Cosmetic composition containing a pterocarpus soyauxii wood extract and the use thereof for depigmenting or whitening the skin

Abstract

The invention relates to a cosmetic and / or dermatological composition comprising a Pterocarpus soyauxii wood extract, as a depigmenting or skin-whitening agent. The wood extract is present in the composition at a content ranging from 0.05 to 10% by weight relative to the total weight of the composition, and comprises a high proportion of ellagitannins and / or gallotannins. The extract is in particular a hydroglycerinated extract obtained by extraction in a mixture of water and glycerin, preferably assisted by ultrasound. The invention also relates to a composition containing the wood extract, to a non-therapeutic method for depigmenting or whitening the skin, and to a non-therapeutic use.

Description

Cosmetic composition containing an extract of Pterocarpus soyauxii wood and its use for depigmenting or whitening the skin

[0001] The present invention relates to a composition for cosmetic use containing an extract of Pterocarpus soyauxii wood, cosmetic products containing such a composition, their non-therapeutic use for depigmenting the skin and a non-therapeutic method for depigmenting the skin.

[0002] The close link between tyrosinase activity and melanogenesis is of crucial importance in the field of dermatological research, particularly with regard to the cosmetic industry. Tyrosinase, a key enzyme in the process of melanogenesis, plays a vital role in the conversion of L-tyrosine to L-DOPA, a precursor of melanin. This melanin is responsible for the coloration of the skin, hair, and eyes. Therefore, regulating tyrosinase activity is a central point in the development of cosmetic products aimed at influencing skin pigmentation.

[0003] Natural molecules rich in tyrosinase inhibitory activity have been studied and used in the cosmetic industry to control skin pigmentation. For example, kojic acid, a derivative of the fungus Aspergillus oryzae, is known for its tyrosinase inhibitory activity. It has been widely used in cosmetic products to alleviate hyperpigmentation problems. Additionally, flavonoids found in certain plants, such as arbutin from Arctostaphylos uva-ursi, have also been shown to inhibit tyrosinase activity. These natural compounds work by interfering with tyrosinase function, which can reduce melanin production and alleviate skin pigmentation problems.

[0004] Patent FR 2 761 595 describes compositions containing santalins, namely extracts of red wood of the genus Pterocarpus, for example P. santalinus, P. osun, P. soyauxii, P. erinaceus, P. indicus, as coloring agents to obtain a skin coloring close to tanning.

[0005] There remains a need for compositions having tyrosinase inhibition activity, capable of inducing a decrease or control of melanin production and of promoting or preventing skin pigmentation disorders.

[0006] Extracts of padouk woodPterocarpus soyauxiiobtained by ultrasound-assisted extraction in a mixture of water and glycerin were found to contain a significant content of water-soluble tannins, particularly branched tannins of the ellagitannin type, and surprisingly demonstrated inhibitory activity on tyrosinase in in vitro tests on human melanocytes. This activity could be attributed to the exceptional richness of tannins present in these extracts and to the fact that these tannins were found to be in an active form demonstrating an unusual ability to inhibit tyrosinase. Without wishing to be bound by theory, it is possible that the process of ultrasound-assisted extraction in a mixture of water and glycerin allowed to concentrate and stabilize these tannins in the extract, thus improving its effectiveness as a cosmetic ingredient for tyrosinase inhibition.

[0007] The present invention relates firstly to a cosmetic and / or dermatological composition, characterized in that it comprises, in a cosmetically acceptable carrier, at least one extract of Pterocarpus soyauxii wood, as a skin depigmentation, lightening and / or bleaching agent, and / or as an antioxidant and / or anti-aging agent. The invention aims in particular to eliminate or reduce dark and / or colored spots appearing on the skin or more generally on keratin materials, due to an increased concentration of melanin in the keratinocytes located on the surface of the skin.

[0008] The wood extract may in particular be present in the composition at a content ranging from about 0.05 to about 10%, preferably ranging from about 0.5 to about 5% by weight, for example about 1, 2, 3, 4, or 5%, relative to the total weight of the composition. The composition therefore contains such a percentage by weight of the wood extract, containing the materials extracted from the wood, in particular ellagitannins and / or gallotannins.

