Novel uses, in particular dermatological uses, of an extract of the microalga dunaliella tertiolecta

Abstract

The present invention relates to a D. tertiolecta extract or a composition comprising same, for use in preventing the appearance of and / or reducing acne and / or reducing dysseborrhoea and thereby purifying the skin, and / or preventing the appearance of and / or reducing acne lesions and thereby reducing imperfections, and / or reducing inflammation and thereby soothing the skin. The extract is also effective in maintaining and / or improving the barrier function, and / or improving skin texture. The invention also relates to a dermatological composition comprising a D. tertiolecta extract.

Description

[0001] TITLE: New uses, particularly dermatological, of an extract of the microalgae Dunaliella tertiolecta

[0002] FIELD OF THE INVENTION

[0003] The invention relates to new uses, particularly dermatological uses, of an extract of the microalgae Dunaliella tertiolecta.

[0004] STATE OF THE ART

[0005] Acne is a skin manifestation with multiple causes. It can have a hormonal or genetic origin, or more simply appear due to poor hygiene. There are two main types of acne: non-inflammatory acne (retentional acne) and inflammatory acne. Retentional acne is characterized by oily and shiny skin, dilated pores, the presence of blackheads (open comedones) and whiteheads under the skin (microcysts or closed comedones). The most severe, inflammatory acne, manifests itself by the appearance of red papules and pustules, or even deep cysts or nodules. It is a complex manifestation due to excess sebum in the pilosebaceous follicles, associated with hyperproliferation and abnormal differentiation of keratinocytes around the follicles. A third, inflammatory component, is due to the presence of the bacterium Cutibacterium acnes.In addition to the psychological consequences of acne, especially during adolescence, acne can leave relatively unsightly marks. Molecules such as azelaic acid, naturally present in the skin, are known to reduce acne by reducing the amount of C. acnes, or molecules such as clindamycin, sodium sulfacetamide, or erythromycin have already shown their effectiveness against acne.

[0006] However, these are antibiotics for the latter. Solutions based on plant extracts also exist in the fields of cosmetics and dermatology. Examples include nettle leaf, aloe vera, lavender, and tea tree extracts, which are known for their anti-inflammatory activity and effectiveness against acne. Vitamin D and phytosterols are also known for their anti-acne action.

[0007] However, there is a need for effective alternative solutions, natural, i.e., non-antibiotic, in this field. This is precisely what the present invention addresses by proposing a natural microalgae extract, particularly effective on acne, acne lesions, sebum quality and skin texture. Indeed, the Applicant has surprisingly discovered that an extract of the microalgae Dunaliella tertiolecta was effective on acne, in particular by reducing the quantity of the Cutibacterium acnes bacteria, on the reduction of acne lesions and on the quality of sebum in particular.

[0008] The microalga Dunaliella tertiolecta is a green microalga of the genus Dunaliella, comprising more than 20 different species, in the family Dunaliellaceae. This alga was first isolated in Norway (Oslofjord, 1938).

[0009] The D. tertiolecta extract that is the subject of the present invention has the advantage of being produced on an industrial scale from natural microalgae biomass, produced in a photobioreactor under perfectly controlled light, temperature and pH conditions. The extract according to the invention does not induce skin allergies. It also has several effects on the skin such as maintaining the barrier function and improving skin texture.

[0010] To the Applicant's knowledge, no prior art describes an extract of D. tertiolecta or a composition comprising it for its use in preventing the appearance and / or reducing acne by reducing the quantity of the bacteria Cutibacterium acnes and / or acne lesions, nor in reducing inflammation and thus soothing the skin. Nor does anything describe the use of an extract of this strain for maintaining and / or improving the barrier function and / or for improving the texture of the skin, in particular oily skin, or acne-prone or acne-prone skin.

[0011] STATEMENT OF THE INVENTION

[0012] A first subject of the invention thus relates to an extract of D. tertiolecta or a composition comprising it for its use in preventing the appearance and / or reducing acne and / or in reducing dysseborrhea and thus purifying the skin, and / or in preventing the appearance and / or reducing acne lesions and thus reducing imperfections and / or in reducing inflammation and thus soothing the skin. The invention also relates to a non-therapeutic cosmetic use of an extract of Dunaliella tertiolecta or a composition comprising it for maintaining and / or improving the barrier function and / or improving the texture of the skin, in particular reducing the visibility and / or size of pores, in particular of oily skin, and thus improving the appearance and / or comfort of oily skin.

[0013] In particular, the extract used according to the invention or the composition comprising it is used on oily skin or acne-prone or acne-prone skin. Another subject relates to a composition, advantageously a dermatological composition, comprising such an extract.

[0014] The invention also relates to an extract of Dunaliella tertiolecta or composition comprising it for its use according to the invention or a composition as defined according to the invention for its use on any area of ​​the face and / or any area of ​​the body chosen from the arms, including the forearms, the back, the torso, the chest, the neck, the décolleté, advantageously on any area of ​​the skin of the face chosen from the cheeks, the cheekbones, the forehead, the contour of the nose, the nasolabial fold, the temples, the contour of the eyes, the chin, the contour of the mouth and / or the lips, and advantageously again on any area of ​​the cheeks, the forehead, the contour of the nose, the temples, the nasolabial fold, and / or the contour of the mouth. The invention finally relates to the non-therapeutic cosmetic use of an extract of D.tertiolecta or a composition comprising it for maintaining and / or improving the barrier function and / or improving the texture of the skin, in particular reducing the visibility and / or size of pores, in particular of oily skin, and / or for improving the appearance and / or comfort of oily skin.

[0015] DETAILED DESCRIPTION OF THE INVENTION

[0016] A first object therefore relates to an extract of D. tertiolecta or a composition comprising it for its use in preventing the appearance and / or reducing acne and / or in reducing dysseborrhea and thus purifying the skin, and / or in preventing the appearance and / or reducing acne lesions and thus reducing imperfections, and / or in reducing inflammation and thus soothing the skin.

[0017] According to a particular embodiment, the extract of D. tertiolecta or a composition comprising it reduces the quantity of the bacteria Cutibacterium acnes for use in preventing the appearance and / or reducing acne.

[0018] In an advantageous embodiment of the invention, the use is by topical route. By "by topical route" is meant the application directly to the skin and / or the lips or the spraying on their surface of the extract according to the invention or of the composition comprising it. For the purposes of the invention, the skin includes the scalp. The extract of D. tertiolecta according to the invention or the composition comprising it is topically acceptable, that is to say that it (for the composition) does not induce an allergic reaction, it is not toxic or irritating. The extract according to the invention or the composition comprising it can be applied or sprayed on any area of ​​skin chosen from any area of ​​the face and / or the body. By "any area of ​​the body" is meant any area of ​​the arms, back, torso, chest and neck.The term "any area of ​​the face" means any area chosen from the cheeks, cheekbones, forehead, nose contour, nasolabial fold, temples, eye contour, chin, mouth contour, and / or lips. The D. tertiolecta extract used according to the invention or the composition comprising it is advantageously applied to any area of ​​the face, in particular to the cheeks, cheekbones, forehead, nose contour, nasolabial fold, temples and / or lips.

