Novel dermatological uses of extracts from the microalga Dunaliella tertiolecta

Abstract

This invention provides a natural microalgae extract that is particularly effective against acne, acne lesions, sebum quality, and skin texture. [Solution] The present invention relates to an extract of D. tertiolecta or a composition containing the same for use in preventing and / or reducing acne and / or seborrheic disorders and in skin cleansing, and / or for preventing and / or reducing acne lesions and / or reducing imperfections and / or reducing inflammation and in / or soothing the skin. The extract is also effective in maintaining and / or improving barrier function and / or improving skin texture. A skin composition containing an extract of D. tertiolecta is also described.

Description

Technical Field

[0001] The present invention relates to a new use of an extract of the microalgae Dunaliella tertiolecta, particularly for dermatological use.

Background Art

[0002] Acne is a skin disorder caused by multiple factors. It can be of hormonal or genetic origin, or simply appear as a result of poor hygiene. There are two main types of acne: non-inflammatory acne (acne vulgaris) and inflammatory acne. Acne vulgaris is characterized by oily and shiny skin, enlarged pores, blackheads (open comedones), and subcutaneous whiteheads (microcysts or closed comedones). The most severe form of inflammatory acne appears as red papules and pustules, and even deep cysts or nodules. It is a complex disorder caused by excessive sebum in the sebaceous follicles in combination with hyperproliferation and abnormal differentiation of keratinocytes around the hair follicles. Inflammation, a third factor, is caused by the presence of the bacterium Cutibacterium acnes. In addition to the psychological consequences of acne, especially in adolescence, acne can leave relatively ugly marks. Molecules naturally present in the skin, such as azelaic acid, are known to reduce acne by decreasing the amount of C. acnes, or molecules such as clindamycin, sodium sulfacetamide, and erythromycin have already been proven to be effective against acne.

[0003] However, with regard to the latter, these are antibiotics. Solutions based on plant extracts also exist in the fields of cosmetics and dermatology. Such examples include extracts of nettle leaves, aloe vera, lavender, and tea tree, the anti-inflammatory properties and effectiveness of which against acne are known. Vitamin D and phytosterols are also known for their anti-acne effects.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, there is a need for effective natural alternative solutions in this field, namely solutions that do not involve antibiotics. This is precisely what the present invention addresses by providing a natural microalgae extract that is particularly effective against acne, acne lesions, sebum quality, and skin texture. [Means for solving the problem]

[0005] Surprisingly, the applicant discovered that an extract of the microalga Dunaliella tertiolecta is effective in treating acne, particularly by reducing the amount of Cutibacterium acnes bacteria, reducing acne lesions, and improving the quality of sebum.

[0006] The microalga D. tertiolecta is a genus of Dunaliella, a microgreen alga belonging to the family Dunaliellaceae, which includes more than 20 different species. This alga was first isolated in Norway (Oslofjord, 1938).

[0007] The D. tertiolecta extract, the subject of this invention, has the advantage of being produced on an industrial scale from natural microalgae biomass produced in a photobioreactor under completely controlled light, temperature, and pH conditions. The extract according to this invention does not induce skin allergies. It also has several effects on the skin, such as maintaining barrier function and improving skin texture.

[0008] To the best of the applicant's knowledge, the prior art does not describe any extract of D. tertiolecta, nor any composition containing it, for use in preventing the onset of acne and / or reducing acne by reducing the amount of Cutibacterium acnes bacteria and / or acne lesions, or for reducing inflammation and consequently soothing the skin.

[0009] There is no mention of the use of extracts from this strain for maintaining and / or improving skin barrier function, and / or for improving skin texture, particularly oily skin, acne-prone skin, or acne-prone skin.

[0010] Disclosure of the invention Therefore, the first object of the present invention relates to an extract of D. tertiolecta or a composition containing the same for use in preventing and / or reducing acne and / or seborrheic disorders and in skin cleansing, and / or for preventing and / or reducing acne lesions and / or reducing imperfections and / or inflammation and in / or soothing the skin. The present invention also relates to the non-therapeutic cosmetic use of an extract of D. tertiolecta or a composition containing the same for maintaining and / or improving skin barrier function and / or improving skin texture, particularly for reducing the visibility and / or size of pores in oily skin, and in / or improving facial appearance and / or comfort of oily skin.

[0011] Specifically, the extracts or compositions containing the same used in accordance with the present invention are used for oily skin, acne-prone skin, or acne-prone skin.

[0012] Another objective is to relate to compositions containing such extracts, preferably compositions for skin use.

[0013] The present invention also relates to an extract of D. tertiolecta or a composition containing the same for use according to the present invention, or a composition defined according to the present invention for use on any area of ​​the face and / or on any area of ​​the body selected from the arms, back, torso, chest, neck and décolletage, including the forearms, preferably on any area of ​​facial skin selected from the cheeks, cheekbones, forehead, around the nose, nasolabial folds, temples, around the eyes, chin, around the mouth and / or lips, and more preferably on any area of ​​the cheeks, forehead, around the nose, temples, nasolabial folds and / or around the mouth.

[0014] The present invention relates to the non-therapeutic cosmetic use of D. tertiolecta extract or compositions containing it for maintaining and / or improving skin barrier function and / or improving skin texture, particularly for reducing the visibility and / or size of pores in oily skin, and / or improving facial appearance and / or comfort of oily skin. [Modes for carrying out the invention]

[0015] Therefore, the first objective is to relate to an extract of D. tertiolecta or a composition containing the same for use in preventing and / or reducing acne and / or reducing seborrheic disorders and thus in skin cleansing, and / or for preventing and / or reducing acne lesions and / or reducing imperfections and / or reducing inflammation and thus in soothing the skin. In particular, an extract of D. tertiolecta or a composition containing the same reduces the amount of Cutibacterium acnes bacteria when used in preventing and / or reducing acne.

[0016] In advantageous embodiments of the present invention, use is topical. "Topical" means direct application to the skin and / or lips or spraying the extract or composition containing the present invention onto their surfaces. For the purposes of the present invention, skin includes the scalp.

[0017] The D. tertiolecta extract or composition containing the same according to the present invention is topically tolerable; that is, it does not induce allergic reactions and is neither toxic nor irritating. The extract or composition containing the same according to the present invention can be applied or sprayed onto any area of ​​skin selected from any area of ​​the face and / or body. "Any area of ​​the face" means any area selected from the cheeks, cheekbones, forehead, around the nose, nasolabial folds, temples, around the eyes, chin, around the mouth, and / or lips. The D. tertiolecta extract or composition containing the same used in accordance with the present invention is advantageously applied to the face, particularly to any area of ​​the cheeks, cheekbones, forehead, around the nose, nasolabial folds, temples, and / or lips.

