HK1050841B - Ajuga turkestanica extract and its cosmetic uses - Google Patents

Description

The present invention relates to a new extract of the Ajuga turkestanica plant and its applications in the cosmetic field.

The use of ecdysteroids to strengthen the water barrier of the skin by their action on keratinocyte differentiation is described in French patent FR 2 696 075.This patent cites a large number of ecdysteroid sources in both animal and plant fields.Among these many sources, two plants of the Ajuga family are in particular, namely Ajuga iva and Ajuga decumbens.

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This plant was used in traditional medicine as a herbal tea for its tonic and liver-protective properties.

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The first object of the present invention is extracts which are themselves new products and which, by extension, also concern cosmetic compositions and uses of these extracts in the field of cosmetics.

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The inventors of the present invention inferred from the properties of the extracts and combinations of the invention that these extracts and combinations were particularly active in regulating and/or enhancing the functionality of AQP3 aquaporins.

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The invention is based on the discovery that, by selecting particularly polar solvent media, extracts of the Ajuga turkestanica plant can be obtained with particularly interesting cosmetic properties and that some of these extracts contain combinations of active substances which, when used in cosmetics, lead to the same remarkable cosmetic properties. These extracts and combinations in particular improve the differentiation of keratinocytes, which improves skin hydration and has a particularly effective anti-aging effect. Furthermore, the authors of the present invention have noted that the extracts and combinations of the invention have a particularly effective effect on regulating the hydrological flow in the epidermis, the activity of keratinocytes and the activity of aquaproteins, which can be linked to the function of the AQP3 base.

Thus, according to one of its essential characteristics, the invention concerns an extract of the plant Ajuga turkestanica, characterised by the fact that it contains at least one ecdysteroid and at least one iridoid and that it can be obtained by extraction of at least part of that plant by means of a solvent or a mixture of solvents consisting of 0 to 60% by weight of water, the remainder of that solvent or mixture of solvents being at least one alcohol in C1 to C4, and/or acetone and/or butyl glycol and/or propyl glycol.

The extraction process used to prepare the extracts of the invention is advantageously applied under such conditions as to allow the extraction to be carried out with the said solvent or mixture of solvents for 1 to 4 hours.

The extraction process used to prepare the extracts of the invention is advantageous under such conditions as to allow the extraction to be carried out at the ebb of the solvent or mixture of solvents for 1 to 4 hours.

The extraction may be carried out on the whole plant or on a part of the plant, but the roots of the plant are preferably used for the preparation of the extracts of the invention.

The proportions of water and alcohol or water and acetone in the solvent or mixture of solvents used to implement the extraction process for the preparation of the extracts of the invention may vary widely; however, a proportion of water between 0 and 50% by weight is preferred for alcoholic solvents or acetone.

The proportions of water and butylene glycol or propylene glycol in the solvent or mixture of solvents used for the implementation of the extraction process for the preparation of the extracts of the invention may vary widely, but a proportion of water close to 50% by weight is preferred for butylene glycol or propylene glycol.

The solvent mixture used to implement the extraction process for the preparation of the extracts of the invention may be any mixture of C1 to C4 alcohols, water, butylene glycol or propylene glycol.

The preferred alcohols for the implementation of the process for the preparation of the extracts of the invention are methanol and ethanol.

The preparation of the extracts according to the invention is advantageously based on water-ethanol, water-methanol, water-acetone, water-propylene glycol or water-butylene glycol mixtures.

In the case of water-ethanol mixtures, a mixture containing 70 to 90% ethanol and 30 to 10% water is preferably chosen, preferably a mixture containing 80% ethanol for 20% water.

In the case of water-methanol mixtures, a mixture containing 70 to 90% methanol and 30 to 10% water is preferably chosen, preferably a mixture containing 80% methanol for 20% water.

In the case of water-acetone mixtures, a mixture containing 70 to 90% acetone and 30 to 10% water is preferably chosen, preferably a mixture containing 80% acetone for 20% water.

In the case of water-propylene glycol mixtures, a mixture containing 40 to 60% propylene glycol and 60 to 40% water, preferably 50% propylene glycol for 50% water, is preferable.