[0019] In particular, the D. tertiolecta extract according to the invention is used on acne-prone or acne-prone skin. Here, the term "acne-prone skin" means skin with non-inflammatory acne (retentional acne) or mild, moderate or severe inflammatory acne. The term "acne-prone skin" means skin that does not have acne, but is prone to acne, including, within the meaning of the invention, oily skin and combination to oily skin. Oily skin is skin with excess sebum.

[0020] By "preventing the appearance and / or reducing acne" according to the invention, we mean in particular reducing the quantity of the bacteria Cutibacterium acnes and / or reducing the inflammation induced by acne by reducing the production of pro-inflammatory cytokines (IFNy, I La).

[0021] In particular, the term "preventing the appearance and / or reducing acne" means reducing the quantity of the bacterium Cutibacterium acnes present on human skin in the presence of the extract of D. tertiolecta according to the invention or of the composition comprising it. In an advantageous embodiment, this is a reduction of at least 26%, advantageously of at least 50% of the quantity of C. acnes in vitro in the presence of the crude extract of D. tertiolecta according to the invention as defined below, in comparison with the quantity of C. acnes measured without extract, under the conditions detailed in example 2a). The results are presented in Table 1.

[0022] In another embodiment of the invention, the term "preventing and / or reducing acne" means reducing acne-induced inflammation. Advantageously, in this case, the reduction in inflammation is evaluated by measuring the amount of interferon gamma (IFNγ) in an inflammatory skin explant model maintained in survival in the presence of the crude extract of D. tertiolecta according to the invention. Advantageously, the reduction in IFNγ is at least 20%, preferably at least 30% in the presence of the extract according to the invention compared to the amount of IFNγ measured in the absence of extract, under the conditions detailed in Example 2b) (Table 2). By reducing inflammation, the extract according to the invention or the composition comprising it are effective in soothing the skin. By "soothing the skin" we mean reducing inflammation by reducing in particular the quantity of interferon gamma (IFNY) as described above.

[0023] Alternatively, "preventing the appearance and / or reducing acne" means reducing acne-induced inflammation by reducing the level of interleukin ILa measured in vivo in the context of a clinical study detailed in Example 2c). Thus, the level of ILa is measured at time TO and T28 days of the clinical study after taking samples from the surface of the skin using a cotton swab within the population having received twice-daily application of a cream comprising the oily extract according to the invention as defined below and on the placebo population (Table 3).

[0024] By "preventing the appearance and / or reducing acne lesions" according to the invention, is meant in particular preventing and / or reducing the appearance of comedones and / or pustules and / or papules, and / or reducing hyperkeratinization of the skin and / or reducing dysseborrhea and / or promoting and / or improving cell renewal and cohesion of the basal laminae in keratinocytes and / or fibroblasts. In particular, by "preventing the appearance and / or reducing acne lesions" is meant preventing and / or reducing the appearance of comedones and / or pustules and / or papules. These lesions can also leave relatively unsightly scars. Here, comedones are understood to mean micro-comedones, blackheads and whiteheads. These acne lesions, in particular scars, are imperfections that one seeks to eliminate.

[0025] In one embodiment, "preventing the appearance and / or reducing acne lesions" means reducing hyperkeratinization of the skin. Advantageously, the reduction in hyperkeratinization is measured via the reduction in the number of horny layers at the follicular ostia in the presence of the oily extract according to the invention. The follicular ostia are the pilosebaceous orifices at which hairs emerge. It is also at this level that sebum accumulates. In the presence of the C. acnes bacterium, cell proliferation is increased at the excretory duct of the pilosebaceous follicles, the horny lamellae then obstructing the follicles. Advantageously, the reduction is at least 20%, still advantageously at least 29% in the presence of a deposit on explant at a rate of 15 pL / cm 2of explant of the oily extract according to the invention diluted in TMC oil (Medium Chain Triglycerides) at a concentration of 1.5% by weight relative to the total weight of the composition and the TMC oil, the reduction being measured on skin explants, under the conditions described in example 3a) (Table 4).

[0026] By preventing the appearance and reducing acne lesions in particular, the extract of D. tertiolecta or the composition comprising it are effective in reducing imperfections. In another embodiment of the invention, the term "preventing the appearance and / or reducing acne lesions" means reducing dysseborrhea, corresponding to a modification of the composition of sebum and generating oxidized sebum. Oxidized sebum in fact leads to the appearance of acne lesions, primarily comedones. Sebum is a mixture of several types of lipids: triglycerides, free fatty acids, cerides, cholesterol and squalene. It is an increase in the oxidation of sebum that will induce the formation of acne lesions. The term "reducing dysseborrhea" thus means reducing the peroxidation of membrane lipids. The peroxidation of lipids at the level of cell membranes generates malonaldehyde (MDA) type compounds.This molecule in fact constitutes a marker of oxidative stress. Thus, the term “reducing the peroxidation of membrane lipids” very advantageously means reducing the amount of MDA. Thus, the reduction in the amount of MDA is at least 14%, advantageously at least 28% in the presence of the oily extract according to the invention. In an advantageous embodiment, the reduction in the amount of MDA is measured on an explant of healthy skin in the presence of the composition according to the invention under the conditions as detailed in example 3b). The results are presented in Table 5.

[0027] By reducing dysseborrhea on the one hand and by reducing the quantity of the C. acnes bacteria as previously described on the other hand, the extract of D. tertiolecta or the composition comprising it are also particularly effective in purifying the skin.

[0028] In yet another embodiment of the invention, the reduction in acne lesions is evaluated directly in vivo in the context of the clinical study previously described (Protocol of Example 2c). Thus, in this context, the extract of D. tertiolecta is effective in reducing scars due to acne, by at least 2%, advantageously by at least 4% after 28 days of twice-daily application of the cream comprising the oily extract according to the invention, in comparison with the placebo cream (Example 3c) (Table 6).

[0029] In yet another embodiment, "preventing the appearance of and / or decreasing acne lesions" means increasing gene expression of markers of cell renewal and basal lamina cohesion in keratinocytes and / or fibroblasts. Advantageously in this case, the crude extract of D. tertiolecta makes it possible to increase by at least 50% the expression of the genes 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), in particular by at least 100%, at least 60%, at least 115%, at least 60%, at least 110%, 50% and 50% respectively the expression of the genes 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).Advantageously, gene expression is measured by real-time quantitative PCR, under the conditions described in example 3d) (Table 7).

[0030] By preventing and / or reducing acne lesions and / or increasing the expression of cell renewal markers, the extract according to the invention or the composition comprising it are thus effective in reducing skin imperfections.

[0031] The D. tertiolecta extract according to the invention is also indicated for improving the appearance and / or comfort of oily skin.

