COSMETIC CARE METHOD BASED ON PHOTOACTIVE EXTRACTS OF MICROALGAE

Abstract

The present invention concerns a cosmetic care method for the skin comprising the steps of applying, to the skin, a cosmetic composition comprising photoactive extracts of at least one microalgae, and exposing the area to which the composition has been applied to light. The invention also comprises a device for cosmetic care according to the method, and a kit comprising a cosmetic composition comprising photoactive extracts of at least one microalgae and a lighting device according to the invention. The invention finally comprises the use of the device according to the invention for an anti-aging and/or anti-wrinkle treatment and/or a treatment promoting the healing of the skin area.

Claims

1. Cosmetic care method for a region of the skin, comprising the successive steps of: applying, to the skin region, a cosmetic composition comprising photoactive extracts of at least one microalga; exposing the skin region to which said composition has been applied to a light source emitting light at a wavelength of between 400 and 750 nm.

2. Cosmetic care method according to claim 1, characterized in that the photoactive extracts of microalgae are selected from extracts of Tetraselmis suecica, Dunaliella salina, Rhodomonas salina, Rhodella maculata, Haematochococcus pluvialis, Porphyridium cruentum, Cyanophora paradoxa, Cylindrotheca closterium, Diacronema lutheri, Selenastrum capricornutum, Synechococus sp., Isochrysis sp., Tisochrysis lutea Phaeodactylum tricornutum, Arthrospira platensis, Stichococcus bacillaris, Xanthonema sp., Nostoc sp., Pseudanabaena galeata, Chaetoceros calcitrans, Dunaliella Tertiolecta, Chlamydomonas reinhardtii, Tetraselmis tetrathele and/or Porphyridium purpureum.

3. Cosmetic care method according to claim 1, characterized in that the photoactive extracts of microalgae are extracts of Dunaliella salina.

4. Cosmetic care method according to claim 1, characterized in that the photoactive extracts of microalgae are extracts of Tetraselmis suecica.

5. Cosmetic care method according to claim 1, characterized in that said light is red light having a wavelength of between 625 and 670 nm, preferably 645 nm, and an intensity of from 140 to 180 μmol.Math.s.sup.−1.Math.m.sup.−2 photons, preferably 155 to 170 μmol.Math.s.sup.−1.Math.m.sup.−2 photons.

6. Cosmetic care method according to claim 1, characterized in that the exposure to the light is achieved using electroluminescent diodes, laser, and/or intense pulsed light.

7. Cosmetic care method according claim 1, characterized in that the time of exposure to the light is from 1 second to 60 minutes, preferably from 30 seconds to 40 minutes.

8. Lighting device for cosmetic care according to the method according to claim 1, said device consisting of a housing comprising a light source, characterized in that said light source emits light in a spectrum of wavelengths of between 400 and 750 nm, preferably between 625 and 670 nm, and an intensity of from 140 to 180 μmol.Math.s.sup.−1.Math.m.sup.−2 photons, preferably between 155 and 170 μmol.Math.s.sup.−1.Math.m.sup.−2 photons.

9. A method of anti-aging and/or anti-wrinkle treatment and/or a treatment promoting the healing of the skin region using the device according to claim 8.

10. Kit for skin care, comprising: a cosmetic composition comprising photoactive extracts of at least one microalga; a lighting device for cosmetic care according to claim 8.

11. Kit for skin care according to claim 10, characterized in that said composition comprises photoactive extracts of Tetraselmis suecica and/or of Dunaliella salina.

Description

FIGURES

[0122] FIG. 1: Production of ROS following light exposure (645 nm) for 25 minutes (in gray) for a plurality of photoactive extracts of microalgae, at a dilution factor of 500. The results when the extracts are kept in the dark are shown in black.

[0123] FIG. 2: Influence of the exposure duration on the production of oxidative molecules (ROS), depending on the extracts. The extracts originating from Dunaliella salina (DS) (FIG. 2A), Tetraselmis suecica (TS) (FIG. 2B), and Rhodomonas salina (RS) (FIG. 2C), are kept in the dark (i), or exposed for 1 minute (ii), 10 minutes (iii) or continuously (iv), to light exposure at 645 nm.

[0124] FIG. 3: Genes evaluated during the study of the effectiveness on the expression of the mRNA of cells of the skin by microfluidic RT-qPCR.

[0125] FIG. 4: Red LED module (wavelength=645 nm) preset to 160 μmol/m.sup.2/s used for photoactivation (Example 5).

