WO1999018927A1

WO1999018927A1 - Compositions for cosmetic and dermopharmaceutical use containing a plant extract obtained from clover (trifolium sp.)

Info

Publication number: WO1999018927A1
Application number: PCT/FR1998/002163
Authority: WO
Inventors: Karl Lintner
Original assignee: Sederma S.A.
Priority date: 1997-10-14
Filing date: 1998-10-06
Publication date: 1999-04-22
Also published as: FR2769502B1; FR2769502A1; AU9448598A

Abstract

The invention concerns compositions for cosmetic and dermopharmaceutical use containing, in sufficient amount, a plant extract obtained from clover (Trifolium sp.), more particularly selected among the Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L. varieties. With the molecules of plant origin thus obtained, the extract can imitate the effects of some steroid hormones. The cosmetic or dermopharmaceutical compositions containing said plant extract are advantageously used for all postmenopausal conditions where it is necessary to improve hydration, skin tonus and to obtain a skin smoothing effect.

Description

Title: Compositions for cosmetic or dermopharmaceutical use containing a plant extract obtained from clover (Trifolium sp.).

Menopause is a natural physiological stage which corresponds, around the age of fifty, to a drop in the hormonal secretions responsible for fertility (estrogens and progesterone) and therefore to a significant drop in their blood and tissue concentrations.

The very numerous negative consequences of this phenomenon on the human organism can be improved by medical treatments which consist in administering, by general way, exogenous hormones which correct this induced hormonal imbalance. Cosmetic and dermopharmaceutical approaches can also improve the personal comfort and beauty of postmenopausal women. Indeed, certain consequences of menopause, clearly visible, relate to skin aging such as, for example, drying of the skin, the appearance or aggravation of wrinkles due to a decrease in skin tone as well as decrease in skin thickness.

The invention subject of this present patent, is the discovery that ^a plant extract obtained from clover {Trifolium sp.), More particularly chosen among the varieties Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L, when properly performed, is capable of correcting all these defects which disrupt the normal life of postmenopausal women. The previous plant extract of clover (Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L) is obtained from the whole plant or, preferably, from the flowering and dried aerial parts, by ethanolic extraction in a ratio of 15 grams of plants for 85 grams of solvent. After drying, the dry extract is taken up in butylene glycol. Analysis by liquid phase chromatography carried out under high pressure (HPLC) of the plant extract thus obtained reveals the presence of molecules of the isoflavone family such as genistein, daidzein, biochanin A, pratensin and coumesterol. . The present invention demonstrates that these molecules, when properly extracted by those skilled in the art as described above, are true phytoestrogens, which, when applied topically, are capable of mimicking locally the beneficial effects of estrogens, of human or animal origin or synthetic, administered systemically.

The example of obtaining the plant extract obtained from clover (Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L) previously described which is the subject of this present patent, is not limiting. It is indeed possible to make the clover extract by other methods such as, for example, simple decoction, leaching, extraction under reflux, extraction by means of ultrasound or microwave or finally counter-current techniques, without this list being exhaustive.

Furthermore, the extraction solvents mentioned above are not limiting and can be chosen from water, propylene glycol. butylene glycol, glycerin, polyethylene glycol, methyl or ethyl ethers of diglycols, cyclic polyols, ethoxylated or propoxylated diglycols. alcohols (methanol, ethanol, propanol, butanol). or any mixture of these solvents. For clarity in this document, among the various benefits that have been found during development of ^the extract of clover Trifolium subterraneum {L.

Trifolium repens L., Trifolium pratense L) previously described being the subject of this patent, only three examples will demonstrate three specific effects and especially useful in post-menopausal cases, by means of an in vitro experiment and two studies in vivo performed in volunteers. Example 1

For 24 hours, human fibroblates from the same cell culture are placed in the presence of supplemented standard culture medium. or not for the controls, with the clover extract previously described at a concentration of either 0.3% or 1%. The stimulation of protein synthesis is evaluated by colorimetry (so-called Biuret reaction).

