New cosmetic uses of an extract of the tetradesmus obliquus microalga

Abstract

The present invention relates in particular to the cosmetic or nutraceutical use of an extract of the Tetradesmus obliquus microalga or of an oily ingredient comprising same, for increasing the pigmentation of the skin and / or the hair and nails, advantageously the hair, and / or for maintaining the uniformity of the complexion and / or for preparing the skin for tanning and / or for promoting relaxation and well-being.

Description

[0001] New cosmetic uses of an extract from the microalga Tetradesmus obliquus

[0002] Scope of the invention

[0003] The present invention relates to the cosmetic or nutraceutical use of an extract of Tetradesmus obliquus or an oily ingredient containing it to increase the pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain an even complexion and / or to prepare the skin for tanning and / or to promote relaxation and well-being. Said Tetradesmus obliquus extract or the oily ingredient containing it also has a sun protection boosting effect.

[0004] State of the art

[0005] Melanogenesis is a natural biological process involving an increase in melanin synthesis by specialized cells called melanocytes. These cells are located in the basal lamina of the epidermis, above the dermis. The melanin produced is then transferred to the upper layers of the skin, particularly to keratinocytes, via melanosomes, structures specific to melanocytes. Responsible for the pigmentation of the skin and its appendages, the melanin produced by melanocytes plays a role in the evenness of skin tone and prepares the skin for tanning.

[0006] It is well known that UV rays, particularly UVA, directly affect the dermis by inducing the production of reactive oxygen species (ROS) and increasing the activity of metalloproteinases, which are responsible, among other things, for the degradation of the dermis's constituent fibers. The well-known consequence is premature skin aging and the appearance of unsightly pigmentation spots.

[0007] The paradox is that the sun has a positive effect on health, at least in terms of its positive impact on individual well-being. It is known that sun exposure helps reduce stress by lowering cortisol levels, leading people to spontaneously seek out the benefits of sunlight. Cortisol, often called the stress hormone, is secreted by the adrenal glands following stimulation of the pituitary gland by adrenocorticotropic hormone (ACTH) and plays a significant role in the immune system, metabolism, and sleep. However, it is also known that cortisol is produced by keratinocytes and melanocytes in the epidermis. In fact, these cells possess all the necessary enzymatic machinery to synthesize cortisol from cholesterol. Furthermore, they respond to ACTH stimulation.

[0008] However, aware of the harmful effects on their skin, people who expose themselves to the sun want to protect themselves from UV rays and / or prepare their skin for sun exposure. In this context, oral supplements containing L-tyrosine, carrot extract, grape seed extract, steviol, or carotenoids such as lycopene are already known to increase skin pigmentation or prolong the effects of tanning. On the other hand, very few topical cosmetic solutions exist. Therefore, there is a need in the cosmetics industry for the availability of effective and natural alternative ingredients. In the nutraceutical field, there is also a need for alternative solutions. Furthermore, the sunscreens present in sunscreens to protect the skin from UV radiation are known for their physical barrier effect on the skin against UV rays.However, these filters are difficult to formulate, are not natural, and must not always be free of impact on human health or on ecosystems, particularly marine ones. Therefore, in the cosmetics industry, there is also a need for natural ingredients that are not harmful to health and do not have a negative impact on the environment.

[0009] Unexpectedly, the Applicant discovered that an extract of the microalga Tetradesmus obliquus was particularly effective at pigmenting the skin and its appendages while maintaining an even skin tone, thus preparing the skin for tanning. Furthermore, as will be demonstrated later in the application, this extract has proven effective in promoting relaxation and well-being after topical application. By increasing skin and hair pigmentation on the one hand, and promoting relaxation and well-being on the other, without any UV exposure, the extract exhibits effects mimicking the beneficial effects of UV rays (skin pigmentation, relaxation, and well-being).

[0010] Furthermore, the Applicant has shown that this extract, in combination with organic or inorganic UV filters, enhances the sun protection provided by said UV filters. The extract is described as a sun protection booster. By protecting the skin from UV rays, the extract has the advantage of being a complete natural ingredient that can be used both as a tanning preparation and as UV protection. Thus, the extract according to the invention will be advantageously used in compositions for the prevention and / or treatment of the harmful effects of UV radiation on the skin and / or its appendages.

[0011] The extract according to the invention is a natural, non-irritating solution for the skin, obtained from microalgae biomass cultivated under controlled conditions. It is easily incorporated into cosmetic or nutraceutical formulations and can be produced quickly and easily on an industrial scale. The microalga Tetradesmus obliquus belongs to the Scenedesmaceae family, which comprises more than ten distinct species. The T. obliquus species has two distinct morphotypes.

[0012] Application CN 110236994 describes an anti-aging cosmetic composition comprising an extract of Phaeodactylum tricornutum, an extract of Euglena minuta, and an extract of Scenedesmus obliquus, the latter being described for its antioxidant activity. Application EP3381442 describes a cosmetic composition comprising an aqueous or dry extract of a modified strain of Scenedesmus rubescens as an anti-aging cosmetic composition protecting the skin from the effects of electromagnetic radiation. This is a distinct strain, and the cosmetic applications are different.

[0013] Thus, to the Applicant's knowledge, nothing describes the use of an extract of Tetradesmus obliquus to increase the pigmentation of the skin and / or hair, to maintain the homogeneity of the complexion and / or to prepare the skin for tanning, and / or to promote relaxation and well-being, nor the use of such an extract as a sun protection booster agent.

[0014] Description of the invention

[0015] A first objective concerns the cosmetic use of an extract of the microalga Tetradesmus obliquus or an oily ingredient containing it to increase the pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain the homogeneity of the skin tone and / or to prepare the skin for tanning and / or to promote relaxation and well-being.

[0016] A second object relates to a cosmetic composition for topical application to the skin and / or its appendages comprising, in a physiologically acceptable environment:

[0017] (i) an oily ingredient comprising:

[0018] From 0.5% to 5% by weight, or even more advantageously between 0.5% and 3.5% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient,

[0019] From 0.05% to 1% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.06% to 0.25% by weight, and

[0020] From 96% to 99.45% by weight of a vegetable oil, preferably a medium-chain triglyceride (MCT) oil and preferably coconut oil, relative to the total weight of the oily ingredient and

[0021] (ii) possibly also at least one cosmetically acceptable excipient chosen in particular from additional oils such as vegetable oils, in particular argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or algae, including a microalga, in particular olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, moisturizers, thickeners, shine enhancers, texturizing agents, film-forming agents, organic or mineral sunscreens, pigments, colorants, perfumes, biological additives, chelating agents, astringents, the polymers, reducing agents, pH regulating agents, humectants,Conditioning agents, and mixtures thereof.

[0022] Another purpose relates to the nutraceutical use of Tetradesmus obliquus extract or an oily ingredient containing it to increase pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain the homogeneity of skin tone and / or to prepare the skin for tanning and / or to promote relaxation and well-being.