In the case of water-butylene glycol mixtures, a mixture containing 40 to 60% butylene glycol and 60 to 40% water, preferably 50% butylene glycol for 50% water, is preferable.

It has been shown that the extracts of the invention contain advantageously combinations containing one part by weight of at least one ecdysteroid and two to four parts by weight, preferably three parts by weight, of at least one iridoid.

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As an advantageous variant, the ecdysteroids in these combinations are preferably chosen from the group consisting of ecdysterone, 2,3-monoacetonide of ecdysterone, turkesterone, cysterone, 22-acetyl-cysterone and alpha-ecdysone.

Another advantageous variant is that the iridoids contained in these combinations are chosen from the group consisting of the harpagide and its 8-O-acetyl derivative.

According to a favourable variant, the various ecdysteroids in these combinations are composed, expressed as 30 to 35% ecdysterone, 20 to 25% turkesterone, 20 to 24% 22-acetyl-cysterone, 11 to 15% 2,3-monoacetone of ecdysterone, 6 to 7% alpha-ecdysone, 2 to 4% cysterone.

According to another advantageous variant, iridoids are composed, expressed in terms of weight, of 60-70% 8-O-acetylharpagide and 30-40% harpagide.

As previously described, the extracts of the invention have a special keratinocyte differentiation activity, which allows them to contribute to the strengthening of the water barrier role of the epidermis, thus improving its hydration and playing an anti-aging role, improving the appearance and quality of the skin, thus resulting in a beautiful, soft skin.

Tests performed by the inventors of the present invention have shown that the remarkable properties of the extracts of the invention are also obtained with the particular ecdysteroid and iridoid combinations as defined above.

Thus, according to a second aspect, the present invention concerns the use of an extract of the Ajuga turkestanica plant or a combination of at least one ecdysteroid and at least one iridoid as defined above as a cosmetic agent enhancing keratinocyte differentiation. This activity on keratinocyte differentiation leads to an improvement in the water barrier function of the epidermis and, therefore, to a moisturizing effect, an anti-aging effect, and also allows to improve the appearance and quality of the skin to provide, in particular, beautiful skin, softer skin.

As previously described, the tests performed by the inventors have demonstrated the activity of the extracts of the invention and the combinations defined above on the transport of water in the epidermis, activity at least partly related to an action also demonstrated by the inventors on the regulation and/or functionality of AQP3 aquaporins.

It is well known that, as skin ages, it becomes thinner, drier, giving the thin, scaly appearance found especially in the elderly. In the skin, it is well known that there is a water gradient from the basal layer of the epidermis to the most superficial layers of the stratum corneum. However, the inventors of the present invention, after studying the transport of water on emergent cultures of treated and controlled normal human keratinocytes, showed by means of permeability measures that the extracts of the invention allowed to increase the water flows in the epidermis and in particular the water reabsorption flows to the basal layer of the epidermis leading to better hydration and hydration of the basal layers of the epidermis in particular.

Other studies by the inventors of the present invention have also demonstrated the effect on AQP3 aquaporins.

Thus, in another respect, the invention relates to the use of the extracts of the invention and combinations as defined above as a cosmetic agent regulating, in the epidermis, water flow and water reabsorption.

The invention also relates to the use of these extracts or combinations as a cosmetic agent for moisturizing the epidermis.

The invention also relates, in a fifth respect, to a cosmetic composition, in particular with keratinocyte differentiation activity, improving the function of the water barrier of the epidermis. The moisturizing, anti-aging effect of the composition is to improve the appearance and quality of the skin and to improve its hydration by regulating the flow of water and water reabsorption in the epidermis, characterised by the fact that it contains a quantity of a cosmetically effective extract of the Ajuga turkestanica plant as defined above or of a combination as defined above for the intended purpose.

The extract content of Ajuga turkestanica should preferably be between 0,005% and 10%, preferably between 0,01 and 2% by weight of the total weight of the composition.