[0009] According to a preferred embodiment, the wood extract and therefore the composition contains ellagitannins. Preferably, the ellagitannins are present in an amount of about 200 to about 1200 mg, in particular about 400 to about 900 mg per liter of wood extract.

[0010] According to a preferred embodiment, the wood extract and therefore the composition contains gallotannins. Preferably, the gallotannins are present preferably in an amount of about 100 to about 900 mg, in particular about 200 to about 700 mg per liter of wood extract.

[0011] Most preferably, the composition contains ellagitannins and gallotannins, in particular in the respective quantities which can be calculated from, in particular, the percentage of extract in the composition and its content of the respective tannins.

[0012] According to a preferred method, the extract is a hydroglycerin extract obtained by extraction in a mixture of water and glycerin. The extraction is preferably assisted by ultrasound.

[0013] Preferably, the composition contains glycerin, in particular the glycerin used during extraction. The composition may comprise in particular from about 15 to about 60%, typically between about 20 and about 50%, typically between about 30 and about 50% by weight of glycerin relative to the total weight of the composition.

[0014] The invention also relates to a non-therapeutic use of such a composition, as a cosmetic agent for depigmentation, lightening and / or whitening of the skin.

[0015] The invention also relates to a non-therapeutic method for depigmenting, lightening and / or whitening an area of ​​human skin, comprising a step of topical application of an effective amount to said targeted area of ​​skin of a subject of a cosmetic and / or dermatological composition as defined herein.

[0016] The invention also relates to a non-therapeutic method for ensuring an antioxidant and / or anti-aging effect, comprising a step of topical application of an effective amount to an area of ​​skin of a subject of a cosmetic and / or dermatological composition as defined herein.

[0017] Preferably, the methods of the invention comprise the application of a composition containing at least one hydroglycerin extract of Pterocarpus soyauxii wood, comprising said extract, water and glycerin.

[0018] In particular, but not limited to, the methods provide for the application of said cosmetic composition to the skin of an individual having a dull complexion, an uneven complexion, brownish pigmentation spots, and / or aging spots.

[0019] The invention also relates to a hydroglycerin extract (or raw composition) of Pterocarpus soyauxii wood. Said extract comprises the material extracted from the wood, water and glycerin. In the various subjects of the invention, the material extracted from the wood can be defined as being the material derived from the wood, and it can be quantified from the dry matter point of view. The tannin contents are expressed per liter of extract.

[0020] According to one method, the content of the extract in dry matter from the wood is equal to or greater than approximately 15% by weight, preferably between approximately 15 and approximately 60%, typically between approximately 20 and approximately 50%, typically between approximately 30 and approximately 50% by weight relative to the total weight of the composition.

[0021] Preferably, the wood extract comprises ellagitannins, preferably in an amount of about 200 to about 1200 mg, in particular about 400 to about 900 mg of ellagitannins per liter of extract.

[0022] Preferably, the wood extract comprises gallotannins, preferably in an amount of about 100 to about 900 mg, in particular about 200 to about 700 mg of gallotannins per liter of extract.

[0023] Most preferably, the wood extract contains ellagitannins and gallotannins, especially in the respective quantities mentioned above.

[0024] This extract can be used to form the cosmetic or dermatological composition mentioned here.

[0025] According to other advantageous aspects, each of the different objects of the invention may comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations.

[0026] In one aspect, the extract is a hydroglycerin extract. This extract has in particular been produced in a mixture of water and glycerin. In particular, the extraction has been carried out in a hydroglycerin solvent containing water and from about 15 to about 60% by weight of glycerin in the solvent, preferably from about 20 to about 50% by weight, more preferably from about 30 to about 50% by weight, for example about 30, about 40 or about 50%. It is not prohibited to use a solvent having a glycerin content of less than 20% by weight, but the extraction efficiency suffers and therefore the final tannin content, and this may require further concentration, which is desired to be avoided. It is also possible to use a solvent having a glycerin content greater than 50 or 60% by weight, but the higher viscosity may cause industrial complications.

[0027] In one aspect, the extraction is assisted by high frequency ultrasound, particularly a frequency of between about 20 and about 1000 kHz.