[0023] Another object relates to a cosmetic or nutraceutical skincare process for the skin and / or its appendages to increase the pigmentation of the skin and / or appendages, advantageously of the hair, and / or to maintain the homogeneity of the complexion and / or to prepare the skin for tanning, and / or to promote relaxation and well-being, comprising (i) the topical application to the skin and / or its appendages of an extract of Tetradesmus obliquus or of an oily ingredient comprising it as defined according to the invention, or of a cosmetic composition comprising it as defined in the invention, or (ii) the oral administration of an extract of Tetradesmus obliquus or of an oily ingredient comprising it as defined in the invention or of a nutraceutical composition comprising it as defined in the invention.

[0024] The present invention further relates to the non-therapeutic cosmetic or nutraceutical use of an extract of Tetradesmus obliquus or an oily ingredient comprising it, as defined in the invention, in combination with at least one UV filter present in the same composition or in a separate composition, as an agent to enhance the sun protection effect provided by the UV filter(s). Another object relates to an oily ingredient comprising an extract of Tetradesmus obliquus as defined in the invention, or a topical cosmetic composition as defined in the invention, or a nutraceutical composition as defined in the invention, for use in the prevention and / or treatment of the adverse effects of UV radiation on the skin and / or its appendages.

[0025] The terms "cosmetic use" or "nutraceutical use" refer to a non-therapeutic use, which is neither pharmaceutical nor dermatological, according to a specialist in the field, a dermatologist. The use is not intended to treat skin or skin appendages requiring therapeutic treatment but is intended for skin or skin appendages considered healthy. "Healthy skin" is defined here as skin free from injury, lesion, scar, allergy, wound, redness, infection, and / or a dermatological disorder such as vitiligo, acne, and / or dermatitis. For the purposes of this invention, skin includes the scalp. Similarly, for the purposes of this invention, skin exposed to the sun is considered healthy skin that does not require therapeutic treatment.

[0026] For the purposes of this invention, "topical application" means the direct application or spraying of the extract or the oily ingredient containing it onto at least one area of ​​skin on the face and / or body. The body area may be any area of ​​the arms, shoulders, legs, thighs, back, torso, chest, neck, feet, hands, and / or buttocks. "Facial area" means any area of ​​the cheeks, cheekbones, forehead, nose, nasolabial folds, temples, eye area, chin, and / or mouth. "Skin appendages" means hair.Advantageously, the extract according to the invention or the oily ingredient comprising it is applied topically to at least one area of ​​the body and / or face and / or hair, the body area being chosen from the décolleté, face, arms, shoulders, belly, legs and the hair being advantageously the hair.

[0027] Thus, the uses described within the framework of the present invention are intended for healthy skin and / or healthy hair and nails.

[0028] Detailed description of the invention

[0029] A first objective therefore concerns the cosmetic use of an extract of the microalga Tetradesmus obliquus or an oily ingredient containing it to increase the pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain the homogeneity of the skin tone and / or to prepare the skin for tanning, and / or to promote relaxation and well-being.

[0030] The term "increasing skin and / or hair pigmentation" means that the extract according to the invention is capable of increasing melanin synthesis from melanocytes, resulting in skin browning or hair pigmentation observable with the naked eye. Advantageously, the extract according to the invention is capable of increasing by at least 5%, advantageously by at least 10% or even by at least 16%, the amount of melanin measured in vitro in a melanocyte culture in the presence of the Tetradesmus obliquus extract according to the invention, advantageously the crude extract of T. obliquus as described in Example 1a), under the conditions detailed in Example 2a) (Table 1).In another embodiment of the invention, "increasing skin pigmentation and / or hair growth" means increasing by an average of 15%, in particular by an average of 20%, or even 30%, the skin color measured on skin expiants in the presence of the oily ingredient comprising the crude extract of T. obliquus according to the invention compared with the skin color measured on the control expiants without extract (coconut oil) under the conditions detailed in Example 2b) (Table 2).

[0031] In yet another embodiment of the invention, "increasing skin pigmentation and / or hair growth" means increasing by at least 1.7%, advantageously by more than 2%, the pigmentation index measured in vivo by colorimetry in the presence of the oily ingredient comprising the crude extract of T. obliquus according to the invention, compared to an oily ingredient without extract, in the context of an in vivo study conducted under the conditions described in Example 2c) (Tables 3 and 4).

[0032] Alternatively, "increasing skin and / or hair pigmentation" means decreasing the luminance parameter (L*) measured by chromametry within the same in vivo study detailed in Example 2c). In an advantageous embodiment of the invention, the decrease in luminance L* is more than 1.5% compared to the beginning of the study, advantageously more than 2.5%. The results are presented in Table 5.

[0033] In yet another embodiment, the extract of T. obliquus, and advantageously the oily ingredient comprising it, is effective in increasing hair pigmentation. Advantageously, the increase in hair pigmentation is measured in an in vivo study within a population of individuals with white hair, advantageously a proportion of white hair of at least 5%, preferably at least 10%, and most preferably at least 15%.

[0034] Furthermore, the extract of T. obliquus, and particularly its oily component, has a skin tone-evening effect, advantageously concomitant with its pigmenting effect; that is, the skin is pigmented uniformly, thus preserving skin tone homogeneity. Here, "maintaining skin tone homogeneity" refers to a non-significant difference over the measurement time of the luminance parameter L* measured between different parts of the abdomen of the study population in vivo, under the conditions detailed in Example 2c) (Table 6), and advantageously before skin exposure to UV radiation.

[0035] The extract of T. obliquus, and particularly the oily component containing it, is also effective in maintaining skin pigmentation under UV light. "Maintaining skin pigmentation under UV light" refers to maintaining the skin pigmentation index when UV stress is applied to the skin. It is known that sun exposure induces skin pigmentation. In an advantageous embodiment, the pigmentation index is measured chromametrically using the luminance parameter L* after exposure to UV-A rays, within the framework of the in vivo study as described in Example 2c). The results are presented in Table 7.

[0036] Thus, by naturally increasing skin pigmentation, that is, without UV exposure, the T. obliquus extract, the oily ingredient containing it, and the cosmetic composition containing the oily ingredient are specifically designed to prepare the skin for tanning. Therefore, for the purposes of this invention, "preparing the skin for tanning" means increasing skin pigmentation before UV exposure.

[0037] Based on the principle that melanin synthesized by melanocytes migrates to the upper layers of the epidermis via melanosomes, that keratinocytes and melanocytes are capable of synthesizing cortisol, the so-called stress hormone, and that sun exposure is known to decrease levels of this hormone, it was found, in a particularly surprising way, that the extract of T. obliquus, and more specifically the oily ingredient containing it, had the effect of lowering cortisol levels, thus promoting relaxation and well-being. In particular, "promoting relaxation and well-being" refers here to lowering cortisol levels after topical application to the skin of the population in the in vivo study described above, of the cream containing the oily ingredient according to the invention, compared to the cortisol levels measured after application of the placebo cream, in the context of the in vivo study described in Example 2c).