[0018] Specifically, the D. tertiolecta extract according to the present invention is used on acne-prone skin or acne-prone skin. Here, "acne-prone skin" means skin with non-inflammatory acne (acne vulgaris) or mild, moderate, or severe inflammatory acne. "Acne-prone skin" means skin that does not have acne but is prone to developing acne, and within the scope of the present invention, this includes oily skin and combinations with oily skin. Oily skin is skin with excess sebum.

[0019] Specifically, the D. tertiolecta extract according to the present invention is used on acne-prone skin or acne-prone skin. Here, "acne-prone skin" means skin with non-inflammatory acne (acne vulgaris) or mild, moderate, or severe inflammatory acne. "Acne-prone skin" means skin that does not have acne but is prone to developing acne, and within the scope of the present invention, this includes oily skin and combinations with oily skin. Oily skin is skin with excess sebum.

[0020] The term "prevention of acne development and / or reduction of acne" according to the present invention specifically means reducing the amount of Cutibacterium acnes bacteria and / or reducing acne-causing inflammation by reducing the production of pro-inflammatory cytokines (IFNγ, ILα).

[0021] Specifically, “prevention of acne development and / or reduction of acne” means reducing the amount of Cutibacterium acnes present on human skin in the presence of D. tertiolecta extract or a composition containing the same according to the present invention. In a favorable embodiment, this involves a reduction of at least 26%, and preferably at least 50%, in vitro in the presence of the crude extract of D. tertiolecta according to the present invention, as defined below, compared to the amount of C. acnes measured without the extract under the conditions detailed in Example 2a). The results are presented in Table 1.

[0022] In another embodiment of the present invention, “prevention and / or reduction of acne” means reducing acne-causing inflammation. Advantageously, in this case, the reduction of inflammation is assessed by measuring the amount of interferon-gamma (IFNγ) in a viable inflammatory skin explant model in the presence of a crude extract of D. tertiolecta according to the present invention. Advantageously, the reduction in IFNγ is at least 20%, preferably at least 30%, in the presence of the extract according to the present invention compared to the amount of IFNγ measured in the absence of the extract under the conditions detailed in Example 2b) (Table 2).

[0023] By reducing inflammation, the extract according to the present invention or a composition containing the same is effective in calming the skin. Therefore, "calming the skin" specifically means reducing inflammation by reducing the amount of interferon gamma (IFNγ) as described above. Alternatively, "prevention and / or reduction of acne onset" means reducing acne-induced inflammation by reducing the level of interleukin ILα measured in vivo in the clinical trial detailed in Example 2c).

[0024] Therefore, the ILα level was measured after samples were taken from the skin surface using a cotton swab at time points D0 and D28 of the clinical trial in a population and a placebo population that received twice-daily application of a cream containing the oily extract according to the present invention as defined below (Table 3).

[0025] "Prevention and / or reduction of acne lesion onset" according to the present invention specifically means prevention and / or reduction of the onset of pustules and / or pustules and / or papules, and / or reduction of skin hyperkeratosis and / or seborrhea abnormalities, and / or promotion and / or improvement of cell regeneration and basal layer aggregation of keratinocytes and / or fibroblasts. Specifically, "prevention and / or reduction of acne lesion onset" means preventing and / or reducing the onset of pustules and / or pustules and / or papules. Note that such lesions may leave relatively ugly scars. Pustules here mean micro-pustules, black pustules, and white pustules. Such acne lesions, especially scars, are an imperfection that requires exclusion.

[0026] In one embodiment, "prevention and / or reduction of acne lesion onset" means reducing skin hyperkeratosis. Advantageously, the reduction of hyperkeratosis is measured by reducing the number of corneocyte layers at the level of the hair follicle opening in the presence of the oily extract according to the present invention. The hair follicle opening is the sebaceous gland opening of the hair follicle where the hair appears. This is also the place where sebum accumulates.

[0027] In the presence of C. acnes bacteria, cell proliferation increases in the excretory ducts of sebaceous hair follicles, followed by corneocytic lamellae obstructing the hair follicles. Advantageously, the reduction is due to 15 μL / cm³ of the oily extract according to the present invention diluted with MCT oil (medium-chain triglycerides) at a concentration of 1.5% by weight based on the total weight of the composition and MCT oil. 2 The proportion of explants is at least 20%, and more preferably at least 29%, in the presence of deposits on the explants, and the reduction is measured on skin explants under the conditions described in Example 3a) (Table 4).

[0028] Specifically, extracts of D. tertiolecta or compositions containing it are effective in reducing imperfections by preventing the development of acne lesions and reducing acne lesions.

[0029] In another embodiment of the present invention, “prevention of the development of acne lesions and / or reduction of acne lesions” means the reduction of seborrheic abnormalities that correspond to changes in the composition of sebum and generate oxidized sebum. Oxidized sebum causes the development of acne lesions, mainly comedones. Sebum is a mixture of several types of lipids: triglycerides, free fatty acids, celides, cholesterol, and squalene. It is the increase in sebum oxidation that induces the formation of acne lesions. For this reason, “reduction of seborrheic abnormalities” means the reduction of membrane lipid peroxidation. Lipid peroxidation in cell membranes generates compounds such as malondialdehyde (MDA). This molecule is an oxidative stress marker. Therefore, “reduction of membrane lipid peroxidation” is understood to most favorably mean a reduction in the amount of MDA. For this reason, the reduction in the amount of MDA is at least 14%, and favorably at least 28%, in the presence of the oily extract according to the present invention.

[0030] In a favorable embodiment, the reduction in MDA amount is measured on healthy skin explants in the presence of the composition according to the present invention, under the conditions detailed in Example 3b). The results are shown in Table 5.

[0031] By reducing seborrheic disorders on the one hand and reducing the amount of C. acnes bacteria described above on the other hand, D. tertiolecta extract or compositions containing it are also particularly effective for skin cleansing.

[0032] In yet another embodiment of the present invention, the reduction of acne lesions is directly evaluated in vivo as part of the clinical trials described above (protocol of Example 2c). In this regard, the D. tertiolecta extract is effective in reducing acne scars by at least 2%, preferably at least 4%, after 28 days of application of a cream containing the oily extract according to the present invention twice daily, compared to a placebo cream (Example 3c) (Table 6). In yet another embodiment, “prevention of the development of acne lesions and / or reduction of acne lesions” means increasing the gene expression of markers for cell regeneration and basal layer aggregation in keratinocytes and / or fibroblasts. Advantageously, in this case, the crude extract of D. tertiolecta increases the expression of HBEGF (heparin-binding EGF-like growth factor), EGF (epidermal growth factor), laminin-2 (LAMC2), CD44 marker, fibronectin 1 (FN1), integrin beta-4 (ITGB4), and laminin alpha-5 (LAMA5), and specifically increases the expression of HBEGF (heparin-binding EGF-like growth factor), EGF (epidermal growth factor), laminin-2 (LAMC2), CD44 marker, fibronectin 1 (FN1), integrin beta-4 (ITGB4), and laminin alpha-5 (LAMA5) by at least 100%, at least 60%, at least 115%, at least 60%, at least 110%, 50%, and 50%, respectively. Advantageously, gene expression is measured by quantitative real-time PCR under the conditions described in Example 3d) (Table 7).

