FR2831434A1 - Use of an extract of Plectranthus, especially Plectranthus argentatus, as a skin colorant in cosmetic artificial skin tanning compositions - Google Patents

Abstract

The use of an extract of a Plectranthus to prepare a composition intended to color the skin. Independent claims are also included for the following: (1) a method of cosmetic treatment to color the skin consisting of the application of a sufficient quantity of Plectranthus extract or the composition containing it; (2) composition comprising an extract of Plectranthus is a physiologically acceptable carrier.

Description

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The present invention relates to novel compositions comprising at least one extract of at least one plant of the genus Plectranthus, for imparting to the skin an artificial coloration close to natural tanning and to their uses in the aforementioned cosmetic field.

Nowadays, it is important to look good and tanned skin is always a sign of good health. However, natural tanning is not always desirable insofar as it requires prolonged exposure to UV radiation, in particular UV-A radiation which is liable to induce skin damage, particularly in the case of sensitive skin or skin continuously exposed to solar radiation. It is therefore desirable to find an alternative to natural tanning that is compatible with the requirements of such skins.

Most cosmetic products for artificial tanning of the skin are based on carbonyl derivatives allowing, by interaction with the amino acids of the skin, the formation of colored products.

For this purpose, it is known that dihydroxyacetone, or DHA, is a particularly interesting product which is commonly used in cosmetics as an artificial tanning agent for the skin; applied on the latter, especially on the face, it provides a tanning effect or browning appearance similar to that which may result from prolonged exposure to the sun (natural tanning) or under a UV lamp.

However, the use of DHA may have certain disadvantages. So, the
DHA has an unfortunate tendency, more or less pronounced depending on the nature of the medium in which it is formulated, to degrade over time, this degradation usually resulting in an undesirable yellowing of the compositions that contain it. Such a phenomenon makes that the activity of DHA, and in particular its ability to color the skin, can be decreased at the time of application of these compositions to the skin. Thus, the intensity of the coloration obtained on the skin may appear as still insufficient.

 Another disadvantage of DHA is the slowness with which the coloring develops: it is indeed necessary to count several hours (3 to 5 hours in general) for the coloring to be revealed. In addition, the color produced on the skin by

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 DHA is often considered too yellow by users.

There is therefore a growing demand for quick-acting self-tanning products that impart a closer coloration to natural tanning.

In order to meet this need, it has been proposed to associate DHA with various products: thus, WO 95/15742 describes the association of DHA with amino acids. However, the use of such combinations is very impractical in that it requires either a two-step application or complex separate packages. Document FR-2 726 761 describes the association of DHA with lawsone and / or juglone: again this association is unsatisfactory, because this time the risk of awareness it presents.

Thus, we are always looking for new products and new compositions for artificially conferring on the skin a color close to the natural tan in a simple, effective, fast and without risk.

However, following extensive research conducted in the field of artificial coloring of the skin, the Applicant has now discovered that the use of particular compounds makes it possible to give the skin a durable artificial coloring close to natural tanning, and this immediately after application to the skin.

The subject of the present invention is therefore a new composition, characterized in that it comprises, in a physiologically acceptable support, a sufficient quantity of at least one extract of at least one plant of the genus Plectranthus for coloring the skin.

 The present invention further relates to the novel use of at least one extract as defined above in, or for the manufacture of, compositions for coloring the skin.

 The subject of the present invention is also a process for the cosmetic treatment of the skin intended for coloring it, characterized in that it consists in applying thereon an effective quantity of an extract or a cosmetic composition as defined herein. -above.

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 The compositions and uses according to the invention make it possible to obtain an artificial coloration close to natural tanning in an exceptionally short period of time. Thus, an immediate coloration is obtained which allows a visualization of the application and consequently a better homogeneity in the spreading of the composition on the skin and thus of the resulting coloration. In addition, the artificial coloration obtained on the skin according to the invention is extremely close to the natural tan and also very resistant to water and time (it can persist on the skin for several days).

Other features, aspects and advantages of the present invention will appear on reading the detailed description which follows.

The plants of the genus Plectranthus are described in the encyclopedia The Good Gardener of Editions La Maison Rustique and concerning the 153sth edition of this work, under the direction of JN Burte with the collaboration of G.

Aymonin.

sans limitation : Plectranthus coleoides, Plectranthus elegans, Plectranthus hereroensis, Plectranthus argents. Plectranthus plants belong to the family Labiateae and the genus comprises about 25 species, among which are found for example and

without limitation: Plectranthus coleoides, Plectranthus elegans, Plectranthus hereroensis, Plectranthus silver.

