WO2015018596A1

WO2015018596A1 - A method and a kit for colouring keratinous fibers

Info

Publication number: WO2015018596A1
Application number: PCT/EP2014/064906
Authority: WO
Inventors: Lalitha Balakrishnan; Praful Gulab Rao LAHORKAR; Suman MAJUMDER
Original assignee: Unilever NV; Conopco Inc
Current assignee: Unilever NV; Conopco Inc
Priority date: 2013-08-05
Filing date: 2014-07-11
Publication date: 2015-02-12
Anticipated expiration: 2016-02-05

Abstract

The invention relates to a method and a kit for colouring keratinous fibers especially human hair. The invention more particularly relates to generating black coloured hair while minimising the off odour generated when a conventional penetration agent like cysteine is used in such methods.

Description

A METHOD AND A KIT FOR COLOURING KERATINOUS FIBERS

Field of the invention

The invention relates to a method and a kit for colouring keratinous fibers especially human hair. The invention more particularly relates to generating black coloured hair while minimising the off odour generated when a conventional penetration agent like cysteine is used in such methods. Background of the invention

Presently, the number of people wishing to have their hair coloured has increased. In order to obtain a uniform colour over the hair, permanent hair colours are used more often than temporary and semi-permanent hair colours. There are several permanent hair colouring methods. One is the so called oxidative dye approach. This is based on the oxidation of a p- phenylenediamine or p-aminophenol by hydrogen peroxide, in the presence of various couplers. This has been in use for a very long time and is used to generate a wide range of shades that are both lighter and darker than natural hair colour. Since the final coloured molecules are quite large, these hair colours are resistant to removal by shampooing. Such permanent oxidative dyes are usually marketed as two component systems - one containing the dye precursors in an alkaline base, and the other is a solution of hydrogen peroxide.

Another class of dyes are based on metal complexes with polyphenols. These generally come in two parts: a metal salt solution and a developer solution. This method is preferred over the oxidative dye approach since they involve use of mostly materials of natural origin. People generally perceive that synthetic chemicals have a damaging effect on their hair. They also believe that use of dyes involving synthetic actives can cause allergenic reactions in some people in addition to damage to structure of hair fibre. Thus, more and more people are opting for colourant systems that use actives obtained from natural sources.

Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field. A method of colouring hair comprising contacting hair with an iron or copper salt followed by contacting with gallic acid or an ester thereof, is known. Most methods and compositions to colour hair usually require harsh conditions like high alkalinity (with use of materials like ammonia) or oxidants like hydrogen peroxide in order to ensure penetration of the colourant into the hair and thereby provide high colouring efficacy. Alternately an amino acid, cysteine has been used. The issue with cysteine is that when used in hair dyes, an offensive odour due to generation of volatile sulphur compounds is produced. This has been overcome in the present invention by derivatising cysteine with various specific agents that on the one hand retains its penetration efficacy while minimizing the formation of volatile sulphur compounds. The present invention thus provides an odour free hair dying method and kit with high colouring efficacy. Further, potential damage to hair that have been reported to occur due to use of cysteine is avoided. Yet another advantage of the present invention is that it enables formulating over a wider range of pH conditions depending on the type of derivatisation.

US5104413 (Kao, 1992) discloses a hair dye composition comprising the following three components (A), (B) and (C): (A) one or more cysteine derivatives and glutathione, or a salt thereof; (B) an aromatic alcohol and/or a compound represented by the following general formula R₂ -OCH₂ CH₂ OCH₂ CH₂ OH wherein R 2 represents an alkyl group carrying one to five carbon atoms; and (C) a dye. The above patent publication does not disclose the cysteine derivatives claimed in the present invention and is further directed to shampoo fastness. WO 2012/065576 (NATURAL MEDICINE INST OF ZHEJIANG YANGSHENGTANG CO LTD, 2001 -06-14) discloses compositions for dyeing hair. The hair dyeing composition discloses a softening preparation comprising N-acetyl cysteine, a dye preparation comprising tea-polyphenol (comprising epigallo catechin gallate), and a mordant preparation comprising ferrous sulfate and cysteine hydrochloride. The above patent application uses N-acetyl cysteine as a softening agent and not as a penetrating agent and does not address the issue of odour. Further N-acetyl cysteine is expected to show properties which are closer to cysteine and cannot be compared to other cysteine derivatives as such. It is an object of the present invention to provide enhanced blackness to hair using polyphenol - metal complex.