[0033] By preventing and / or reducing acne lesions and / or increasing the expression of cell regeneration markers, the extract or composition containing the same according to the present invention is effective in reducing skin imperfections.

[0034] The D. tertiolecta extract according to the present invention is also adapted to improve facial appearance and / or oily skin comfort.

[0035] Accordingly, the present invention also relates to the non-therapeutic cosmetic use of an extract of D. tertiolecta or a composition containing the same for maintaining and / or improving skin barrier function and / or improving skin texture, particularly for reducing the visibility and / or size of pores in oily skin, and / or improving facial appearance and / or comfort of oily skin. "Cosmetic use" means non-therapeutic use. It is neither a medicinal nor a dermatological use by a dermatologist who is an expert in the art. The use is not intended to treat skin that requires therapeutic treatment and is intended to be for so-called healthy skin. Here, "healthy skin" means skin that does not have any wounds, lesions, scars, allergies, ulcers, redness, infections, and / or dermatological disorders, such as vitiligo, acne, and / or dermatitis. For the purposes of the present invention, skin includes the scalp.

[0036] Extracts of D. tertiolecta are indeed effective in maintaining and / or improving skin barrier function and / or improving skin texture. Specifically, D. tertiolecta extracts are effective in improving the texture of oily, acne-prone, or acne-prone skin.

[0037] "Maintaining and / or improving the skin barrier function" specifically means maintaining and / or increasing the gene expression of caspase 14 (cysteine-aspartate protease CASP14) and / or involucrin (INV) and / or loricrin in keratinocytes in the presence of the D. tertiolecta extract according to the present invention. These proteins are involved in keratinocyte differentiation and participate in the formation of the outermost layer of the skin, the stratum corneum (or corneocyte layer). This is a physical barrier that limits water loss from the skin, particularly through evaporation. Therefore, in one embodiment, improvement of skin barrier function means increasing the gene expression of CASP14 by at least 70%, and preferably at least 140%, in the presence of the crude D. tertiolecta extract according to the present invention.

[0038] Alternatively, it is an increase of at least 20%, preferably at least 40%, in the gene expression of involucrin in the presence of the crude extract of D. tertiolecta according to the present invention. Alternatively, it is an increase of at least 45%, preferably at least 90%, in the gene expression of loricrin in the presence of the crude extract of D. tertiolecta according to the present invention. In all embodiments described herein, the crude extract of D. tertiolecta according to the present invention is, advantageously, an extract obtained by extraction in ethanol, and more advantageously, obtained under the conditions of Example 1a). The results are presented in Example 4a) (Table 8).

[0039] Furthermore, within the scope of the present invention, “improvement of skin texture” preferably means reducing the visibility and / or size of skin pores on oily skin, acne-prone skin, or acne-prone skin. For this reason, in one embodiment of the present invention, improvement of skin texture is evaluated in vivo in the presence of a cream containing the oily extract according to the present invention as part of a clinical trial already described above, the protocol of which is detailed in Example 2c) (Example 5) (Table 9).

[0040] Therefore, by reducing the pore size, the oily extract or composition containing the same according to the present invention is effective as an astringent active ingredient or an astringent composition.

[0041] By improving skin texture, and specifically by reducing the visibility and / or size of pores, the D. tertiolecta extract of the present invention is thus particularly suitable for improving facial appearance and / or comfort of oily skin.

[0042] Extract according to the present invention Within the scope of the present invention, "extract of D. tertiolecta" means any extract obtained from any biomass by any extraction method known to those skilled in the art, including solid-liquid extraction.

[0043] The extract according to the present invention can be obtained from frozen biomass after microalgae cultivation or from fresh biomass. The biomass may be dried before extraction. It may be concentrated by removing all or part of the water by centrifugation, filtration, sedimentation, or flocculation, whether or not a drying step by freeze-drying or vacuum drying, drum drying, atomization, or any other process that reduces the water content of the biomass is used in combination. Here, “dried biomass” means biomass having a water content of less than 15%, preferably less than 10%, and more preferably less than 5%. Advantageously, in connection with the present invention, the biomass is frozen before extraction. It is then thawed and filtered before extraction.

[0044] In one embodiment, an extract of D. tertiolecta according to the present invention is obtained by extraction (known as solid-liquid extraction) with a solvent or solvent mixture selected from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, alcohol selected from ethanol, methanol, and isopropanol, natural oil or branched oil, glycol, polyol, and mixtures thereof, a 99 / 1 to 1 / 99 (w / w) ratio water / alcohol mixture, and a 99 / 1 to 1 / 99 (w / w) ratio water / glycol mixture. Preferably, the extract is obtained in ethanol, i.e., in ethanol as the sole solvent.

[0045] According to another preferred embodiment, the extract is obtained in a water / ethanol mixture. Biomass extraction can be carried out in the presence of 0.1% to 20% by weight, preferably 1% to 20% by weight, more preferably 5% to 15% by weight, and most preferably 10% by weight of biomass, based on the total weight of biomass and solvent.

[0046] Extraction can be carried out at temperatures ranging from 4°C to 300°C, including room temperature, i.e., 20°C. Preferably, it can be carried out at temperatures ranging from 20°C to 50°C, and even more preferably at 30°C. Extraction can be carried out for 30 minutes to 12 hours, preferably 1 hour to 4 hours, more preferably 1 hour to 2 hours, and most preferably 1 hour.

[0047] Subcritical water extraction According to a first embodiment of the present invention, biomass extraction is carried out in water under subcritical conditions at a temperature in the range of 100°C to 300°C, preferably 120°C to 250°C, and more preferably 120°C. Extraction can be carried out at a given temperature or at progressively increasing temperatures. In an advantageous embodiment of the present invention, extraction is carried out at a temperature of 120°C. In an alternative embodiment, it is carried out according to a gradient of three increasing temperatures between 100°C and 200°C, for example, 120°C, 140°C, then 160°C, or 110°C, 130°C, then 150°C, or 120°C, 145°C, then 170°C.

[0048] Extraction under "subcritical conditions" means extraction in the presence of water, at a temperature above 100°C and a pressure below 221 bar, while leaving the water in a liquid state, but with a viscosity and surface tension lower than that of water at room temperature, thereby increasing its dielectric constant. For this reason, the extraction pressure is advantageously 150 bar to 250 bar, preferably 200 to 221 bar, in a pressure extraction autoclave.