[0032] Thus, the invention also relates to the non-therapeutic cosmetic use of an extract of D. tertiolecta or a composition containing it to maintain and / or improve the barrier function and / or improve the texture of the skin, in particular to reduce the visibility and / or size of pores, in particular of oily skin, and / or to improve the appearance and / or comfort of oily skin. The term "cosmetic use" means a non-therapeutic use. It is neither a pharmaceutical use nor a dermatological use according to a specialist in the field, a dermatologist. The use is not intended to treat skin requiring therapeutic treatment but is intended for so-called healthy skin. Here, the term "healthy skin" means skin that does not have any injury, lesion, scar, allergy, wound, redness, infection, and / or a dermatological disorder such as vitiligo, acne and / or dermatitis. For the purposes of the invention, the skin includes the scalp.

[0033] Indeed, D. tertiolecta extract is effective in maintaining and / or improving barrier function, and / or improving skin texture. In particular, D. tertiolecta extract is effective in improving the texture of oily skin or acne-prone or acne-prone skin.

[0034] The expression "maintaining and / or improving the barrier function of the skin" is thus understood to mean, in particular, maintaining and / or increasing the gene expression of caspase 14 (cysteine-aspartic acid protease, CASP14) and / or involucrin (INV) and / or loricrin in keratinocytes in the presence of the D. tertiolecta extract according to the invention. These proteins are in fact involved in the differentiation of keratinocytes, participating in the formation of the stratum corneum (or horny layer), the most superficial layer of the skin. It is a physical barrier which, among other things, limits water loss by evaporation in the skin. Thus, in one embodiment, improving the barrier function of the skin means increasing the gene expression of CASP14 by at least 70%, advantageously by at least 140% in the presence of the crude extract of D. tertiolecta according to the invention.Alternatively, it is an increase of at least 20%, advantageously at least 40% of the gene expression of involucrin in the presence of the crude extract of D. tertiolecta according to the invention. Still alternatively, it is an increase of at least 45% and advantageously at least 90% of the gene expression of loricrin in the presence of the crude extract of D. tertiolecta according to the invention. In all the embodiments described herein, the crude extract of D. tertiolecta according to the invention is advantageously an extract obtained by extraction in ethanol, and even more advantageously that obtained under the conditions of example 1a). The results are presented in example 4a) (Table 8).

[0035] Furthermore, within the meaning of the invention, the expression "improving the texture of the skin" means reducing the visibility and / or the size of skin pores, advantageously on oily skin or acne-prone or acne-prone skin. Thus, in one embodiment of the invention, the improvement in skin texture is evaluated in vivo in the presence of a cream comprising the oily extract according to the invention in the context of the clinical study already described above, the protocol of which is detailed in example 2c) (Example 5) (Table 9).

[0036] By reducing the size of the pores, the oily extract according to the invention or the composition comprising it are therefore effective as an astringent active ingredient or astringent composition.

[0037] By improving the texture of the skin and in particular by reducing the visibility and / or size of pores, the extract of D. tertiolecta according to the invention is thus particularly indicated for improving the appearance and / or comfort of oily skin.

[0038] Extract according to the invention

[0039] For the purposes of the invention, the term “D. tertiolecta extract” means any extract obtained from any biomass by any extraction method known to those skilled in the art, including solid-liquid extraction.

[0040] The extract according to the invention can be obtained from frozen biomass after cultivation of the microalgae or from fresh biomass. The biomass can be dried before extraction. It can be concentrated by removing all or part of the water by centrifugation, filtration, sedimentation, flocculation, coupled or not with a drying step by freeze-drying or vacuum drying, drum drying, spray drying or any other process making it possible to reduce the water content of the biomass. Here, the term "dry biomass" is understood to mean a biomass whose water content is less than 15%, preferably less than 10%, still preferably 5%. Advantageously, within the scope of the invention, the biomass is frozen before extraction. It is then thawed and then filtered before extraction.

[0041] In one embodiment, the extract of D. tertiolecta according to the invention is obtained by extraction (called solid-liquid) in a solvent or a mixture of solvents chosen from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol chosen from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, and mixtures thereof, a water / alcohol mixture in a proportion of 99 / 1 to 1 / 99 (w / w), and a water / glycol mixture in a proportion of 99 / 1 to 1 / 99 (w / w). Preferably, the extract is obtained in ethanol, that is to say in ethanol as the sole solvent.

[0042] According to another preferred embodiment, the extract is obtained in a water / ethanol mixture.

[0043] The extraction of the biomass can be carried out in the presence of a quantity of biomass of 0.1% to 20% by weight, preferably of 1% to 20%, still preferably of 5% to 15% and very preferably of 10% by weight relative to the total weight of the biomass and the solvent.

[0044] The extraction can be carried out at a temperature ranging from 4°C to 300°C, including room temperature, i.e. a temperature of 20°C. It is advantageously carried out at a temperature ranging from 20°C to 50°C, even more advantageously at 30°C. The extraction can be carried out for a period ranging from 30 minutes to 12 hours, advantageously from 1 hour to 4 hours, even more advantageously from 1 hour to 2 hours and very advantageously for 1 hour.

[0045] Subcritical water extraction

[0046] According to a first embodiment of the invention, the extraction of the biomass is carried out in water under subcritical conditions, at a temperature ranging from 100°C to 300°C, advantageously from 120°C to 250°C, still advantageously at 120°C. The extraction can be carried out at a given temperature or at successive increasing temperatures. In an advantageous embodiment of the invention, the extraction is carried out at a temperature of 120°C. In an alternative mode, it will be carried out according to a gradient of three increasing temperatures between 100°C and 200°C, such as 120°C, 140°C then 160°C or 110°C, 130°C then 150°C, or even 120°C, 145°C then 170°C.Extraction under "subcritical conditions" means extraction in the presence of water, under conditions of temperature above 100°C and pressure below 221 bars, the water remaining in the liquid state but having a viscosity and surface tension lower than that of water at room temperature, increasing its dielectric constant. Thus, the extraction pressure is between 150 bars and 250 bars, preferably between 200 and 221 bars, advantageously in a pressurized extraction autoclave.

[0047] Supercritical CO2 extraction

[0048] According to another embodiment of the invention, the extraction of the biomass is carried out by supercritical CO2 extraction. In this case, said extraction may optionally be carried out in the presence of a co-solvent chosen from ethanol, acetone, methanol or any of their combinations. Alternatively, the supercritical CO2 extraction may be carried out alone without the presence of a co-solvent and continued by an additional extraction with a polar solvent chosen from ethanol, acetone, methanol, hexane, heptane, advantageously ethanol. Advantageously, within the scope of the invention, the supercritical CO2 extraction is carried out in the presence of ethanol (10%) as co-solvent. The supercritical CO2 extraction conditions are such that the pressure measured in bar is greater than 74 bar, advantageously greater than 100 bar, and even more advantageously 150 bar.The temperature is above 35°C, preferably above 45°C, and preferably above 50°C.