It is another object of the present invention to enhance the blackness by ensuring penetration of the dye into the desired keratinous fibers while minimizing off -odours experienced heretofore when agents like cysteine are used.

Summary of the invention

The present invention provides for a method of colouring keratinous fibers comprising the steps of contacting the keratinous fibers with

(i) a penetration enhancer selected from a cysteine derivative of the general formula

Wherein Ri and R₂ are combinations selected from any one of:

(a) When R-i is a C₃ to d₅ alkyl group, R₂ is a H atom;

(b) When R-i is a O-t-butyl group, R₂ is a Ci to do alkyl group; and

(c) When R-i is a sesquiterpene group selected from one of R₃ or R₄ or R₅, R₂ is a

Ci to do alkyl group;

Where R3 is a glycyrrhetinic acid residue

Where R4 is a ursolic acid residue

Where R5 is a oleanoic acid residue

(ii) a polyphenol and

(iii) a metal ion selected from the group consisting of Cu²⁺, Cu⁺, Fe²⁺ and Fe³⁺; where contacting is in any order

It is particularly preferred that the method comprises the steps of contacting the fibers with a first composition comprising the penetration enhancer and the polyphenol and a second composition comprising the metal ion.

Detailed description of the invention

These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the invention. The word "comprising" is intended to mean "including" but not necessarily "consisting of or "composed of." In other words, the listed steps or options need not be exhaustive. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Similarly, all percentages are weight/weight percentages unless otherwise indicated. Except in the operating and comparative examples, or where otherwise explicitly indicated, all numbers in this description indicating amounts of material or conditions of reaction, physical properties of materials and/or use are to be understood as modified by the word "about". Numerical ranges expressed in the format "from x to y" are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format "from x to y", it is understood that all ranges combining the different endpoints are also contemplated.

"Keratinous fibres" as used herein, is meant to include fibres which contain keratin of mammals including humans e.g. hair on the body and head. By colouring is meant changing the colour generally from grey which is a state where the keratin content is low to a colour which includes black or brown. Preferred colour to be achieved as per the present invention is black or brown with at the most a minimal blue tint. Most preferred colour is black. A composition to achieve this may be generally classified as leave-on or rinse off, preferably rinse off. This may be achieved by including the actives in well known hair care products like shampoo, conditioner and combinations of these.

According to the first aspect of the present invention, there is provided a method of colouring keratinous fibers with a metal ion, a polyphenol, and a penetration enhancer selected from a cysteine derivative of the general formula:

The present invention envisages various polyphenols which may be used. The polyphenol is preferably galic acid or an ester thereof, rosmarinic acid, butein, a hydroxyflavone or the polyphenol is present as an extract of Glycyrrhiza glabra.

Gallic acid and a few of the commonly occuring esters have the structure given below:

Gallic acid Methyl gallate Ethyl gallate Propyl gallate

Gallic acid and ester of gallic acid preferably having an alkyl chain length of 1 to 4 carbon atoms are preferred for use in the present invention of which ethyl, methyl or propyl gallate is preferred. Of these, methyl or propyl gallate are further more preferred. Alternately and as a preferred aspect, the gallic acid is present as an extract of a plant species of the Terminalia genus, or an extract of Embelica officinalis, or Mucuna pruriens. Of these, the extract of the Terminalia or Embelica species is preferred. The extract is preferably of the leaf, stem, seed, flower or fruit of the above plant. A suitable method of preparing an extract of the plants comprises the steps of

(i) Extracting the plant source with a hydroalcoholic solvent comprising 50 to 90% of a C1 - C3 alcohol at a temperature of 70 to 85° C for 10 to 60 minutes;

(ii) separating the solvent from the mixture; and

(iii) Concentrating and drying the solvent extract to prepare the desired extract.