[0049] Supercritical CO2 extraction According to another embodiment of the present invention, biomass extraction is carried out by supercritical CO2 extraction. In this case, the extraction may optionally be carried out in the presence of a cosolvent selected from ethanol, acetone, methanol, or any combination thereof. Alternatively, supercritical CO2 extraction may be carried out alone without a cosolvent, followed by an additional extraction with a polar solvent selected from ethanol, acetone, methanol, hexane, and heptane, preferably ethanol. Advantageously, in connection with the present invention, supercritical CO2 extraction is carried out in the presence of ethanol (10%) as a cosolvent. The conditions for supercritical CO2 extraction are such that the pressure, measured in bar units, is greater than 74 bar, preferably greater than 100 bar, and more preferably greater than 150 bar. The temperature is greater than 35°C, preferably greater than 45°C, and more preferably greater than 50°C.

[0050] Alcohol or water alcohol extraction In a particularly advantageous embodiment of the present invention, the extract is obtained from alcohol extraction. The extract is prepared from 15% by weight of fresh biomass, centrifuged, and then vacuum-dried. The biomass is then pulverized and extracted at a temperature of 30°C for 1 hour in the presence of ethanol as the sole solvent. According to a specific method, the extract used in accordance with the present invention is an activated carbon bleached extract. Thus, according to one embodiment, the obtained extract can then be bleached with activated carbon so as to remove chlorophyll, as described in Example 1a), the carbon is removed by filtration, and the extract is filtered.

[0051] The resulting extract is called an ethanol extract or an extract obtained by ethanol extraction. It is a crude extract.

[0052] In another advantageous embodiment of the present invention, the extract is prepared from frozen biomass and then vacuum-dried. It is then pulverized and extracted in a 30 / 70 (v / v) water / ethanol mixture at a temperature of 20°C for 2 hours. The extract is then bleached with activated carbon under the conditions described in Example 1b), and the carbon is removed. The resulting crude extract is referred to as the water-alcohol extract.

[0053] The D. tertiolecta extract according to the present invention can be used as is in powder form (referred to as the "raw extract"), or can be dispersed in oil (referred to as the "oil preparation" or "oil extract" according to the present invention), or can be incorporated into the final composition together with "dermatologically acceptable excipients," i.e., excipients that are non-irritating and non-toxic to the skin (incorporation of the raw extract or, preferably, the oil extract into the final composition). According to the present invention, "excipient" means any compound other than the D. tertiolecta extract and any additional active ingredients present in the composition and / or used in the manufacture of the composition and / or product.

[0054] Typically, two or more excipients are used in the formulation of a composition to improve stability, bioavailability, appearance of the composition, and ease of production. Excipients are advantageously selected from natural oils, particularly vegetable oils such as argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from algae, including plants or microalgae, particularly those selected from olive oil, rapeseed oil, linseed oil, sunflower oil, and medium-chain triglyceride (MCT) oils, other oils such as C11-C13 alkanes, ester oils, and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, humectants, thickeners, texturers, conditioners, glossants, film-forming agents, pigments, colorants, fragrances, antimicrobial additives, chelating agents, astringents, polymers, reducing agents, pH adjusters, and mixtures thereof.

[0055] According to a particular embodiment, the composition comprises several excipients, particularly water, glycol, polymer, thickener (also called viscosity enhancer), emollient, and mixtures thereof.

[0056] Oily extract (also called oily preparation) According to a particular embodiment, the extract used in accordance with the present invention is dispersed in at least one vegetable oil to form an “oilly preparation” and is also referred to as an “oilly extract,” which can be used as is or constitute an intermediate preparation of a final composition containing additional components.

[0057] In certain embodiments, the extract used in accordance with the present invention may be dispersed in any oil extracted from plants or algae, including microalgae, particularly oils selected from olive oil, rapeseed oil, linseed oil, sunflower oil, and medium-chain triglyceride (MCT) oil. Medium-chain triglyceride (MCT) means an ester of glycerol and a saturated fatty acid, the hydrocarbon chain having 6 to 12 carbon atoms. Thus, the MCT oil may be obtained from other fats and oils, but is selected from coco oil, preferably coconut oil, palm kernel oil, and palm oil. Advantageously, within the spirit of the present invention, the vegetable oil is MCT oil, preferably coco oil, and very advantageously coconut oil.

[0058] In certain embodiments, the oil is present in an amount ranging from 50% to 99.8% by weight, preferably 75% to 99.5% by weight, very preferably 97.5% to 99.4% by weight, and even more preferably 98% to 99% by weight, based on the total weight of the oily preparation. The oily preparation may be used as is, or it may function as a dermatological intermediate preparation, including other components and dermatological excipients, such as those described above.

[0059] Therefore, in preferred embodiments of the present invention, the oily extract includes coconut oil. According to a particular preferred embodiment, coconut oil is added to the crude extract of D. tertiolecta obtained according to Example 1a) or 1b) in an amount ranging from 97.5% to 99.4% by weight, preferably 98% to 99% by weight, based on the total weight of the oily extract.

[0060] According to certain preferred embodiments, the oily extract also advantageously contains an antioxidant, preferably vitamin E, in an amount ranging from 0.1% to 0.5% by weight based on the total weight of the oily preparation.

[0061] Advantageously, vitamin E is present in an amount of 0.10% by weight based on the total weight of the oily preparation. Here, "vitamin E" means a tocopherol selected from α-tocopherol, γ-tocopherol, β-tocopherol, or δ-tocopherol, or a tocotrienol selected from α-tocotrienol, β-tocotrienol, γ-tocotrienol, or δ-tocotrienol.

[0062] Therefore, in certain preferred embodiments, the extract is in the form of an oily extract comprising: (i) 0.5% to 2% by weight, preferably 1% by weight, of a crude extract of Dunaliella tertiolecta based on the total weight of the oily extract; (ii) 97.5% to 99.4% by weight, preferably 98% to 99% by weight, of vegetable oil, preferably medium-chain triglyceride (MCT) oil, more preferably coconut oil, based on the total weight of the oily extract; and (iii) 0.10% to 0.5% by weight, preferably 0.10% by weight, of an antioxidant, preferably vitamin E, more preferably α-tocopherol, based on the total weight of the oily extract. Specifically, the oily extract comprises 0.5% to 2% by weight, preferably 1% by weight, of an extract of Dunaliella tertiolecta prepared according to Example 1a).

[0063] The oily extract (or oily preparation) may be used as is or as an intermediate composition of a final composition that includes other ingredients and cosmetic excipients, such as those described above.

[0064] final composition The “final composition” according to the present invention means a) a crude extract (or dried product), or preferably an oily extract according to the present invention comprising a crude extract and at least one vegetable oil, for example, those described above, specifically coconut oil, and preferably an antioxidant, specifically vitamin E; and b) at least one cosmetically or dermatologically acceptable excipient, and one or more additional components selected from additional oils, such as vegetable oils, in particular argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or plants or microalgae. This means a composition comprising any oil selected from those extracted from algae, including, in particular, selected from olive oil, rapeseed oil, linseed oil, sunflower oil, medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils, and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, humectants, thickeners, texturers, conditioners, glossing agents, film-forming agents, pigments, colorants, fragrances, antimicrobial additives, chelating agents, astringents, polymers, reducing agents, pH adjusters, and mixtures thereof. The composition may also contain water. The total amount of dermatologically acceptable excipients also includes the amount of water, if present.