[0049] Alcoholic or hydro-alcoholic extraction

[0050] In a particularly advantageous embodiment of the invention, the extract is obtained from an alcoholic extraction. The extract is prepared from a quantity of 15% by weight of fresh biomass, centrifuged and then dried under vacuum. The biomass is then ground and extracted in the presence of ethanol as the sole solvent for a period of 1 hour at a temperature of 30°C. According to a particular embodiment, the extract used according to the invention is an extract decolorized with activated carbon. Thus, according to one embodiment, the extract obtained can then be decolorized with activated carbon to remove the chlorophyll, the carbon is removed by filtration and then the extract is filtered, as described in example 1a). The extract obtained is referred to as an ethanolic extract or an extract obtained by ethanolic extraction. It is a crude extract.

[0051] In another advantageous embodiment of the invention, the extract is prepared from frozen biomass, then dried under vacuum. It is then ground and extracted in a water / ethanol mixture in a proportion of 30 / 70 (v / v) for a period of 2 hours at a temperature of 20°C. The extract is then decolorized with activated carbon and then the carbon is removed by filtration, under the conditions as described in example 1 b). The crude extract obtained is referred to as a hydro-alcoholic extract.

[0052] The crude extract obtained is, according to these last two embodiments, in liquid form. It can be dried by lyophilization or vacuum drying or drum drying, advantageously it is lyophilized to obtain a powder form.

[0053] The D. tertiolecta extract according to the invention can be used as is (we will speak of "crude extract") in powder form or dispersed in an oil (we will speak of "oily preparation" or "oily extract" according to the invention), or incorporated into a final composition (incorporation of the crude extract or advantageously of the oily extract into the final composition) with a "dermatologically acceptable excipient", i.e. an excipient that is non-irritating to the skin and non-toxic. By "excipient" according to the invention, we mean any compound, other than the D. tertiolecta extract and any additional active ingredients, present in a composition and / or used in the manufacture of the composition and / or the product. Usually, more than one excipient is used in the formulation of a composition to promote stability, bioavailability, appearance of the composition and ease of manufacture of the composition.

[0054] The excipient is advantageously chosen from natural oils, in particular vegetable oils, such as argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium chain triglyceride (MCT) oil, additional oils such as C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, humectants, emollients, surfactants, moisturizers, thickeners, texturizing agents, conditioners, glossing agents, film-forming agents, pigments, colorants, perfumes, antimicrobial agents, chelating agents, astringent agents, polymers, reducing agents, pH regulating agents, and mixtures thereof.

[0055] According to a particular embodiment, the composition comprises several excipients and in particular excipients chosen from water, glycols, polymers, thickeners (otherwise known as viscosity agents), emollients, and mixtures thereof.

[0056] Oily extract (also called oily preparation) According to a particular embodiment, the extract used according to the invention is dispersed in at least one vegetable oil to form an “oily preparation” also called “oily extract”, which can be used as is or constitute an intermediate preparation of a final composition comprising other additional ingredients.

[0057] According to a particular embodiment, the extract used according to the invention can be dispersed in any oil extracted from a plant or an algae, including a microalgae, in particular chosen from olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil. By medium-chain triglycerides (MCT), we mean esters of glycerol and saturated fatty acids, the hydrocarbon chain of which has from 6 to 12 carbon atoms. A MCT oil can thus be chosen from coconut oil, advantageously coconut oil, palm kernel oil and palm oil but can be obtained from other fats or oils. Advantageously for the purposes of the invention, the vegetable oil is a MCT oil, very advantageously coconut oil.

[0058] According to a particular embodiment, said oil is present in an amount by weight ranging from 50% to 99.8% by weight relative to the total weight of the oily preparation, advantageously from 75% to 99.5%, very advantageously in an amount ranging from 97.5% to 99.4%, still advantageously ranging from 98% to 99% by weight relative to the total weight of the oily preparation. This oily preparation can be used as is or serve as an intermediate preparation for a composition, in particular a dermatological composition, further comprising other dermatological ingredients and excipients such as those described above.

[0059] Thus, in a preferred embodiment of the invention, the oily extract comprises coconut oil. According to a particular and preferred embodiment, to the crude extract of D. tertiolecta obtained according to examples 1a) or 1b), is added an amount of coconut oil ranging from 97.5% to 99.4% by weight, advantageously ranging from 98% to 99% by weight relative to the total weight of the oily extract.

[0060] According to a particular and preferred embodiment, said oily extract further advantageously comprises an antioxidant and preferably vitamin E in an amount ranging from 0.1% to 0.5% by weight relative to the total weight of the oily preparation. Advantageously, the vitamin E is present in an amount of 0.10% by weight relative to the total weight of the oily preparation. Here, the term "vitamin E" means a tocopherol chosen from α-tocopherol, γ-tocopherol, β-tocopherol or 5-tocopherol, or a tocotrienol chosen from α-tocotrienol, β-tocotrienol, γ-tocotrienol or 5-tocotrienol. Advantageously, it is α-tocopherol.Thus, according to a particular and preferred embodiment, the extract is in the form of an oily extract comprising (i) from 0.5% to 2% by weight, preferably 1% by weight of a crude extract of Dunaliella tertiolecta relative to the total weight of the oily extract, (ii) from 97.5% to 99.4%, preferably from 98% to 99% by weight of a vegetable oil relative to the total weight of the oily extract, preferably a medium chain triglyceride (MCT) oil and more preferably a coconut oil and (iii) from 0.10% to 0.5% by weight relative to the total weight of the oily extract, preferably 0.10% by weight of an antioxidant, preferably vitamin E, more preferably α-tocopherol. In particular, the oily extract comprises from 0.5% to 2% by weight, preferably 1% by weight of an extract of Dunaliella tertiolecta prepared according to example 1a).

[0061] This oily extract (or oily preparation) can be used as is or used as an intermediate composition in the preparation of a final composition further comprising other cosmetic ingredients and excipients such as those described above.

[0062] Final composition

[0063] By "final composition" according to the invention is meant a composition comprising a) the crude (or dry) extract, or advantageously the oily extract according to the invention, consisting of the crude extract and at least one vegetable oil such as those described above and in particular a coconut oil, and advantageously in addition an antioxidant, in particular vitamin E, and b) at least one cosmetically or dermatologically acceptable excipient and one or more additional ingredients chosen from additional oils such as vegetable oils chosen in particular from argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or an algae, including a microalgae, chosen in particular from olive oil, rapeseed oil, linseed oil, sunflower oil, an oil with medium-chain triglycerides (MCT), C11-C13 alkanes, ester oils and mixtures thereof,among preservatives, emulsifiers, emollients, surfactants, humectants, moisturizers, thickening agents, texturizing agents, conditioning agents, glossing agents, film-forming agents, pigments, colorants, perfumes, antimicrobial agents, chelating agents, astringents, polymers, reducing agents, pH regulating agents, and mixtures thereof. The composition may further contain water. The water content, when present, is also included in the total content of dermatologically acceptable excipients. Advantageously, a content of Dunaliella tertiolecta extract according to the invention, preferably of oily extract according to the invention, ranging from 1% to 5% by weight, preferably from 1% to 3% by weight, and better still from 1% to 2% by weight relative to the total weight of the final composition, will be used in a final composition of the invention.and even more preferably the oily extract obtained according to example 1a).,

[0064] Thus, the cosmetically or dermatologically acceptable excipient(s) and the additional ingredient(s) are present, by weight relative to the total weight of the (final) composition, in a total content ranging from 95% to 99%, advantageously from 97% to 99% and better still from 98% to 99%, relative to the total weight of the final composition.