[0038] In an advantageous embodiment of the invention, this involves a decrease in cortisol levels of at least 25% greater in the presence of the oily ingredient, compared to the cortisol levels measured in the group receiving the placebo cream. Advantageously, the cortisol level is measured after saliva samples are collected under the conditions described in Example 4. The results are presented in Table 8. Cortisol is synthesized locally by keratinocytes and melanocytes. A decrease in the overall cortisol level measured in saliva can therefore be correlated with a decrease in the cortisol level in the epidermis after topical application of the oily ingredient according to the invention, the cortisol synthesized locally by the keratinocytes being subsequently transported.

[0039] The extract, and more advantageously the oily ingredient that includes it, therefore has the ability to mimic the beneficial effects of the sun, without exposure: both by increasing the pigmentation of the skin and / or hair, but also by promoting relaxation and well-being.

[0040] The Applicant also showed in example 5 that the extract and more advantageously the oily ingredient which comprises it has the capacity, in the presence of UV filters (organic and inorganic bases illustrated in example 5), to increase the sun protection provided by said UV filters and thus increase the protection of the sun filter against UV.

[0041] The term "to increase the protection of sunscreens against UV rays" refers to the ability of the T. obliquus extract, and more advantageously the oily ingredient containing it, to increase the effectiveness of sunscreens against UV rays. For the purposes of this invention, "UV rays" refers to both UV-A and UV-B rays, and "sunscreen" or "UV filter" refers to mineral filters, organic filters, and mixtures thereof, preferably mineral filters. Mineral sunscreens, unlike organic filters, do not penetrate the skin's epidermis; their action consists of reflecting UV rays. Zinc oxide and titanium dioxide are examples. Organic filters, on the other hand, penetrate the skin and protect it by inactivating UV rays through a chemical reaction. Octinoxate, oxybenzone, and avobenzone are examples of organic filters and their active ingredients.The extract according to the invention, and advantageously the oily ingredient comprising it, are herein referred to as sunscreen activators or "SPF boosters" or "sunscreen boosters." In an advantageous embodiment of the invention, the oily ingredient comprising the T. obliquus extract increases UV protection by raising the SPF and / or UVA index of mineral and / or organic sunscreens, compared to the SPF or UVA index calculated in the control (mineral or organic base only) under the conditions detailed in Example 5. The results are presented in Table 9. By increasing skin and / or hair pigmentation, and by increasing sunscreen protection against UV radiation, the T. obliquus extract according to the invention, and more advantageously the oily ingredient comprising it, are useful for increasing skin protection against UV radiation.

[0042] Finally, the Applicant has also shown that the T. obliquus extract, and in particular the oily ingredient comprising it, has a protective effect against the harmful effects of UV radiation. In particular, Example 6 demonstrates the ability of the extract according to the invention to reduce UV-induced inflammation. Specifically, this reduction in inflammation is reflected in the maintenance of the interleukin IL-8 level measured in the in vivo study already described (Example 2c and Example 6) after skin exposure to UV-A rays. The results are presented in Table 10.

[0043] Obtaining extracts

[0044] According to a particular embodiment of the invention, the culture of Tetradesmus obliquus is conducted under controlled conditions within dedicated systems such as open culture tanks of the "raceways" or "open bonds" type, or closed systems such as photobioreactors. The photobioreactors may be horizontal or vertical tubular photobioreactors, planar or columnar photobioreactors. Advantageously, within the scope of the invention, the microalgae are cultured in photobioreactors, advantageously horizontal tubular photobioreactors. The microalgae are cultured according to batch, fed-batch, continuous, semi-continuous, turbidostat, or chemostat culture methods.

[0045] For the purposes of this invention, "Tetradesmus obliquus extract" means any extract—referred to interchangeably as crude or dry extract—obtained from any biomass produced from any culture of the microalga Tetradesmus obliquus. This crude extract is therefore distinct from the oily ingredient as defined later in this description.

[0046] The biomass obtained from the culture can be used fresh or frozen and / or dried before extract preparation. It can be concentrated by removing all or part of the water using processes such as centrifugation, filtration, flocculation, and sedimentation, with or without subsequent drying steps such as freeze-drying, vacuum drying, drum drying, spray drying, or any other process that reduces the biomass's water content. Cell lysis processes can then be implemented, such as the application of pressure, electrical currents, shear forces, the use of enzymes, or any other process that disrupts the structure of tissues, organs, cells, or organelles.

[0047] The term "dry biomass" here refers to dehydrated microalgal biomass comprising less than 15%, advantageously less than 10%, and even more advantageously less than 5% water. Preferably, within the scope of the invention, the biomass obtained after cultivation is frozen before drying. The biomass may be pre-centrifuged and then filtered to remove residual water before extraction. According to a particular and preferred method, the drying step after freezing is carried out in a vacuum oven at a temperature above 55°C, advantageously above 60°C.

[0048] According to a particular embodiment of the invention, the extract is obtained by extraction in a solvent or a mixture of solvents selected from water, acetone, butanone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol selected from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or glycol / water in a proportion of 99 / 1 to 1 / 99 (w / v), or by supercritical CO2 extraction.

[0049] In one embodiment of the invention, the biomass extraction is a solid-liquid extraction in the presence of a solvent or solvent mixture selected from water, acetone, butanone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol selected from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or glycol / water in a proportion of 99 / 1 to 1 / 99 (w / v). The solid-liquid extraction of biomass according to the invention is generally carried out from a quantity of biomass of 0.1 to 20% by weight, advantageously from 1% to 20% by weight, very advantageously from 5% to 15% by weight, and even more advantageously from 11% by weight relative to the total volume of biomass and extraction solvent.

[0050] Extraction can be carried out at temperatures ranging from 4°C to 300°C, preferably from 15°C to 120°C, and even more preferably from 4°C to 80°C, including ambient temperature, i.e., 25°C. Advantageously, it is carried out at temperatures between 20°C and 50°C, and even more advantageously at 30°C. According to a first embodiment of the invention, biomass extraction is carried out in water under subcritical conditions, at temperatures ranging from 100°C to 300°C, advantageously from 120°C to 250°C, and even more advantageously at 120°C. Extraction can be carried out at a given temperature or at successively increasing temperatures. In an advantageous embodiment of the invention, extraction is carried out at a temperature of 120°C.In an alternating mode, the extraction will be conducted along 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" refers to extraction in the presence of water, at temperatures above 100°C and pressures below 221 bar. The water remains in a liquid state but has a viscosity and surface tension lower than that of water at ambient temperature, thus increasing its dielectric constant. Therefore, the extraction pressure is between 150 bar and 250 bar, preferably between 200 bar and 221 bar, advantageously in a pressure extraction autoclave.

