°C, for a period of between 2 minutes and 5 minutes, preferably 3 minutes, and then is left to cool to ambient temperature. According to another embodiment of the process of the invention, the decontamination is carried out b) by sterilization, i.e. by applying to the mixture of pre-hydrolysed henna and aqueous medium, a temperature greater than or equal to 100°C, preferably by applying steam at a temperature in particular of between 100°C and 180°C, more particularly between 100°C and 125°C. According to one variant, the decontamination process is carried out by c) the method known to those skilled in the art termed "appertization". Preferentially, the mixture of pre-hydrolysed henna and aqueous medium of the process of the invention is packaged in a hermetically closed container which is subjected to a temperature of between 100 and 150°C, more particularly between 110 and 120°C. The mixture of pre-hydrolysed henna and aqueous medium remains at this temperature particularly for between 1 minute and 2 hours, more particularly between 5 minutes and 1 hour, preferentially between 6 minutes and 30 minutes, and then is left to cool to ambient temperature. According to one particular embodiment of the invention, the decontamination process is carried out by d) the method known to those skilled in the art termed "tyndallization". In particular, the mixture of pre-hydrolysed henna and aqueous medium of the process of the invention is heated batchwise at low temperature. More particularly, the mixture is heated at a temperature between 40 and 70°C, preferentially at a temperature of between 45 and 60°C, for a period of between 15 minutes and 1 hour, preferably for 30 minutes, and then the mixture is left to cool to ambient temperature. This cycle is repeated every 24 hours. Preferably, the number of heating cycles applied to the mixture of pre-hydrolysed henna and aqueous medium is included inclusively between 1 and 20, preferably between 2 and 10, in particular 5 cycles. According to one advantageous variant, the mixture of pre-hydrolysed henna and aqueous medium is subjected to e ) steam at a temperature greater than 100°C. This method can be carried out under a pressure higher than atmospheric pressure, in which case an autoclave and e) the method termed "autoclaving" will be used. The term "autoclave" is intended to mean a container or receptacle, which has thick walls and which can be hermetically closed, designed to perform vapour sterilization under pressure (of a few bar), in which case the sterilizing agent is saturated steam under pressure or superheated water.

With steam sterilization it is known practice to use parameters D, Z , F0 and Sterility Assurance Level or SAL (see, for example: http://fr.wikipedia.org/wiki/Autoclave; http://www.biosafety.be/CU/PDF/Autoclave_SBB_D201 1_2505_39_FR.pdf). The value D or "decimal reduction time" is a thermal characteristic of the microorganism. It represents the time required, at a given temperature, for 90% reduction of the population of said microorganisms (or for reduction by 1 logarithm). For example, for G. stearothermophilus, the reduction time D at 121°C is 1.5 minutes. The value Z or "heat inactivation value" is the change in temperature required to reduce the value of D by one logarithm. For example, for G. stearothermophilus, the heat inactivation value Z is 10°C.

The value F0 or "sterilizing value" is the number of minutes required to kill a given number of microorganisms of which the value Z is 10°C at a temperature of 121 .1°C. The value F is the number of minutes required to kill a given number of microorganisms with a value Z at a certain temperature. For example, mention may be made of the following microorganisms:

For the decontamination, and in particular sterilization, cycles, three parameters are taken into account, in particular 1) the number of types of microorganism, 2) the value of D, and 3) the Sterility Assurance Level (SAL) = probability of survival of a microorganism after the sterilization process, this degree generally being fixed between 10 5 and 10 6 , which means a probability of less than one microorganism in 1000 or in 1 million after decontamination. According to the particular mode of the invention, the "Overkill Approach" is required; when choosing a heat-resistant bacterial strain or spores at a load of 10 6 , the value D of which at 121 .1°C is between 2 and 2.5 minutes, the reduction required is then 30 minutes. At 121 .1°C, 30 minutes will be required in order to sterilize a load of 106 microorganisms with a probability of one microorganism in one million after the sterilization cycle.

In particular, during the deactivation, the sterilizing value F0 applied to the henna or indigo according to the invention is between 1 minute and 30 minutes, at 121 . 1 °C, more particularly between 2 minutes and 20 minutes, at 121 .1°C, preferentially between 5 minutes and 10 minutes at 121 .1°C, better still F0 is 6 minutes at 121 °C, which is equivalent to 20 minutes at 110°C. More particularly, the sterilization process is carried out in one or more cycles of 4 steps: i) Simultaneous increase in pressure and in temperature by injection of heat- transfer fluid (steam or superheated water); ii) The stationery-phase or sterilization temperature is maintained for a period of time given by the sterilization scale; iii) Cooling by decreasing the temperature and pressure couple; then iv) Return to atmospheric pressure. The pressure and temperature sterilization values are defined according to the Regnault table. Preferentially, the number of cycles is included inclusively between 1 and 20, preferably between 2 and 10, in particular 3 cycles. According to one variant, step i) is preceded by a step which consists of a succession of vacuum-applying operations and of steam injections in order to increase effectiveness of the sterilization stationary phase by removing the air contained in the sterilization chamber and in the load to be sterilized. More particularly, the mixture of pre-hydrolysed henna and aqueous medium of the process of the invention is i) heated at a temperature of between 120 and 150°C, more particularly at 134°C, at a pressure of between 2 and 4 bar, more particularly at a pressure of 2.2 bar, ii) for a period of between 5 minutes and 1 hour, more particularly between 10 minutes and 25 minutes, such as for 18 min, this being over the entire area to be sterilized, iii) followed by cooling to ambient temperature and iv) decreasing the pressure to atmospheric pressure. Preferentially, the number of cycles is included inclusively between 1 and 10, preferably between 2 and 5, in particular 3 cycles. According to one particular embodiment of the invention, the mixture of pre-hydrolysed henna and aqueous medium is decontaminated by f) the method known to those skilled in the art termed "pascalization". More particularly, the mixture of pre-hydrolysed henna and aqueous medium of the process undergoes a treatment at very high pressure or "ultrapressure" preferentially of between 1000 and 8000 bar, more preferentially between 2000 and 6000 bar, better still between 3000 and 5000 bar, such as 4000 bar. According to one particular embodiment , the duration of the pascalization cycle is between 5 minutes and 1 hour. According to one particular embodiment of the invention, the mixture of pre-hydrolysed henna and aqueous medium is decontaminated by g) "ionizing radiation". Ionizing radiation is also known under the following terms: "gamma-radiation", "cold pasteurization" or "radioconversion" of the products to be decontaminated. The mixture of pre-hydrolysed henna and aqueous medium must be irradiated for a period of time sufficiently long for the microorganisms (bacteria and moulds) targeted to be inactivated. According to one embodiment, the mixture of pre-hydrolysed henna and aqueous medium is irradiated by the "radappertization" method known to those skilled in the art. Preferably, the irradiation is carried out on the mixture of pre-hydrolysed henna and aqueous medium at a dose of inclusively between 10 and 50 kilo Gray (KGy), preferentially between 12 and 30 KGy. According to one embodiment, the mixture of pre-hydrolysed henna and aqueous medium is irradiated by the "radicidation" method known to those skilled in the art. Preferably, the irradiation is carried out on the mixture of pre-hydrolysed henna and aqueous medium at a dose of inclusively between 1.8 and 18 KGy, preferentially between 2 and 15, better still between 5 and 8 KGy. According to one embodiment, the mixture of pre-hydrolysed henna and aqueous medium is irradiated by the "radurization" method known to those skilled in the art. Preferably, the irradiation is carried out on the mixture of pre-hydrolysed henna and aqueous medium at a dose of less than or equal to 1, preferably of between 0.4 and 1 KGy. More particularly, the decontamination 2) is carried out according to the pasteurization, sterilization, gamma-irradiation, or pascalization techniques. In particular, the decontamination 2) is carried out under steam at a temperature of greater than 100°C, particularly at a temperature of greater than 110°C, preferably at a temperature of between 115°C and 150°C. In particular, the sterilization is carried out 2) for a period of between 1 minute and 1 hour, more particularly between 10 minutes and 40 minutes, preferentially between 15 minutes and 30 minutes. According to one particular embodiment, the decontamination of the mixture of pre- hydrolysed henna and aqueous medium is carried out by gamma-irradiation at a dose of between 5 and 15 KGy, preferably around 12 KGy.

Composition comprising the pre-hydrolysed henna and ready-to-use composition comprising pre-hydrolysed henna and indigo:

A subject of the invention is also a composition comprising pre-hydrolysed henna, resulting from the preparation process as defined previously, preferably the composition A as defined previously, optionally comprising one or more fatty substances, which are preferably liquid at ambient temperature, and optionally one or more adjuvants chosen from polyols. More particularly, the composition contains between 1% and 40% by weight of pre- hydrolysed and decontaminated henna, between 0 and 15% by weight of fatty substance, which is in particular liquid at ambient temperature and at atmospheric pressure, such as copra oil, between 0 and 10% by weight of polyols, and qs % by weight of demineralized or distilled water per 100 grams of composition. Another subject of the invention is a ready-to-use composition, i.e. a composition prepared just before application to the keratin fibres, preferably between 1 second and 20 minutes, such as 5 minutes, before application to the keratin fibres, from the mixing of a composition comprising pre-hydrolysed henna, resulting from the preparation process as defined previously, preferably using the composition A as defined previously, and of a composition B comprising indigo which is non-decontaminated or which has been decontaminated according to any one of the techniques a) to f) as defined previously. According to one particular embodiment of the invention, the process for dyeing keratin fibres of the invention also uses a composition B which comprises indigo, in particular indigo- producing plant powder, preferably in fine particles. It is understood that the indigo-producing plant powder is different from an extract. Specifically, an extract is a product of maceration in solvents, generally organic solvents, whereas the powder according to the invention is a pure natural product originating from indigo-producing plants, reduced by grinding or other mechanical means, into fine particles. Preferentially, the composition B comprises at least 10% by weight of indigo-producing plants powder relative to the total weight of the composition. As indigo-producing plants, mention may be made of numerous species derived from the following genera: - Indigofera such as Indigofera tinctoria, Indigo suffruticosa, Indigofera articulata, Indigofera arrecta, Indigofera gerardiana, Indigofera argenta, Indigofera indica, Indigofera longiracemosa; - Isatis such as Isatis tinctoria; - Polygonum or Persicaria such as Polygonum tinctorium (Persicaria tinctoria); - Wrightia such as Wrightia tinctoria; - Calanthe such as Calanthe veratrifolia; and - Baphicacanthus such as Baphicacanthus cusia. Preferably, the indigo-producing plant is of the genus Indigofera and more particularly is Indigofera tinctoria. Use may be made of all or part (in particular the leaves in particular for Indigofera tinctoria) of the indigo-producing plant. The indigo-producing plant powder may be screened to obtain particles with upper limit sizes corresponding to the orifices or mesh sizes of the screen particularly between 35 and 80 mesh (US). According to one particular mode of the invention, the size of the indigo-producing plant powder particles is fine. According to the invention, a particle size of less than or equal to 500 µ η is more particularly intended. Preferentially, the powder is constituted of fine particles with sizes inclusively between 50 and 300 µ η and more particularly between 10 and 200 m . It is understood that said indigo-producing plant particles preferentially have a moisture content of between 0 and 10% by weight relative to the total weight of the powders. The composition B according to the invention comprises indigo-producing plant powder in an amount particularly inclusively between 10% and 90% by weight, more particularly between 15% and 70%, or even between 20% and 60% by weight and more particularly between 25% and 50% by weight, relative to the total weight of said composition.