In addition, the extract of the Ajuga turkestanica plant according to the present invention is advantageously used in the compositions of the invention in combination with any other active ingredient known to man of science, in particular with any other active ingredient selected from the group consisting of vitamin A and its esters, in particular palmitate and vitamin A acetate, vitamin E and its esters, in particular phosphate and vitamin E acetate, vitamin C and its derivatives, in particular ascorbyl phosphate of magnesium, xanthocyanins, in particular caffeine, magnesium chloride, corticosteroid acid, asiveratride, panacoside, soybean extracts, ellagic acid, saponin, calcium chloride, isocyanate, isocyanate, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride, calcium chloride,

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In general, the cosmetic compositions of the invention contain cosmetically acceptable excipients or media for topical application to the skin.

The compositions of the invention may be formulated in any cosmetically acceptable form, in particular as a cream, gel, lotion.

The invention also relates to a cosmetic treatment of the skin by which a cosmetically effective amount of the invention extract or combination as defined above is applied to the skin.

It is understood that the invention thus enables the particularly unexpected properties observed for the extract of the Ajuga turkestanica plant to be implemented.

Other purposes, characteristics and advantages of the invention will be clearly apparent to the user from the following explanatory description made with reference to a test of activity to improve keratinocyte differentiation and a test showing water transport in the epidermis. Various examples of cosmetic composition formulations are also given merely for illustration purposes and therefore in no way limit the scope of the invention. In the examples, all percentages are given by weight, unless otherwise stated.

Examples - Preparation of extract according to the invention

Hot extraction of the roots of Ajuga turkestanica is carried out with a solvent composed of 80% ethanol and 20% water.

10 kg of dry matter (roots of Ajuga turkestanica) are exposed to 160 kg of solvent (ethanol-water mixture in the respective 80/20 ratio) at 50°C for 2 hours.

The whole is cooled to room temperature (about 21°C).

The cooled assembly is then filtered on a 5μm filter (to remove suspended and precipitated material).

The filtered assembly is evaporated dry (to remove the extraction solvent).

The dry evaporated solution is added to 1 litre of water.

The solution taken from 1 litre of water undergoes a strong homogenization (by agitation) plus ultrasound.

The homogenised assembly is rapidly frozen at -40°C and maintained at this temperature for about 4 hours.

The frozen assembly is then freeze-dried.

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This extract has been analysed using conventional analytical techniques, including: use of specific detectors for reaction chemistry,high performance liquid chromatography (HLHP),high performance thin film chromatography (HPC),gas chromatography (GPC), and has the following composition as a percentage by weight: The use of the active substance in the active substance is not restricted to the following substances: ecdysterone 2.75 %turkesterone 2.00 %22-acetyl-cysterone 1.93 %2.3-monoacetone of ecdysterone 1.18 %alpha-ecdysone 0.59 %cysterone 0.27 %jugasterone B 0.028 %jugalactone 0.016 %8-O-acetyl-harpagide 16.70 %harpagide 9.20 %pectin substances 24.30 %tannins 4.92 %water 6.95 %monosaccharides (fructose, glucose) 19.98 %candres 6.97%.

This extract can be incorporated into cosmetic formulations.

It is of course possible to improve this extract by subjecting it to purification to remove, for example, tannin forms, polysaccharide forms, polypeptide forms and chlorophyll pigments.

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- B Demonstration of the activity of the extract of the invention on the differentiation of normal human keratinocytes

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The present trial uses this extract to measure the differentiation of normal human keratinocytes in emergent cell culture.

For the purposes of the invention, keratinocyte differentiation refers to all the processes involved in the maturation of keratinocytes into komeocytes.

To this end, cell cultures derived from human keratinocytes treated with the invention extract and untreated cultures were compared according to morphological criteria by optical or electron microscopy techniques.

The more specific test conditions are now described below.

(a) Obtaining cultures of normal human keratinocytes, abbreviated KHN

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(b) Re-constructed epidermis

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The cultures are produced in a two-compartment system (upper/lower) using COSTAR plates containing 12 wells marketed by D. DUTSCHER inside which are deposited 12 mm diameter Transwell-clear COSTAR inserts also marketed by DUTSCHER.

KHN are sown on Transwell-clear at a rate of 115 000 KHN per insert and grown by immersion in SFMc medium until confluence, with culture medium added in the upper compartment.