[0028] According to one aspect, the extraction is carried out according to a protocol comprising heating the solvent (in particular water and glycerin) to a temperature of between approximately 30 and approximately 50°C, typically approximately 40°C, then raw material and hot solvent (ratio between approximately 5 and approximately 20% by weight, typically approximately 10% by weight of raw material in the solvent) are placed in an ultrasonic extractor, and the extraction is carried out under ultrasound for approximately 45 to approximately 2 hours, typically approximately 1 hour, at a suitable ultrasonic power, for example approximately 24 Hz.

[0029] According to one aspect, the extraction is carried out according to a protocol comprising the maceration of the raw material in the solvent (in particular water and glycerin) at room temperature (e.g. approximately 20-25°C), for approximately 18 to approximately 48 hours, typically approximately 24 hours (ratio between approximately 5 and approximately 20% by weight, typically approximately 10% by weight of raw material in the solvent), then extraction under ultrasound for approximately 45 to approximately 2 hours, typically 1 hour, in an ultrasonic extractor, at a suitable ultrasonic power, for example approximately 24 Hz.

[0030] In one aspect, the wood raw material subject to extraction is in the form of wood chips or fragments.

[0031] According to one aspect, the extract therefore contains glycerin, and in particular substantially all of the glycerin used during the extraction, and water. The extract is liquid, or even more or less thick or viscous, depending on the glycerin content. The composition may in particular comprise from approximately 20 to 50%, preferably from approximately 30 to approximately 50% by weight of glycerin relative to the weight of the extract.

[0032] In one aspect, solvents other than glycerol may be used, including glycols such as butylene glycol and propanediol, or NaDES (Natural Deep Eutectic Solvents). The extract and compositions may therefore comprise this solvent.

[0033] In one aspect, the crude extract or composition further comprises one or more preservatives, such as sodium levulinate and / or sodium benzoate. This allows its preservation, prior to its formulation into a cosmetic composition.

[0034] The cosmetic or dermatological composition according to the invention comprises a physiologically acceptable medium suitable for topical application, i.e. compatible with the skin, and constitutes a composition for topical application, cosmetic and / or dermatological, whitening and / or depigmenting.

[0035] This composition can be more or less fluid and have the appearance of a white or colored cream, an ointment, a milk, a lotion, a serum, a paste, a mousse. It can possibly be applied to the skin in the form of an aerosol. It can also be presented in solid form, for example in the form of a stick.

[0036] The compositions in accordance with the present invention may further comprise conventional cosmetic adjuvants, in particular a cosmetic adjuvant chosen from fatty substances, organic solvents, ionic or non-ionic thickeners, softeners, humectants, opacifiers, stabilizers, emollients, silicones, anti-foaming agents, insect repellents, perfumes, preservatives, anionic, cationic, non-ionic, zwitterionic or amphoteric surfactants, substance P antagonists, substance CGRP antagonists, fillers, polymers, propellants, alkalizing or acidifying agents or any other ingredient usually used in the cosmetic and / or dermatological field.

[0037] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0038] This is a graph showing the phytochemical characteristics of extracts obtained using different extraction methods; the left ordinate shows the concentration in mg / ml of gallotannins (1 er plot) and ellagitannins (2 ème plot) for each extract or batch (noted L and number); the right ordinate shows the concentration in mg / ml of total polyphenols (PTT) and sugars (*10 = values ​​to be multiplied by 10) reported in the form of the respective curves.

[0039] This is a graph showing the HPLC quantification of pterostilbene in µM in the same extracts as those in the.

[0040] This is a graph showing biological characteristics of the same extracts; the left ordinate shows the concentration in mg / ml of CUPRAC (*10 = values ​​to be multiplied by 10), ABTS and DDPH (plots from left to right for each marker and each extract or batch); the right ordinate shows the percentage of inhibition of tyrosinase, reported as a curve.

[0041] This is an HPLC chromatogram showing the phytochemical composition of extract L0207.

[0042] This is a graph showing the quantification of melanin levels. The melanin contents of each experimental group are expressed as relative values ​​(% vs control) and presented as mean + / - SD. ***p<0.001; **p<0.01; * p<0.05 – One-way ANOVA and Dunnett's post-hoc test for multiple comparisons compared to the Alpha-MSH group (alpha=0.05).