[0051] According to another embodiment of the invention, biomass extraction is carried out by supercritical CO2 extraction. In this case, said extraction may optionally be conducted in the presence of a co-solvent selected from ethanol, acetone, methanol, or any combination thereof. Alternatively, supercritical CO2 extraction may be carried out alone without a co-solvent and followed by a further extraction with a polar solvent selected from ethanol, acetone, methanol, hexane, heptane, advantageously ethanol. Advantageously, within the scope of the invention, supercritical CO2 extraction is carried out in the presence of ethanol (10%) as a 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 further advantageously greater than 150 bar.According to this embodiment, the temperature is above 35°C, advantageously above 45°C, and even more advantageously above 50°C.

[0052] According to a particular and preferred embodiment of the invention, the extract of Tetradesmus obliquus is obtained by solid-liquid extraction in an alcohol / water mixture, in a proportion of 99:1 to 1:99 (w / v), advantageously further in a proportion of 95:5 to 90:10 (w / v). Even more advantageously, the extract is obtained by extraction in ethanol as the sole solvent.

[0053] Thus, in a first advantageous embodiment of the invention, the extract is obtained from frozen and then dried biomass, in particular in a vacuum oven at over 55°C, of ​​Tetradesmus obliquus, by solid-liquid extraction in ethanol as the sole solvent at a temperature of 30°C. The drying step in the vacuum oven inactivates or destroys certain molecules, in particular phenolic compounds.

[0054] The amount of biomass used for extraction is advantageously 5% to 15% by weight, and even more advantageously 11% by weight, relative to the total volume of biomass and solvent. The crude extract obtained is decolorized with activated carbon and then filtered under the conditions described in Example 1a). The activated carbon decolorization step removes chlorophyll from the extract by adsorption, as well as any residual phenolic compounds that were not degraded by the vacuum drying step prior to extraction.The residual ethanol is evaporated and then the extract can be used as is ("crude extract") in powder form or dispersed in an oil (in which case it will be referred to as "oily extract" or "oily ingredient" according to the invention) or incorporated into a final cosmetic composition (incorporation of the crude extract or the oily ingredient into the final cosmetic composition), comprising at least one cosmetically acceptable excipient as defined in the rest of the description.

[0055] According to a second advantageous embodiment, the Tetradesmus obliquus extract is obtained from frozen and then dried biomass, in particular in a vacuum oven at over 55°C, by supercritical CO2 extraction at a temperature of 50°C and a pressure of 150 bar in the presence of ethanol as a co-solvent (10%). The extract obtained is rinsed with water and then filtered under the conditions described in Example 1b).

[0056] Crude extracts of T. obliquus obtained, particularly by drying the biomass under vacuum at over 55°C, advantageously over 60°C, prior to extraction, and filtration through activated carbon, contain negligible quantities, i.e., undetectable by dedicated chromatographic techniques known to those skilled in the art, or even no longer contain any phenolic compounds. Here, "phenolic compounds" refers to any compound possessing a hydrocarbon aromatic ring and at least one hydroxyl group (-OH) attached to the aromatic ring.The term "phenolic compounds" advantageously refers to gallic acid (CyHeO₂, molar mass 170.11 g / mol, CAS No. 149-91-7), caffeic acid (C₆H₈O₄, molar mass 180.15 g / mol, CAS No. 331-39-5), vanillic acid (C₆H₅SO₄, molar mass 168.14 g / mol, CAS No. 121-34-6), paracoumaric acid (C₆H₈O₃, molar mass 164.158 g / mol, CAS No. 501-98-4), hesperidin (C₂₈H₃₄O₁₅, molar mass 610.56 g / mol, CAS No. 520-26-3), and ferulic acid (C₁₀H₁₀O₄, molar mass 194.184 g / mol, CAS No. 149-91-7). No. 1135-24-6), rutin also called rutoside (C27H30O16, molar mass 610.517 g / mol, CAS No. 153-18-4), quercetin (C15H10O7, molar mass 302.23 g / mol, CAS No. 117-39-5) and cinnamic acid (C9H8O2, molar mass 148.158 g / mol, CAS No. 140-10-3), also advantageously vanillic acid, ferulic acid and rutin.Since certain phenolic compounds such as rutin and vanillic acid are known for their depigmenting activity, the suppression of said phenolic compounds in the extract according to the invention thus makes it possible to promote the pro-pigmenting effect of the extract.

[0057] In a particular embodiment of the invention, the Tetradesmus obliquus extract comprises a lutein content of less than 3% by weight relative to the total weight of the composition. Advantageously, the extract comprises a total carotenoid content, particularly p-carotene, α-carotene, and zeaxanthin, other than lutein, of 3% or less by weight relative to the total weight of the extract. Further advantageously, said extract does not contain lycopene.

[0058] Obtaining the oily ingredient:

[0059] In one embodiment of the invention, the Tetradesmus obliquus extract (crude extract) is dispersed in at least one vegetable oil, thus forming an oily ingredient, also referred to as an oily preparation of Tetradesmus obliquus. This oily ingredient can be incorporated into a final cosmetic or nutraceutical composition, including a cosmetic or nutraceutical excipient, or it can be used alone.

[0060] In an advantageous embodiment, the Tetradesmus obliquus extract is dispersed in any oil extracted from a plant or alga, including a microalga, and in particular selected from olive oil, rapeseed oil, linseed oil, sunflower oil, or a medium-chain triglyceride (MCT) oil. Medium-chain triglycerides (MCTs) are understood to be esters of glycerol and saturated fatty acids, the hydrocarbon chain of which has 6 to 12 carbon atoms. A medium-chain triglyceride oil can thus be selected from coconut oil, advantageously coconut oil, palm oil, or palm oil, but may be obtained from other fats or oils. Advantageously, in the context of the invention, the vegetable oil is a medium-chain triglyceride oil, most advantageously coconut oil.

[0061] In a particular embodiment, the oil is present in an amount by weight ranging from 50% to 99.8% by weight relative to the total weight of the composition, advantageously from 75% to 99.5% by weight relative to the total weight of the oily ingredient, and further advantageously from 96% to 99.45%. The oily ingredient can be used as is or as an intermediate preparation for a nutraceutical composition or a cosmetic composition further comprising other ingredients and excipients such as those described above. In a preferred embodiment of the invention, the oily ingredient comprises coconut oil. In a particular and preferred embodiment for topical cosmetic use, the Tetradesmus obliquus extract obtained according to Examples 1a) or 1b), is supplemented with an amount of coconut oil ranging from 96% to 99.45% by weight relative to the total weight of the oily ingredient.Thus, the content of Tetradesmus obliquus extract (crude extract) ranges from 0.5% to 5% by weight, and advantageously ranges from 0.5% to 3.5% by weight relative to the total weight of the oily ingredient.

[0062] Advantageously, the oily ingredient comprises a vitamin E content ranging from 0.05% to 1% by weight relative to the total weight of the oily ingredient, and advantageously a content ranging from 0.06% to 0.25% by weight, most advantageously 0.1%. For the purposes of this invention, "vitamin E" means a tocopherol selected from α-tocopherol, γ-tocopherol, β-tocopherol, or 5-tocopherol, or a tocotrienol selected from α-tocotrienol, γ-tocotrienol, γ-tocotrienol, or 5-tocotrienol. Advantageously, it is α-tocopherol.