To standardize the results, the quantity of protein measured is expressed per 1000 cells present in the test. Compared to control experiments, in the presence of either 0.3% or 1% of clover extract, the increase in protein concentration is 33.5 ± 1.5% and 56.2 ± 2.12 respectively. %. Thus, this in vitro test demonstrates the stimulating potential at the cutaneous level of the clover extract described above, an effect directly linked to firming and thickening of excessively thin skin. Example 2

This example demonstrates the skin moisturizing effect obtained, in vivo, on the legs of 13 adult female volunteers. The hydrating power of the clover extract previously described, incorporated at 5% in a gel conventionally used in cosmetics, was compared with that of a placebo (the same gel but without clover extract) and with an absence of treatment.

This test can be briefly described as follows. The hydration level of the skin is measured by the skin's electrical capacity using a cometometer (Courage and

Khazaka, model CM 820), a technique conventionally used in cosmetology. Indeed, the electrical properties of the surface layers of the skin are strongly linked to its water content.

Three independent sites are identified using adhesives and pen markings then, after a period of 20 minutes of rest in a seated position, the measurements corresponding to the TO are carried out in triplicate, at each site. Each of the two gels studied (placebo and clover extract) is then applied until complete penetration, on an independent site, at a rate of 20 μl per site. The third site previously identified does not receive any product. The volunteers remain at rest. Three measurements per site are carried out every hour, and this, for 7 hours. The temperature and humidity of the room where the test is carried out are kept constant throughout the test.

The following table shows the variations, in percentage compared to TO, of the measurements carried out for 7 hours. The values indicated correspond to the averages calculated from the 3 measurements carried out.

T O T + 1H T + 2H T + 3H T + 4H T + 5H T + 6H T + 7H

Nothing 0 -0.3 -2.0 +0.5 +0.5 +0.1 +0.9 -0.9

Placebo 0 +0.5 0.0 +2.8 +1.9 +4.0 +1.1 +0.2

Extract 0 +25.8 +21.2 +25.3 +22.8 +25.7 +21.7 +22.0

The gel containing the clover extract previously described clearly demonstrates a strong hydrating power since not only the skin hydration is increased from 22% to 25% compared to the start of the test but, moreover, it is perfectly constant and this for at least the 7 hours that the test lasts. Under the same conditions, the placebo gel (without the clover extract), has no hydrating effect, just as it can be seen when no product is applied.

Example No. 3 This example reports the anti-wrinkle effect obtained, in vivo, on a panel made up of 13 adult female volunteers. The anti-wrinkle power of the extract described above, incorporated at 5% in a cream conventionally used in cosmetics, is compared to that of a placebo (the same cream but without clover extract). The creams are applied to precisely identified sites, located on the corner of the right or left eye, in a randomized distribution, twice a day, for 28 days.

The parameter considered is the skin surface, at the contour of the eye (called wrinkles of the leg ^goose). The quantifications of the different relief variables are carried out by computer-video analysis of silicone impressions taken on the surface of the skin according to the protocols described by Corcuff et al. (1985, Int. J. Cosm. Sci. 7: 117-126) and Corcuff et al. (1995, in Handbook of non-invasive methods and the skin, Serup

& Jemec eds., CRC Press: 89-96). The table below indicates the difference, in percentage, of the average values obtained between T +28 days and TO for the average depths of the main wrinkle (column A) or for all the folds (column B), for the density main folds (column C) as well as for roughness measurement (column D). The presence of a star next to the value indicates a statistically significant difference between the measurements at T + 28 and at TO (t test of

Student, p <0.01).

_ _ _ _

Placebo 0.2 + 0.5 - 1.1 + 3.8 Extract - 18.2 * - 21.1 * - 36.9 * - 19.9 *

The cream containing the clover extract previously described clearly demonstrates a powerful anti-wrinkle effect since there is a statistically significant difference between the start and the end of the in vivo study and this, on all four parameters conventionally used in this indication. It should be noted that under the same experimental conditions, the same cream has absolutely no effect if the plant extract obtained from the clover previously described has not been incorporated, which clearly demonstrates that it is only at the extract previously described in this patent which can be attributed to the beneficial effect observed.

The plant extract obtained from the clover previously described can be used in any galenic form used in cosmetics or dermopharmacy: O / W and W / O emulsions, milks, lotions, gelling and viscous polymers, surfactants and emulsifiers, ointments, hair lotions , shampoos, soaps, sticks and pencils, sprays, body oils, without this list being exhaustive.