[0043] This is a graph showing the quantification of tyrosinase levels. Tyrosinase levels of each experimental group are expressed as relative values ​​(% vs control) and indicated as mean + / - SD ***p<0.001; **p<0.01; * p<0.05 – one-way ANOVA and Dunnett's post-hoc test for multiple comparisons compared to the Alpha-MSH group (alpha=0.05).

[0044] Example 1: Extraction, quantification and biological data:

[0045] The extraction is carried out using a cold extraction process assisted by high-frequency ultrasound (20–1000 kHz). This significantly increases the extraction of molecules of interest while reducing the duration. The ultrasound causes the formation of bubbles, and a growth of these bubbles in size until they reach a critical size where they spontaneously implode, creating a zone of intense energy. The bursting of the cavitation bubbles by a cycle of expansion and contraction on the raw material causes the bursting of the cell wall and thus allows the enrichment of the solvent in molecules of interest.

[0046] Several solvents were used during the extractions:

[0047] - Water,

[0048] - Phytosolvent B (birch sap),

[0049] - Glycerin water (20% glycerin by weight),

[0050] - Glycerin water (30% glycerin by weight),

[0051] - Glycerin water (40% glycerin by weight),

[0052] - Glycerin water (50% glycerin by weight).

[0053] Two types of extractions were compared with these solvents.

[0054] Extraction method A: heating the solvent to 40°C, raw material and hot solvent (ratio 10% by weight of raw material in the solvent) placed in an ultrasonic extractor, and extraction under ultrasound for 1h, ultrasonic power of 24 Hz.

[0055] Extraction method B: maceration of the raw material in the solvent at room temperature for 24 hours (ratio 10% by weight of raw material in the solvent), then extraction under ultrasound for 1 hour in an ultrasonic extractor, ultrasonic power of 24 Hz.

[0056] Table 1 shows that glycerine extracts are much more concentrated in dry matter and that the dry matter content obtained is similar whether method A or method B is used (see L0136 vs. L0141).

[0057] LotL0135L0136L0137L0140L0141L0142L0205L0206L0207Extraction methodAAABBBAAASolventDemineralized waterDemineralized water + glycerin 20%Birch sap (Bottle)Demineralized waterDemineralized water + glycerin 20%Birch sap (Bottle)Demineralized water + glycerin 30%Demineralized water + glycerin 40%Demineralized water + glycerin 50%Humidity MP (Desiccator, 105°C, standard, automatic = mode 1)10.20%Dry matter (Desiccator, 105°C, standard, automatic = mode 1)0.10%24.80%0.80%0.17%24.90%0.87%32.2%41.68%52.6%pH5,095,074,095,034,994,015,365, 325.32Brix2222,82,921,73,321,328,242RI1,3361,3671,3371,3371,3671,3381,3661,3781,403

[0058] As shown in Figures 1 and 2, glycerin extracts are more highly enriched in antioxidant molecules than water or phytosolvent extracts. This is demonstrated by the total polyphenols assay (TPA), and by gallotannins and ellagitannins measurements. Similarly, the molecular marker, pterostilbene, is more strongly detected in 30, 40 and 50% glycerin extracts than in the other solvents used.