[0065] The extract used according to the invention or the composition comprising it is preferably applied topically.

[0066] Another subject of the invention thus relates to a topical composition comprising the extract of D. tertiolecta as described above, advantageously the oily extract of D. tertiolecta, and advantageously it is a cosmetic composition or a dermatological composition.

[0067] According to a particular embodiment, the composition of the invention is a topical cosmetic or dermatological composition comprising, by weight relative to the total weight of the composition, a quantity ranging from:

[0068] - from 1% to 5% by weight, preferably from 1% to 3% by weight, advantageously from 1% to 2% by weight of an oily extract of Dunaliella tertiolecta, and

[0069] - from 95% to 99%, advantageously from 97% to 99%, still advantageously from 98% to 99%, by weight of cosmetically or dermatologically acceptable excipient(s) and possible additional (active) ingredients, characterized in that said oily extract of Dunaliella tertiolecta comprises (i) from 0.5% to 2% by weight, preferably 1% by weight of a crude extract of Dunaliella tertiolecta relative to the total weight of the oily extract, (ii) from 97.5% to 99.4%, preferably from 98% to 99% by weight of a vegetable oil relative to the total weight of the oily extract, preferably a medium chain triglyceride (MCT) oil and still preferably a coconut oil and (iii) from 0.10% to 0.5% by weight relative to the total weight of the oily extract, preferably 0.10% % by weight of an antioxidant, preferably vitamin E, more preferably α-tocopherol.Knowing that the oily extract of Dunaliella tertiolecta according to the invention itself comprises (i) preferably 1% by weight of a crude extract of Dunaliella tertiolecta relative to the total weight of the oily extract, this results in the final composition, by an active ingredient content ranging from 0.0001% to 0.0005% by weight, preferably from 0.0001% to 0.0003% by weight, advantageously from 0.0001% to 0.0002% of an extract of Dunaliella tertiolecta.

[0070] The cosmetically or dermatologically acceptable excipient and / or additional ingredient are as defined above.

[0071] The composition is used to prevent the appearance and / or reduce acne and / or to reduce dysseborrhea and thus purify the skin, and / or to prevent the appearance and / or reduce acne lesions and thus reduce imperfections and / or to reduce inflammation and thus soothe the skin.

[0072] In particular, it decreases the amount of Cutibacterium acnes for use in preventing and / or reducing acne.

[0073] By reducing the amount of Cutibacterium acnes and / or reducing dysseborrhea, the composition is thus effective in purifying the skin.

[0074] Furthermore, the topical composition according to the invention makes it possible, according to another embodiment, to maintain and / or improve the barrier function, and / or to improve the texture of the skin, in particular by reducing the size of the pores, particularly in oily skin, or acne-prone or acne-prone skin.

[0075] It is particularly useful for improving the appearance and / or comfort of oily skin, or acne-prone or acne-prone skin.

[0076] The final composition may also include other active ingredients or additional ingredients inducing a synergistic effect with the D. tertiolecta extract according to the invention, or a complementary effect. In this respect, active ingredients or cosmetic ingredients such as vitamin D, vitamin D3, or one of their precursors or one of their metabolites, and / or phytosterols have a known action in particular on the prevention and treatment of acne.

[0077] The composition may also comprise one or more other microalgae extracts, and in particular an extract of Tisochrysis lutea, advantageously an oily or ethanolic extract and advantageously an oily extract marketed under the name Luteana™ by the Applicant; an extract of Phaeodactylum tricornutum, advantageously an oily or ethanolic or hydro-alcoholic extract and in particular an oily extract marketed under the name PhycoAge™ by the Applicant; an extract of Porphyridium cruentum, advantageously an ethanolic extract or an aqueous soluble extract, and in particular an aqueous extract marketed under the name Renouvellance™ by the Applicant; or a hydrolyzate of ethanolic extraction co-product of P. tricornutum marketed under the name PhycoSi™ by the Applicant.These different extracts can be combined in the same composition or in a set (kit) of compositions to be used in combination or alternately on the skin to be treated.

[0078] The composition, in particular the dermatological composition, may be in the form of a cream, a serum, a gel, a soap, a dermatological bar, a shower gel, an aqueous or oily solution, an oil-in-water emulsion or a water-in-oil emulsion, a mask, a lotion, an ointment, a shampoo, a conditioner, a scalp treatment, a patch, a mousse, in particular a cleansing mousse, or a stick. The composition may also be in the form of a patch or be encapsulated in a form chosen from spheres, microspheres, liposomes. Advantageously, the composition is in the form of a cream or a serum.

[0079] Thus, a composition comprising the oily extract according to the invention, advantageously the oily extract derived from the extract of D. tertiolecta obtained by extraction in ethanol and still advantageously derived from the extract of D. tertiolecta as obtained in example 1a) is used within the meaning of the invention to prevent the appearance and / or reduce acne and / or prevent and / or reduce dysseborrhea and thus purify the skin, and / or prevent and / or reduce acne lesions and thus reduce imperfections, and / or reduce inflammation and thus soothe the skin. In a particular embodiment, the extract according to the invention or the composition comprising it is used to prevent the appearance and / or reduce acne by reducing the quantity of the C. acnes bacteria, and / or acne lesions of oily skin.

[0080] In one embodiment of the invention, the extract of D. tertiolecta, advantageously the oily extract (oily preparation) or the composition comprising it, advantageously the dermatological composition according to the invention, is used topically on any area of ​​the face and / or any area of ​​the body chosen from the arms, including the forearms, the back, the torso, the chest, the neck, the décolleté, advantageously on any area of ​​the skin of the face chosen from the cheeks, the cheekbones, the forehead, the contour of the nose, the nasolabial fold, the temples, the contour of the eyes, the chin, the contour of the mouth and / or the lips, and advantageously again on any area of ​​the cheeks, the forehead, the contour of the nose, the temples, the nasolabial fold, and / or the contour of the mouth. Examples below referring to the description are presented. These examples are illustrative and should not limit the scope of the invention.

[0081] Unless otherwise stated, temperature is expressed in degrees Celsius (°C), pressure in bar, percentages are given in weight / weight (w / w) or weight / volume (w / v).

[0082] EXAMPLES

[0083] Example 1: Methods of preparing an extract of Dunaliella tertiolecta

[0084] Example 1a) obtained by ethanolic extraction

[0085] The strain from which the D. tertiolecta biomass is derived is a strain first isolated in Norway in 1928. It is commercially available under the reference CCAP 19 / 6B from the Culture Collection of Algae and Protozoa (CCAP, Scotland, UK), or under the reference UTEX LB999 from the Culture Collection of Algae of the University of Texas at Austin (UTEX). The cultivation and maintenance conditions of the strain are indicated by these collection holders.