Rosmarinic acid, a phenolic compound commonly occurring in the species of Lamiaceae and Boraginaceae, has the following chemical structure

Rosmarinic acid may be synthetically prepared or may be extracted from natural sources and purified for use in the present invention. Rosmarinic acid, for use in the present invention is preferably extracted from one or more of the following plants: Rosmarinus officinalis, Ocimum sanctum, Thymus vulgaris, Melissa officinalis, Salvia officinalis, Anchusa officinalis and Coleus blumei. The leaves, seeds or roots part of the plant is preferably used for extraction of rosmarinic acid, more preferably the leaf. Of the various plants, Rosmarinus officinalis and Ocimum sanctum are most preferred for extraction of Rosmarinic acid for use in the present invention.

Butein is a compound of the chalcone family and has the chemical structure given below. Butein is specifically a dihydroxychalcone

Butein may be synthetically prepared or may be extracted from natural sources and purified for use in the present invention. Butein, for use in the present invention is preferably extracted from the following plants: Butea monosperma, Rhus verniciflua, Semecarpus anacardium, Dalbergia odorifera, Caragana jubata. The flower, bark, stem, heartwood or root part of the plant is preferably used for extraction of butein, more preferably the flower part. Of the various plants, Butea monosperma is most preferred for extraction of butein for use in the present invention. Hydroxyflavone compound for use in the first composition of the method of the present invention has the general structure:

where Ri is H, OH, OCH₃, or O-Glucose

and R₂ is H, OH, OCH₃, or O-Glucose.

A preferred hydroxyflavone compound of is baicalin, baicalein or mixture thereof. Baicalin has the structure

Thus in Baicalin Ri is an O-Glucose unit and R₂ is a Hydrogen atom.

Baicalin may be synthetically prepared or may be extracted from natural sources and purified for use in the present invention. A preferred natural source for extraction of baicalin for use in the present invention is preferably Scutellaria baicalensis. The leaves, seeds or root of the plant is preferably used for extraction of baicalin, more preferably the root. Alternately, another trihydroxyflavone, baicalein, may be present in carrying out the method of the invention. Baicalein has the structure

Thus in Baicalein Ri is an OH group and R₂ is a Hydrogen atom.

When Scutellaria baicalensis, is used for extraction, the extract usually comprises both baicalin and baiclein, the mixture of which is especially preferred for use in the method of the invention.

Other additional hydroxyflavone compounds may be included in carrying out the method of the invention by using an extract of a plant material selected from celery, peppermint, saw thistle, Chinese cabbage, chamomile, thyme or parsley. An especially preferred additional hydroxyflavone compound is apigein.

Yet another source of polyphenol for use in the method of the invention is an extract of Glycyrrhiza glabra. Licorice (or liquorice), the dried roots and rhizomes of Glycyrrhiza glabra (family Leguminosae), has been used as a natural sweetener and a flavorant. Licorice is also one of the oldest and most popular herbal medicines in the world. The chemical compound isolated from licorice are mainly triterpene saponins and flavonoids. The extract of Glycyrrhiza glabra for use in the present invention comprises higher than 0.5% total phenols preferably dihydrostilbene or dihydrophenanthrene. They have the following chemical structure

The leaves, seeds, roots or stem part of the plant is preferably used for extraction of total phenols from Licorice, more preferably the root. The polyphenol for use in the first composition of the method of the invention is preferably used as an aqueous composition at 0.1 to 10 wt%, preferably 0.2 to 2 wt% by weight of said aqueous composition. Another essential element of the method of the invention is a penetration enhancer selected from a cysteine derivative of the general formula:

The various possible combinations of R1 and R2 by which the general structure of cysteine may be derivatised are:

(a) When R-i is a C₃ to d₅ alkyl group, R₂ is a H atom.

(b) When R-i is a O-t-butyl group, R₂ is a Ci to do alkyl group.