Plectranthus elegans, Plectranthus hereroensis, Plectranthus argentatus. The extract of at least one plant of the genus Plectranthus used according to the invention may be a plant extract of a species chosen from Plectranthus coleoides,

Plectranthus elegans, Plectranthus hereroensis, Plectranthus argentatus.

Preferably, according to the invention, the extract of at least one plant of the genus Plectranthus is an extract of Plectranthus argentatus.

To the knowledge of the applicant, their use as a skin coloring agent as defined above has never been described.

The extract of at least one plant of the genus Plectranthus used according to the invention can be obtained from plant material derived from whole plant or part of plant such as leaves, stems, flowers, petals, roots or still dedifferentiated cells.

By dedifferentiated plant cells is meant any plant cell not

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 presenting none of the characters of a particular specialization and able to live by itself and not in dependence with other cells.

Preferentially according to the invention, the whole plant is used, particularly the stem and / or leaves, very particularly leaves.

The extract of at least one plant of the genus Plectranthus may be any extract prepared from any plant material derived from at least one plant of the genus Plectranthus grown in vivo or derived from in vitro culture.

In vivo culture is understood to mean any culture of conventional type, ie in soil in the open air or in the greenhouse or above ground.

By in vitro culture is meant all the techniques known to those skilled in the art which artificially allows the production of a plant or part of a plant. The selection pressure imposed by the physicochemical conditions during the growth of plant cells in vitro makes it possible to obtain a standardized plant material that is available throughout the year, unlike plants grown in vitro.

Preferably, according to the invention, a plant of the genus Plectranthus derived from in vitro culture is used.

Any extraction method known to those skilled in the art can be used to prepare the extract according to the invention.

 In particular, mention may be made of alcoholic extracts, in particular ethanolic or hydroalcoholic extracts.

 Preferably according to the invention, the extract is an aqueous extract.

 It is also possible to use an extract prepared by the method described in the French patent application No. 95-02379 filed by the applicant.

Thus, in a first step the plant material is milled in a cold aqueous solution and in a second step the suspended particles are removed from the aqueous solution from the first stage. This aqueous solution corresponds to the extract.

 Optionally, in a third step, the aqueous solution resulting from the second step is sterilized.

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This extract can then be lyophilized.

The first step may advantageously be replaced by a simple freezing operation of the plant tissues (for example at -20 ° C. or alternatively at 180 ° C. in liquid nitrogen), followed by an aqueous extraction taking up the second and third steps below. described above.

The cold treatment makes it possible to freeze the enzymatic activities, the sterilizing filtration avoids the degradation of the active ingredients by the microorganisms of the environment. Finally, the water vehicle is compatible with ex vivo receptors and facilitates cosmetic or pharmaceutical formulations.

It is known that plant extracts contain oxidases responsible, inter alia, for the oxidation of said extracts. However, such an oxidation leads to a dark brown color of the extracts and to a pungent odor rendering them incompatible with their use in cosmetics. In this connection, a laccase having a molecular weight greater than 100,000 daltons is particularly known.

Thus, advantageously, the extract obtained can be fractionated by any known fractionation method for eliminating oxidases and in particular polyphenoloxidase. For example, the extract of the invention can be filtered on a dialysis membrane in order to eliminate molecules with a molecular weight greater than 100,000 daltons. It is also possible to subject the extract to fractionation by selective precipitation.

Other methods make it possible to protect oneself from oxidation phenomena. In particular, the extract can also be stabilized. Any known stabilization method can be used according to the invention. For example, the extract of the invention can be stabilized by sparging nitrogen to remove dissolved oxygen or by adding cysteine and! or sulfur derivatives at a final concentration of between 0.5 g / t and 10 g / t and preferably between 1 g / i and 2.5 g / t.

 Obviously the extract according to the invention can be fractionated and stabilized.

 The extract can constitute by itself the active ingredient of the compositions of the invention.

 An example of an extract preparation that can be used according to the invention is given elsewhere in the examples.

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Preferably, the extract of at least one plant of the genus Plectranthus is present in the compositions according to the present invention in proportions sufficient to impart to the skin, after application, a coloration similar to the coloration obtained as a result of natural tan. It is thus generally present in proportions of between 0.05% and 20% by weight relative to the total weight of the composition, and preferably between 0.5% and 10% by weight relative to the total weight of the composition. .

The compositions contemplated by the present invention may, of course, contain one or more other skin-coloring agents, for example mono or polycarbonyl derivatives, such as isatin, alloxane, ninhydrin, glyceraldehyde or mesotartaric aldehyde. pyrazoline-4,5-dione derivatives, these skin coloring agents may or may not be associated with direct dyes or indole derivatives.