EXAMPLES

Example 1: Preparation of Samples

[0126] Characterization of the production of oxidative molecules in the extracts of microalgae:

[0127] The extracts of the algae Dunaliella salina (DS), Dunaliella tertiolecta (TD), Tetraselmis suecica (TS), Chlamydomonas reinhardtii (CR), Haematococcus pluvialis (HP), Tetraselmis tetrathele (TT), Rhodomonas salina (RS), Porphyridium purpureum (PP), Rhodella maculata (RM) are selected to characterize the increase in the production of oxidative molecules when they are stimulated with light.

[0128] In order to achieve this, the algae are placed in 200 ml cultures. After a cell count at a wavelength of 680 nm, 100 to 150 ml of the solution containing the algae are then centrifugated for 10 minutes at 12,000 rpm.

[0129] The cake is then ground, and the ground material is adjusted to 5.0.10.sup.5 cells/ml in 150 ml PBS.

[0130] After a cell count at a wavelength of 680 nm, this adjusted ground material is then centrifugated for 10 minutes at 12,000 rpm.

[0131] Finally, the supernatant is filtered at 0.2 μm in order to obtain the sample ready to be analyzed.

[0132] Once ready for analysis, the samples made up of extracts of these algae are placed: [0133] 1. In the dark, and 15 μl of the reaction medium are added to 30 ml of supernatant filtered at 0.2 μm; [0134] 2. In the dark, and 15 μl of the reaction medium are added to 30 ml of supernatant filtered at 0.2 μm, followed by continuous exposure to light at 645 nm, at an intensity of 166 μmol.Math.s.sup.−1.Math.m.sup.−2. [0135] 3. In the dark, and 30 ml of supernatant filtered at 0.2 μm are exposed to bubbling with dinitrogen for 30 minutes, and then mixed with 15 μl of reaction medium. A step of light exposure is then carried out, at 645 nm, at an intensity of 166 μmol.Math.s.sup.−1.Math.m.sup.−2.

Example 2: Screening of Strains

[0136] The various extracts are then studied, keeping them in the dark or exposing them for 25 minutes to light exposure of 645 nm, at a dilution factor of 500, by means of fluorescence analyses performed using a spectrofluorometer. The parameters are as follows:

[0137] Ex: 500 Em: 522

[0138] Ex. scanning range 495-505

[0139] Em. scanning range 400-650

[0140] The results are shown in FIG. 1.

[0141] These results show an increase in the production of ROS after light exposure, for all the extracts studied.

[0142] In detail, the production of ROS is 5 times greater for the extracts of DS, 5.5 times greater for the extracts of TD, 3.6 times greater for the extracts of TS, 2.1 times for the extracts of CR, 2 times for the extracts of PP, 6.8 times for the extracts of RS, 2.3 times for the extracts of RM, 3.1 times for the extracts of HP, and 3.4 times for the extracts of TT.

Example 3: Influence of the Exposure Duration

[0143] The extracts are then studied on the basis of the exposure duration. The 4 stages studied are: [0144] Extracts kept in the dark [0145] Extracts having 1 minute of light exposure at 645 nm [0146] Extracts having 10 minutes of light exposure at 645 nm [0147] Extracts continuously exposed to light exposure at 645 nm

[0148] The results for DS (FIG. 2A), TS (FIG. 2B), and RS (FIG. 2C) are shown in FIG. 2.

[0149] These results show a constant ROS production in the dark, whatever the extract of microalgae.

[0150] For the exposure at 1 minute, the extracts of DS, TS and RS reveal an increase in the production of ROS which wears off after approximately 20/25 minutes. The production increases, to reach a maximum at around 20/25 minutes, and then drops. Thus, at most an increase of approximately 2.5 times is observed for DS, of 5 times for TS, and of approximately 3 time for RS.

[0151] Following exposure for 10 minutes, the extracts of DS, TS and RS exhibit an increase in the production of ROS which is greater than that characteristic after exposure at 1 minute. The production increases, to reach a maximum at around 25/30 minutes, and then drops. Thus, at most an increase of approximately 4.5 times is observed for DS, of 7 times for TS, and of 5 time for RS, compared with the lack of exposure.