[0059] Several biological characteristics were then evaluated with the following methods and the results obtained are presented in the examples that follow in relation to the figures: CUPRAC: the antioxidant capacity is measured using the so-called CUPRAC (CUPric Reducing Antioxidant Capacity) method; this method allows the total antioxidant capacity (CAT) of hydrophilic and hydrophobic samples to be measured. The copper (II) – neocuproine (2,9-dimethyl-1,10-phenanthroline) reagent is capable of oxidizing antioxidants, generating a colored product that can be measured by colorimetry at 450nm. ABTS: the antioxidant capacity is measured using the so-called ABTS (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate)) colorimetric method, which allows the simultaneous determination of hydrophilic and lipophilic antioxidants. It generates the direct production of the blue / green ABTS + chromophore.The addition of antioxidants to the pre-formed radical cation reduces its ABTS depending on the antioxidant activity and their concentration. This capacity is measured at 630nm.DPPH: The antioxidant capacity is measured using the so-called DPPH method which measures the antioxidant activity of compounds capable of transferring hydrogen atoms. The compound (DPPH•+: 2,2-diphenyl 1-picrylhydrazyl) is a colored and stable radical cation of purple color measured by spectrophotometer at 630nm. The antioxidant compounds, which are capable of transferring an electron to DPPH+, cause a discoloration of the solution. This reaction is rapid and proportional to the antioxidant capacity of the sample.Anti-tyrosinasein tubo: Tyrosinase activity was measured using L-DOPA as substrate and is measured at 490nm after 15 minutes of reaction.Evaluation of melanin synthesis and quantification of tyrosinase levels on cells: Primary human melanocytes were used.They were seeded at 15,000 cells per well in a 96-well plate (visualization in situ biomarkers). The cells were cultured in M254 medium. M254 medium is a solution specifically formulated for the culture and growth of melanocytes. It includes a balanced combination of amino acids, vitamins, organic compounds, trace minerals, and inorganic salts. This medium is free of antibiotics, antimycotics, hormones, growth factors, and proteins. It is in liquid, sterile form, and is prepared with a concentration of 200 µM calcium chloride, thus promoting an environment conducive to the culture of normal human epidermal melanocytes. It was supplemented with Human Melanocyte Growth Supplement (HMGS; FCS 10%) at 37°C in humidified air with 5% CO2.Stressful conditions occur in the presence of alpha-MSH, a peptide hormone that stimulates melanocytes in the skin to produce melanin.

[0060] Lamontre then shows that glycerin extracts are enriched in antioxidant compounds, and this is all the more so as the glycerin content is high. In particular, batch L0207 (glycerin water 50%) is the one that is most enriched in hydrophilic and hydrophobic compounds with antioxidant activities (CUPRAC).

[0061] Similarly, the anti-tyrosinase tubo anti-aging test demonstrated approximately 86% inhibition of the tyrosinase enzyme for glycerin extracts. These results reflect the properties of glycerin extracts, due to their composition, to prevent / reduce hyperpigmentation and even out skin tone.

[0062] Example 2: characterization of the 50% glycerin extract from example 1:

[0063] PHYSICO-CHEMICAL CHARACTERISTICSCriteriaIntervalsLot L0207pH; 20°C (direct)4.5 – 6.26.00Total dry matter (total DM)40% – 60%52.6%Refractive index1.395 – 1.4101.403Brix35% - 60%42%QUANTIFICATIONSDosagesIntervalsBatch L0207Total polyphenol content (%)800 – 2000 mg / L1323.84 ±0.04 mg / LSugar content100 – 500 mg / L310.93 ±0.8 mg / LEllagitannins content400 – 900 mg / L674.88 ±9.92 mg / LGallotannins content200 – 700 mg / L431.27 ±6.42 mg / L pterostilbene25 – 55 µM38.57 ±1.82 µM

[0064] By intervals we mean the expected values ​​due to variations related to the wood and the implementation of the extractions. Total MS includes glycerin.

[0065] Example 3: Formulation of a product or plant extract with preservatives, allowing storage:

[0066] [Table 3]: Product Formulation (Water / Glycerin / Preservative): INCI Name CAS No. / EINECS Concentration Aqua 7732-18-5 / 231-791-245.8 – 46.8% Glycerin 56-81-5 / 200-289-544.0 – 45.8% Pterocarpus Soyauxii Wood Extract Batch L020 78.0 – 9.5% Sodium Levulinate (Preservative) 19856-23-6 / 243-378-40.70 – 0.73% Sodium Benzoate (Preservative) 532-32-1 / 208-534-80.34 – 0.37%

[0067] Example 4: Assessment of melanin synthesis and quantification of tyrosinase levels

[0068] To evaluate the efficacy, Padouk extracts (L0207) were diluted to 1% and 3% in M254 medium for 24h with 10 µM of melanotropic hormone (alpha-MSH), then sampled (Table 4). Kojic acid at 100 µM was used as an inhibitor reference for melanogenesis. The term “stress” refers to the presence of alpha-MSH.

[0069] Table 4: experimental groupsdescriptiontreatment(s)controluntreated, unstressedAlpha-MSHuntreated, stressed 24hAlpha-MSH + padouk 3%24h contact, stressed 24hAlpha-MSH + padouk 1%24h contact, stressed 24hAlpha-MSH + kojic acid 100 µm24h contact, stressed 24h

[0070] Melanin content was visualized by in situ visualization under bright-field microscopy (not shown). Alpha-MSH significantly increased melanin production compared to the control group, which was neutralized by 100 µM kojic acid. Cell treatments showed differential melanin levels.