(c) When R-i is a sesquiterpene group selected from one of R₃ or R₄ or R₅, R₂ is a Ci to do alkyl group;

Where R3 is a glycyrrhetinic acid residue

Where R4 is a ursolic acid residue

Where R5 is a oleanoic acid residue

Of the various possibilities (a), (b) and (c) listed above, the most preferred option is to have Ri as a C₃ to d₅ alkyl group and R₂ as a H atom. A further preferred option as per this embodiment is to have Ri as a C5 to C12 alkyl group and R2 as a H atom. The cysteine derivative for use in the first composition of the method of the invention is preferably present in 0.1 to 15%, more preferably 0.5 to 8% by weight of the first composition. The first composition preferably has a pH in the range of 4 to 10. Lauroyl cysteine, which is one of the most preferred cysteine derivative for use in the method of the invention may be prepared using a process as given below:

Preparation of cysteine derivatives

5 gm of cysteine is taken in a two-necked round bottom flask. 4.3 ml of ethanolamine and 470 ml of methanol are added into it. The mixture is stirred on a magnetic stirrer for 10 minutes. One neck of the flask is connected to a dropping funnel and the other is closed with a stopper. 10 ml of Lauroyl chloride in 40 ml of THF (tetra hydro furan) is added drop-wise using a dropping funnel. The reaction is kept at room temperature (about 25 °C) for about 24 hours. Solvent from the reaction mixture is removed using rota vapour. Small amount of water is added to precipitate the desired compound Lauroyl cysteine. The desired compound lauroyl cysteine is filtered and dried over vacuum.

According to the present invention preferred metal ions are selected from the group consisting of Cu²⁺, Cu⁺, Fe²⁺ and Fe³⁺. It is preferred that when the metal ion is Cu²⁺ or Cu⁺, it is delivered through a copper salt. Preferred copper salts are copper chloride, copper formate, copper sulfate, copper tartarate, copper ascorbate or copper gulconate, more preferably copper chloride or copper formate. The copper salt is preferably used as an aqueous solution at 0.2 to 10 wt%, preferably 0.5 to 5 wt% by weight of said aqueous solution. When the metal ion is iron, it could be in the Fe²⁺ or Fe³⁺ state and it is preferably present as an iron salt. Preferred iron salts are iron chloride (II), iron chloride (III), iron gluconate, iron sulphate, iron formate, iron ascorbate, or iron tartrate more preferably iron chloride (II) or iron chloride (III). The iron salt is preferably used as an aqueous composition at 0.2 to 10 wt%, preferably 1 to 6 wt% by weight of said aqueous composition. Of the various metal ions, Cu^2+I Fe³⁺ or Fe²⁺ are preferred for use in the present invention.

The keratinous fiber as per the invention is preferably human or animal hair, preferably human hair. The above method may be carried out by contacting the hair using a complex of the metal salt with polyphenol along with cysteine derivative that has been pre-prepared as a composition. When the complex is pre-prepared, it is preferred that the composition is prepared not more than 60 minutes, preferably not more than 20 minutes, further more preferably not more than 5 minutes before contacting the keratinous fibres. An alternate and preferred way of achieving this is to prepare the complex insitu on the keratinous fibres by contacting the fibres first with a composition comprising the penetration enhancer and the polyphenol followed by contacting the fibres with another composition comprising the metal ion. When the sequential steps mentioned above are carried out, the steps are preferably carried out not more than 30 minutes, preferably not more than 5 minutes apart. When the process is carried out involving the sequential steps as described above, it is preferred that the fibres are rinsed with water between the two steps.

The step of contacting the fibres with the pre-prepared metal complex with polyphenol is preferred over the sequential sub-steps described above.

The composition comprising the polyphenol is preferably present in aqueous solution at a pH at 25 °C in the range of 4 to 10. The composition comprising the metal ion is preferably present in aqueous solution at a pH at 25 °C in the range of 4 to 7. Without wishing to be bound by theory, it is believed that the metal ion forms a complex with the polyphenol which imparts the colour to the fibres in an enhanced manner by inclusion of the cysteine derivative. This may be formed insitu on the keratinous fibres by carrying out the reaction on the fibres or the complex may be prepared ex- situ and then applied on to the keratinous fibres. Once the complex is formed, the pH is preferably in the range from 4 to less than 7. Once the fibres have been treated with the complex, they are preferably rinsed with plenty of water to be substantially free of the complex. The complex is preferably applied on the fibres from 5 to 60 minutes, more preferably 15 to 45 minutes in order to obtain maximum efficacy of colour formation.