In a preferred embodiment of the invention, the compositions further comprise dihydroxyacetone (DHA).

que l'isatine, l'alloxane, la ninhydrine, le glycéraldéhyde, l'aldéhyde mésotartrique, les dérivés de pyrazoline-4, 5-dione, la dihydroxyacétone. Thus, the subject of the present invention is also a composition, characterized in that it comprises, in a physiologically acceptable support, an extract of at least one plant of the genus Plectranthus as defined above and another coloring agent skin. Preferably, according to the invention, the skin coloring agent is chosen from mono or polycarbonyl derivatives such as

such as isatin, alloxane, ninhydrin, glyceraldehyde, mesotartaric aldehyde, pyrazoline-4,5-dione derivatives, dihydroxyacetone.

Most preferably, the skin coloring agent is dihydroxyacetone (DHA).

In fact, the dihydroxyacetone and the extracts of at least one plant of the genus Plectranthus defined above exhibit excellent chemical compatibility within the compositions containing them, as well as a very good complementarity of the colorations they confer on the skin. which allows, by associating them in adequate proportions, to achieve an artificial coloration of the skin remarkably close to the color conferred by the natural tan.

The skin coloring agent is present in the compositions according to the invention in proportions allowing the combination of the two agents of the

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 coloring of the skin to give the skin, after application, a coloration as close as possible to that obtained after a natural tan. The coloring agent of the skin is thus generally present in an amount by weight of between 0.5% and 10% by weight relative to the total weight of the composition, and preferably between 1% and 7% by weight relative to to the total weight of the composition.

The dihydroxyacetone may also be applied to the skin in the form of an independent composition, separately from the composition comprising the extract of at least one plant of the genus Plectranthus, for example before or after the application of the latter.

In a preferred embodiment of the cosmetic treatment method according to the invention, a composition comprising dihydroxyacetone is firstly applied, then, in a second step, the composition comprising the extract of at least one plant of the genus Plectranthus, in order to qualify according to the wishes of the user the coloration sometimes judged a little yellow brought by the dihydroxyacétone alone.

The compositions according to the invention may also contain one or more hydrophilic or lipophilic active UVA and / or UVB sunscreens, or coated or uncoated metal oxide pigments.

The compositions according to the invention may be cosmetic or dermatological compositions. Preferably, according to the invention, the compositions are cosmetic compositions.

les tensioactifs, les charges, les séquestrants, les polymères, les propulseurs, les agents alcalinisant ou acidifiants, les colorants, ou tout autre ingrédient habituellement utilisé dans le domaine, en particulier pour la fabrication de compositions anti-solaires sous forme d'émulsions. The compositions in accordance with the present invention may furthermore comprise conventional adjuvants, chosen especially from fatty substances, organic solvents, ionic or nonionic thickeners, softeners, antioxidants, anti-free radical agents, opacifiers and stabilizers. , emollients, silicones, α-hydroxy acids, anti-foam agents, moisturizers, vitamins, fragrances, preservatives,

surfactants, fillers, sequestering agents, polymers, propellants, basifying or acidifying agents, dyes, or any other ingredient normally used in the field, in particular for the manufacture of sunscreen compositions in the form of emulsions.

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The fatty substances may consist of an oil or a wax or mixtures thereof. By oil is meant a liquid compound at room temperature. By wax is meant a compound which is solid or substantially solid at ambient temperature and whose melting point is generally greater than 35 C.

"Finsolv TN"par la société Finetex, le palmitate d'octyle, le lanolate d'isopropyle, les triglycérides dont ceux des acides caprique/caprylique), les esters et éthers gras oxyéthylénés ou oxypropylénés ; siliconées (cyclométhicone, polydiméthysiloxanes ou PDMS) ou fluorées, les polyalkylènes. As oils, mention may be made of mineral oils (petroleum jelly); vegetable (sweet almond oil, macadamia oil, blackcurrant seed oil, jojoba oil); synthetics such as perhydrosqualene, alcohols, acids or fatty esters. (such as C12-C15 alcohol benzoate sold under the trade name

"Finsolv TN" by Finetex, octyl palmitate, isopropyl lanolate, triglycerides, including those of capric / caprylic acids), oxyethylenated or oxypropylenated esters and fatty ethers; silicone (cyclomethicone, polydimethylsiloxane or PDMS) or fluorinated, polyalkylenes.

Waxy compounds that may be mentioned include paraffin wax, carnauba wax, beeswax and hydrogenated castor oil.