Process for dyeing keratin fibres using the pre-hydrolysed and decontaminated henna and, optionally, decontaminated indigo

Another subject of the invention is a process for dyeing keratin fibres, in particular human keratin fibres, such as the hair, comprising: 1) a step of applying, to said fibres, the composition of the invention as defined previously; followed by 2) a step of rinsing said keratin fibres, preferably with water. Particularly in step 1), the composition is left on the keratin fibres for a period of between 15 minutes and 3 hours, preferably between 30 minutes and 2 hours, preferably for 1 hour. According to one variant in particular, the step of applying the composition of the invention is carried out at a temperature between 20°C and 30°C, such as 27°C. Preferably, the time during which the composition of the invention is left on the keratin fibres is 1 hour at 27°C. A first variant of the process of dyeing keratin fibres of the invention consists in applying, to the keratin fibres, a composition comprising pre-hydrolysed and decontaminated henna, in particular A as defined previously. A second variant of the process for dyeing keratin fibres of the invention consists in applying, to the keratin fibres, the ready-to-use composition as defined previously, which results from mixing between a composition comprising pre-hydrolysed and decontaminated henna, and in particular the composition A , and a composition B comprising indigo as defined previously, the indigo being non-decontaminated or decontaminated according to any one of the techniques a) to f) as defined previously; in particular, B is in the form of a poultice. Preferably, the ready-to-use composition comprises a mixture of henna powder and indigo-producing plant powder in an amount particularly inclusively between 15% and 100% by weight, more particularly between 20% and 80%, or even between 25% and 70% by weight and more particularly between 25% and 60% by weight, relative to the total weight of said ready-to-use composition. According to one embodiment of the invention, the composition A as defined previously also comprises indigo-producing plant powder, preferably in fine particles, as defined previously, and in amounts as defined for the ready-to-use composition. Preferably, the composition A as defined previously is not packaged with indigo. According to one particular embodiment of the dyeing process of the invention, the process comprises: 1) a step of simultaneously applying to said fibres: i) a composition comprising pre-hydrolysed and decontaminated henna as defined previously; and ii) an aqueous composition B comprising indigo-producing plant powder as defined hereinafter; particularly, said compositions are left on said fibres for a period of between 15 minutes and 3 hours, preferably between 30 minutes and 2 hours, particularly at a temperature of between 20°C and 30°C, preferably for 1 hour at 27°C, followed by 2) a step of rinsing said keratin fibres, preferably with water. Particularly, the amount of indigo-producing plant powder of the composition B is greater than 10% by weight, more particularly inclusively between 10% and 90% by weight, even more particularly between 15% and 70%, preferentially between 20% and 60% by weight, more preferentially between 25% and 50% by weight, relative to the total weight of the composition B. The weight ratio of henna powder and of indigo-producing plant powder after mixing preferably ranges from 95% to 5% of henna powder per 5% to 95% of indigo-producing plant powder, particularly from 75% to 25% of henna powder per 25% to 75% of indigo-producing plant powder, and more particularly from 55% to 45% of henna powder per 45% to 55% of indigo-producing plant powder by weight relative to the total weight of the mixture, in particular of the mixture of the two compositions A and B. A mixture of 50% henna powder and 50% indigo-producing plant powder is particularly appreciated. A third variant of the process for dyeing keratin fibres of the invention consists in applying, to the keratin fibres, the composition A which also comprises indigo-producing plant powder as defined previously. Preferably, the composition i) comprising pre-hydrolysed and decontaminated henna as defined previously does not comprise indigo. The dyeing process of the invention preferentially uses amounts of henna powder and of indigo which observe the henna powder / indigo-producing plant powder weight ratio inclusively between 80 / 20 and 75 / 25, particularly between 75 / 25 and 45 / 65, preferentially between 70 / 30 and 40 / 60. According to one particular embodiment, the composition B is in the form of a poultice as defined previously. According to one embodiment, the composition B is not decontaminated, it is used as it is with henna originating from an indigo-producing plant without it having been subjected to a decontamination step a) to f) as defined previously. According to one variant, the composition B is decontaminated according to any one of the decontamination methods a) to f) as defined previously. Preferably, the decontamination of the composition B is carried out under steam at a temperature of greater than 100°C, particularly at a temperature of greater than 110°C, preferably at a temperature of between 115°C and 150°C, in particular by sterilization. The time during which the indigo is subjected to steam is between 1 minute and 1 hour, more particularly between 10 minutes and 40 minutes, preferentially between 15 minutes and 30 minutes. According to another particular embodiment, the decontamination of the composition B is carried out by g) ionizing radiation, i.e. particularly by the "radappertization" method, preferably the irradiation is carried out on the composition B at a dose inclusively between 20 and 50 KGy, more preferentially between 25 and 30 KGy. According to a particularly advantageous process, the keratin fibres are, after the application of the decontaminated composition comprising the pre-hydrolysed henna, in particular the composition A, and/or after the application of the composition B as defined previously: a) either mechanically wiped with a towel or absorbent paper, b) or dried by heat with as a heat source (convection, conduction or radiation) by passing over, for example, a stream of a warm gas such as air necessary to evaporate off the solvent(s); heat sources that may be mentioned include a hairdryer, hairdrying hood, a hair-straightening iron, an infrared ray dispenser and any other standard heating appliances. Irrespective of the application method, the application temperature of the decontaminated composition comprising the pre-hydrolysed henna, in particular the composition A and/or of the composition B ranges from ambient temperature (15 to 25°C) to 80°C and more particularly from 15 to 45°C. Thus, after application of the decontaminated composition comprising the pre-hydrolysed henna, in particular the composition A and/or after application of the composition B preferably in the form of a poultice according to the invention, the head of hair may advantageously be subjected to a heat treatment by heating to a temperature ranging from 30 to 60°C. In practice, this operation may be performed using a styling hood, a hairdryer, an infrared ray dispenser or other standard heating appliances. According to a first variant of the invention, the dyeing process uses the following steps: - application of a mixture of pre-hydrolysed and decontaminated henna as defined previously + optionally decontaminated indigo in water, left on for a period of between 30 minutes and 3 hours, preferably between 30 minutes and 2 hours, this being at a temperature between 20 and 30°C, preferably for 1 hour at 27°C, with or without a plastic film; - rinsing with water; - optional post-treatment with a basic composition preferably comprising sodium bicarbonate or potassium bicarbonate, a thickener such as hydroxyethylcellulose, and deionized or demineralized or distilled water, said composition being left on for a period of between 10 and 40 minutes, preferably between 15 and 30 minutes, followed by rinsing with water and optionally by maintaining the head of hair under a plastic film; - optional heat treatment, at a temperature of between 40 and 60°C for a period of between 30 minutes and 2 hours, preferably at 45°C for 1 hour (for example with a heating hood), of the wet hair under a plastic film, or without a plastic film with a steampod; - drying in the open air or with a hairdryer. The proportions of the pre-hydrolysed henna/indigo mixture, calculated in terms of solids, are 80/20 to 20/80, preferentially 75/25 to 45/65, more preferentially 70/30 to 40/60 (limits included). Very preferably, the keratin fibres after the dyeing step are not shampooed for 24 hours. According to another advantageous variant of the invention, the dyeing process uses the following steps: - application of a mixture of pre-hydrolysed and decontaminated henna as defined previously + optionally decontaminated indigo in water, left on for a period of between 30 minutes and 3 hours, preferably between 30 minutes and 2 hours, this being at a temperature between 20 and 30°C, preferably for 1 hour at 27°C, with or without a plastic film; - rinsing with water; - post-treatment with a basic composition preferably comprising sodium bicarbonate or potassium bicarbonate, a thickener such as hydroxyethylcellulose, and deionized or demineralized or distilled water, said composition being left on for a period of between 10 and 40 minutes, preferably between 15 and 30 minutes, followed by rinsing with water and optionally by maintaining the head of hair under a plastic film; - heat treatment, at a temperature of between 40 and 60°C for a period of between 30 minutes and 2 hours, preferably at 45°C for 1 hour (for example with a heating hood), of the wet hair under a plastic film, or without a plastic film with a steampod; - drying in the open air or with a hairdryer. The proportions of the pre-hydrolysed henna/indigo mixture, calculated in terms of solids, are 80/20 to 20/80, preferentially 75/25 to 45/65, more preferentially 70/30 to 40/60 (limits included). According to another advantageous variant of the invention, the dyeing process uses the following steps: - application of a mixture of pre-hydrolysed and decontaminated henna as defined previously + optionally decontaminated indigo in water, left on for a period of between 30 minutes and 3 hours, preferably between 30 minutes and 2 hours, this being at a temperature between 20 and 30°C, preferably for 1 hour at 27°C, with or without a plastic film; - rinsing with water; - post-treatment with a basic composition preferably comprising sodium bicarbonate or potassium bicarbonate, a thickener such as hydroxyethylcellulose, and deionized or demineralized or distilled water, said composition being left on for a period of between 10 and 40 minutes, preferably between 15 and 30 minutes, followed by rinsing with water and optionally by maintaining the head of hair under a plastic film; - maintaining the wet hair under a plastic film at ambient temperature for a period of between 30 minutes and 2 hours, preferably for 1 hour; - drying in the open air or with a hairdryer. The proportions of the pre-hydrolysed henna/indigo mixture, calculated in terms of solids, are 80/20 to 20/80, preferentially 75/25 to 45/65, more preferentially 70/30 to 40/60 (limits included). Very preferably, the keratin fibres after the dyeing step are not shampooed for 24 hours. Use may be made, both as means for heating and straightening the head of hair, of a heating iron at a temperature ranging from 60°C to 220°C and preferably from 120°C to 200°C. A particular embodiment of the invention relates to a dyeing process which is performed at ambient temperature (25°C).