At the confluence of the KHNs, the SFMc medium is removed from the upper compartment, and the differentiation medium is then added from the extract of the plant Ajuga turkestanica according to the present invention and then added to the lower compartment, so as to obtain an emergent air/liquid interface culture.

The main composition of the differentiation medium is as follows: DMEM: HAM's F12 from Gibco containing 5% foetal calf serum also from Gibco.

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The control cultures received the same proportion of DMSO as the treated cultures, i.e. 0.1% v/v, and the rate of change of medium and duration of treatment were identical to those of the treated cultures.

(c) Treatment of cultures for microscopic analysis

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Semi-fine cuts are then made for observation by optical microscopy and ultra-fine cuts for observation by electron microscopy.

(d) Comments by the Commission

The semi-fine blue-coloured sections of toluidine under optical microscopy showed that the thickness of the coeocyte layers of the stratum comeum of the epidermis was very considerably increased in the reconstituted epidermis treated with the extract according to the invention, compared with the reconstituted epidermis of the test culture.

In fact, the stratum comeum of the control cell cultures was observed to be very reduced, whereas the treatment with the extract of the Ajuga turkestanica plant of the invention was able to restore a corneal layer of normal thickness.

The total thickness of the culture is the same in both cases, so it can be observed that there are more basal and suprabasal keratinocyte layers for the control culture. Here there is an effect of the extract of the invention on keratinocyte differentiation. It is at the precise point of the interface between the last suprabasal layer of keratinocyte and the first stratum comeum coeocyte layer that the observations are then made in transmission electron microscopy which are then reported below.

On the other hand, for emergent cell cultures treated with the extract of the invention at doses of 10 μg/ml and 25 μg/ml, the same type of keratinocyte differentiation profile is observed, which shows a uniformity between all the cultures treated compared to the control culture which is indeed very different. (a) Control cell culture at 30 000 magnification: (b) For emergent cell cultures treated with the extract of the invention at doses of 2.5, 10, 25 μg/ml respectively, the same observations can be made: Many very well differentiated keratin filaments attached to the keratin plate, keratin filaments oriented parallel to the comaeocyte, corneal envelope clearly visible on the KH side, small keratin-thickness, compact presence of comaeodes, and observable intercommotile space (lipid).

The results of these tests show that the extracts of the invention appear to be extremely active at low doses.In the tests carried out, the extract of the invention acts at the concentration of 2.5 μg/ml on intercellular cohesion specifically at one of the key layers of the epidermis at the interface between the corneal layer and the basal layers.

Because of its original nature, this extract optimizes the adhesion between the living layers and the corneal layer, which had not been observed in vitro until now.

The extract of the invention improves the organization and attachment of keratin filaments to desmosomal plates. This strongly suggests that the corneal layer can undergo local deformation due to physical stresses without being damaged by excellent local elasticity. Furthermore, the general effect of the extract of the invention on the formation of a good quality corneal layer, by producing light-weight corneocytes with a visible corneal envelope and a well-compacted keratin network, suggests a regulatory action on the hydration of the surface layers of the epidermis.

The invention is intended to enhance the hydrological barrier of the epidermis, to improve the condition of the epidermis and thus the appearance and quality of the skin, which will appear beautiful and soft.

C - Demonstration of the effect of an extract of the invention on the transport of water in the skin

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J0 is the day on which the crops which have reached the confluence emerge from their culture medium and are exposed to the air.

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To perform permeability measurements, the filters are arranged in a measuring chamber composed of two compartments filled with culture medium. The luminal compartment (top of the culture) is closed by a catheter connected to a horizontal capillary tube filled with dye. Any fluid movement results in a displacement of the dye that can be measured.

A = 0 the cells do not have a significant barrier to water passage as demonstrated by massive water absorption when hydrostatic pressure is applied in the luminal compartment.

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Temps de traitement en jours
J6	- 0,49	0,76
J17	- 0,015	0,12

A negative value indicates a secretion, a positive value an absorption flow. Unlike control cells for which a water secretion is measured, the cells treated with the extract of Ajuga turkestanica according to the invention absorb water significantly. The importance of this absorption decreases to j=17 but remains very significant. The reason for this decrease is due to the increase in the thickness of the epidermis and the formation of the stratum corneum and its waterproofness. The water flows are therefore less.