It is possible to incorporate the plant extract obtained from clover (Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L) previously described, in cosmetic vectors such as liposomes, chylomicrons, macro-, micro- and nanoparticles as well as macro-, micro- and nanocapsules, to absorb them on powdery organic polymers, talcs, bentonites and other mineral supports. The plant extract obtained from clover (Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L) previously described can be combined in cosmetic compositions with any other ingredient usually used in cosmetics: extraction lipids and / or synthesis, gelling and viscosifying polymers, surfactants and emulsifiers, water- or liposoluble active principles, extracts from other plants, tissue extracts, marine extracts. The plant extract obtained from the clover described above is used either in liquid form or in dry form obtained by conventional techniques of precipitation, drying, evaporation, atomization or lyophilization

The concentrations of the plant extract obtained from clover (Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L) previously described can vary between 0.01%) and 50% (w / w), preferably between 0.5% > and 5% by weight, in the finished product. The plant extract obtained from clover is advantageously used in cosmetic or dermopharmaceutical applications which correct and / or repair at the cutaneous level, the effects of aging, hormonal disturbances or menopause. These cosmetic or dermopharmaceutical compositions are used for the preparation of drugs for all skin care, particularly the effects of aging, hormonal disturbances or menopause.

Claims

1. Cosmetic or dermopharmaceutical compositions, characterized in that they contain an extract of clover (Trifolium sp.).

2. Cosmetic or dermopharmaceutical compositions according to claim 1, characterized in that the clover used can be chosen more particularly from the varieties Trifolium subterraneum L., Trifolium repens L., Trifolium pratense L ..

3. Cosmetic or dermopharmaceutical compositions according to claims 1 to 2, characterized in that the clover extract is obtained from the whole plant or, preferably from the flowering and dry aerial part.

4 A method of obtaining cosmetic or dermopharmaceutical compositions according to claims 1 to 3 characterized in that the extraction solvents used are chosen from water, propylene glycol, butylene glycol, glycerin, polyethylene glycol, ethers methyl or ethyl diglycols, cyclic polyols, ethoxylated or propoxylated diglycols, alcohols (methanol, ethanol, propanol, butanol), or any mixture of these solvents.

5. Method of obtaining according to claim 4 characterized in that the clover extract is obtained by ethanolic extraction then, that after drying, the dry extract is taken up in butylene glycol.

6. Method for obtaining cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3, characterized in that the extraction carried out from clover can be replaced by maceration techniques or by other methods such as, for example. for example, simple decoction, leaching, reflux extraction, extraction using ultrasound or microwaves or finally countercurrent techniques.

7 cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3 characterized in that the clover extract is used either in liquid form or in dry form obtained by conventional techniques of precipitation, drying, evaporation . atomization or freeze-drying.

8. Cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3 or 7 characterized in that the concentration of the clover extract is between 0.01% and 50%> (w / w), preferably between 0.5% and 5% by weight, in the finished product.

9. Cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3, 7 or 8 characterized in that the clover extract can be used in any galenical form used in cosmetics or dermopharmacy: O / W and W / O emulsions , milks, lotions, gelling and viscosifying polymers, surfactants and emulsifiers, ointments, hair lotions, shampoos, soaps, sticks and pencils, sprays, body oils.

10. Cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3 or 7 to 9 characterized in that the clover extract is incorporated in cosmetic vectors such as liposomes, chylomicrons, macro-, micro- and nanoparticles as well as macro-, micro- and nanocapsules, or absorbed on powdery organic polymers, talcs, bentonites and other mineral supports.

11. Cosmetic or dermopharmaceutical compositions according to any one of claims 1 to 3 or 7 to 10 characterized in that the clover extract is combined in the cosmetic compositions with any other ingredient usually used in cosmetics: extraction lipids and / or synthetic, gelling and viscous polymers, surfactants and emulsifiers, water- or liposoluble active principles, extracts from other plants, tissue extracts, marine extracts.

12. Use of the composition according to any one of claims 1 to 3 or 7 to 11, in cosmetic applications which correct and / or repair at the cutaneous level, the effects of aging, hormonal disturbances or menopause.

13. Cosmetic or dermopharmaceutical compositions according to 12 used for the preparation of medicaments for all skin care, particularly the effects of aging, hormonal disturbances or menopause.