[0065] An extract of Dunaliella tertiolecta according to the present invention, preferably an oily extract according to the present invention, and more preferably an oily extract according to Example 1a), may be advantageously used in an amount ranging from 1% to 5% by weight, preferably 1% to 3% by weight, and more preferably 1% to 2% by weight, based on the total weight of the final composition.

[0066] Therefore, one or more cosmetically or dermatologically acceptable excipients and one or more additional components are present in a total amount of 95% to 99% by weight, preferably 97% to 99% by weight, and more preferably 98% to 99% by weight, based on the total weight of the (final) composition.

[0067] Extracts or compositions containing the same used in accordance with the present invention are preferably applied topically.

[0068] Another object of the present invention is further relating to a topical composition comprising, more preferably, an oily extract of D. tertiolecta as described above, and more preferably, a cosmetic or dermatological composition.

[0069] According to a particular embodiment, the composition of the present invention is present in an amount within the following range, based on the total weight of the composition: -1% to 5% by weight, preferably 1% to 3% by weight, favorably 1% to 2% by weight of Dunaliella tertiolecta oily extract, -95% to 99% by weight, preferably 97% to 99% by weight, and more preferably 98% to 99% by weight, cosmetic or dermatologically acceptable excipients and possible additional (active) ingredients, A cosmetic or topical skin composition comprising the oily extract of Dunaliella tertiolecta, characterized in that the oily extract of Dunaliella tertiolecta comprises (i) 0.5% to 2% by weight, preferably 1% by weight, of a crude extract of Dunaliella tertiolecta based on the total weight of the oily extract; (ii) 97.5% to 99.4% by weight, preferably 98% to 99% by weight, of vegetable oil, preferably medium-chain triglyceride (MCT) oil, more preferably coconut oil, based on the total weight of the oily extract; and (iii) 0.10% to 0.5% by weight, preferably 0.10% by weight, of an antioxidant, preferably vitamin E, more preferably α-tocopherol, based on the total weight of the oily extract.

[0070] If it is found that the oily extract of Dunaliella tertiolecta according to the present invention (i) preferably contains 1% by weight of the crude extract of Dunaliella tertiolecta based on the total weight of the oily extract, then the amount of active material in the final composition will be in the range of 0.0001% to 0.0005% by weight, preferably 0.0001% to 0.0003% by weight, and advantageously 0.0001% to 0.0002% by weight of the Dunaliella tertiolecta extract.

[0071] Cosmetic or dermatologically acceptable excipients and / or additional ingredients are as defined above.

[0072] The composition is used for the prevention and / or reduction of acne, and / or for the reduction of seborrheic disorders and thus for skin cleansing, and / or for the prevention and / or reduction of acne lesions and thus for the reduction of imperfections, and / or for the reduction of inflammation and thus for skin soothing. Specifically, it reduces the amount of Cutibacterium acnes in its use in the prevention and / or reduction of acne. By reducing the amount of Cutibacterium acnes and / or for the reduction of seborrheic disorders, the composition is thus active in skin cleansing.

[0073] In addition, according to another embodiment, the topical composition according to the present invention maintains and / or improves the skin barrier function, and / or improves skin texture by reducing pore size, particularly in oily skin, acne-prone skin, or acne-prone skin. It is especially useful for improving facial appearance and / or comfort in oily skin, acne-prone skin, or acne-prone skin.

[0074] The final composition may also contain other activators or additional ingredients that provide synergistic or complementary effects with the D. tertiolecta extract. In this regard, activators or cosmetic ingredients, such as vitamin D, vitamin D3, or one of their precursors, or even one of their metabolites, and / or phytosterols, are certainly well known to have effects, particularly in the prevention or treatment of acne.

[0075] The composition may also include one or more other microalgae extracts, particularly extracts of Tisochrysis lutea, preferably an oily extract or ethanol extract, preferably an oily extract commercialized by the applicant under the name Luteana®; extracts of Phaeodactylum tricornutum, preferably an oily extract, ethanol extract, or water-alcohol extract, particularly an oily extract commercialized by the applicant under the name PhycoAge®; extracts of Porphyridium cruentum, preferably an ethanol extract or soluble water extract, particularly a water extract commercialized by the applicant under the name Renouvellance®; or furthermore, a hydrolysate of the ethanol extract co-product of P. tricornutum commercialized by the applicant under the name PhycoSi®.

[0076] These various extracts can be used in single compositions, as a set of compositions (kits) to be used in combination, or in combination on skin to be treated as an alternative.

[0077] Compositions, particularly skin compositions, may be in the form of creams, serums, gels, soaps, skin bars, shower gels, aqueous or oily solutions, oil-in-water emulsions or water-in-oil emulsions, masks, lotions, ointments, shampoos, conditioners, scalp treatments, patches, foams (especially cleansing foams), or sticks. Compositions may also be in the form of patches or encapsulated in a form selected from spheres, microspheres, or liposomes. Advantageously, compositions are in the form of creams or serums.

[0078] Therefore, compositions containing the oily extract according to the present invention, preferably oily extracts derived from D. tertiolecta obtained by ethanol extraction, and more preferably those derived from D. tertiolecta extract obtained in Example 1a), are used in accordance with the present invention for the prevention and / or reduction of acne, and / or for the prevention and / or reduction of seborrheic abnormalities, thereby for skin purification, and / or for the prevention and / or reduction of acne lesions, thereby for the reduction of imperfections, and / or for the reduction of inflammation, thereby for skin soothing. In particular embodiments, the extract or composition containing the present invention is used to prevent and / or reduce acne by reducing the amount of C. acnes bacteria and / or acne lesions on oily skin.

[0079] In one embodiment of the present invention, an extract of D. tertiolecta, preferably an oily extract (oily preparation), or a composition containing the same, preferably a skin composition according to the present invention, is applied topically to any area of ​​the face and / or any area of ​​the body selected from the arms, back, torso, chest, neck, and décolletage, including the forearms, preferably any area of ​​facial skin selected from the cheeks, cheekbones, forehead, around the nose, nasolabial folds, temples, around the eyes, chin, around the mouth, and / or lips, and more preferably any area of ​​the cheeks, forehead, around the nose, temples, nasolabial folds, and / or around the mouth.