The Commission has

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D - Demonstration of the effect of an extract of the invention on the functionality of AQP3 aquaporins

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In example C, the extract of the invention has been shown to greatly increase the reabsorption flows of water in the human epidermis. Given the importance of the measured water flows, these can only be explained by water transport controlled by AQP3. A transcellular passage through the phospholipid bilayer of the keratinocyte plasma membrane would be of much lower amplitude. A control has ruled out the possibility of a peri-cellular passage of water.

Therefore, the inventors of the present invention inferred that these extracts were particularly active in regulating and/or enhancing aquaporins 3 (AQP3) functionality.

E - Cosmetic compositions

In the cosmetic formulations described below, extracts of Ajuga turkestanica are dry extracts, unless otherwise specified.

E1 - Moisturising and nutritious anti-aging emulsion

Extrait d'Ajuga turkestanica (extrait S)	0,025 g
Acétate de vitamine E	0,100 g
Palmitate de vitamine A	0,010 g
Ascorbyle phosphate de magnésium	0,200 g
Céramides de blé	0,200 g
Protéines de blé	1,000 g
Filtre UVA-UVB	5,000 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica (extract S) used in this emulsion is the extract described above in example A.

This nourishing emulsion improves skin hydration, especially of the epidemic, the skin's fineness and grain and reduces wrinkles.

E2 - Moisturising gel that strengthens and restructures

Extrait d'Ajuga turkestanica (extrait S)	0,040 g
Aspartate de magnésium	0,100 g
Extrait de Centella asiatica	0,100 g
Saponines de soja	0,050 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica (extract S) used in this gel is the extract described above in example A.

This moisturizing gel, which is applied daily to the face, neck and chest, has a tense effect on the skin and improves its flexibility and firmness.

E3 - Restorative liposomal moisturising gel

Extrait d'Ajuga turkestanica (extrait S)	0,020 g
Lecithine de soja	2,000 g
Acétate de vitamine A	0,010 g
Vitamine E	0,010 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica (extract S) used in this gel is the extract described above in example A.

This liposomal gel is used daily, preferably in the evening and on the face, to improve skin elasticity and moisture, and to promote regeneration.

E4 - Moisturizing and toning lotion

Extrait d'Ajuga turkestanica (extrait S)	0,030 g
Eau de source marine concentrée en oligoéléments	10,000 g
Extrait de Panax Ginseng	0,200 g
AMP cyclique	0,010 g
Caféine	0,100 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica (extract S) used in this lotion is the extract described above in example A.

This moisturizer is applied daily to the face, preferably in the morning to achieve a more beautiful, glowing skin.

E5 - Moisturizing and soothing fluid

Extrait d'Ajuga turkestanica	0.04 g
Chlorure de manganèse	0,10 g
D-xylose	0,10 g
Céramides de blé	0,20 g
Extrait de réglisse	0,10 g
Acétate de vitamine E	0.20 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica used in this fluid is an extract obtained with a solvent composed of 80% methanol and 20% water.

This fluid is used as a daily topical application on the face and body.

E6 - Moisturising mascara

Extrait d'Ajuga turkestanica	0,025 g
Acide hyaluronique	0,500 g
D-xylose	0.200 g
Pigments colorés	10.000 g
Cires	30,000 g
Excipient avec conservateurs et parfums	qsp. 100g

The extract of Ajuga turkestanica used in this mascara is an extract obtained with a solvent composed of 80% acetone and 20% water.

E7 - Rehydrating and anti-aging patch after sun exposure

Extrait d'Ajuga turkestanica	0,5 g
Glycyrrhizinate d'ammonium	0.5 g
Dextran sulfate	0,2 g
Excipient pour patch	qsp. 100g

The extract of Ajuga turkestanica used in this patch is an extract obtained with a solvent composed of 50% propylene glycol and 50% water.

E8 - Moisturising antiseptic cream for sores, small superficial wounds and irritation redness

Extrait d'Ajuga turkestanica	0,4 g
Extrait de Phellodendron amurense	0,1 g
Acide fusidique	2,0 g
Excipient	qsp. 100g

The extract of Ajuga turkestanica used in this cream is an extract obtained with a solvent composed of 50% butylene glycol and 50% water.