Fatty substance(s):

According to one preferred embodiment of the invention, the compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B, as defined previously, or a mixture thereof, also comprise the ingredient a) one or more fatty substances, which may be identical or different. The term "fatty substance" is intended to mean an organic compound that is insoluble in water at ordinary temperature (25°C) and at atmospheric pressure (760 mmHg) (solubility of less than 5%, preferably less than 1% and even more preferentially less than 0.1%). They bear in their structure at least one hydrocarbon-based chain comprising at least 6 carbon atoms or a sequence of at least two siloxane groups. In addition, the fatty substances are generally soluble in organic solvents under the same temperature and pressure conditions, for instance chloroform, dichloromethane, carbon tetrachloride, ethanol, benzene, toluene, tetrahydrofuran (THF), liquid petroleum jelly or decamethylcyclopentasiloxane. According to one preferred embodiment of the invention, the compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B, as defined previously, or a mixture thereof, comprise a) one or more oils, which may be identical or different. The term "o/T is intended to mean a "fatty substance" as defined previously that is liquid at ambient temperature (25°C) and at atmospheric pressure (760 mmHg); the viscosity at 25°C is preferably less than 1200 cps and better still less than 500 cps (defined, for example, from the Newtonian plateau determined using an ARG2 rheometer from TA Instruments equipped with a spindle with cone-plate geometry 60 mm in diameter and with an angle of 2 degrees over a shear stress range of from 0.1 Pa to 100 Pa). The term "non-silicone o/T is intended to mean an oil not containing any silicon atoms (Si) and the term "silicone o/T is intended to mean an oil containing at least one silicon atom.

More particularly, the oils are chosen from non-silicone oils and in particular C6-Ci 6 hydrocarbons or hydrocarbons containing more than 16 carbon atoms and in particular alkanes; oils of animal origin; triglyceride oils of plant origin; essential oils; fluoro oils or glycerides of synthetic origin, fatty alcohols; fatty acid and/or fatty alcohol esters other than triglycerides, fatty acid amides and silicone oils. Preferably, the oils are not oxyalkylenated or glycerolated ethers.

Preferably, the oils do not comprise any C2-C3 oxyalkylene units or any glycerolated units. Preferably, the oils are not fatty acids which, in salified form, give water-soluble soaps. The oils that can be used in the compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B, as defined previously, or a mixture thereof, may be silicones. The silicones may be volatile or non-volatile, cyclic, linear or branched silicones, which are unmodified or modified with organic groups, having a viscosity from 5 10 6 to 2.5 m2/s at 25°C, and preferably 1x10 5 to 1 m2/s. Preferably, the silicone is chosen from polydialkylsiloxanes, in particular polydimethylsiloxanes (PDMSs), and organomodified polysiloxanes comprising at least one functional group chosen from poly(oxyalkylene) groups, amino groups and alkoxy groups. Organopolysiloxanes are defined in greater detail in Walter Noll's "Chemistry and Technology of Silicones" (1968), Academic Press. They may be volatile or non-volatile. When they are volatile, the silicones are more particularly chosen from those having a boiling point of between 60°C and 260°C, and even more particularly from: (i) cyclic polydialkylsiloxanes including from 3 to 7 and preferably from 4 to 5 silicon atoms. These are, for example, octamethylcyclotetrasiloxane sold in particular under the name Volatile Silicone ® 7207 by Union Carbide or Silbione ® 70045 V2 by Rhodia, decamethylcyclopentasiloxane sold under the name Volatile Silicone ® 7158 by Union Carbide, and Silbione ® 70045 V5 by Rhodia, and mixtures thereof. Mention may also be made of cyclocopolymers of the dimethylsiloxane/methylalkylsiloxane type, such as Volatile Silicone® FZ 3109 sold by the company Union Carbide, having formula:

with D " : Si - O — with D' : - Si ~ 0 —

C H3 C H Mention may also be made of mixtures of cyclic polydialkylsiloxanes with organosilicon compounds, such as the mixture of octamethylcyclotetrasiloxane and tetratrimethylsilylpentaerythritol (50/50) and the mixture of octamethylcyclotetrasiloxane

and oxy-1 , 1 '-bis(hexa-2,2,2',2',3,3'-trimethylsilyloxy)neopentane; ) linear volatile polydialkylsiloxanes containing 2 to 9 silicon atoms and having a viscosity of less than or equal to 5 10 6 m2/s at 25°C. A n example is decamethyltetrasiloxane sold in particular under the name SH 200 by the company Toray Silicone. Silicones belonging to this category are also described in the article published in Cosmetics and Toiletries, Vol. 9 1, Jan. 76, P. 27-32 - Todd & Byers "Volatile Silicone fluids for cosmetics". Use is preferably made of non-volatile polydialkylsiloxanes, polydialkylsiloxane gums and resins, polyorganosiloxanes modified with the organofunctional groups above, and mixtures thereof. These silicones are more particularly chosen from polydialkylsiloxanes, among which mention may be made mainly of polydimethylsiloxanes bearing trimethylsilyl end groups. The viscosity of the silicones is measured at 25°C according to Standard ASTM 445 Appendix C. Among these polydialkylsiloxanes, mention may be made, in a nonlimiting manner, of the following commercial products: - the Silbione® oils of the 47 and 70 047 series or the Mirasil® oils sold by Rhodia, for instance the oil 70 047 V 500 000; - the oils of the Mirasil® series sold by the company Rhodia; - the oils of the 200 series from the company Dow Corning, such as DC200 with a viscosity of 60 000 mm2/s; - the Viscasil® oils from General Electric and certain oils of the SF series (SF 96, SF 18) from General Electric. Mention may also be made of polydimethylsiloxanes having dimethylsilanol end groups known as dimethiconol (CTFA), such as the oils in the 48 series from Rhodia. The fatty alcohols, fatty acid amides and fatty acid esters that can be used as fatty substances a) in the compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B as defined previously, or a mixture thereof, are in the form of oils. It is recalled that, for the purposes of the invention, fatty alcohols, esters and acids more particularly have at least one linear or branched, saturated or unsaturated hydrocarbon-based group comprising 6 to 30 carbon atoms, which is optionally substituted, in particular with one or more hydroxyl groups (in particular 1 to 4). If they are unsaturated, these compounds may comprise one to three conjugated or unconjugated carbon-carbon double bonds.

More precisely, ingredient b) may represent an ester of a C1-C10 alcohol and of a C6- acid as -C C30 fatty such R-C(0)-0-R' with R representing a linear or branched C6 30 alkyl or a -C and linear or branched C6 30 alkenyl group, comprising one or two unsaturations, R representing a linear or branched C1-C10 alkyl group.

Preferentially, R represents a linear C10-C20 alkyl group and R' represents a C -C6 alkyl group that is preferably branched, such as isopropyl myristate. According to another advantageous variant, the ingredient ii) represents one or more amides of a C6-C3o fatty acid and of a primary or secondary, preferably primary, C1-C10 amine, such as those of formula R"-C(0)-N(R a)-R"' with R" representing a linear or branched -C -C C6 3o alkyl or a linear or branched C6 30 alkenyl group, comprising one or two unsaturations, which may be substituted with one or more hydroxyl groups, or (di)(Cr

C6)(alkyl)amino, and R'" representing a linear or branched C1-C10 alkyl group, Ra representing a hydrogen atom or an alkyl group as defined for R'". Preferably, R" represents a C14-C20 alkenyl group, Ra represents a hydrogen atom and R'" represents a C -C6 alkyl group optionally substituted with (di )(Ci -C4)(alkyl)amino such as oleylamidopropyldimethylamine.

As regards the C6-Ci 6 alkanes, they are linear or branched, and possibly cyclic. Examples that may be mentioned include hexane, dodecane and isoparaffins such as isohexadecane and isodecane. The linear or branched hydrocarbons containing more than 16 carbon atoms may be chosen from liquid paraffins, petroleum jelly, liquid petroleum jelly, polydecenes, and hydrogenated polyisobutene such as Parleam®. Among the animal oils, mention may be made of perhydrosqualene. Among the triglycerides of plant or synthetic origin, mention may be made of liquid fatty acid triglycerides containing from 6 to 30 carbon atoms, for instance heptanoic or octanoic acid triglycerides, or alternatively, for example, sunflower oil, corn oil, soybean oil, marrow oil, grapeseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, arara oil, castor oil, avocado oil, caprylic/capric acid triglycerides, for instance those sold by the company Stearineries Dubois or those sold under the names Miglyol® 810, 812 and 818 by the company Dynamit Nobel, jojoba oil and shea butter oil. Among the fluoro oils, mention may be made of perfluoromethylcyclopentane and perfluoro-1 ,3-dimethylcyclohexane, sold under the names Flutec® PC1 and Flutec® PC3 by the company BNFL Fluorochemicals; perfluoro-1 ,2-dimethylcyclobutane; perfluoroalkanes such as dodecafluoropentane and tetradecafluorohexane, sold under the names PF 5050® and PF 5060 ® by the company 3M, or bromoperfluorooctyl sold under the name Foralkyl® by the company Atochem; nonafluoromethoxybutane and nonafluoroethoxyisobutane; perfluoromorpholine derivatives such as 4-(trifluoromethyl)perfluoromorpholine sold under the name PF 5052® by the company 3M. Among the essential oils contained in the composition of the invention, mention may be made of those mentioned in Ullmann's Encyclopedia of Industrial Chemistry ("Flavors and Fragrances", Karl-Georg Fahlbusch et al., Published Online: 15 JAN 2003, DOI: 10.1002/14356007.a1 1_141 ). According to one preferred embodiment, the fatty substance(s) a) is (are) different from essential oils. Preferably, the oil(s) of the invention are non-silicone oils. The term "non-silicone o/V is intended to mean an oil not containing any silicon atoms (Si) and the term "silicone o/ is intended to mean an oil containing at least one silicon atom.