[0080] Refer to the description for the following examples. These examples are illustrative and do not limit the scope of the invention. Unless otherwise specified, temperature is given in degrees Celsius (°C), pressure in bar, and percentages are given in wt / w or wt / volume (w / v). [Examples]

[0081] Example 1: Method of preparing an extract of Dunaliella tertiolecta Example 1a) Obtained by ethanol extraction The biomass-derived strain of D. tertiolecta was first isolated in Norway in 1928. It is available for purchase from the Algal and Protist Culture Collection (CCAP, Scotland, UK) under reference number CCAP19 / 6B, or from the Algal Culture Collection at the University of Texas at Austin (UTEX) under reference number UTEX LB999. Conditions for culturing and maintaining the strain are indicated by these collection holders.

[0082] Fresh biomass was collected from autotrophic photobioreactor cultures of either of the above strains, centrifuged, and then vacuum-dried.

[0083] The biomass was crushed and extracted at 30°C for 1 hour at a ratio of 100 g of dry biomass per liter of solvent in the presence of ethanol as the sole solvent. The residual biomass was removed by filtration, the extract was bleached with activated carbon, and then the solvent was evaporated. The carbon was removed by filtration.

[0084] The obtained crude extract is in liquid form. It is possible to obtain a powder form by freeze-drying the crude extract.

[0085] Composition of the oily extract (oily preparation) according to the present invention: MCT coconut oil in an amount of 98.5% by weight based on the total weight of the composition, the liquid extract (crude extract) obtained above, and α-tocopherol (final concentration 0.15% w / w) were mixed by homogenization. The dry extract content of D. tertiolecta was 1% of the oily extract.

[0086] Example 1b) Obtained by water-alcohol extraction Fresh biomass was collected from autotrophic photobioreactor cultures of either strain from Example 1a), centrifuged, and then vacuum-dried. It was pulverized and extracted at 20°C for 2 hours in the presence of a water / ethanol mixture (30 / 70, v / v) as the solvent (100 g dry biomass / L solvent). The residual biomass was removed by filtration, the extract was bleached with activated carbon, and then the solvent was evaporated. The carbon was removed by filtration, and the extract was filtered.

[0087] The crude extract obtained in this way is in liquid form and can be dried by freeze-drying to obtain a powder form.

[0088] Composition of the oily extract (oily preparation) according to the present invention: MCT coconut oil in an amount of 99% by weight based on the total weight of the composition, the liquid extract (crude extract) obtained above, and α-tocopherol (final concentration 0.05% w / w) were mixed by homogenization. The dry extract content of D. tertiolecta was 1% of the oily extract.

[0089] Example 2: Effects of Dunaliella tertiolecta extract on the prevention and reduction of acne Example 2a) Reduction of the amount of Cutibacterium acnes Protocol: Strain C. acnes ATCC® 6919®, Gram+ was cultured in a suitable medium (Mueller-Hinton agar containing 5% sheep blood) to obtain a bacterial suspension, which was adjusted to an optical density of 0.33 (600 nm). The bacterial suspension was transferred to a 96-well plate, and a crude extract of D. tertiolecta (Example 1a) was added to the suspension to a final concentration of 0.75% or 1% (v / v), or ethanol was added to the suspension as a negative control.

[0090] Next, the suspension was cultured in BHI medium (Brain Heart Infusion Broth, Merck) under stirring (280 rpm) at 37°C for 48 hours.

[0091] Optical density was read every 6 hours over a 48-hour period (D2), including the 24-hour period (D1).

[0092] The results are presented in Table 1 below (average percentage reduction in optical density compared to negative control for D0, D1, and D2, n=3). The reduction in optical density reflects a reduction in the number of bacteria, Cutibacterium acnes. result:

[0093] [Table 1]

[0094] Conclusion: D. tertiolecta extract was effective in reducing the amount of C. acnes bacterial suspension by at least 26%, and by more than 50% in just 24 hours, thus demonstrating its efficacy in reducing acne and allowing the skin to be cleansed.

[0095] Example 2b) Reduction of inflammation (IFNγ) in an inflammatory model of skin explants. Protocol: Inflammatory skin explant models were prepared as follows: Non-pathological skin fragments from plastic surgery were cultured in wells in the presence of a specific culture medium containing antibiotics and fetal bovine serum. The cultures were maintained at 37°C (5% CO2) for 4 days.

[0096] To mimic an inflammatory model similar to acne-induced inflammation, 10 μM substance P (BACHEM), gram + bacterial extract (1 μg / mL culture peptidoglycan from Micrococcus aureus, similar to C. acnes (SIGMA, Ref. 53243)), and 10 ng / mL interleukin ILα (GIBCO, Life Technologies) (referred to here as the inflammatory mixture) were added at D0 of a 4-day culture (positive control).

[0097] An oily extract according to the present invention (oily preparation according to Example 1a), diluted in MCT coconut oil at a concentration of 0.75% w / w or 1% w / w, or MCT coconut oil as a negative control, was immediately applied topically at a rate of 15 μL / cm2 per explant (D0), followed by 4-day culture on D1. On D1 and D2, culture medium was collected, frozen at -32°C, and mixed for enzyme-coupled immunosorbent assay (ELISA). The amount of IFNγ was measured by spectrophotometric measurement at 450 nm using the ELISA assay (IFNγ concentration in pg / mL units) (Elabscience). Explants were also cultured under the exact same conditions, except without the application of the above inflammatory mixture, the oily extract according to the present invention, and the MCT coconut oil ("non-inflammatory control").

[0098] Results were reported based on biopsy weight and expressed in pg / mg units (average of 4 samples). result:

[0099] [Table 2]

[0100] Conclusion: Inflammation induced by a mixture of substance P, ILα, and M. aureus peptide (amount of IFNγ) (positive control) was reduced by at least 20% and up to over 33% in the presence of the oily extract according to Example 1a), in contrast to MCT coconut oil as a negative control, and this can be attributed to an anti-inflammatory effect. Therefore, the oily extract according to the present invention is effective in reducing inflammation by reducing the production of pro-inflammatory cytokines (IFNγ), whether or not it is caused by acne. The oily extract and the D. tertiolecta extract are effective in reducing skin inflammation and, consequently, soothing the skin.

[0101] Example 2c) Reduction of interleukin Ilα levels in vivo (clinical trial) Protocol: A clinical trial was conducted in a group of 40 female Caucasian volunteers aged 25–45 years with mild to moderate acne. The volunteers were given a cream containing either the oily extract according to the present invention (cream of Example 7) prepared in Example 1a) or a placebo cream (containing tartrazine (CI 19140) as a coloring agent instead of the oily extract according to the present invention) at a final concentration of 2% by weight (w / w) based on the total weight of the cream, applied twice daily to their faces for 28 days (20 individuals who received the cream containing the extract and 20 individuals who received the placebo cream).