Among the organic solvents, mention may be made of lower alcohols and polyols.

The thickeners may be chosen in particular from crosslinked polyacrylic acids, guar gums and modified or unmodified celluloses such as hydroxypropyl guar gum, methylhydroxyethylcellulose and hydroxypropylmethylcellulose.

Of course, one skilled in the art will take care to choose the optional additional compound (s) mentioned above and / or their amounts in such a way that the advantageous properties intrinsically attached to the use of at least one extract of less a plant of the genus Plectranthus according to the invention are not, or not substantially, altered by the addition or additions envisaged.

The compositions according to the invention can be prepared according to the techniques well known to those skilled in the art, in particular those intended for the preparation of oil-in-water (O / W) or water-in-water emulsions. oil (W / O).

This composition may be in particular in the form of an emulsion, simple or complex (O / W, W / O, O / W / H or El HIE) such as cream, milk, or in the form of a gel or a cream gel, in the form of a lotion, powder,

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 stick solid and possibly be packaged in aerosol and be in the form of foam or spray.

Preferably, the compositions according to the invention are in the form of an oil-in-water emulsion.

In the case of an emulsion, the aqueous phase thereof may comprise a nonionic vesicle dispersion prepared by known methods (Bangham, Standish and Watkins, J. Mol Biol 13, 238 (1965), FR 2). 315,991 and FR 2,416,008).

Concrete but non-limiting examples illustrating the invention will now be given.

EXAMPLE 1 Preparation of an extract of Plectranthus argentatus: 50 grams of leaves of Plectranthus argentatus, taken fresh, are finely cut in the presence of 10 ml of 0.05M phosphate buffer at pH7, the whole is then ground in the Turrax at 24000 rpm at 40C (ice bath).

The extract obtained is centrifuged at 10000 g and then filtered on a paper membrane of porosity 0.7 μm to remove cell debris. The juice obtained can be used as it is, after sterilizing filtration, to maintain its stability over time, or freeze-dried. The yield of freeze-dried product obtained with respect to the raw material used is of the order of 20%. EXAMPLE 2 Skin Coloring Test: The extract obtained in Example 1 is applied on the inside of the front arm of 2 volunteer subjects (A and B), to evaluate the color obtained.

The skin is colored immediately.

 The color of the skin is evaluated before and after dyeing, in the L a b system, using a Minolta Chromameter (model CR200).

 In the system L a b, the three parameters denote respectively the intensity (L), the shade (a) and the saturation (b).

 According to this system, the higher the value of L, the lighter or less intense the color. Conversely, the lower the value of L, the darker the color

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 very intense. a and b indicate two color axes, a indicates the green / red color axis and b the blue / yellow color axis. Values close to zero for a and b correspond to gray shades.

dans laquelle : AL= L-H, Aa=a-aoetAb =b-bo, L, a, et b représentant respectivement l'intensité, la nuance et la saturation de la peau après coloration, Lo, ao et bo représentant respectivement l'intensité, la nuance et la saturation de la peau avant coloration. The coloring (AE) can be calculated by applying the following equation:

in which: AL = LH, Aa = a-aoetAb = b-bo, L, a, and b respectively represent the intensity, the shade and the saturation of the skin after staining, Lo, ao and bo respectively representing the intensity , the shade and saturation of the skin before staining.

The higher the AE value, the greater the difference in color between the unstained skin and the colored skin.

The following values are observed:

<Tb>
<tb> AL <SEP> Aa <SEP> Ab <SEP> AE
<tb> A-7, <SEP> 58 <SEP> 5, <SEP> 00 <SEP> 11, <SEP> 07 <SEP> 14,32
<tb> B-7, <SEP> 13 <SEP> 3, <SEP> 14 <SEP> 11, <SEP> 03 <SEP> 13, <SEP> 50
<Tb>
These results confirm the ability of Plectranthus argentatus to color the skin in orange tones.

Example 3: Examples of formulations illustrating the invention and particularly the compositions according to the invention combining at least one extract of at least one plant of the genus Plectranthus and DHA. These compositions were obtained by simple mixing of the various components.