E9 - Moisturising and nourishing anti-aging emulsion

Ecdystérone	0,007 g
Turkestérone	0,005 g
22-acétyl-cyastérone	0,005 g
2,3-monoacétonide d'ecdystérone	0.003 g
Alpha-ecdysone	0,0015 g
Cyastérone	0,0007 g
8-O-acétyl-harpagide	0.04 g
Harpagide	0,02 g
Acétate de vitamine E	0,100 g
Palmitate de vitamine A	0,010 g
Ascorbyle phosphate de magnésium	0,200 g
Céramides de blé	0.200 g
Protéines de blé	1.000 g
Filtre UVA-UVB	5,000 g
Excipient avec conservateurs et parfums	qsp. 100g

Claims (32)

1. Extract of the plant Ajuga turkestanica containing at least one ecdysteroid and at least one iridoid, characterized in that it contains one part by weight of at least one ecdysteroid and 2 to 4 parts by weight, preferably 3 parts by weight, of at least one iridoid.
2. Extract according to claim 1, characterized in that said ecdysteroid is selected from the group consisting of ecdysterone, ecdysterone 2,3-monoacetonide, turkesterone, cyasterone, 22-acetylcyasterone and alpha-ecdysone.
3. Extract according to claim 1 or 2, characterized in that said iridoid is selected from the group consisting of harpagide and its 8-O-acetyl derivative.
4. Extract according to one of claims 1 to 3, characterized in that said ecdysteroids contained in said extract are composed of 30 to 35% of ecdysterone, 20 to 25% of turkesterone, 20 to 24% of 22-acetylcyasterone, 11 to 15% of ecdysterone 2,3-monoacetonide, 6 to 7% of alpha-ecdysone and 2 to 4% of cyasterone, the percentages being expressed by weight.
5. Extract according to one of claims 1 to 4, characterized in that said iridoids contained in said extract are composed of 60 to 70% of 8-O-acetylharpagide and 30 to 40% of harpagide, the percentages being expressed by weight.
6. Extract according to one of claims 1 to 5, characterized in that it is obtainable by extraction of at least part of said plant by means of a solvent or solvent mixture consisting of 0 to 60% by weight of water, the remainder of said solvent or solvent mixture consisting of at least one C₁ to C₄ alcohol and/or acetone and/or butylene glycol and/or propylene glycol.
7. Extract according to claim 6, characterized in that said extraction is performed with said solvent or solvent mixture for 1 to 4 hours.
8. Extract according to claim 6, characterized in that said extraction is performed at the reflux temperature of said solvent or solvent mixture for 1 to 4 hours.
9. Extract according to one of claims 6 to 8, characterized in that said extraction is performed on the whole of said plant.
10. Extract according to one of claims 6 to 8, characterized in that said extraction is performed on the roots of said plant.
11. Extract according to one of claims 6 to 10, characterized in that said solvent or solvent mixture is a mixture of water and ethanol.
12. Extract according to claim 11, characterized in that the mixture of water and ethanol is a mixture containing 70 to 90% of ethanol and 30 to 10% of water, preferably 80% of ethanol to 20% of water.
13. Extract according to one of claims 6 to 10, characterized in that said solvent or solvent mixture is a mixture of water and methanol.
14. Extract according to claim 13, characterized in that said mixture of water and methanol is a mixture containing 70 to 90% of methanol and 30 to 10% of water, preferably 80% of methanol to 20% of water.
15. Extract according to one of claims 6 to 10, characterized in that said solvent or solvent mixture is a mixture of water and acetone.
16. Extract according to claim 15, characterized in that the mixture of water and acetone is a mixture containing 70 to 90% of acetone and 30 to 10% of water, preferably 80% of acetone to 20% of water.
17. Extract according to one of claims 6 to 10, characterized in that said solvent or solvent mixture is a mixture of water and propylene glycol.
18. Extract according to claim 17, characterized in that the mixture of water and propylene glycol is a mixture containing 40 to 60% of propylene glycol and 60 to 40% of water, preferably 50% of propylene glycol to 50% of water.
19. Extract according to one of claims 6 to 10, characterized in that said solvent or solvent mixture is a mixture of water and butylene glycol.