[0063] Thus, according to a particular and preferred method, the extract of Tetradesmus obliquus is included in an oily ingredient comprising:

[0064] From 0.5% to 5% by weight, or even more advantageously between 0.5% and 3.5% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient,

[0065] From 0.05% to 1% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.06% to 0.25% by weight, and

[0066] From 96% to 99.45% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and preferably coconut oil, relative to the total weight of the oily ingredient.

[0067] In a particular embodiment of the invention, the oily ingredient comprises a lutein content of less than 0.05% by weight relative to the total weight of the oily ingredient, preferably less than 0.02% (w / w). Advantageously, the oily ingredient comprises a total carotenoid content, particularly p-carotene, α-carotene, and zeaxanthin, other than lutein, of less than or equal to 0.05% by weight, preferably less than 0.02% by weight relative to the total weight of the oily ingredient. Most advantageously, the oily ingredient does not comprise lycopene.

[0068] Cosmetic composition

[0069] Another object of the invention relates to a cosmetic composition for topical application to the skin and / or its appendages comprising, in a physiologically acceptable medium:

[0070] (i) an oily ingredient comprising: From 0.5% to 5% by weight, more advantageously between 0.5% and 3.5% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient,

[0071] From 0.05% to 1% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.06% to 0.25% by weight, and

[0072] From 96% to 99.45% by weight of a vegetable oil, preferably a medium-chain triglyceride (MCT) oil and preferably coconut oil, relative to the total weight of the oily ingredient and

[0073] (ii) possibly also at least one cosmetically acceptable excipient chosen in particular from additional oils such as vegetable oils, in particular argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or algae, including a microalga, in particular olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, moisturizers, thickeners, shine enhancers, texturizing agents, film-forming agents, organic or mineral sunscreens, pigments, colorants, perfumes, biological additives, chelating agents, astringents, the polymers, reducing agents, pH regulating agents, humectants,Conditioning agents, and mixtures thereof.

[0074] According to a particular embodiment of the invention, the cosmetic composition of the invention as defined above further comprises at least one UV filter selected from an organic UV filter, an inorganic UV filter, and mixtures thereof.

[0075] The cosmetic composition therefore generally comprises at least one cosmetically acceptable excipient and the Tetradesmus obliquus extract, more advantageously the oily ingredient containing it. Advantageously, the oily ingredient is included in the cosmetic composition at a concentration by weight relative to the total weight of the composition ranging from 0.1% to 10% by weight, advantageously from 0.25% to 5% by weight, and further advantageously at 1.5% by weight relative to the total weight of the composition.

[0076] The cosmetic composition is advantageously presented in a form suitable for topical application, chosen from among a cream, lotion, gel, soap, spray, oil, oil-in-water or water-in-oil emulsion, aerosol, foam, ointment, serum, stick, powder, sunless tanning product, dry shampoo, shampoo, hair coloring solution, conditioner, skin or hair mask, leave-in hair treatment, and hairspray. It can also be encapsulated in the form of spheres, microspheres, or liposomes. Advantageously, it is presented as a cream, spray, or oil. The cosmetic composition is useful for increasing the pigmentation of the skin and / or hair, particularly hair. It also promotes relaxation and well-being.

[0077] The cosmetic composition may also include any cosmetic ingredient or active ingredient having a similar or identical effect of increasing skin and / or hair pigmentation, with or without a synergistic effect. As such, any pro-pigmenting active ingredient and / or plant-based active ingredient may be used in combination, and advantageously those chosen from among tyrosine, vitamin D, dihydroxyacetone, sage extract, rosemary extract, Buriti oil (Mauritia flexuosà), carrot oil, Chaulmoogra oil, annatto extract (B / xa orellana'), and mixtures thereof.

[0078] The cosmetic composition may also include any active ingredient having an effect complementary to that of the invention, and in particular any active ingredient for skin and / or hair hydration, and / or any anti-aging active ingredient, whether it acts on skin firmness or as an anti-wrinkle active. In this respect, the Tetradesmus obliquus extract, and more advantageously the oily ingredient containing it, may be combined with one or more microalgae extracts, and in particular an extract of the microalga Phaeodactylum tricornutum known as an anti-aging active, advantageously an ethanolic extract, further advantageously the extract marketed as an oily ingredient by the Applicant under the name PhycoAge™ as a plumping active; or an extract of a co-product of ethanolic extraction of P.Tricornutum, marketed by the Applicant under the name PhycoSi™, is used to exfoliate the skin, reduce its microrelief, and increase cell renewal. Also mentioned is an extract of the microalga Tisochrysis lutea and, advantageously, an ethanolic extract marketed by the Applicant under the name Luteana™, which provides a soothing effect on the skin and maintains homeostasis. Finally, the cosmetic composition may include an extract of Porphyridium cruentum, particularly that marketed by the Applicant under the name Renouvellance™ for its protective effect against UV radiation and pollution, and / or an extract of the microalga Dunaliella tertiolecta, especially that marketed by the Applicant under the name DunaPure™ for its skin-purifying, soothing, and blemish-reducing effects.

[0079] In a particularly advantageous embodiment of the invention, the cosmetic composition comprises a lutein content of less than 0.002% by weight relative to the total weight of the cosmetic composition, preferably less than 5 x 10⁻¹¹ 4 %. Advantageously, the cosmetic composition comprises a total carotenoid content, particularly p-carotene, α-carotene and zeaxanthin, other than lutein, of less than or equal to 0.001%, preferably less than 5x10⁻¹² 4 % relative to the total weight of the cosmetic composition. Very advantageously, the cosmetic composition does not contain lycopene.

[0080] Cosmetic formulations are useful for increasing skin and / or hair pigmentation, and / or for maintaining an even skin tone. They also help prepare the skin for tanning.

[0081] Another object of the invention relates to the nutraceutical use of an extract of Tetradesmus obliquus or an oily ingredient containing it to increase the pigmentation of the skin and / or its appendages, advantageously of the hair, and / or to maintain an even complexion, and / or to prepare the skin for tanning, and / or to promote relaxation and well-being. The nutraceutical use is advantageously carried out orally. Advantageously, the T. obliquus extract is as defined in this application.The extract is advantageously obtained by extraction in a solvent or solvent mixture selected from water, acetone, butanone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol selected from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or a glycol / water mixture in a proportion of 99:1 to 1:99 (w / v), or alternatively by supercritical CO2 extraction. Preferably, the T. obliquus extract is obtained by extraction in ethanol as the sole solvent.

[0082] The extract of T. obliquus is used in proportions suitable for oral nutraceutical use. It is advantageously contained within an oily ingredient. Thus, for oral nutraceutical use, the oily ingredient comprises:

[0083] A content ranging from 8% to 79.85% by weight, advantageously from 20% to 50% by weight, in weight relative to the total weight of the oily ingredient, of Tetradesmus obliquus extract.