[0086] Fresh biomass from autotrophic photobioreactor culture of either of the above strains was collected, centrifuged and then dried under vacuum. It was ground and extracted in the presence of ethanol as the sole solvent, in a proportion of 100 g of dry biomass / L of solvent, for 1 hour at a temperature of 30°C. The residual biomass was removed by filtration and the extract was decolorized with activated carbon and the solvent evaporated. The carbon was removed by filtration.

[0087] The crude extract thus obtained is in a liquid form. The crude extract can be dried by lyophilization to obtain a powder form.

[0088] Composition of the oily extract (oily preparation) according to the invention:

[0089] An amount by weight relative to the final weight of the composition, of 98.5% MCT coconut oil was mixed by homogenization with the liquid extract obtained above (crude extract) as well as α-tocopherol (0.15% final w / w). The amount of dry extract of D. tertiolecta is 1% in the oily extract.

[0090] Example 1b) obtained by hydro-alcoholic extraction

[0091] Fresh biomass from a photobioreactor culture in autotrophic mode of one or other of the strains in Example 1a) was recovered, centrifuged and then dried under vacuum. It was ground and extracted in the presence of a water / ethanol mixture (30 / 70; v / v) as solvent (100 g of dry biomass / L solvent) for 2 hours at a temperature of 20°C. The residual biomass was removed by filtration and the extract was decolorized with activated carbon and then the solvent was evaporated. The carbon was removed by filtration and then the extract was filtered. The crude extract thus obtained is in a liquid form and can be dried by lyophilization to obtain a powder form.

[0092] Composition of the oily extract (oily preparation) according to the invention:

[0093] An amount by weight relative to the final weight of the composition, of 99% MCT coconut oil was mixed by homogenization with the liquid extract obtained above (crude oily extract) as well as α-tocopherol (0.05% final w / w). The amount of dry extract of D. tertiolecta is 1% in the oily extract.

[0094] Example 2: Effect of Dunaliella tertiolecta extract on the prevention and reduction of acne

[0095] Example 2a) Decrease in the quantity of Cutibacterium acnes

[0096] Protocol ', the strain C. acnes ATCC® 6919™, Gram + was cultured in appropriate medium (Mueller-Hinton agar containing 5% sheep blood) then a bacterial suspension was obtained and adjusted to an optical density (600 nm) of 0.33. The bacterial suspension was transferred to a 96-well plate and the crude extract of D. tertiolecta (Example 1a) at final concentrations (v / v) of 0.75% or 1% or ethanol as a negative control was added to the suspension. The suspension was then cultured for a period of 48 hours at a temperature of 37°C with shaking (280 rpm) in BHI medium (Brain Heart Infusion broth, Merck). The optical density was read every 6 hours during the 48 hours (D2), including after 24 hours (D1). The results are presented in Table 1 below (mean % decrease in optical density compared to the negative control at times D0, D1 and D2; n=3).The decrease in optical density reflects a decrease in the number of Cutibacterium acnes bacteria.

[0097] Result :

[0098] [Table 1]

[0099] Conclusion: D. tertiolecta extract reduced the amount of suspended C. acnes bacteria by at least 26% and more than 50% in just 24 hours, demonstrating its effectiveness in reducing acne and thus purifying the skin.

[0100] Example 2b) Reduction of inflammation (IFNy) on inflammatory skin explant model

[0101] Protocol: An inflammatory skin explant model was prepared as follows: non-pathological skin fragments from plastic surgery were cultured in culture wells in the presence of a specific culture medium including antibiotics and fetal calf serum. The culture was maintained for a period of 4 days at 37°C (5% CO2).

[0102] In order to mimic an inflammatory model close to acne-induced inflammation, 10 pM of substance P (BACHEM), a gram+ bacterial extract (peptidoglycan of Micrococcus aureus, close to C. acnes at 1 pg / mL culture (SIGMA, Ref 53243) and 10 ng / mL of interleukin ILa (GIBCO, Life Technologies) (referred to here as inflammatory mixture) were added at the JO time of the 4-day culture (Positive control). The oily extract according to the invention (oily preparation according to example 1a)) diluted in TMC coconut oil at a concentration by weight of 0.75% w / w or 1% w / w or TMC coconut oil as a negative control was immediately applied topically (JO) at a rate of 15 pL / cm 2of explant then at time D1 of the 4-day culture. At times D1 and D2, the culture media were collected, frozen at -32°C and mixed for enzyme-linked immunosorbent assay (ELISA). The amount of IFNy was measured by ELISA assay with spectrophotometric reading at 450 nm (IFNy concentration in pg / ml) (Elabscience). Explants were further cultured under identical conditions but without application of the above inflammatory mixture and without oil extract according to the invention or with MCT coconut oil (“Non-inflamed control”).

[0103] Results were reported as biopsy weight and expressed as pg / mg (mean of 4 samples).

[0104] Result :

[0105] [Table 2]

[0106] (* p value < 0.05 significant result; ns = not significant)

[0107] Conclusion: The inflammation (IFNy amount) induced by the mixture of substance P, ILa and M. aureus peptide (positive control) was reduced in the presence of the oily extract according to example 1a) by at least 20% and up to more than 33%, in contrast to MCT coconut oil as a negative control to which no anti-inflammatory effect can be attributed. The oily extract according to the invention is therefore effective in reducing inflammation, whether or not due to acne, by decreasing the production of pro-inflammatory cytokine (IFNy). The oily extract and the D. tertiolecta extract are effective in reducing skin inflammation and thus soothing the skin.

[0108] Example 2c) Decrease in the quantity of interleukins Ha in vivo (Clinical study)

[0109] Protocol: A clinical study was conducted on a population of 40 Caucasian female volunteers, aged 25 to 45 years, with skin presenting mild to moderate acne. A cream comprising a final concentration by weight relative to the total weight of the cream of 2% (w / w) of the oily extract according to the invention as prepared in Example 1a) (Cream of Example 7) or a placebo cream (comprising tartrazine (Cl 19140) as a colorant instead of the oily extract according to the invention) was applied twice a day for 28 days to the faces of the volunteer population (20 individuals received the cream comprising the extract and 20 individuals received the placebo cream).

[0110] At times T0 and T28 days of the clinical study, samples were collected from the surface of the skin of the cheeks (approximately 4cmx4cm) using a cotton swab (SWAB type sample; 3M) from the population who received twice-daily application of the cream comprising the oily extract according to example 1a) (2% final w / w) and from the placebo population. The samples were placed in Eppendorf tubes and stored at a temperature of -20°C after sampling. Quantification of Ia was then performed by ELISA (Enzyme-Linked Immuno Assay).