A suitable way to enable the method of the invention is to carry out the step of contacting the keratinous fibres with the polyphenol by including it in a shampoo composition while the metal ion is included in a conditioner composition. Thus, this aspect will ensure that people first use the shampoo to wash their hair, which is the usual practise. Thereafter people rinse their hair with water followed by applying the conditioner on the hair followed by a further step of rinsing with water.

A more preferred option of delivering the benefits of the invention is that the polyphenol along with the cysteine derivative is included in a composition in the form of a gel/ cream which are of a leave-on nature. After a predetermined period of time of contact of this composition with the desired keratinous fibres, they may be rinsed with water. Thereafter a leave-on composition in the form of a cream or gel containing the metal ion may be applied to the fibres or the metal ion may be included in a wash off composition like a shampoo or a conditioner to enable the method of the invention.

Alternately the metal salt and the polyphenol along with the cysteine derivative are included in two separate compartments of a shampoo composition and are mixed just prior to application on to the keratinous fibres which need to be coloured.

The above methods of delivering the benefits of the invention may be enabled by providing for a kit for colouring keratinous fibres comprising (i) a 'composition A' comprising a penetration enhancer selected from a cysteine derivative of the general formula

Wherein Ri and R₂ are combinations selected from any one of:

(a) When R-i is a C₃ to d₅ alkyl group, R₂ is a H atom;

(b) When R-i is a O-t-butyl group, R₂ is a Ci to C₁0 alkyl group; and

Where R3 is a glycyrrhetinic acid residue

Where R4 is a ursolic acid residue

Where R5 is a oleanoic acid residue

(ii) a 'composition B' comprising a polyphenol;

(iii) a 'composition C comprising a metal ion selected from the group consisting of Cu²⁺, Cu⁺, Fe²⁺ and Fe³⁺; and

(iv) instructions for use.

In a preferred aspect the first composition which is a mixture of Composition A and Composition B has a pH in the range of 4 to 10 and the Composition C has a pH in the range of 4 to 7. In the kit either of the compositions may independently be chosen from any one of an oil, a microemulsion, a gel, a cream, a conditioner or a shampoo. The invention will now be illustrated with the help of the following non-limiting examples.

Examples

Examples A, B and 1 -3: Comparision of the colour obtained using the method of the invention as compared to conventional methods

All experiments were performed on switches of white hair as the starting substrate. The colour of the white hair was measured using the following method: A Minolta CR-10 hand held color reader was used to measure the colour of hair switches. This instrument measures reflected light using 8° illumination/diffuse viewing and gives the colour difference expressed in L^*a^*b^* and dE^* or L^*C^*H^* and dE^*. For the current studies, measurements were made in L^*a^*b^*. The white hair had the following L^*a^*b^* value

L^* = 79.3, a^* = 0.2, b^* = 9.3

It is desirous as per the invention to obtain high darkness (blackness of the hair) and this is indicated by an L^* value less then 40, preferably less than 30. Experiments on colouring hair were carried out as given below.

To conduct the following experiments a shampoo and a conditioner composition were prepared as below: Shampoo composition:

Ingredient Wt%

Sodium laureth sulfate (SLES) 8

Sodium lauryl sulfate (SLS) 7

Cocamide monoethanol amine (CMEA) 2

Cocamidopropyl betaine (CAPB) 2

Glycerine 1

Fragrance 0.7

Water To 100 Conditioner composition:

Example A: In this example propyl gallate was added in the shampoo at 1 % and iron gluconate was added in the conditioner at 4%. The white hair was first treated with the shampoo for five minutes and then with the conditioner for 5 minutes. The hairs were then rinsed and dried using a hair drier and the colour intensity was measured using the chromameter.

Example 1 : In this example the white hair was first treated with an 8% solution of lauroyi cysteine at pH 9 (adjusted with triethanol amine) followed by the treatment as per Example A.

Example 2: In this example the lauroyi cysteine (at 2.0%) was added in the shampoo composition. The procedure followed was otherwise same as Example A.

Example 3: In this example the lauroyi cysteine (at 2.0%) was added in the conditioner composition. The procedure followed was otherwise same as Example A.

Example B: In this example cysteine was used instead of lauroyi cysteine and the procedure was otherwise same as Example 2.