[0102] During clinical trials on days D0 and D28, samples were collected from the surface of cheek skin (approximately 4cm x 4cm) using cotton swabs (SWAB type sample, 3M) from the group that received the cream containing the oily extract according to Example 1a) (final 2% w / w) twice daily, and from the placebo group. The samples were placed in Eppendorf tubes and stored at -20°C after sampling. Subsequently, Ilα was quantified by ELISA (enzyme-linked immunoassay). result:

[0103] [Table 3]

[0104] Conclusion: Application of a cream containing an oily extract (including an extract of D. tertiolecta according to the present invention) twice daily reduced the amount of interleukin-1α more efficiently than a placebo cream after 28 days. The oily extract and the D. tertiolecta extract are effective in reducing skin inflammation and, consequently, soothing the skin.

[0105] Example 3: Effect of Dunaliella tertiolecta extract on reducing acne lesions Example 3a) Reduction of hyperkeratosis (number of corneocyte layers at the hair follicle opening level) Protocol: Human skin fragments were postoperatively collected from neck and face lifts of four female donors aged 23, 26, 29, and 30 years and cultured in culture wells in the presence of a specific culture medium adapted to maintain survival and containing antibiotics and fetal bovine serum. In D0, D1, D2, and D3, 15 μL / cm³ of the oily extract according to Example 1a) (1.5% (w / w) concentration in MCT oil) or MCT coconut oil as a control was added. 2 The explant was added in proportion to the culture maintained at 37°C (5% CO2) for a total period of 4 days. After 4 days of incubation, biopsies were performed, then fixed with formalin and embedded in paraffin for histochemical analysis. The histochemical sections were stained with hematoxylin and eosin (HE). The results are presented in Table 4 below. result:

[0106] [Table 4]

[0107] Conclusion: Oily extracts of D. tertiolecta reduced the number of corneocyte layers at the hair follicle opening by more than 29%, in contrast to the negative control (MCT coconut oil) and similar to glycolic acid as the positive control. Therefore, the compositions according to the present invention are efficient in reducing acne lesions.

[0108] Example 3b) Reduction of seborrheic abnormalities: Reduction of membrane lipid peroxidation on skin explants Protocol: Lipid peroxidation in a skin explant model subjected to oxidative stress was measured by ELISA assay using the kit (SIGMA, ref. MAK085) as follows: Human skin fragments were cultured under the exact same conditions as described in Example 3a). UVA (4 J / cm³) was delivered by a stimulator (Vilbert Lourmat, Marnes la Vallee, France) containing a UVA lamp in combination with a Vilbert Lourmat RMX-365 / 312 radiometer, along with UVB radiation provided by tubes (T-20.L-312). 2 ) and UVB (10 J / cm²) 2 The explant was irradiated by applying radiation. Immediately after irradiation, the explant was 1 cm long. 2 Explants were cultured for 2 days in the presence of an oily extract prepared according to Example 1a) at a composition ratio of 15 μL per explant (final concentration of 1.5% wt (w / w) in MCT coconut oil) (added on day 1). Biopsies were frozen on day 2 (-32°C).

[0109] Measurement of MDA (malondialdehyde, a marker of lipid oxidation): Epidermis was extracted in Lysis buffer containing BHT (butylated hydroxytoluene) (300 μL). After centrifugation, the supernatant was used to measure the binding of two molecules of thiobarbituric acid (TBA) to one molecule of MDA. Under these conditions, a pink chromogenic complex was formed, and its amount was evaluated by spectrophotometry at 532 nm. A calibration curve was created using standard MDA solution (4.17 mol / L). The amount of MDA was expressed relative to the weight of the epidermis. The results are shown in Table 5 and are expressed in nmol / L MDA / mg epidermis (n=4). result:

[0110] [Table 5]

[0111] Conclusion: Oily extracts of D. tertiolecta reduce membrane lipid peroxidation, demonstrating their ability to reduce MDA levels by 28%. The extract is thus effective in improving the quality of sebum.

[0112] Example 3c) In vivo reduction of acne lesions In the population that received topical application of the cream containing the oily extract according to the present invention and the placebo population, scarring was quantified by dermatologist experts at timepoint days D0 and D28 of the clinical trial detailed in the protocol of Example 2c) (2% final w / w). Analysis was performed under uniform light to eliminate bias induced by ambient light (Evalux® bench). result:

[0113] [Table 6]

[0114] Conclusion: The cream containing the oily extract (oily preparation) comprising D. tertiolecta extract according to the present invention reduced the average number of acne scars by 49% after 28 days of application twice daily, compared to the application of a placebo cream (45% reduction in scarring). The oily extract and the D. tertiolecta extract are effective in reducing acne lesions such as scarring and thereby reducing skin imperfections.

[0115] Example 3d) Increased gene expression of markers for cell regeneration and basal layer aggregation in keratinocytes and / or fibroblasts Protocol: Increased expression of genes encoding the proteins HBEGF (heparin-binding EGF-like growth factor), EGF (epidermal growth factor), laminin-2 (LAMC2), marker CD44, fibronectin-1 (FN1), integrin beta-4 (ITGB4), and laminin alpha-5 (LAMA5) was measured by microfluidic RT-qPCR (Biomark-HD® Fluidigm) as follows: Human keratinocytes from a 27-year-old donor and human fibroblasts from a 33-year-old donor were cultured separately in specific culture medium in 96-well plates (concentration of 10,000 cells / well). After 24 hours of incubation, a crude extract of D. tertiolecta prepared according to Example 1a) was added to the fibroblast or keratinocyte culture at a final concentration of 0.05% by weight relative to the culture volume, or ethanol was added as a negative control (final 0.05% w / v).

[0116] The culture medium was incubated with the extract or control (EtOH) for a further 24 hours, then mRNA was extracted using a kit (Thermofisher, Waltham, USA), and the reverse transcription step was performed using a second kit (High-Capacity cDNA Reverse Transcription Kit; Thermo Fisher). A pre-amplification step using specific primers was performed on the cDNA of each gene. Gene primers were designed online using specific tools well known to those skilled in the art (e.g., Primer3 or GenScript). Real-time PCR (Q-PCR) was performed using the TaqMan / EvaGreen system (Thermofisher). The number of PCR cycles was 35. The experiment was performed in triplicate form (n=3).

[0117] The results are presented in Table 7 (K: keratinocyte, F: fibroblast). result:

[0118] [Table 7]

[0119] Conclusion: The results demonstrate an increase in the expression of all genes analyzed for cell regeneration and genes encoding basal layer constituent proteins, regardless of whether they are fibroblasts (LAMC2, EGF) or keratinocytes. Therefore, the oily extract of D. tertiolecta according to the present invention is efficient in activating cell regeneration and increasing basal layer cohesiveness, improving skin appearance and texture, and is therefore beneficial for skin exhibiting scarring or acne lesions.