According to a preferred variant of the invention, the oil(s) are chosen from C6-Ci 6 alkanes, polydecenes, liquid esters of a fatty acid and/or of a fatty alcohol, and liquid fatty alcohols, or mixtures thereof.

Better still, the oils are chosen from liquid petroleum jelly, C6-Ci 6 alkanes and polydecenes. In this preferred variant, the oil(s) are chosen from mineral oils such as liquid petroleum jelly. According to another most particularly preferred mode of the invention, the oils are chosen from oils of natural origin, more particularly oils of plant origin, preferentially chosen from jojoba oil, babassu oil, sunflower oil, olive oil, coconut oil, Brazil nut oil, marula oil, corn oil, argan oil, soybean oil, marrow oil, grapeseed oil, linseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, arara oil, coriander oil, almond oil, castor oil, avocado oil, shea butter oil and also rapeseed oil, borage oil, evening primrose oil, pomegranate oil, mango oil, palm oil, cottonseed oil and copra oil. More particularly, the oils of plant origin are chosen from avocado oil, olive oil, coconut oil, copra oil, argan oil and sunflower oil; preferentially, the oil(s), ingredient a) of the invention, is (are) chosen from copra oils. According to one preferred embodiment of the invention, the composition comprising the pre-hydrolysed henna, and in particular the composition A as defined previously, comprises one or more oils in an amount inclusively between 1% and 80% by weight, relative to the total weight of the composition, more particularly between 2% and 50% by weight, preferentially between 3% and 30% by weight and more preferentially between 5% and 15% by weight, relative to the total weight of said composition. Composition B used in the process of the invention preferably comprises one or more oils in an amount particularly inclusively between 1% and 80% by weight, more particularly between 2% and 50% by weight, preferentially between 3% and 40% by weight and more preferentially between 5% and 25% by weight, relative to the total weight of said composition. According to another particular embodiment of the invention, the compositions comprising the pre-hydrolysed henna and the indigo, in particular the composition A or B, as defined previously, or a mixture thereof, comprise a) one or more butters, which may be identical or different. For the purposes of the present invention, the term "butter" (also known as a "pasty fatty substance") is intended to mean a lipophilic fatty compound with a reversible solid/liquid change of state, comprising at a temperature of 25°C and at atmospheric pressure (760 mmHg), a liquid fraction and a solid fraction. In other words, the starting melting point of the pasty compound can be less than 25°C. The liquid fraction of the pasty compound measured at 25°C can represent 9% to 97% by weight of the compound. This liquid fraction at 25°C preferably represents between 15% and 85% and more preferably between 40% and 85% by weight. Preferably, the butter(s) have an end melting point of less than 60°C. Preferably, the butter(s) have a hardness of less than or equal to 6 MPa. Preferably, the butters or pasty fatty substances have, in the solid state, an anisotropic crystal organization, which is visible by X-ray observation. Within the context of the invention, the melting point corresponds to the temperature of the most endothermic peak observed in thermal analysis (DSC) as described in the standard ISO 11357-3; 1999. The melting point of a pasty substance or of a wax may be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold under the name DSC Q2000 by the company TA Instruments. As regards the measurement of the melting point and the determination of the end melting point, the sample preparation and measurement protocols are as follows: A sample of 5 mg of pasty fatty substance, preheated to 80°C and withdrawn with magnetic stirring using a spatula that is also heated, is placed in a hermetic aluminium capsule, or a crucible. Two tests are performed to ensure the reproducibility of the results. The measurements are performed on the abovementioned calorimeter. The oven is flushed with nitrogen. Cooling is performed by an RCS 90 heat exchanger. The sample is then subjected to the following protocol: it is first placed at a temperature of 20°C, and then subjected to a first temperature rise passing from 20°C to 80°C, at a heating rate of 5°C/minute, then is cooled from 80°C to -80°C at a cooling rate of 5°C/minute and finally subjected to a second temperature rise passing from -80°C to 80°C at a heating rate of 5°C/minute. During the second temperature increase, the variation of the difference in power absorbed by the empty crucible and by the crucible containing the sample of butter is measured as a function of the temperature. The melting point of the compound is the value of the temperature corresponding to the top of the peak of the curve representing the variation in the difference in power absorbed as a function of the temperature. The end melting point corresponds to the temperature at which 95% of the sample has melted. The liquid fraction by weight of the butter at 25°C is equal to the ratio of the heat of fusion consumed at 25°C to the heat of fusion of the butter. The heat of fusion of the pasty compound is the heat consumed by the compound in order to change from the solid state to the liquid state. The butter is said to be in the solid state when all of its mass is in crystalline solid form. The butter is said to be in the liquid state when all of its mass is in liquid form. The heat of fusion of the butter is equal to the integral of the entire melting curve obtained using the abovementioned calorimeter, with a temperature rise of 5 or 10°C/rminute, according to Standard ISO 11357-3:1999. The heat of fusion of the butter is the amount of energy required to make the compound change from the solid state to the liquid state. It is expressed in J/g. The heat of fusion consumed at 25°C is the amount of energy absorbed by the sample to change from the solid state to the state that it has at 25°C, composed of a liquid fraction and a solid fraction. The liquid fraction of the butter measured at 32°C preferably represents from 30% to 100% by weight of the compound, preferably from 50% to 100%, more preferably from 60% to 100% by weight of the compound. When the liquid fraction of the butter measured at 32°C is equal to 100%, the temperature of the end of the melting range of the pasty compound is less than or equal to 32°C. The liquid fraction of the butter measured at 32°C is equal to the ratio of the heat of fusion consumed at 32°C to the heat of fusion of the pasty compound. The heat of fusion consumed at 32°C is calculated in the same way as the heat of fusion consumed at 23°C. As regards the measurement of the hardness, the sample preparation and measurement protocols are as follows: According to one particular embodiment of the invention, the compositions A and B as defined previously, or a mixture thereof according to the invention, or the butter are placed in a mould 75 mm in diameter which is filled to approximately 75% of its height. In order to overcome the thermal history and to control the crystallization, the mould is placed in a Votsch VC 0018 programmable oven, where it is first placed at a temperature of 80°C for 60 minutes, then cooled from 80°C to 0°C at a cooling rate of 5°C/minute, and then left at the stabilized temperature of 0°C for 60 minutes, and then subjected to a temperature rise ranging from 0°C to 20°C, at a heating rate of 5°C/minute, and then left at the stabilized temperature of 20°C for 180 minutes. The compression force measurement is taken using a TA/TX2i texturometer from Swantech. The spindle used is chosen according to the texture: - cylindrical steel spindle 2 mm in diameter for very rigid starting materials; - cylindrical steel spindle 12 mm in diameter for starting materials which are not very rigid . The measurement comprises three steps: - a first step after automatic detection of the surface of the sample, where the spindle moves at a measuring speed of 0 .1 mm/second , and penetrates into the composition according to the invention or the butter to a penetration depth of 0.3 mm, and the software notes the maximum force value reached; - a second step, known as relaxation, where the spindle remains in this position for one second and the force is noted after 1 second of relaxation; and finally - a third step, known as withdrawal, where the spindle returns to its original position at a speed of 1 mm/second, and the withdrawal energy of the probe (negative force) is noted. The hardness value measured during the first step corresponds to the maximum compression force measured in newtons divided by the area of the texturometer cylinder expressed in mm2 in contact with the butter or the composition according to the invention. The hardness value obtained is expressed in megapascals or MPa. According to a preferred mode of the invention, the particular butter(s) are of plant origin, such as those described in Ullmann's Encyclopedia of Industrial Chemistry ("Fats and Fatty Oils", A . Thomas, published on 15/06/2000, DOI : 10.1002/1 4356007.a1 0_1 73, point 13.2.2.2. Shea Butter, Borneo Tallow, and Related Fats (Vegetable Butters)). It may more particularly be mentioned that the ingredient a) is chosen from shea butter, Karite Nilotica butter (Butyrospermum parkii), galam butter, (Butyrospermum parkii), Borneo butter or fat or tengkawang tallow (Shorea stenoptera), shorea butter, ill ip butter, madhuca butter or Bassia madhuca longifolia butter, mowrah butter (Madhuca latifolia), katiau butter (Madhuca mottleyana), phulwara butter (M. butyracea), mango butter (Mangifera indica), murumuru butter (Astrocaryum murumuru), kokum butter (Garcinia indica), ucuuba butter (Virola sebifera), tucuma butter, painya butter (Kpangnan) (Pentadesma butyracea), coffee butter (Coffea arabica), apricot butter (Prunus armeniaca), macadamia butter (Macadamia ternifolia), grapeseed butter (Vitis vinifera), avocado butter (Persea gratissima), olive butter (Olea europaea), sweet almond butter (Prunus amygdalus dulcis), cocoa butter (Theobroma cacao) and sunflower butter.