<Tb>
<Tb>

Composition <SEP> A <SEP>:
<tb> Montanov68 * <SEP> 7, <SEP> 5 <SEP>%
<tb> Dimethicone <SEP> 0.5 <SEP>%
<tb> Finsolv <SEP> TNvTN <SEP> 15.0 <SEP>%
<tb> Propylene <SEP> glycol <SEP> 10.0 <SEP>%
<Tb>

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<Tb>
<tb> Dihydroxyacetone <SEP> 5.0 <SEP>%
<tb> Extract <SEP> from <SEP> Plectranthus <SEP> argentatus <SEP> 5.0 <SEP>%
<tb> Conservatives <SEP> qs
<tb> Water <SEP> qsp <SEP> 100.0 <SEP>%
<Tb>
Composition B:

<Tb>
<tb> Extract <SEP> from <SEP> Plectranthus <SEP> argentatus <SEP> 7.0 <SEP>%
<tb> Ceteareth <SEP> 30 <SEP> 7.0 <SEP>%
<tb> Stearate <SEP> of <SEP> Glyceryl <SEP> 2.0 <SEP>%
<tb> Alcohol <SEP> Cetyl <SEP> 1.5 <SEP>%
<tb> Polydimethylsiloxane <SEP> 1.5 <SEP>%
<tb> Oil <SEP> of <SEP> paraffin <SEP> 15.0 <SEP>%
<tb> Glycerin <SEP> codex <SEP> pure <SEP> 20.0 <SEP>%
<tb> Demineralized <SEP> Water <SEP> q. <SEP> s. <SEP> p. <SEP> 100.0 <SEP>%
<tb> Conservatives <SEP> q. <SEP> s.
<Tb>

Composition C:

<Tb>
<tb> extract <SEP> from <SEP> Plectranthus <SEP> argentatus <SEP> 15,0 <SEP>%
<tb> Dihydroxyacetone <SEP> 1.0 <SEP>%
<tb> Ethanol <SEP> 30.0 <SEP>%
<tb> Demineralized <SEP> water <SEP> qsp <SEP> 100.0 <SEP>%
<Tb>
*: Cetylstearyl glucoside / cetylstearyl alcohol mixture sold by Seppic **: C12 / C15 alcohol benzoate sold by Finetex

Claims (18)

1. A composition, characterized in that it comprises, in a physiologically acceptable carrier, a sufficient amount of at least one extract of at least one plant of the genus Plectranthus to color the skin. 2. Composition according to claim 1, characterized in that the plant of the genus Plectranthus is of a species selected from Plectranthus. Coleoides, Plectranthus elegans, Plectranthus hereroensis, Plectranthus argentatus. 3. Composition according to claim 2, characterized in that the plant of the genus Plectranthus is an extract of Plectranthus argentatus. 4. Composition according to any one of the preceding claims, characterized in that the plant material is derived from whole plant or part of plant such as leaves, stems, flowers, petals, roots or even dedifferentiated cells . 5. Composition according to claim 4, characterized in that the plant material is derived from the leaves. 6. Composition according to any one of the preceding claims, characterized in that the plant material is derived from at least one plant of the genus Plectranthus grown in vivo or derived from in vitro culture. 7. Composition according to claim 6, characterized in that the plant material of at least one plant of the genus Plectranthus is cultured in vitro. 8. Composition according to any one of the preceding claims, characterized in that the extract is an aqueous extract. 9. Composition according to any one of the preceding claims, characterized in that the extract is in a weight amount representing from 0.05% to 20% of the total weight of the composition. 10. Composition according to the preceding claim, characterized in that the extract is in a weight amount representing 0.5% to 10% of the total weight of the composition. <Desc / Clms Page number 13> 11. Composition according to any one of the preceding claims, characterized in that it further comprises another skin coloring agent. 12. Composition according to claim 11, characterized in that the skin coloring agent is chosen from mono or polycarbonyl derivatives such as isatin, alloxane, ninhydrin, glyceraldehyde, mesotartaric aldehyde, pyrazoline-4,5-dione derivatives, dihydroxyacetone. 13. Composition according to claim 12, characterized in that the skin coloring agent is dihydroxyacetone. 14. Composition according to any one of claims 11 to 13, characterized

 in that the skin coloring agent is present in the composition in an amount of between 0.5 and 10%. 15. Composition according to claim 14, characterized in that the skin coloring agent is present in the composition in an amount of between 1 and 7% by weight, relative to the total weight of the composition. 16. Use of at least one extract of at least one plant of the genus Plectranthus in a composition or for the preparation of a composition, the extract or composition being intended to color the skin. 17. A cosmetic treatment method for dyeing the skin, characterized in that it consists in applying thereon an effective amount of an extract of at least one plant of the genus Plectranthus or a composition as defined in US Pat. any one of claims 1 to 15. 18. The method of claim 17, characterized in that it comprises the two following steps: - i) is applied to the skin a composition comprising dihydroxyacétone, - ii) is applied to the skin a composition as defined in any of claims 1 to 10.