[0120] Example 4: Maintenance and enhancement of skin barrier function in the presence of Dunaliella tertiolecta extract or a composition containing it: Increased gene expression of involucrin, loricrin, and caspase-14. Protocol: As detailed in Example 3d), the increase in the expression of genes encoding the proteins involucrin, caspase 14 (CASP14), and loricrin was measured by real-time RT-PCR in the presence of the oily extract of D. tertiolecta according to Example 1a) at the same final concentration of 0.05% (v / v). The results are shown in Table 8 (n=3). result:

[0121] [Table 8]

[0122] Conclusion: The D. tertiolecta extract according to Example 1a) increased the expression of the genes encoding caspase 14, involucrin, and loricrin by at least 140%, 40%, and 90%, respectively. This demonstrates its effectiveness in maintaining and / or improving skin barrier function and is particularly beneficial for damaged skin such as acne-prone or acne-prone skin.

[0123] Example 5: Improvement of skin texture in vivo: Reduction of skin pore size Protocol: In addition, a clinical trial was conducted as detailed in the protocol of Example 2c) to evaluate the size of skin pores after 28 days of application of the cream containing the oily extract according to Example 1a) twice daily. Digital 2D images of the faces of the test population were taken in vivo at time points D0, D7, and D28 under diffuse and polarized light to measure the reduction in skin pore size (VISIA® software). The use of dedicated software enabled the measurement of skin pore size and density expressed in pixels. Statistical analysis of pore size was performed using Student's t-test and Wilcoxon test based on time point D0 (Table 9).

[0124] [Table 9]

[0125] Conclusion: Application of a cream containing an oily extract (oily preparation) of D. tertiolecta according to the present invention twice daily resulted in a significant 12% reduction in pore size after 28 days of application, in contrast to the mere 11% reduction measured in the presence of a placebo cream.

[0126] Example 6: Example of a cream containing the oily extract according to the present invention Each component is given as a weight percentage relative to the total weight of the formulation. Phases A, B, C, D, and E are mixed by techniques well known to those skilled in the art.

[0127] [Table 10]

[0128] When applied to the facial skin, especially the T-zone (forehead, nose, cheeks, and chin), the cream prevents the development of acne lesions, particularly scarring, and / or reduces existing acne lesions, while simultaneously improving the skin barrier function and / or improving skin texture.

Claims

1. An extract of Dunaliella tertiolecta or a composition containing the same for use in preventing the onset of acne and / or reducing acne, and / or reducing seborrheic disorders and thus purifying the skin, and / or preventing the onset of acne lesions and / or reducing acne lesions and thus reducing imperfections, and / or reducing inflammation and thus soothing the skin.

2. An extract of Dunaliella tertiolecta or a composition containing the same, characterized in that the extract or a composition containing the same reduces the amount of the bacterium Cutibacterium acnes, as described in claim 1, for use in preventing the development of acne and / or reducing acne.

3. An extract of Dunaliella tertiolecta or a composition containing the same for use according to claim 1 or 2, characterized in that the extract is bleached with activated carbon.

4. An extract of Dunaliella tertiolecta for use according to any one of claims 1 to 3, characterized in that the extract is obtained by extraction with a solvent or solvent mixture selected from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, ethanol, methanol, isopropanol, an alcohol selected from natural oils or branched oils, glycols, polyols, and mixtures thereof, a 99 / 1 to 1 / 99 (w / w) ratio water / alcohol mixture, and a 99 / 1 to 1 / 99 (w / w) ratio water / glycol mixture, or a composition containing the same.

5. An extract of Dunaliella tertiolecta for use according to any one of claims 1 to 4, characterized in that the extract is obtained by extraction with ethanol, or a composition containing the same.

6. An extract of D. tertiolecta or a composition containing the same for use according to any one of claims 1 to 5, characterized in that the extract or a composition containing the same is applied topically.

7. An extract of Dunaliella tertiolecta or a composition containing the same for use according to any one of claims 1 to 6, characterized in that the extract or a composition containing the same is applied to oily skin, acne-prone skin, or acne-prone skin.

8. Based on the total weight of the aforementioned composition, the amount is within the following range: - An oily extract of Dunaliella tertiolecta in an amount of 1% to 5% by weight, preferably 1% to 3% by weight, and more preferably 1% to 2% by weight, - 95% to 99% by weight, preferably 97% to 99% by weight, and more preferably 98% to 99% by weight of dermatologically acceptable excipients and possible additional components, A topical cosmetic or skin composition comprising, wherein the oily extract of Dunaliella tertiolecta comprises (i) 0.5% to 2% by weight, preferably 1% by weight, of a crude extract of Dunaliella tertiolecta based on the total weight of the oily extract; (ii) 97.5% to 99.4% by weight, preferably 98% to 99% by weight, of vegetable oil, preferably medium-chain triglyceride (MCT) oil, more preferably coconut oil, based on the total weight of the oily extract; and (iii) 0.10% to 0.5% by weight, preferably 0.10% by weight, of an antioxidant, preferably vitamin E, more preferably α-tocopherol, based on the total weight of the oily extract.

9. The cosmetic or dermatological composition according to claim 8, characterized in that the cosmetic or dermatologically acceptable excipient is selected from preservatives, emulsifiers, emollients, surfactants, humectants, thickeners, texturers, conditioners, glossing agents, film-forming agents, pigments, colorants, fragrances, antimicrobial additives, chelating agents, astringents, polymers, reducing agents, pH adjusters, and mixtures thereof.

10. A cosmetic or skin composition according to claim 8 or 9, which is in the form of a cream, serum, gel, soap, skin bar, shower gel, aqueous or oily solution, oil-in-water emulsion or water-in-oil emulsion, mask, lotion, ointment, shampoo, conditioner, scalp treatment, patch, foam, particularly cleansing foam, or stick.

11. A skin composition according to any one of claims 8 to 10 for use according to any one of claims 1 to 7.

12. An extract of Dunaliella tertiolecta or a composition comprising the same for use according to any one of claims 1 to 7, for use on any area of ​​the face and / or any area of ​​the body selected from the arms including the forearms, back, torso, chest, neck and décolletage, preferably on any area of ​​facial skin selected from the cheeks, cheekbones, forehead, around the nose, nasolabial folds, temples, around the eyes, chin, around the mouth and / or lips, and more preferably on any area of ​​the cheeks, forehead, around the nose, temples, nasolabial folds and / or around the mouth, or a composition according to any one of claims 8 to 10.

13. Non-therapeutic cosmetic use of Dunaliella tertiolecta extract or compositions containing it for maintaining and / or improving skin barrier function and / or improving skin texture, particularly for reducing the visibility and / or size of pores, especially in oily skin.

14. The non-therapeutic cosmetic use according to claim 13, characterized in that the extract of Dunaliella tertiolecta or a composition containing the same is used as an astringent active ingredient or an astringent composition.

15. Non-therapeutic cosmetic use of the Dunaliella tertiolecta extract or composition containing the same according to claim 13 or 14 for improving facial appearance and / or comfort of oily skin.

16. The non-therapeutic cosmetic use according to any one of claims 13 to 15, characterized in that the extract of Dunaliella tertiolecta is as defined in any one of claims 3 to 5.

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