[0084] From 0.15% to 1.25% by weight relative to the total weight of the oily ingredient, advantageously from 0.5% to 1% by weight of vitamin E.

[0085] From 20% to 90% by weight and advantageously from 60% to 90% by weight of coconut oil, relative to the total weight of the oily ingredient.

[0086] By increasing the pigmentation of the skin and / or hair, advantageously of the hair, the extract of T. obliquus according to the invention and more advantageously the oily ingredient comprising it, is useful orally to maintain the homogeneity of the complexion and / or to prepare the skin for tanning, and / or to promote relaxation and well-being.

[0087] The extract of T. obliquus, and advantageously the oily ingredient containing it, is incorporated into a nutraceutical composition. Here, "nutraceutical composition" is understood to mean indiscriminately a food supplement, a nutritional supplement, or a nutraceutical supplement.

[0088] Preferably in this case, the content of oily ingredient by weight relative to the total weight of the nutraceutical composition ranges from 10% to 70% by weight, advantageously it ranges from 20% to 50% by weight.

[0089] Advantageously, the nutraceutical composition includes at least one orally acceptable excipient. "Orally acceptable" here refers to an inert excipient that is non-toxic to humans. The orally acceptable excipient is selected from among the following: carriers, bulking agents, preservatives, acidifying agents, emulsifying agents, humectants, gelling agents, lubricating agents, coating or encapsulating agents, stabilizing or dispersing agents, sweetening agents, and mixtures thereof. It can be ingested orally safely and without side effects. Examples of carriers include maltodextrin, acacia gum, cellulose and its derivatives (methylcellulose, ethylcellulose, and microcrystalline cellulose), calcium phosphate, inulins, flours (rice flour, coconut flour, or others), starches and their derivatives, talc, and locust bean gum.Preservatives are chosen from sodium sorbate or sodium benzoate; acidifying agents are chosen in particular from citric acid or sodium citrate; emulsifying agents are chosen from lecithin, phospholipids, and polyethylene glycols; humectants are chosen from glycerin, sorbitol, and dextrose. Bulking agents include mannitol, lactose, sorbitol, starch, microcellulose, hydroxypropyl methylcellulose, crosscarmelose, polyvinylpyrrolidone, calcium phosphate (anhydrous or hydrated di- and tribasic), citric acid or tartaric acid, sodium, potassium, or calcium carbonates, silica cellulose, and acacia gum.Lubricating agents (anti-caking agents) include magnesium stearate, stearic acid, lecithins, colloidal silica, rice extract, talc, glyceryl dibehenate, and bamboo extract standardized for silica content. Coating or encapsulating agents include gelatin, hydroxypropyl methylcellulose, pululane, beeswax, and carnauba wax. Gelling agents include native or pregelatinized starches, carrageenans, pectin, alginates, agar-agar, xanthan gum, and gelatin. Stabilizing or dispersing agents include alginates, acacia gum, and phospholipids. Finally, among the sweetening agents, we will mention maltitol, xylitol, sucralose, sorbitol, agave syrup, glucose syrup, sucrose, fructose, stevia extract, honey, isomalt, or maltitol.The excipient is advantageously present in the composition according to the invention in quantity, by weight relative to the total weight of the composition, ranging from 1% to 90% by weight, advantageously between 1% and 50% by weight, further advantageously between 1.5% and 10% by weight relative to the total weight of the composition.

[0090] Advantageously, the nutraceutical composition is presented in a form suitable for oral administration, chosen from among a capsule, softgel, tablet, lozenge, orodispersible tablet, orodispersible granule, pill, orodispersible lozenge, softgel, syrup, ampoule, or suspension. In one particular form, the nutraceutical composition is not presented as a lozenge or chewing gum.

[0091] This nutraceutical composition is effective in increasing skin and / or hair pigmentation, advantageously hair pigmentation, and / or in maintaining even skin tone and / or in preparing the skin for tanning, and / or in promoting relaxation and well-being.

[0092] In a particular embodiment of the invention, the nutraceutical composition comprises a lutein content of less than 0.15% by weight relative to the total weight of the composition. Advantageously, the nutraceutical composition comprises a total carotenoid content, particularly p-carotene, alpha-carotene, and zeaxanthin, other than lutein, of less than or equal to 0.2% by weight. Further advantageously, the nutraceutical composition does not comprise lycopene.

[0093] Cosmetic or nutraceutical treatment process

[0094] Another object of the invention relates to a cosmetic or nutraceutical skincare process for the skin and / or its appendages to increase skin pigmentation and / or appendages, advantageously hair pigmentation, and / or to maintain even skin tone and / or to prepare the skin for tanning, and / or to promote relaxation and well-being, comprising (i) the topical application to the skin and / or its appendages of an extract of Tetradesmus obliquus or an oily ingredient comprising it as defined above, or of a cosmetic composition comprising it as defined above, or (ii) the oral administration of an extract of Tetradesmus obliquus or an oily ingredient comprising it as defined above or of a nutraceutical composition comprising it as defined above.

[0095] The cosmetic treatment process is therefore particularly dedicated to preparing the skin for tanning.

[0096] In an advantageous embodiment of the invention, the cosmetic care process comprises the application of the Tetradesmus obliquus extract, the oily ingredient comprising it or the cosmetic composition comprising said extract or said oily ingredient, to at least one area of ​​the body and / or face and / or hair, the body area being advantageously chosen from the décolleté, face, arms, shoulders, belly, legs and the hair being advantageously the hair.

[0097] Other uses

[0098] Another object of the invention relates to the cosmetic or nutraceutical, non-therapeutic use of a Tetradesmus obliquus extract or an oily ingredient containing it, as defined above, in combination with at least one UV filter present in the same composition or in a separate composition, as an agent to enhance the sun protection effect provided by the UV filter(s). The Tetradesmus obliquus extract or an oily ingredient containing it will also be referred to as an "SPF booster" or "sun protection booster" when combined with at least one UV filter, the UV filter(s) being either in the same composition as the extract according to the invention or in a separate composition.

[0099] According to a first mode, the oily extract or ingredient according to the invention and the UV filter(s) are in the same cosmetic composition for topical application on the skin and / or its appendages.

[0100] According to another embodiment, the extract or oily ingredient according to the invention is in a topical cosmetic composition A and the UV filter(s) are in a topical cosmetic composition B separate from composition A, compositions A and B being able to be applied to the skin and / or its appendages simultaneously or sequentially, preferably composition A with the extract or oily ingredient is applied before composition B.

[0101] According to yet another mode, the extract or oily ingredient according to the invention is in an oral nutraceutical composition A and the UV filter(s) are in a topical cosmetic composition B, compositions A and B being able to be used simultaneously or sequentially, preferably composition A with the extract or oily ingredient is administered before (tanning preparation effect) and / or during (sun protection booster effect) the application of composition B.