20. Extract according to claim 19, characterized in that the mixture of water and butylene glycol is a mixture containing 40 to 60% of butylene glycol and 60 to 40% of water, preferably 50% of butylene glycol to 50% of water.
21. Cosmetic composition, especially with activity in the differentiation of keratinocytes, which improves the function of the epidermis as a water barrier and has a hydrating effect and an anti-ageing effect, said composition being intended to improve the appearance and quality of the skin and to improve its hydration by regulation of the water fluxes and the water absorption in the epidermis, characterized in that it contains a cosmetically effective amount, for the intended purpose, of an extract of the plant Ajuga turkestanica as defined in one of claims 1 to 20.
22. Cosmetic composition, especially with activity in the differentiation of keratinocytes, which improves the function of the epidermis as a water barrier and has a hydrating effect and an anti-ageing effect, said composition being intended to improve the appearance and quality of the skin and to improve its hydration by regulation of the water fluxes and the water absorption in the epidermis, characterized in that it contains a cosmetically effective amount, for the intended purpose, of an association comprising one part by weight of at least one ecdysteroid and 2 to 4 parts by weight, preferably 3 parts by weight, of at least one iridoid.
23. Composition according to claim 22, characterized in that said ecdysteroid is selected from the group consisting of ecdysterone, ecdysterone 2,3-monoacetonide, turkesterone, cyasterone, 22-acetylcyasterone and alpha-ecdysone.
24. Composition according to claim 22 or 23, characterized in that said iridoid is selected from the group consisting of harpagide and its 8-O-acetyl derivative.
25. Composition according to one of claims 22 to 24, characterized in that the ecdysteroids present in said association are composed of 30 to 35% of ecdysterone, 20 to 25% of turkesterone, 20 to 24% of 22-acetylcyasterone, 11 to 15% of ecdysterone 2,3-monoacetonide, 6 to 7% of alpha-ecdysone and 2 to 4% of cyasterone, the percentages being expressed by weight.
26. Composition according to one of claims 22 to 25, characterized in that the iridoids present in said association are composed of 60 to 70% of 8-O-acetyl-harpagide and 30 to 40% of harpagide, the percentages being expressed by weight.
27. Composition according to one of claims 21 to 26, characterized in that it contains from 0.005 to 10% by weight, preferably from 0.01 to 2% by weight, based on the total weight of said composition, of an extract as defined in one of claims 1 to 20 or an association as defined in one of claims 22 to 26.
28. Composition according to one of claims 21 to 27, characterized in that it also contains at least one substance selected from the group comprising vitamin A and its esters, particularly vitamin A palmitate and acetate, vitamin E and its esters, particularly vitamin E phosphate and acetate, vitamin C and its derivatives, particularly magnesium ascorbylphosphate, xanthines, particularly caffeine, asiatic acid, madecassic acid, asiaticosides, madecassosides, extracts of Centella asiatica, ellagic acid, soya saponins, extracts of Bertholletia, extracts of Panax Ginseng, pure sea water, magnesium aspartate, manganese chloride, cyclic AMP, D-xylose, hyaluronic acid, calcium gluconate, isoflavones, ammonium glycyrrhizinate, corticosteroids, extracts of Phellodendron amurense, resveratrol and piceids.
29. Non-therapeutic use of an extract according to one of claims 1 to 20 or an association as defined in one of claims 22 to 26 as a cosmetic agent for improving the differentiation of keratinocytes.
30. Non-therapeutic use of an extract according to one of claims 1 to 20 or an association as defined in one of claims 22 to 26 as a cosmetic agent for regulating the water fluxes and the water absorption in the epidermis.
31. Non-therapeutic use of an extract according to one of claims 1 to 20 or an association as defined in one of claims 22 to 26 as a cosmetic agent for hydrating the epidermis.
32. Method of cosmetic skin treatment, characterized in that a cosmetically effective amount of an extract according to one of claims 1 to 20 or an association as defined in one of claims 22 to 26 is applied to the skin.