[0071] Intercellular melanin levels (%) are reported in Table 5 and in theas mean values ​​+ / - SD per experimental group normalized to control.

[0072] Table 5. Melanin ContentMean (% vs. control)Standard DeviationEfficiency (%)P-Value (vs. alpha-MSH)NTontrol1007100%***<0.00013Alpha-MSH194100% / / 3Alpha-MSH + Padouk 3%814100%***<0.00013Alpha-MSH + Padouk 1%117981%***<0.00013Alpha-MSH + Kojic acid 100 µm456100%***<0.00013

[0073] The presence of the active ingredient significantly inhibited alpha-MSH-mediated melanin synthesis.

[0074] Tyrosinase quantification was visualized in situ by epifluorescence microscopy (not shown). Alpha-MSH significantly increased tyrosinase levels compared to the control (unstimulated) group. The presence of 100 µM kojic acid inhibited alpha-MSH induction of tyrosinase levels. Cell treatments with the active ingredient showed differential tyrosinase levels.

[0075] Intercellular tyrosinase levels (%) are shown in Table 6 and in the bar graph as mean values ​​+ / - SD per experimental group normalized to control (). The presence of the active ingredient significantly inhibited the increase in tyrosinase levels induced by alpha-MSH.

[0076] Table 6. Tyrosinase ContentMean (% vs. control)Standard DeviationEfficiency (%)P-Value (vs. a-MSH)NTontrol1003100%***<0.00013Alpha-MSH13120% / / 3Alpha-MSH + Padouk 3%101398%***<0.00013Alpha-MSH + Padouk 1%112360%***<0.00013Alpha-MSH + Kojic acid 100 µM106481%***<0.00013 Conclusion :

[0077] The presence of the active ingredient (Padouk L0207) significantly inhibits (p<0.05) the synthesis of melanin, PADOUK at 3% and 1% (respectively 100% and 81%) and significantly prevents (p<0.05) the increase in tyrosinase levels induced by alpha-MSH, PADOUK at 3% and 1% (respectively 98% and 60%).

[0078] In conclusion, the active ingredient PADOUK showed inhibitory effects on melanogenesis by effectively inhibiting the increase in melanin synthesis induced by alpha-MSH and modulating tyrosinase levels.

Claims

Cosmetic and / or dermatological composition, characterized in that it comprises, in a cosmetically acceptable carrier, at least one extract of Pterocarpus soyauxii wood, as a skin depigmentation, lightening and / or whitening agent. Composition according to claim 1, characterized in that it comprises a wood extract content ranging from 0.05 to 10%, preferably from 0.5 to 5% by weight of extract relative to the total weight of the composition. Composition according to claim 1 or 2, characterized in that the wood extract contains ellagitannins and / or gallotannins, preferably in an amount of 200 to 1200 mg, in particular 400 to 900 mg of ellagitannins per one liter of extract; and / or 100 to 900 mg, in particular 200 to 700 mg of gallotannins per one liter of extract. Composition according to any one of the preceding claims, characterized in that the extract is a hydroglycerin extract obtained by extraction in a mixture of water and glycerin, preferably assisted by ultrasound. Composition according to any one of the preceding claims, characterized in that it contains glycerin, preferably in a proportion of 15 to 60% by weight of glycerin relative to the total weight of the composition. A non-therapeutic method for depigmenting, lightening and / or bleaching an area of ​​human skin, comprising a step of topically applying an effective amount to said targeted area of ​​skin of a subject of a composition as defined in any one of claims 1 to 5. Hydroglycerin extract of Pterocarpus soyauxii wood, comprising water, glycerin, and ellagitannins, preferably in a proportion of 200 to 1200 mg, in particular 400 to 900 mg of ellagitannins per liter of extract. Extract according to claim 7, characterized in that the content of the extract in dry matter from the wood is equal to or greater than 15% by weight, preferably between 15 and 60%, better still between 20 and 50%, by weight relative to the total weight of the extract. Non-therapeutic use of a composition as described in any one of claims 1 to 5, as a cosmetic agent for depigmenting, lightening or whitening the skin.

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