[0102] Another object of the invention relates to an oily ingredient comprising an extract of Tetradesmus obliquus as defined above, or a topical cosmetic composition as defined above, or a nutraceutical composition as defined above, for use in the prevention and / or treatment of the adverse effects of UV radiation on the skin and / or its appendages.

[0103] The present invention also relates to the use of a composition comprising the extract or oily ingredient according to the invention for the manufacture of a composition for use in the prevention and / or treatment, in a subject, of the harmful effects of UV radiation on the skin and / or its appendages. The present invention also relates to the use of a composition comprising the extract or oily ingredient according to the invention for the prevention and / or treatment, in a subject, of the harmful effects of UV radiation on the skin and / or its appendages. The present invention also relates to a method for preventing or treating the harmful effects of UV radiation on the skin and / or its appendages in a subject in need, comprising the topical or oral administration to the subject of an effective amount of a composition comprising the extract or oily ingredient according to the invention.

[0104] Examples referring to the description are given below for illustrative purposes only and shall not limit the scope of the invention. Unless otherwise stated, temperature is expressed in degrees Celsius (°C), pressure in bar, and percentages are given on a weight-by-weight basis (w / w). Ppm stands for Parts Per Million (0.01% = 100 ppm).

[0105] Example 1: Methods of obtaining extracts of Tetradesmus obliquus

[0106] The Tetradesmus obliquus strain used in the invention was first isolated in Germany in 1976. Two distinct strains were used in the invention and were obtained from the collections of the University of Austin, Texas, USA (Culture Collection of Algae, strain UTEX 393) and the Culture Collection of Algae & Protozoa (CCAP 276 / 48). These are Tetradesmus obliquus strains.

[0107] The microalga T obliquus was cultured under autotrophic conditions in a 5000L photobioreactor, under controlled temperature, pH and light conditions (pH maintained at 8.0; controlled temperature of 24°C; constant light of 50 pmol.m" 2 .s" 1 The culture was harvested at the end of the exponential growth phase, and the biomass was then separated from the culture medium by centrifugation. The culture medium was then discarded.

[0108] Example 1a) Once separated from its culture medium by centrifugation, the T. obliquus biomass was frozen and then dried, specifically in a vacuum oven at over 55°C. An amount of Tetradesmus obliquus biomass representing 11% by weight relative to the total volume of biomass and solvent was then extracted in ethanol as the sole solvent at a temperature of 30°C. The resulting extract (referred to interchangeably as 'extract' or 'crude extract') was decolorized with activated carbon and then filtered. The residual ethanol was evaporated. The crude extract is in liquid form. It can be used as is or freeze-dried to obtain a powder.

[0109] Example 1b) Once separated from its culture medium by centrifugation, the T. obliquus biomass was frozen and then dried, specifically in a vacuum oven at over 55°C. The T. obliquus biomass was then extracted by supercritical CO2 extraction at a temperature of 50°C and a pressure of 150 bar in the presence of ethanol as a co-solvent (10%). The resulting extract was rinsed with water and then filtered. The extract obtained (referred to interchangeably as 'extract' or 'crude extract') is in liquid form. It can be used as is or freeze-dried to obtain a powder.

[0110] Ex. 1c) Obtaining oily ingredients

[0111] The crude liquid extracts obtained in examples 1a) and 1b) can be used as is or each be dispersed in coconut oil to obtain the oily ingredient of the invention as follows.

[0112] For topical cosmetic use, a final concentration of 2% Tetradesmus obliquus crude extract by weight relative to the total weight of the oily ingredient was dispersed in 97.5% coconut oil, followed by the addition of 0.5% α-tocopherol by weight. For nutraceutical use (oral administration), a final concentration of 20% Tetradesmus obliquus crude extract by weight relative to the total weight of the oily ingredient was dispersed in 79.5% coconut oil, followed by the addition of 0.5% α-tocopherol by weight.

[0113] These oily ingredients can be used alone in liquid form (oil) or dried to obtain a powder. They can be incorporated into cosmetic or nutraceutical compositions.

[0114] Example 2: Increase in skin pigmentation in the presence of an extract of Tetradesmus obliquus

[0115] Example 2a) In vitro measurement of the increase in melanin levels

[0116] Protocol: Adult human melanocytes (NH₂EM) were suspended and seeded in two sets of 24-well plates and then cultured in commercially available MGM-4 (Melanocyte Growth Medium-4) for 72 hours. The 1 èreOne plate was used to measure melanin levels. The second plate was used to measure cell density. The plates were subjected to the same protocol as follows: 72 hours post-inoculation, the culture medium was discarded and replaced with a culture medium containing the crude extract of T obliquus as described in Example 1a) at a final volume concentration of 0.05% or 0.1% relative to the total volume of the culture medium and extract. The same culture medium without the extract (MGM-4 medium as a replacement) (Negative control) was cultured under identical conditions. The media were cultured for 3 days at 37°C (Air / CCh 95% / 5%) and then rinsed with phosphatidylsulfate (PBS). The media contained in the plate intended for measuring melanin levels were extracted in the presence of NaOH-DMSO extraction buffer.The extracts were heated (80°C) for 2 hours and then aliquoted into 96-well plates. Absorbance was measured at 405 nm (SPARK® microplate reader, Tecan™). A standard curve (Synthetic Melanin, Sigma) was established to calculate the melanin concentration in each well. The mean was calculated for each experimental medium (n=4). The media in the plate used to measure cell density were treated with neutral red and then extracted with a solution of acetic acid and ethanol. Absorbance was measured at 540 nm (standard curve established with a standardized suspension of synthetic melanin). The mean cell densities were calculated for each experimental medium (n=4). The melanin concentration was then normalized to the cell density and is expressed in picograms per cell (pg / cell). The percentage increase in melanin levels is reported to the negative control (Table 1).

[0117] Results: Table 1

[0118] [Table 1]

[0119] (*p<0.01, Student's t-test)

[0120] Conclusion: Tetradesmus obliquus extract significantly increased melanin levels at the tested concentrations, up to 17% at a dose of 0.05% (v / v) and up to 34% at a dose of 0.1% (v / v). The extract is therefore particularly effective as a pigment-promoting agent and exhibits a significant dose-response effect.

[0121] Example 2b) Measurement of the increase in melanin levels on skin expiants Protocol: Skin expiants from the abdomen of a healthy 30-year-old Caucasian donor, stored at a temperature of 37°C (5% CO2), were distributed into 4 different experimental groups.

[0122] The expiry samples were cultured for 24 hours in fresh culture medium, and then the oily ingredient (as described in Example 1a) was diluted in coconut oil (at a concentration of 1.5% w / w) (30 pL / cm³).2 ) or the same oily ingredient comprising only coconut oil (100%) as a control, was applied topically for a total period of 3 days to the expiants (30 pL / cm²) 2 A positive control corresponding to vitamin D3 diluted in coconut oil (Vit-D3, Cholecalciferol, Sigma-Aldrich C9756; 0.1 pg in 30 pL / cm2) was also applied. The topical application was repeated 24 hours after the first application. ère application. A negative control without application of any oily ingredient was conducted. After a 24-hour period following the second topical application, the expelled skin was sampled. After a 3-hour culture period, the expelled skin was collected and then frozen at -80°C for in situ analysis of the increase in melanin levels as follows.