[0111] Result :

[0112] [Table 3]

[0113] Conclusion: Twice-daily application of the cream containing the oily extract (containing the D. tertiolecta extract according to the invention) decreased the amount of interleukin 1a more effectively than the placebo cream after 28 days. Both the oily extract and the D. tertiolecta extract are effective in reducing skin inflammation and thus soothing the skin.

[0114] Example 3: Effect of Dunaliella tertiolecta extract on the reduction of acne lesions

[0115] Example 3a) Decrease in hyperkeratinization (number of horny layers at the level of the follicular ostia)

[0116] Protocol: Human skin fragments from a cervico-facial lift of 4 female donors aged 23, 26, 29 and 30 were recovered following an operation and were cultured on culture wells in the presence of a specific culture medium adapted to survival maintenance and comprising antibiotics and fetal calf serum. The oil extract according to example 1a) (at a concentration by weight of 1.5% (w / w) in TMC oil) or TMC coconut oil as a control was added at a rate of 15 μL / cm 2 of explant at time 0, D1, D2 and D3 to the culture maintained for a total period of 4 days at a temperature of 37°C (5% CO2). After 4 days of culture, biopsies were taken then fixed in formalin and included in paraffin for histochemical analysis. The histochemical sections were stained with hemalun, eosin (HE). The results are presented in Table 4 below.

[0117] Results :

[0118] [Table 4]

[0119] (* p value < 0.05 significant result; ns = not significant)

[0120] Conclusion: The oily extract of D. tertiolecta decreased the number of horny layers at the follicular ostia by more than 29%, as did glycolic acid as a positive control, unlike the negative control (TMC coconut oil). The composition according to the invention is therefore effective in reducing acne lesions.

[0121] Example 3b) Reduction of dysseborrhea: reduction of peroxidation of membrane lipids on skin explant

[0122] Protocol: Lipid peroxidation was measured by ELISA in a skin explant model subjected to oxidative stress using a kit (SIGMA, ref. MAK085) as follows: human skin fragments were cultured under the same conditions as those described in Example 3a). The explants were irradiated by applying UVA radiation (4J / cm 2 ) and UVB (10J / cm 2 ), the radiation having been delivered by a stimulator (Vilbert Lourmat, Marnes la Vallée, France) comprising UVA lamps associated with a Vilbert Lourmat RMX-365 / 312 radiometer; the UVB radiation being provided by tubes (T-20.L-312). Immediately after irradiation, the explants were cultured in the presence of the oily extract prepared according to Example 1a) (at a final concentration by weight of 1.5% (w / w) in MCT coconut oil) at a rate of 15 pL of composition per cm 2explant (addition at time D1) for 2 days. The biopsies were frozen (-32°C) at time D2.

[0123] MDA (Malondialdehyde, a marker of lipid oxidation) assay: The epidermis were extracted in a lysis buffer containing BHT (butylated hydroxytoluene) (300 μL). After centrifugation, the supernatant was used to assay the binding of 2 molecules of thiobarbituric acid (TBA) to one molecule of MDA. Under these conditions, a pink chromogenic complex is formed, the quantity of which was evaluated by spectrophotometry at 532 nm. A calibration curve was produced with a standard solution of MDA (4.17 mol / L). The quantity of MDA was related to the weight of the epidermis. The results are presented in Table 5 and are expressed in nmol / L of MDA / mg of epidermis (n = 4). Results:

[0124] [Table 5]

[0125] (* p value < 0.05 significant result; ns = not significant)

[0126] Conclusion: The oily extract of D. tertiolecta has shown its ability to reduce the quantity of MDA measured by up to 28% and thus to reduce the rate of peroxidation of membrane lipids. The extract is thus effective in improving the quality of sebum.

[0127] Example 3c) In vivo reduction of acne lesions

[0128] A quantification of the scars was carried out by an expert dermatologist, at times T0 and T28 days of the clinical study detailed in the protocol of example 2c) within the population having received the topical application of the cream comprising the oily extract according to the invention and the placebo population (2% final w / w). The analysis was carried out under homogeneous light to eliminate biases induced by ambient light (Evalux® bench).

[0129] Result :

[0130] [Table 6]

[0131] Conclusion: The cream comprising the oily extract (oily preparation) comprising the D. tertiolecta extract according to the invention made it possible to reduce the average number of acne scars by 49% after 28 days of twice-daily application, compared to the application of the placebo cream (45% reduction in scars). The oily extract and the D. tertiolecta extract are effective in reducing acne lesions such as scars, and thus reducing skin imperfections. Example 3d) Increase in gene expression of markers of cell renewal and cohesion of basal laminae in keratinocytes and / or fibroblasts

[0132] Protocol: The increase in the expression of genes coding respectively for the proteins 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) 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 96-well plates in specific culture medium (concentration of 10,000 cells per well). After a 24-hour culture period, the crude extract of D. tertiolecta prepared according to Example 1a) was added to the fibroblast or keratinocyte culture at a final concentration by weight relative to the culture volume of 0.05%, or ethanol as a negative control (0.05% w / v final).

[0133] The media were cultured for an additional 24 hours in the presence of the extract or the control (EtOH) then the messenger RNAs were extracted using a kit (Thermofisher, Waltham, USA) and the reverse transcription step was carried out using a second kit (High-Capacity cDNA Reverse Transcription Kit; Thermo Fisher). A preamplification step in the presence of the specific primers for each gene was carried out on chip in the presence of the complementary DNAs for each gene. The gene primers are designed online using a specific tool well known to those skilled in the art (such as Primer3 or GenScript). Real-time PCR (Q-PCR) was carried out using the TaqMan / EvaGreen system kit (Thermofisher). The number of PCR cycles was 35. The experiment was carried out in triplicate (n=3).

[0134] The results are presented in Table 7 (K: Keratinocyte: F: Fibroblast).

[0135] Results :

[0136] [Table 7]

[0137] Conclusion: The results showed an increase in the expression of all analyzed genes of cell renewal and those coding for proteins constituting the basal laminae either in fibroblasts (LAMC2, EGF) or in keratinocytes. The oily extract of D. tertiolecta according to the invention is therefore effective in activating cell renewal and increasing the cohesion of the basal laminae, promoting the appearance and texture of the skin, and therefore advantageously beneficial for skin with scars or acne lesions.

[0138] Example 4: Maintenance and increase of the skin barrier function in the presence of an extract of Dunaliella tertiolecta or a composition comprising it: increase in the gene expression of involucrin, loricrin and caspase 14

[0139] Protocol: The increase in the expression of genes coding for the proteins involucrin, caspase 14 (CASP14) and loricrin was measured in the presence of the same final concentration of 0.05% (v / v) of the oily extract of D. tertiolecta as prepared according to Example 1a), by quantitative real-time RT-PCR as detailed in Example 3d). The results are presented in Table 8 (n=3).

[0140] Results :

[0141] [Table 8]

[0142] Conclusion: The D. tertiolecta extract according to Example 1a) increased the expression of genes coding for caspase 14, involucrin and loricrin, respectively by at least 140%, 40% and at least 90%, demonstrating its effect on maintaining and / or improving the barrier function, particularly advantageous for damaged skin such as acne-prone or acne-prone skin. Example 5: Improvement of skin texture in vivo: reduction in the size of skin pores.