[0152] In the case of continuous exposure, it is observed that the curves are close to those after exposure of 10 minutes. The production thus increases, to obtain a maximum at around 25/30 minutes, and then drops. For DS, a maximum production is observed after 25 minutes, of 3.5 times greater than that in the dark, thus being slightly less than the exposure for 10 minutes. During the first 25 minutes, the progressive increase in the production of ROS is similar to that characteristic for exposure at 10 minutes. However, after 35 minutes, the continuous exposure appears to exhibit a greater production of ROS than that following exposure at 10 minutes. For TS, a maximum production is observed after 30 minutes, of 6 times greater than that in the dark, thus being slightly less than the exposure for 10 minutes. For the first 25 minutes, the progressive increase in the production of ROS is similar to that characteristic of exposure at 10 minutes. However, after 35 minutes, the continuous exposure appears to exhibit a greater production of ROS than that following exposure at 10 minutes. Regarding RS, a maximum production is observed after 25 minutes, of 5 times greater than that in the dark, thus being identical to the exposure for 10 minutes. However, after 35 minutes, the continuous exposure appears to exhibit a lasting production of ROS that is greater than that following exposure at 10 minutes.

[0153] In conclusion, there is no continuous increase in the response, resulting in reaching a specific plateau at each strain of the maximum production of ROS, achieved around 25/30 minutes, and for an exposure rate of 10 minutes. Moreover, it can clearly be seen that the termination of the production is dependent on the exposure duration, the exposures at 1 and 10 minutes showing a decrease in the production of ROS after 20 to 30 minutes.

Example 4: Clinical Evaluation on 30 Subjects of Anti-Aging Cosmetic Care Using a Device that Emits Light at a Wavelength of 645 nm

[0154] The clinical study relates, overall, to 30 women aged between 35 and 70 years.

[0155] a) Performing the session of applying the cosmetic composition, and applying light at 645 nm.

[0156] A clinical dermatological examination of the tone of the skin (analysis by touch) and of the lines or wrinkles is carried out (semi-quantitative scores). Macrophotographs (subject without makeup, standard poses) are taken. Measurements of the surface area of the wrinkles, their depth, and the roughness of the skin are taken at D0 and D28, using a measuring apparatus (Skin Station).

[0157] Application of 0.4 g of composition to the face.

[0158] Exposure of the skin region containing the crow's feet to a lighting device emitting light at a wavelength of between 625 and 670 nm.

[0159] Application of the light source at 645 nm (duration, distance, intensity).

[0160] c) Conclusion

[0161] A clinical improvement is observed, following care using the composition and the device, in 27 of the 30 subjects.

[0162] The product is extremely well tolerated, and the cosmetic assessment is, overall, very good.

[0163] The cosmetic care method according to the invention thus makes it possible to significantly reduce the wrinkles of the skin.

Example 5: Evaluation of the Effectiveness on the Expression of the mRNA of Cells of the Skin by Microfluidic RT-qPCR Following Activation of the Extracts Using Light

[0164] The entirety of this handling is carried out in semi-darkness.

[0165] Material: [0166] module of red LEDs (wavelength=645 nm) preset to 160 μmol/m.sup.2/s, shown in FIG. 4. [0167] 20 ml glass test tube [0168] clamp [0169] support comprising a rod

[0170] Protocol:

[0171] In the semi-darkness, 5 ml of extract are poured into the test tube.

[0172] The test tube is then placed in the center of the module of LEDs by being fixed to the rod of the support by virtue of the clamp.

[0173] The module of red LEDs is then illuminated, and the light is left to act for 10 minutes.

[0174] After this 10 minutes, the light is cut and the sample remains in the semi-darkness.

[0175] The extract contained in the tube is withdrawn using a pipette, without stirring.

[0176] The photoactivated extract is used fresh, in the remainder of the protocol.

[0177] The experiment is performed three times (n=3) on normal human epidermal keratinocytes (NHEK) and normal human dermal fibroblasts (NHDF), where the extracts activated as described above are used.

[0178] Analysis Method:

[0179] The mRNA are extracted and reverse-transcribed into cDNA. The gene expression is quantified using qPCR, and normalized by the expression of reference genes. In order to confirm an activator or inhibitor effect, the values are compared with the reference condition, after contacting with the extracts.

[0180] The genes evaluated are indicated in FIG. 3.

[0181] An increase in the expression of the genes Claudine 1, Collagen, Fibrillin 1 and 2 is observed, as well as, in a general manner, antioxidant genes. At the same time, a reduction in the expression of metallopeptidase 1, 3 and 9 genes, and inflammation, is observed.

[0182] In conclusion, a reduction in the expression of genes promoting cutaneous aging is observed.