The data on the colour (L^* values) obtained from the various examples are given below in Table -1 : Table -1

L*

Examples

Value

Untreated 79.3

Example A 41.1

Example 1 28.8 Example 2 26.7

Example 3 30.1

Example B 27.1

The data in table -1 indicates that the method as per the invention (Examples 1 to 3) gives the desired dark colour comparable to use of cysteine as a penetration enhancer (Example B). However the odour obtained with the method of Example - 2 was compared to Example B and the data is summarized below.

The following samples were tested for odour.

B1 : 8% cysteine solution

B2: hair treated with 8% cysteine solution

B3: 8% cysteine solution in shampoo

2A: 8% lauroyl cysteine solution

2B: hair treated with 8% lauroyl cysteine solution

2C: 8% lauroyl cysteine solution in shampoo

The odour of the above samples were evaluated by ten volunteers who scored the samples on a scale of 0-9 (with 0 being least acceptable and 9 being most acceptable). The average odour scores given by the ten volunteers for each of the ten samples is given in the Table -2 below

Table-2

The data in Table-2 above indicates that use of cysteine derivative provides a more acceptable odour as compared to cysteine.

Claims

1. A method of colouring keratinous fibers comprising the steps of contacting the keratinous fibers with

Wherein Ri and R₂ are combinations selected from any one of:

(a) When R-i is a C₃ to d₅ alkyl group, R₂ is a H atom;

(b) When R-i is a O-t-butyl group, R₂ is a Ci to do alkyl group; and

(c) When R-i is a sesquiterpene group selected from one of R₃ or R₄ or R₅, R₂ is a Ci to C-m alkyl group;

Where R3 is a glycyrrhetinic acid residue

Where R4 is a ursolic acid residue

Where R5 is a oleanoic acid residue

(ii) a polyphenol and

(Hi) a metal ion selected from the group consisting of Cu²⁺, Cu⁺, Fe²⁺ and

Fe 3+.

where contacting is in any order

A method as claimed in claim 1 comprising the steps of contacting the fibers with a first composition comprising the penetration enhancer and the polyphenol and a second composition comprising the metal ion.

A method as claimed in claim 1 or 2 wherein said polyphenol is gallic acid or an ester thereof, rosmarinic acid, butein, a hydroxyflavone or said polyphenol is present as an extract of Glycyrrhiza glabra.

A method as claimed in any one of the preceding claims wherein said keratinous fiber is human or animal hair.

A method as claimed in any one of the preceding claims wherein the penetration enhancer, the polyphenol and the metal ion are not mixed more than 0 to 60 minutes prior to application on the keratinous fibers.

A method as claimed in any one of the preceding claims 2 to 5 comprising a sequential treatment comprising a first step of contacting the keratinous fibers with the first composition and a second step of contacting the fibers with the second composition.

A method as claimed in claim 6 comprising a step of rinsing the fibers with water between the first step and the second step. A method as claimed in any one of the preceding claims wherein said metal ion is present as an aqueous solution of a chloride, sulphate, gluconate, formate, ascorbate or tartarate salt.

A method as claimed in claim 8 wherein the concentration of the solute in the aqueous solution ranges from 0.2 to 10 weight %.

A kit for colouring keratinous fibers comprising (i) a 'composition A' comprising a penetration enhancer selected from a cysteine derivative of the general formula

Wherein Ri and R₂ are combinations selected from any one of:

(a) When R-i is a C₃ to d₅ alkyl group, R₂ is a H atom;

(b) When R-i is a O-t-butyl group, R₂ is a Ci to do alkyl group; and

(c) When R-i is a sesquiterpene group selected from one of R₃ or R₄ R₅, R₂ is a Ci to C-m alkyl group;

Where R3 is a glycyrrhetinic acid residue

Where R4 is a ursolic acid residue

Where R5 is a oleanoic acid residue

(ii) a 'composition B' comprising a polyphenol;

(iv) instructions for use.

A kit as claimed in claim 10 comprising a first composition comprising a mixture of composition A and composition B, said first composition having a pH in the range of 4 to 10.

A kit as claimed in claim 10 or 1 1 wherein the 'composition C has a pH in the range of 4 to 7. 13. A kit as claimed in any one of claims 10 to 12 wherein the compositions are in the form of an oil, microemulsion, gel, cream, conditioner or shampoo.