According to one preferred mode of the invention, the weight content of C 6 fatty acid triglycerides, expressed relative to the total amount of fatty acid triglycerides in the butter(s) according to the invention , is less than 23%. Preferentially, the butter(s) according to the invention are chosen from murumuru butter, ucuuba butter, shorea butter, illipe butter, shea butter and cupuacu butter, and even more preferentially from murumuru butter and ucuuba butter. In one preferred variant of the invention, the weight content of C 6 fatty acid triglycerides, expressed relative to the total amount of fatty acid triglycerides, ranges from 0 to 22%, better still from 0 to 15% and even better still from 2% to 12%. Composition B used in the process of the invention may comprise one or more butters in an amount particularly inclusively between 1% and 80% by weight, more particularly between 2% and 50% by weight, preferentially between 3% and 40% by weight and more preferentially between 5% and 25% by weight, relative to the total weight of said composition. Composition A may comprise one or more butters in an amount particularly inclusively between 1% and 80% by weight, relative to the total weight of the composition, more particularly between 5% and 60% by weight, preferentially between 10% and 40% by weight and more preferentially between 15% and 30% by weight, relative to the total weight of said composition. According to another preferred embodiment of the invention, composition A or B of the invention comprises as ingredient b) a mixture of one or more identical or different oils, as defined previously, and of one or more identical or different butters, as defined previously. The composition which comprises the pre-hydrolysed henna, in particular the composition A , may comprise one or more oils and one or more butters in which the amount [oil(s) + butter(s)] is particularly inclusively between 0.5% and 80% by weight, relative to the total weight of the composition, more particularly between 1% and 50% by weight, preferentially between 2% and 30% by weight and more preferentially between 3% and 15% by weight, relative to the total weight of said composition. In particular, composition B of the invention comprises one or more oils and one or more butters in which the amount [oil(s) + butter(s)] is inclusively between 0.5% and 80% by weight, more particularly between 1% and 50% by weight, preferentially between 2% and 40% by weight and more preferentially between 3% and 25% by weight, relative to the total weight of said composition. According to one particular embodiment of the invention, the compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B, as defined previously, or a mixture thereof, comprise one or more fatty substances a) different from the oils and from the butters as defined previously. According to a particular embodiment of the invention, the composition also comprises one or more waxes, preferably of plant origin. The waxes may be fatty alcohols or fatty esters that are solid at ambient temperature and at atmospheric pressure. According to one particular embodiment of the invention, the composition comprises as third constituent one or more solid fatty alcohols, preferably of plant origin. The fatty alcohols that are suitable for use in the invention are more particularly chosen from linear saturated alcohols comprising from 6 to 30 carbon atoms and preferably from 8 to 30 carbon atoms. Mention may be made, for example, of cetyl alcohol, stearyl alcohol and a mixture thereof (cetearyl alcohol). As regards the solid esters of fatty acids and/or of fatty alcohols, mention may preferably be made of esters of saturated linear fatty acids and of saturated linear fatty alcohols, such as cetyl palmitate, stearyl stearate and cetyl stearate. According to another particular embodiment of the invention, the composition also comprises one or more waxes, other than the fatty alcohols and fatty esters mentioned above, preferably of plant origin. These (non-silicone) waxes are chosen in particular from carnauba wax, candelilla wax, esparto wax, paraffin wax, ozokerite, plant waxes, such as olive tree wax, rice wax, hydrogenated jojoba wax or absolute flower waxes, such as the blackcurrant blossom essential wax sold by the company Bertin (France), animal waxes, such as beeswaxes or modified beeswaxes (cerabellina); other waxes or waxy raw materials that can be used according to the invention are in particular marine waxes, such as that sold by the company Sophim under the reference M82, polyethylene waxes or polyolefin waxes in general.

According to another particular embodiment of the invention, the compositions comprising the decontaminated pre-hydrolysed henna and the indigo, in particular the compositions A and/or B, as defined previously, or a mixture thereof, comprise a) one or more silicone waxes, resins or gums. In the category of polydialkylsiloxanes, mention may be made of the waxes sold under the names Abil Wax ® 9800 and 9801 by the company Goldschmidt, which are polydi(Cr

C2o)alkylsiloxanes. The silicone gums that can be used in accordance with the invention are in particular polydialkylsiloxanes and preferably polydimethylsiloxanes having high number-average molecular weights of between 200 000 and 1 000 000, used alone or as a mixture in a solvent. This solvent can be chosen from volatile silicones, polydimethylsiloxane (PDMS) oils, polyphenylmethylsiloxane (PPMS) oils, isoparaffins, polyisobutylenes, methylene chloride, pentane, dodecane and tridecane, or mixtures thereof. Products that may be used more particularly in accordance with the invention are mixtures such as: - the mixtures formed from a hydroxy-terminated polydimethylsiloxane or dimethiconol (CTFA), and from a cyclic polydimethylsiloxane, also known as cyclomethicone (CTFA), such as the product Q2 1401 sold by the company Dow Corning; - mixtures of a polydimethylsiloxane gum and a cyclic silicone, such as the product SF 1214 Silicone Fluid from the company General Electric; this product is an SF 30 gum corresponding to a dimethicone, having a number-average molecular weight of 500 000, dissolved in the oil SF 1202 Silicone Fluid corresponding to decamethylcyclopentasiloxane; - mixtures of two PDMSs with different viscosities, and more particularly of a PDMS gum and of a PDMS oil, such as the product SF 1236 from the company General Electric. The product SF 1236 is a mixture of a gum SE 30 defined above, with a viscosity of 20 m2/s and of an oil SF 96 with a viscosity of 5 10 6 m2/s. This product preferably includes 15% of gum SE 30 and 85% of an oil SF 96. The organopolysiloxane resins that may be used in accordance with the invention are crosslinked siloxane systems containing the following units:

/2, RS1O3/2 R2Si0 2/2, RsSiOi and Si0 4/2 , in which R represents an alkyl containing 1 to 16 carbon atoms. Among these products, the ones that are particularly preferred are those in which R denotes a C C4 lower alkyl group, more particularly methyl. Among these resins, mention may be made of the product sold under the name Dow Corning 593 or those sold under the names Silicone Fluid SS 4230 and SS 4267 by the company General Electric, which are silicones of dimethyl/trimethylsiloxane structure. Mention may also be made of the resins of the trimethylsiloxysilicate type, sold in particular as X22-4914, X21-5034 and X21-5037 by Shin-Etsu.

Preferably, the fatty substance(s) do not comprise any C2-C3 oxyalkylene units or any glycerolated units. Preferably, the fatty substance(s) used in the composition comprising the henna are liquid, such as the oils chosen from non-silicone oils, and in particular C6-Ci 6 hydrocarbons or hydrocarbons containing more than 16 carbon atoms and in particular alkanes; oils of animal origin; triglyceride oils of plant origin; essential oils; fluoro oils or glycerides of synthetic origin, fatty alcohols; fatty acid and/or fatty alcohol esters other than triglycerides, and silicone oils. More particularly, according to the preparation process of the invention, the fatty substance(s) are chosen from oils of plant origin such as jojoba oil, babassu oil, sunflower oil, olive oil, coconut oil, Brazil nut oil, marula oil, corn oil, argan oil, soybean oil, marrow oil, grapeseed oil, linseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, arara oil, coriander oil, almond oil, castor oil, avocado oil, shea butter oil and also rapeseed oil, borage oil, evening primrose oil, pomegranate oil, mango oil, palm oil, cottonseed oil and copra oil; preferentially, the fatty substance(s) are chosen from avocado oil, olive oil, coconut oil, copra oil, argan oil and sunflower oil; more preferentially, the fatty substance(s) are chosen from copra oil. According to one particular embodiment of the invention, the mixture of the process for preparing the composition according to the invention of step 1) also comprises one or more fatty substances as defined previously, in an amount of between 0.05% and 30%, preferably between 1% and 20%, better still between 5% and 15% by weight relative to the total weight of the mixture of henna and aqueous medium.

The compositions comprising the pre-hydrolysed henna and the indigo, in particular the compositions A and/or B as defined previously, or a mixture thereof, preferably comprise a content of fatty substances different from oil(s) and butter(s) as defined previously ranging from 0.5% to 50% by weight, better still from 1% to 30% by weight and even better still from 1% to 20% by weight relative to the total weight of said composition. Basifying agent(s)

According to one particular embodiment of the invention, the process for dyeing keratin fibres implements a step of post-treatment with one or more basifying agent(s). The alkaline agents are preferably chosen from aqueous ammonia, alkali metal carbonates or bicarbonates, alkanolamines such as monoethanolamine, diethanolamine and triethanolamine, and also derivatives thereof, sodium hydroxide, potassium hydroxide and the compounds having the following formula:

in which formula W is a linear or branched (CrC 6)alkylene group such as propylene, optionally substituted with a hydroxyl group or a Ci-C4 alkyl radical; Ra, b, Rc and Rd, which may be identical or different, represent a hydrogen atom or a C C4 alkyl or -C4 hydroxyalkyl radical. According to one preferred embodiment, the alkaline agent(s) is (are) one or more (bi)carbonate(s). Preferentially, the process for dyeing keratin fibres of the invention uses an aqueous composition comprising one or more carbonates or bicarbonates, which may be identical or different. The term "(bi)carbonates" is intended to mean:

+ 2 2+ 2 a) carbonates of alkali metals (Met2 , C0 3 ), of alkaline-earth metals (Met' , C0 3 ) of + 2 + 2 ammonium ((R"4N )2,C03 ) or of phosphonium ((R"4P )2,C03 with Met' representing an alkaline-earth metal and Met representing an alkali metal, and R", which may be identical or different, represent a hydrogen atom or an optionally

substituted (CrC 6)alkyl group such as methyl, ethyl or hydroxyethyl); and B) bicarbonates, also known as hydrogencarbonates, with the following formulae: + + > R' , HC0 3 with R' representing an alkali metal, an ammonium group R"4N - or + a phosphonium group R"4P - where R", which may be identical or different,

represent a hydrogen atom or an optionally substituted (CrC 6)alkyl group such as methyl, ethyl or hydroxyethyl; and

2+ > Met' (HC0 3 )2, with Met' representing an alkaline-earth metal. More particularly, the (bi)carbonate(s) is (are) chosen from alkali metal or alkaline-earth metal bicarbonates, preferentially alkali metal bicarbonates. Mention may be made of sodium, potassium, magnesium and calcium carbonates or hydrogencarbonates and their mixtures, and in particular of sodium hydrogencarbonate. These hydrogencarbonates can originate from a natural water, for example spring water from the Vichy basin or from La Roche-Posay, or Badoit water (cf. Patent, for example the document FR 2 814 943). Mention may in particular be made of sodium carbonate [497-19-8]

= Na2C0 3, sodium hydrogencarbonate or sodium bicarbonate [144-55-8] = NaHC0 3, and sodium dihydrogencarbonate = Na(HC0 3 )2- According to one advantageous embodiment of the invention, the dyeing process implements, after the rinsing step 2), the application: 3) of an aqueous composition D comprising: i) at least one (bi)carbonate, as defined previously; more particularly, the (bi)carbonates are chosen from alkali metal or alkaline-earth metal and ammonium bicarbonates, preferentially alkali metal bicarbonates; and ii) optionally at least one thickener, in particular chosen from celluloses, preferably

hydroxy(CrC 6)alkylcelluloses; particularly, the composition D is left on said fibres for a period of between 5 minutes and 1 hour, preferably between 10 minutes and 40 minutes, particularly between 15 minutes and 30 minutes, at a temperature of between 20°C and 30°C, preferably at 27°C; 4) optionally, said wet fibres are then subjected to a heat treatment at a temperature particularly of between 35°C and 80°C, preferably between 40 and 60°C, for a period of between 15 minutes and 3 hours, in particular between 30 minutes and two hours, preferably the heat treatment is carried out at 45°C for 1 hour, preferably the wet fibres are placed under plastic films for the heat treatment; 5) optionally, said fibres are then dried in the open air or with a hairdryer.