[0143] Protocol: The clinical study as described in detail in the protocol of Example 2c) was also conducted with the aim of evaluating the size of skin pores after the 28-day period of twice-daily application of the cream comprising the oily extract according to the invention as prepared in Example 1a). The reduction in skin pore size was measured by taking 2D digital photographs under diffuse light and polarized light of the face of the in vivo study population (VISIA® software) at times TO, T7 and T28. The use of dedicated software made it possible to measure the size and density of skin pores expressed in pixels. The statistical analysis of pore size was carried out by a Student test and a Wilcoxon test in relation to time TO (Table 9).

[0144] [Table 9] Decrease in skin pore size in vivo

[0145] (*p<0.05; ***p<0.001)

[0146] Conclusion: twice-daily application of the cream comprising the oily extract (oily preparation) comprising the extract of D. tertiolecta according to the invention significantly reduced the size of skin pores by 12% after 28 days of application, unlike the reduction measured in the presence of the placebo cream which was only 11%.

[0147] Example 6: Example of a cream comprising the oily extract according to the invention

[0148] Each of the components is given as a percentage by weight relative to the total weight of the formulation. Phases A, B, C, D and E are mixed using techniques well known to those skilled in the art.

[0149] [Table 10]

[0150] INCI Phase % (w / w)

[0151] A Water QSP 100

[0152] B Glycols 4.50

[0153] C Sodium polyacrylate 0.50

[0154] D Viscosity agent 1.50

[0155] D Emollients 4.00 E Oily extract of Dunaliella tertiolecta according to

[0156] 2.00 per ex. 1a)

[0157] Applied to the skin of the face, particularly in the T-zone (forehead, nose, cheeks and chin), the cream helps prevent the appearance and / or reduce acne lesions, particularly scars, by also promoting the barrier function and / or improving the texture of the skin.

Claims

CLAIMS 1. Extract of Dunaliella tetiolecta or composition comprising it for use in preventing the appearance and / or reducing acne and / or reducing dysseborrhea and thus purifying the skin, and / or preventing the appearance and / or reducing acne lesions and thus reducing blemishes, and / or reducing inflammation and thus soothing the skin.

2. Extract of Dunaliella tetiolecta or composition comprising it for its use in preventing the appearance and / or reducing acne according to claim 1, characterized in that the extract or the composition comprising it reduces the quantity of the bacteria Cutibacterium acnes.

3. Extract of Dunaliella tertiolecta or composition comprising it for its use according to one of claims 1 or 2, characterized in that the extract is decolorized with activated carbon.

4. Extract of Dunaliella tertiolecta or composition comprising it for its use according to any one of claims 1 to 3, characterized in that the extract is obtained by extraction in a solvent or a mixture of solvents chosen from water, acetone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol chosen from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, and mixtures thereof, a water / alcohol mixture in a proportion of 99 / 1 to 1 / 99 (w / w), and a water / glycol mixture in a proportion of 99 / 1 to 1 / 99 (w / w).

5. Extract of Dunaliella tertiolecta or composition comprising it for its use according to any one of claims 1 to 4, characterized in that the extract is obtained by extraction in ethanol.

6. Extract of Dunaliella tertiolecta or composition comprising it for its use according to any one of claims 1 to 5, characterized in that the extract or the composition comprising it is applied topically.

7. Extract of Dunaliella tertiolecta or composition comprising it for its use according to any one of claims 1 to 6, characterized in that that the extract or composition comprising it is used on oily skin or acne-prone or acne-prone skin.

8. Topical cosmetic or dermatological composition comprising, by weight relative to the total weight of the composition, a quantity ranging from: - from 1% to 5% by weight, preferably from 1% to 3% by weight, advantageously from 1% to 2% by weight of an oily extract of Dunaliella tertiolecta, and - from 95% to 99%, advantageously from 97% to 99%, still advantageously from 98% to 99%, by weight of dermatologically acceptable excipient(s) and possible additional ingredients, relative to the total weight of the final composition, characterized in that said oily extract of Dunaliella tertiolecta comprises (i) from 0.5% to 2% by weight, preferably 1% by weight of a crude extract of Dunaliella tertiolecta relative to the total weight of the oily extract, (ii) from 97.5% to 99.4%, preferably from 98% to 99% by weight of a vegetable oil relative to the total weight of the oily extract, preferably an oil with medium chain triglycerides (MCT) and still preferably a coconut oil and (iii) from 0.10% to 0.5% by weight relative to the total weight of the oily extract, preferably 0.10% by weight of an antioxidant, preferably vitamin E, more preferably α-tocopherol.

9. Cosmetic or dermatological composition according to claim 8 characterized in that the cosmetically or dermatologically acceptable excipient is chosen from preservatives, emulsifiers, emollient agents, surfactants, humectants, moisturizing agents, thickening agents, texturizing agents, conditioning agents, shine agents, film-forming agents, pigments, colorants, perfumes, antimicrobial agents, chelating agents, astringent agents, polymers, reducing agents, pH regulating agents, and mixtures thereof.

10. Cosmetic or dermatological composition according to claim 8 or 9 in the form of a cream, a serum, a gel, a soap, a dermatological bar, a shower gel, an aqueous or oily solution, an oil-in-water emulsion or a water-in-oil emulsion, a mask, a lotion, an ointment, a shampoo, a conditioner, a scalp treatment, a patch, a mousse, in particular a cleansing mousse, or a stick.

11. Dermatological composition according to any one of claims 8 to 10 for its use according to any one of claims 1 to 7.

12. Extract of Dunaliella tertiolecta or composition comprising it for its use according to any one of claims 1 to 7 or composition according to any one of claims 8 to 10, for its use on any area of ​​the face and / or any area of ​​the body chosen from the arms, including the forearms, the back, the torso, the chest, the neck, the décolleté, advantageously on any area of ​​the skin of the face chosen from the cheeks, the cheekbones, the forehead, the contour of the nose, the nasolabial fold, the temples, the contour of the eyes, the chin, the contour of the mouth and / or the lips, and advantageously again on any area of ​​the cheeks, the forehead, the contour of the nose, the temples, the nasolabial fold, and / or the contour of the mouth.

13. Non-therapeutic cosmetic use of an extract of Dunaliella tertiolecta or a composition comprising it to maintain and / or improve the barrier function and / or improve the texture of the skin, in particular to reduce the visibility and / or size of pores, in particular oily skin.

14. Non-therapeutic cosmetic use according to claim 13, characterized in that the extract of Dunaliella tertiolecta or the composition comprising it is used as an astringent active ingredient or astringent composition.

15. Non-therapeutic cosmetic use of an extract of Dunaliella tertiolecta or of a composition comprising it according to claim 13 or 14 to improve the appearance and / or comfort of oily skin.

16. 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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