According to the invention, the (bi)carbonate agent(s) used preferably represent(s) from 0.001% to 20% by weight of the total weight of the composition(s) containing the (bi)carbonate agent(s) and even more preferentially from 0.01% to 10% by weight, better still from 1% to 6%.

Form of the compositions

The compositions comprising the decontaminated pre-hydrolysed henna and the indigo, in particular the compositions A and/or B as defined previously, or a mixture thereof, may be in non-compact clinical forms, such as a lotion, a mousse, a cream or a gel, or in any other form appropriate for dyeing keratin fibres. According to one particular embodiment, the composition B is in compact form and in different forms as a function of the desired compacting, in particular in the form of pebbles, in the form of stones, in the form of soaps, in the form of pyramids, in the form of cartons or in the form of plates.

The compositions The compositions comprising the decontaminated pre-hydrolysed henna and the indigo, in particular the compositions A and/or B as defined previously, or a mixture thereof, used in the process of the invention are cosmetic, i.e. they are cosmetically acceptable and therefore suitable for use for application to keratin fibres, in particular human keratin fibres such as the hair.

According to one particular embodiment of the invention , the process for dyeing keratin fibres uses one or more "mordants", i.e. metal salts conventionally used in "mordanting" (see for example Ullmann 's Encyclopedia of Industrial Chemistry ("Textile Dyeing", Herbert Leube et al., DOI : 10.1002/1 4356007.a26_351 , and in particular point 4.8.2, p. 72 ; ibid, "Metal- complex dyes", Klaus Gryschtol et al., DOI : 10 .1002/1 4356007.a 16_299). According to another particular embodiment of the invention, the process of the invention does not use "mordants", in particular no composition of the invention comprises mordants.

Aqueous composition

The compositions comprising the decontaminated pre-hydrolysed henna and the indigo, in particular the compositions A and/or B , as defined previously, or a mixture thereof, comprise water. This water constitutes all or part of an aqueous phase C . The term "aqueous phase" is intended to mean a phase which comprises essentially water, and also comprises other ingredients that are water-miscible or water-soluble at ambient temperature and at atmospheric pressure, different from polyols. As liquids or solids that may be present in the aqueous phase, mention may be made of: polar or polar protic organic solvents as defined below, different from polyols, salts of inorganic or organic acids or bases, or water-soluble cosmetic active agents. Compositions A , B and/or C may comprise one or more organic solvents. Mention may be made, as organic solvent, for example, of lower Ci-C 4 alkanols, such as ethanol and isopropanol; and also aromatic alcohols, such as benzyl alcohol or phenoxyethanol. The organic solvents are present in proportions preferably of between 0 .1% and 20% by weight approximately and even more preferentially between 0.5% and 10% by weight approximately relative to the total weight of the composition under consideration .

The compositions comprising the decontaminated pre-hydrolysed henna and the indigo, in particular the compositions A and/or B as defined previously, or a mixture thereof, contain water, preferably in an amount ranging from 5% to 90%, better still from 20% to 8%, particularly from 40% to 75% by weight relative to the total weight of said composition . According to one particular embodiment of the invention, the decontaminated composition which comprises the prehydrolysed henna, in particular the composition A , as defined previously, comprises only ingredients of natural origin. According to one particular embodiment of the invention, composition B, as defined previously, comprises only ingredients of natural origin.

During the preparation of the composition comprising the pre-hydrolysed henna, in particular the composition A , one or more clays, which may be identical or different, as defined hereinafter, are, according to one preferred embodiment of the invention, added. Once the clay has been added to the pre-hydrolysed henna composition, it is understood that the composition is decontaminated according to any one of the decontamination methods a) to f) as defined previously. According to another particular embodiment of the invention, the composition B comprises one or more clays, which may be identical or different, as defined hereinafter.

The adjuvants:

The compositions comprising the decontaminated pre-hydrolysed henna, preferably A , the composition B and/or the composition C , as defined previously, of the invention, may also contain various adjuvants conventionally used in hair dye compositions, such as anionic, cationic, non-ionic, amphoteric or zwitterionic polymers or mixtures thereof, anionic, cationic, non-ionic or zwitterionic surfactants, inorganic or organic thickeners, and in particular anionic, cationic, non-ionic and amphoteric polymeric associative thickeners, antioxidants, penetrants, sequestrants, fragrances, buffers, dispersants, conditioning agents other than the butters or oils of the invention, for instance ceramides, film-forming agents, preserving agents, opacifiers and inorganic or organic thickeners such as clays. According to another particular variant, the composition comprising the decontaminated pre-hydrolysed henna, in particular A , and/or B, as defined previously, is (are) in the form of an emulsion, in which case A , B and/or B contain surfactants. The above adjuvants are generally present in an amount for each of them of between 0.01% and 40% by weight relative to the weight of the composition, and preferably between 0.1% and 20% by weight relative to the weight of the composition under consideration. Needless to say, those skilled in the art will take care to select this or these optional additional compound(s) such that the advantageous properties intrinsically associated with the composition comprising the decontaminated pre-hydrolysed henna, in particular A and B, that are useful in the dyeing process in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition(s).

Additional dyes:

The compositions comprising the decontaminated pre-hydrolysed henna, in particular A , B and/or C of the invention as defined previously may also contain one or more additional direct dyes other than the henna powder and/or indigo-producing plant powder. These direct dyes are chosen, for example, from those conventionally used in direct dyeing, and among which mention may be made of any commonly used aromatic and/or non-aromatic dyes such as neutral, acidic or cationic nitrobenzene direct dyes, neutral, acidic or cationic azo direct dyes, natural direct dyes, neutral, acidic or cationic quinone and in particular anthraquinone direct dyes, azine, triarylmethane, indoamine, methine, styryl, porphyrin, metalloporphyrin, phthalocyanine, methine cyanine direct dyes, and fluorescent dyes. Preferentially, the compositions comprising the decontaminated pre-hydrolysed henna, in particular A , B and/or C of the invention as defined previously may also contain one or more natural dyes other than henna and indigo-producing plant(s). Among the natural direct dyes, mention may be made of juglone, isatin, curcumin, spinulosin, apigenidin and orceins. These natural dyes may be added in the form of defined compounds, extracts or plant parts. Said defined compounds from extracts or from plant parts are preferably in the form of powders, in particular fine powders whose particles have sizes identical to that of the henna and/or indigo-producing plant powder a) as defined previously. The natural or non-natural direct dye(s), other than the henna and/or indigo-producing plant powder a), in the composition according to the invention particularly represents from 0.001% to 10% by weight relative to the total weight of the composition and even more preferentially from 0.05% to 5% by weight relative to the total weight of the composition under consideration. Preferably, the compositions comprising the decontaminated pre-hydrolysed henna, in particular A , and also B and/or C of the invention as defined previously do not contain any synthetic direct dyes, i. e. dyes which do not occur naturally. The compositions comprising the decontaminated pre-hydrolysed henna, in particular A , and also B and/or C of the invention as defined previously may also contain one or more oxidation bases and/or one or more couplers conventionally used for dyeing keratin fibres. Among the oxidation bases, mention may be made of para-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols, bis-para-aminophenols, ortho- aminophenols and heterocyclic bases, and the addition salts thereof. Preferentially, the compositions comprising the decontaminated pre-hydrolysed henna, in particular A , B and/or C of the invention do not contain any para-phenylenediamine(s). Among these couplers, mention may be made in particular of meta-phenylenediamines, meta-aminophenols, meta-diphenols, naphthalene-based couplers and heterocyclic couplers, and the addition salts thereof. The oxidation base(s) present in the composition(s) are each generally present in an amount of between 0.001% and 10% by weight, relative to the total weight of the dye composition(s). Preferably, the compositions comprising the decontaminated pre-hydrolysed henna, in particular A , B and/or C , do not contain any oxidation dyes. pH of the compositions

According to one particular mode of the invention, the pH of the aqueous composition comprising the decontaminated pre-hydrolysed henna, in particular A , and also B, is acid to neutral (3.5-6.5) and more preferentially from 5 to 6.5 and/or C is alkaline, i.e. of pH around 8.5 (preferably ranging from 7.5 to 9 , better still from 7.5 to 8.7). According to one particular mode of the invention, the pH of the aqueous composition comprising the decontaminated pre-hydrolysed henna, in particular A, and also B and/or C may be adjusted to the desired value by means of acidifying or alkaline agents normally used in the dyeing of keratin fibres or alternatively using conventional buffer systems. Mention may be made, among the acidifying agents, by way of example, of inorganic or organic acids, such as hydrochloric acid, orthophosphoric acid, sulfuric acid or carboxylic acids. The alkaline agents are as defined previously. I) EXAMPLES OF DYEING Example 1: Henna alone

The percentages are indicated on a weight basis relative to 100 g of composition.

Compositions 1 and 2

Compositions 1 and 2 were prepared by mixing the ingredients of the table in a mixer, and are left stirring at 100 rpm for a period of between 2 hours and 6 hours at ambient temperature (25°C). The compositions are then deflocculated at a rotational speed of 700 rpm for 4 minutes - 900 rpm for 4 minutes. Compositions 1 and 2 are in the form of pastes. These pastes are then bagged under vacuum at a pressure of between 20 and 200 mb, for 1 minute. The packaging is carried out in sealed multilayer pouches under vacuum; in particular, the pouches are constituted of polyethylene terephthalate (PET), polypropylene terephthalate (PPT) and/or polyamide imide (Al). These pastes can also be packaged under an inert atmosphere (argon or nitrogen). The pouches are stored at 25°C for 2 hours, 6 hours and 24 hours.

The pouches are autoclaved with a scale of 110°C for 20 minutes (i.e. F0=6), or irradiated at 12 KGy. The pouches are then opened, and an amount of 20 g of composition comprising the henna is placed on locks of 1 g (20/1 bath ratio) of hair containing 90% natural white hairs (90 NW). The applications are carried out with a leave-on time of 1 h. A control lock was prepared, before henna treatment, and two comparative locks were also dyed with extemporaneously prepared henna which had not been either decontaminated or pre-hydrolysed A, or which had been decontaminated but not pre-hydrolysed B, it being understood that the bath ratio is identical, namely 20 g of composition per 1 g of 90 NW hair.

Colorimetric results

The colouring obtained was measured using a Minolta CM-2600D spectrocolorimeter. In this L*a* b* system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The lower the value of L, the darker or more intense the colour. The higher the value of a* , the redder the shade, and the higher the value of b* , the yellower the shade. The variation in colouration of the locks before and after treatment, also called colour build up, is calculated according to the following equation:

∆ * 2 * * 2 * * 2 E = - L0 ) + (a - a0 ) + (b - b0 ) * * * * * In this equation, L , a and b represent the values measured after dyeing, and L0 , a0 and bo* represent the values before dyeing. The higher the value of ∆ Ε , the greater the colour build-up. In this L* a* b* system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The lower the value of L* , the darker or more intense the colour.

It appears, according to the above results, that the decontaminated pre-hydrolysed henna makes it possible to obtain colours that are very effective in particular in terms of colour buildup, intensity and chromaticity, compared with the non-pre-hydrolysed and non- decontaminated henna.

Comparison of the pre-hydrolysed henna of the invention with the commercial benchmark

The colouring potential of commercially available henna cones (Hathi) containing henna, formulated as a paste but without decontamination and without protection against atmospheric oxygen, was compared with respect to composition 1 of the invention. The comparatives are prepared with an equivalent amount of henna and an identical bath ratio. The results are given in the table below:

It appears that the pre-hydrolysed and decontaminated henna according to the invention makes it possible to obtain shades that are significantly darker (lower L) and more chromatic than the commercially available henna cone products. Example 2: Henna + Indigo

Hair dyeing process 1, action using the pre-hydrolysed and decontaminated henna with indigo:

Composition 3 : based on pre-hydrolysed and decontaminated henna

* pre-hydrolysed according to the technique presented for compositions 1 and 2 , for 6 hours

Bagged under vacuum and decontaminated by autoclaving with F0 of 6

Composition 4 : based on indigo decontaminated using gamma-radiation at 25 KGy

Protocol 1

step - rea men y app ca on o e a r o compos on w c compr ses M sodium bicarbonate (pH 8.3), then leave on for a period of between 15 minutes and 30 minutes. Rinse the hair with water Cover the wet hair with a plastic film and apply above said film a heat of 45°C under a drying hood for one hour step 3 Dry the hair either naturally in the open air, or with a hairdryer, then do not shampoo the hair for 24 hours.

Protocol 2

A variant of step 3 is not to heat over the plastic film and to allow the hair to dry naturally.

Colorimetric results

The colouring obtained was measured using a Minolta CM-2600D spectrocolorimeter. In this L*a* b* system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The lower the value of L, the darker or more intense the colour. The higher the value of a* , the redder the shade, and the higher the value of b* , the yellower the shade. The variation in colouration of the locks before and after treatment, also called colour build- up, is calculated according to the following equation: ∆ * 2 * * 2 * * 2 E = - L0 ) + (a - a0 ) + (b - b0 ) * * * * * In this equation, L , a and b represent the values measured after dyeing, and L0 , a0 and bo* represent the values before dyeing. The higher the value of ∆ Ε , the greater the colour build-up. In this L*a* b* system, L* represents the intensity of the colour, a* indicates the green/red colour axis and b* indicates the blue/yellow colour axis. The lower the value of L* , the darker or more intense the colour.

Colorimetric results

It appears, according to the above results, that the decontaminated pre-hydrolysed henna combined with the indigo, also decontaminated, makes it possible to obtain very strong fundamental colours with very attractive glints.

Study on the henna / indigo ratio

It appears that the extemporaneous application of a composition of pre-hydrolysed and decontaminated henna and of a composition of indigo that has also been decontaminated makes it possible to obtain colourations that are very satisfactory in terms in particular of strength and colour buildup. CLAIMS

1. Process for preparing an aqueous composition comprising pre-hydrolysed and decontaminated henna, consisting: 1) in mixing i) henna powder with ii) an aqueous medium; then 2) subjecting said mixture to a decontamination treatment.

2 . Process according to the preceding claim, in which the henna i) of step 1) is in the aqueous medium in an amount of between 1% and 50%, more particularly of between 10% and 40%, preferably between 20% and 30% by weight relative to the total weight of the mixture.

3. Process according to either one of the preceding claims, in which the aqueous medium ii) of step 1) is water, preferably distilled water, and is in an amount of between 30% and 95%, more preferentially between 50% and 90%, better still between 60% and 80% by weight relative to the total weight of the mixture.

4 . Preparation process according to any one of the preceding claims, in which the mixture of step 1) also comprises one or more fatty substances, that are preferably liquid, such as oils chosen from non-silicone oils; and in particular C6-Ci 6 hydrocarbons or hydrocarbons containing more than 16 carbon atoms and in particular alkanes; oils of animal origin; triglyceride oils of plant origin; essential oils; fluoro oils or glycerides of synthetic origin, fatty alcohols; fatty acid and/or fatty alcohol esters other than triglycerides, and silicone oils.

5. Preparation process according to the preceding claim, in which the fatty substance(s) are chosen from oils of plant origin such as jojoba oil, babassu oil, sunflower oil, olive oil, coconut oil, Brazil nut oil, marula oil, corn oil, argan oil, soybean oil, marrow oil, grapeseed oil, linseed oil, sesame oil, hazelnut oil, apricot oil, macadamia oil, arara oil, coriander oil, almond oil, castor oil, avocado oil, shea butter oil, rapeseed oil, borage oil, evening primrose oil, pomegranate oil, mango oil, palm oil, cottonseed oil and copra oil; preferentially, the fatty substance(s) are chosen from avocado oil, olive oil, coconut oil, copra oil, argan oil and sunflower oil; more preferentially, the fatty substance(s) are chosen from copra oil.

6. Preparation process according to Claim 4 or 5, in which the mixture of step 1) also comprises one or more fatty substances, in an amount of between 0.05% and 30%, preferably between 1% and 20%, better still between 5% and 15% by weight relative to the total weight of the mixture of henna and aqueous medium. 7 . Preparation process according to any one of the preceding claims, in which the mixture of step 1) also comprises one or more adjuvants chosen from polyols and polyol ethers, for instance 2-butoxyethanol, propylene glycol, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, hexylene glycol, and glycerol, more particularly glycerol, preferably in an amount of between 0.01% and 20%, preferably between 0.05% and 15%, better still between 2% and 10% by weight relative to the total weight of the mixture of henna and aqueous medium.

8 . Preparation process according to any one of the preceding claims, in which the mixture of henna i) and aqueous medium ii) of step 1) is left: for a period of between 5 minutes and 48 hours, particularly between 30 minutes and 24 hours, more particularly between 1 hour and 12 hours, preferentially between 2 hours and 6 hours; and/or at a temperature of between 2°C and 60°C, preferentially between 4°C and 45°C, more particularly between 25°C et 40°C such as at ambient temperature (25°C).

9 . Preparation process according to any one of the preceding claims, in which: - the mixture of henna i) and aqueous medium ii) of step 1) is left stirring at a rotational speed of between 1 and 400 revolutions / minute, preferably between 50 and 200 revolutions / minute and more particularly between 70 and 150 revolutions / minute, such as 100 revolutions / minute; and/or - the mixture of henna i) and aqueous medium ii) of step 1) is left in a deflocculating mixer at a rotational speed of between 200 and 1500 revolutions / minute, particularly between 300 and 1000 revolutions / minute, more particularly between 500 and 950 revolutions / minute, preferentially between 700 and 900 revolutions / minute; preferably, these two variants are carried out in a mixer-grinder.

10. Preparation process according to any one of the preceding claims, in which the decontamination treatment is carried out according to a method chosen from: a) pasteurization, particularly "high" pasteurization, and preferably the mixture of pre- hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 is heated at a temperature of between 70°C and 75°C, particularly at 72°C, for a short period of time, preferably between 10 seconds and 30 seconds, such as 15 seconds, and then the mixture is left cool to ambient temperature; b) sterilization at a temperature greater than or equal to 100°C, in particular the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 is steam-sterilized at a temperature of between 100°C and 180°C, more particularly between 100°C and 125°C; c) appertization, in particular the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 is packaged in a hermetically closed container which is subjected to a temperature of between 100 and 150°C, more particularly between 110 and 120°C for a period of between 1 minute and 2 hours, more particularly between 5 minutes and 1 hour, preferentially between 10 minutes and 30 minutes, and then the mixture is left to cool to ambient temperature; d) tyndallization, in particular the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 is heated batchwise at low temperature, more particularly the mixture is heated at a temperature between 40 and 70°C, preferentially at a temperature of between 45 and 60°C, for a period of between 15 minutes and 1 hour, preferably for 30 minutes, and then the mixture is left to cool to ambient temperature; e) autoclaving, in particular the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 is i) heated at a temperature of between 120 and 150°C, more particularly at 134°C, at a pressure of between 2 and 4 bar, more particularly at a pressure of 2.2 bar, ii) for a period of between 5 minutes and 1 hour, more particularly between 10 minutes and 25 minutes, such as for 18 min, this being over the entire area to be sterilized, iii) followed by cooling to ambient temperature and iv) decreasing the pressure to atmospheric pressure; f) pascalization, in particular the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 undergoes an "ultrapressure" treatment preferentially of between 1000 and 8000 bar, more preferentially between 2000 and 6000 bar, better still between 3000 and 5000 bar, such as 4000 bar; and g) ionizing radiation, particularly according to the radicidation method, preferably the radiation is carried out on the mixture of pre-hydrolysed henna and aqueous medium according to any one of Claims 1 to 9 at a dose of inclusively between 1.8 and 18 KGy, more preferentially between 2 and 15, better still between 5 and 8 KGy; more preferentially, the decontamination of the mixture of pre-hydrolysed henna and aqueous medium is carried out by g) gamma-irradiation at a dose of between 5 and 25 KGy, preferably around 12 KGy.

11. Preparation process according to any one of the preceding claims, in which the mixture of henna i) and aqueous medium ii) of step 1) is placed under vacuum and/or vacuum-packaged, in particular at a pressure of between 5 and 400 mb, more particularly between 10 and 300 mb, preferentially between 20 and 200 mb, for a period of time of particularly between 5 seconds and 5 minutes, more particularly between 30 seconds and 3 minutes, preferentially between 45 seconds and 1 minute, followed by decontamination step 2) as defined in Claim 1 or 12, in order to produce a composition A .

12. Preparation process according to the preceding claim, in which, between the vacuum step and decontamination step 2) as defined in Claim 10, the mixture is stored under vacuum and/or under an inert atmosphere such as nitrogen or argon for between 1 hour and 48 hours, in particular between 2 hours and 24 hours, at a temperature of between 4°C and 45°C, preferentially 2 to 6 hours at a temperature between 20 and 40°C, even more preferentially 6 hours at ambient temperature.

13. Aqueous composition comprising pre-hydrolysed and decontaminated henna prepared according to any one of the preceding claims.

14. Aqueous composition according to the preceding claim, which corresponds to the composition A , prepared according to Claim 11 or 12, and preferably which is packaged in a sealed multilayer pouch under vacuum and/or under argon; in particular said pouch is constituted of polyethylene terephthalate (PET), polypropylene terephthalate (PPT) and/or polyamide imide (Al).

15. Ready-to-use composition prepared from the mixing of a composition comprising pre-hydrolysed henna, resulting from the preparation process as defined in any one of Claims 1 to 12, preferably the composition A as defined in Claim 11, and of a composition B comprising indigo-producing plant powder which is non-decontaminated or which has been decontaminated according to any one of the techniques a) to f) as defined in Claim 10.

16. Ready-to-use composition in which the indigo-producing plants(s) is (are) chosen from the species of the following genera: - Indigofera such as Indigofera tinctoria, Indigo suffruticosa, Indigofera articulata, Indigofera arrecta, Indigofera gerardiana, Indigofera argenta, Indigofera indica, Indigofera longiracemosa; - Isatis such as Isatis tinctoria; - Polygonum or Persicaria such as Polygonum tinctorium (Persicaria tinctoria); - Wrightia such as Wrightia tinctoria; - Calanthe such as Calanthe veratrifolia; and - Baphicacanthus such as Baphicacanthus cusia, preferably, the indigo-producing plant(s) is (are) of the genus Indigofera and more particularly is (are) Indigofera.

17. Process for dyeing keratin fibres, in particular human keratin fibres, such as the hair, comprising: 1) a step of applying to said fibres the composition as defined in Claim 13 or 14; particularly, said composition is left on said fibres for a period of between 15 minutes and 3 hours, preferably between 30 minutes 2 hours, particularly at a temperature of between 20°C and 30°C, preferably for 1 hour at 27°C, followed by 2) a step of rinsing said keratin fibres, preferably with water.

18. Dyeing process according to the preceding claim, comprising: 1) a step of simultaneously applying to said fibres: i) a composition comprising pre-hydrolysed and decontaminated henna as defined in Claim 13 or 14; and ii) an aqueous composition B comprising indigo-producing plant powder; particularly the amount of powder of indigo-producing plant(s) as defined in Claim 16, which is greater than 10% by weight, more particularly inclusively between 10% and 90% by weight, even more particularly between 15% and 70%, preferentially between 20% and 60% by weight, more preferentially between 25% and 50% by weight, relative to the total weight of the composition B ; particularly, said compositions being left on said fibres for a period of between 15 minutes and 3 hours, preferably between 30 minutes and 2 hours, particularly at a temperature of between 20°C and 30°C, preferably for 1 hour at 27°C, followed by 2) a step of rinsing said keratin fibres, preferably with water.

19. Dyeing process according to Claim 17 or 18, in which the aqueous composition B is decontaminated, in particular according to a method as defined in Claim 11, preferentially the decontamination of the composition B is carried out by g) ionizing radiation, particularly by the "radappertization" method, preferably the irradiation is carried out on the composition B at a dose of inclusively between 20 and 50 KGy, more preferentially between 25 and 30 KGy.

20. Dyeing process according to any one of Claims 17 to 19, in which the henna powder / indigo-producing plant powder weight ratio o be observed is inclusively between 80 / 20 and 75 / 25, particularly between 75 / 25 and 45 / 65, preferentially between 70 / 30 and 40 / 60.

2 1. Dyeing process according to any one of Claims 17 to 20, in which, after the rinsing step 2): 3) an aqueous composition D comprising: i) at least one alkaline agent, in particular (bi)carbonate, preferably chosen from:

+ 2 2+ 2 - carbonates of alkali metals (Met2 , C0 3 ), of alkaline-earth metals (Met' , C0 3 ) of + 2 + 2 ammonium ((R"4N )2,C0 3 ) or of phosphonium ((R"4P )2,C0 3 with Met' representing an alkaline-earth metal and Met representing an alkali metal, and R", which may be

identical or different, represent a hydrogen atom or an optionally substituted (CrC 6)alkyl group such as methyl, ethyl or hydroxyethyl; and - bicarbonates, or hydrogen carbonates, of the following formulae: + + > R' , HC0 3 with R' representing an alkali metal, an ammonium group R"4N - or a + phosphonium group R"4P - where R", which may be identical or different, represent a

hydrogen atom or an optionally substituted (CrC 6)alkyl group such as methyl, ethyl or hydroxyethyl; and

2+ > Met' (HC0 3 )2, with Met' representing an alkaline-earth metal; more particularly, the (bi)carbonates are chosen from alkali metal or alkaline-earth metal and ammonium bicarbonates, preferentially alkali metal bicarbonates; and ii) optionally at least one thickener, in particular chosen from celluloses, preferably

hydroxy(CrC 6)alkylcelluloses; is applied; particularly, the composition D is left on said fibres for a period of between 5 minutes and 1 hour, preferably between 10 minutes and 40 minutes, particularly between 15 minutes and 30 minutes, at a temperature of between 20°C and 30°C, preferably at 27°C; 4) optionally, said wet fibres are then subjected to a heat treatment at a temperature particularly of between 35°C and 80°C, preferably between 40 and 60°C, for a period of between 15 minutes and 3 hours, in particular between 30 minutes and two hours, preferably the heat treatment is carried out at 45°C for 1 hour, preferably the wet fibres are placed under plastic films for the heat treatment; 5) optionally, said fibres are then dried in the open air or with a hairdryer.

22. Use of the composition as defined in any one of Claims 13 to 15, for dyeing keratin fibres, in particular human keratin fibres, such as the hair. A . CLASSIFICATION O F SUBJECT MATTER INV. A61Q5/06 A61K8/97 A61K36/00 ADD.

According to International Patent Classification (IPC) or to both national classification and IPC

B . FIELDS SEARCHED Minimum documentation searched (classification system followed by classification symbols) A61Q A61K

Documentation searched other than minimum documentation to the extent that such documents are included in the fields searched

Electronic data base consulted during the international search (name of data base and, where practicable, search terms used)

EPO-Internal , WPI Data

C . DOCUMENTS CONSIDERED TO B E RELEVANT

Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No.

J P 2014 019656 A (RAY PLANING CO LTD; 1, 3 ,8, OKINAWA PREFECTURE) 10, 3 February 2014 (2014-02-03) 13-19 ,22 paragraphs [0001] , [0010] , [0011] , 1-22 [0023] , [0025] , [0035]

J P 2002 348215 A (CHU0 AEROSOL KAGAKU KK) 1, 3 ,8, 4 December 2002 (2002-12-04) 10, 13-19 ,22 paragraphs [0001] , [0006] , [0026] 1-22

J P 2004 307444 A ( LAKSMI KK) 1-3 , 7 , 4 November 2004 (2004-11-04) 13-20,22 paragraphs [0003] , [0004] , 1-22 [0009] , [0011] , [0013] , [0015] , [0021]

-/--

X| Further documents are listed in the continuation of Box C . See patent family annex.

* Special categories of cited documents : "T" later document published after the international filing date or priority date and not in conflict with the application but cited to understand "A" document defining the general state of the art which is not considered the principle or theory underlying the invention to be of particular relevance "E" earlier application or patent but published o n or after the international "X" document of particular relevance; the claimed invention cannot be filing date considered novel or cannot be considered to involve an inventive "L" documentwhich may throw doubts on priority claim(s) orwhich is step when the document is taken alone cited to establish the publication date of another citation or other "Y" document of particular relevance; the claimed invention cannot be special reason (as specified) considered to involve an inventive step when the document is "O" document referring to an oral disclosure, use, exhibition or other combined with one o r more other such documents, such combination means being obvious to a person skilled in the art "P" document published prior to the international filing date but later than the priority date claimed "&" document member of the same patent family

Date of the actual completion of the international search Date of mailing of the international search report

16 February 2016 24/02/2016

Name and mailing address of the ISA/ Authorized officer European Patent Office, P.B. 5818 Patentlaan 2 NL - 2280 HV Rijswijk Tel. (+31-70) 340-2040, Fax: (+31-70) 340-3016 Ol ausson Boul oi s , J C(Continuation). DOCUMENTS CONSIDERED TO BE RELEVANT

Category* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No.

SUPRIYA SHIDHAYE ET AL: " Radi ati on 1 , 2 ,4,6, Steri l i sati on Of Henna And Its Oi ntment" , 7 , 10, INDIAN JOURNAL OF PHARMACEUTICAL SCI ENCES, 13-16 MEDKNOW PUBLICATIONS PVT LTD, I N, vol . 58, no. 2 , 1 January 1996 (1996-01-01) , pages 55-58, XP009185979 , ISSN : 0250-474X page 55 - page 56 page 58

WO 2014/174114 A2 (OREAL [FR] ) 1-22 30 October 2014 (2014-10-30) c l aims 1-19

T W 201 414 505 A (PAN , FU CHE) 1-22 16 Apri l 2014 (2014-04-16) the whol e document Patent document Publication Patent family Publication cited in search report date member(s) date

JP 2014019656 A 03-02-2014 P 5733669 B2 10-06-2015 P 2014019656 A 03-02-2014

JP 2002348215 A 04- 12 -2002 NONE

JP 2004307444 A 04-1 1 -2004 NONE

O 2014174114 A2 30- 1 -2014 FR 3004942 A l 31- 10--2014 O 2014174114 A2 30- 10--2014

T 201414505 A 16- 04 -2014 NONE