[0123] Explant sections (5 µm thick) were obtained and fixed with an ethanolic solution (95%) containing 5% acetic acid. Fontana-Masson staining was performed (Sigma-

[0124] Aldrich) according to the supplier's recommendations. The sections were photographed using an epifluorescent microscope (ThermoFisher, EVOS M5000 Imaging System) and the photographs analyzed with image software (ImageJ) (Schneider, 2012). The results are presented in Table 2, showing the percentage increase in melanin levels compared to the untreated negative control and indirectly compared to the control treated with coconut oil without Tetradesmus obliquus extract.

[0125] Results: Table 2 Increase in melanin levels [Table 2] Conclusion: At a dose of 1.5%, the oily ingredient containing T. obliquus extract proved particularly effective in increasing melanin levels in (unstressed) expiants, with an average increase in melanin levels nearly identical to that observed in the presence of vitamin D3, known to stimulate melanin synthesis. In the absence of UV stress, T. obliquus extract demonstrated its ability to increase melanin synthesis in expiants and can be used effectively as a pro-pigmenting agent. In vivo study

[0126] Protocol: A double-blind, in vivo study was conducted on a population of 44 individuals aged 20 to 40 years with healthy skin, understood to mean skin not requiring therapeutic treatment as defined in the present invention, and without pigmentary spots on the evaluated body and facial areas. For a period of 56 days, a cream containing the oily ingredient including T. obliquus extract as described in Example 1a) or the same cream containing the oily ingredient without T. obliquus extract (coconut oil) ('placebo cream') was applied twice daily (morning and evening) every day to the entire body and face, avoiding the eye area. The cream was not rinsed off. Exclusion criteria included: Treatment for a chronic disease, particularly with oral or injectable corticosteroids;

[0127] An inflammatory reaction or a viral or bacterial infection during the

[0128] 2 months before the start of the trial;

[0129] A pathology of the immune system or connective tissues;

[0130] A skin condition such as atopic dermatitis, rosacea, psoriasis, vitiligo.

[0131] - Having ingested or having applied topically to the skin a self-tanning or whitening product.

[0132] Measurements of melanin levels, cortisol levels (Example 4), and pigmentation uniformity were performed on the abdomen at time points T0 (first day of the study), T56 days, and T56+1. Melanin levels (index) were measured using a chromameter on the abdomen of all 44 individuals (Chromameter).

[0133] CR-400) (L* parameter evaluation) and by colorimetry (SkinColorCatch) as follows: A white LED bulb, equivalent to daylight, was applied to the skin via the colorimeter at a 45° angle to eliminate any glare. Measurements were taken at 6 separate locations on the abdomen (3 on the left side and 3 on the right). The results are presented in Tables 4 and 5. Measurement of the pigmentation index and the homogeneity of pigmentation via chromameter: the chromameter allows the chromatic properties of the skin to be quantified by measuring 3 parameters related to color (L*, a** and b*) (L* corresponds to luminance, i.e. the amount of light reflected by the skin; a** measures the position of the color on the red-green axis of the CIELAB coordinate system - positive values ​​a+ indicating red and negative values ​​a- indicating green-; and b* measures the position of the color on the yellow-blue axis of the CIELAB coordinate system - positive values ​​b+ indicating yellow and conversely blue).Chromametric measurement is performed perpendicular to the skin axis.

[0134] A decrease in luminance L* indicates an increase in skin pigmentation. The results are presented in Table 3 (Statistics Table 4).

[0135] In parallel, a measurement of the luminance parameter L* was performed on the left and right abdomens of the study population in vivo at time points T0 and T56 days. A non-significant difference in L* measurement between the left and right abdomens over time indicates the maintenance of homogeneity in skin pigmentation, and therefore of skin tone. The results are presented in Table 6.

[0136] Results :

[0137] Table 3 Pigmentation index by colorimetry

[0138] [Table 3]

[0139] *2-way ANOVA statistical test

[0140] Table 4: Comparison of the pigmentation index between the 2 population groups (the one treated with the cream containing the extract vs the one containing the placebo cream) by statistical analysis (Mann-Whitney test): [Table 4] (s: significant)

[0141] Conclusion: An increase of more than 2% in the melanin index was measured in the population receiving the cream containing the oily ingredient according to the invention, compared to the melanin index measured in the population receiving the placebo cream (without the extract). The oily ingredient containing the Tetradesmus obliquus extract is therefore effective in vivo in increasing skin pigmentation.

[0142] Table 5 Pigmentation index by chromametry [Table 5]

[0143] *p-value; ns: not significant

[0144] Conclusion: A decrease in the luminance parameter L* indicates an increase in the skin pigmentation index. Thus, luminance L* decreased significantly at time T56 days, by more than 2.5%, in the population receiving the T. obliquus extract. The T. obliquus extract and the oily ingredient containing it are therefore effective in increasing skin pigmentation.

[0145] Table 6 Measurement of skin tone homogeneity during pigmentation (Luminance difference L* between the left and right parts of the abdomen) (DI FF MOY) [Table 6]

[0146] Conclusion: The difference between luminance (L*) measured on the left and right sides of the abdomen in the in vivo study population, after 56 days, was not significantly altered despite daily topical application of the cream containing the pigmenting oil ingredient according to the invention. Thus, after 2 months of daily topical application of said ingredient, the skin was homogeneously pigmented. The crude extract of T. obliquus and the oily ingredient containing it are therefore effective in maintaining even skin tone.

[0147] Example 3: Preparing the skin for tanning: maintaining skin pigmentation (evenness of complexion), even under conditions of exposure to UV-A;

[0148] Protocol: The protocol for measuring the skin pigmentation index by chromametry (Luminance L*) is that described in Example 2c) within the framework of the in vivo study. At time T56, the abdomens of the population were exposed to UV-A rays for a period of 25 min in order to evaluate at time T56+1 (i.e. T57) the effects of the oily ingredient according to the invention on pigmentation, after exposure to UV-A (Table 7).

[0149] Table 7: Maintenance of pigmentation index after exposure to UV-A rays (Luminance L*).

[0150] [Table 7]

[0151] (*p-value = 0.0027 Student's t-test)

[0152] Conclusion: One day after exposure to UV-A rays, the luminance measured by chromametry in the group receiving the cream containing the oily ingredient according to the invention was not significantly altered, while the luminance (L*) decreased by 1.55% in the group receiving the placebo cream (MCT coconut oil), indicating an increase in pigmentation in this control group. The oily ingredient containing the T. obliquus extract according to the invention therefore has the ability to maintain skin pigmentation under UV light and prepares the skin for tanning.

[0153] Example 4: Relaxing effect of the oily ingredient comprising the extract of T. obliquus according to the invention: in vivo reduction of cortisol content (described as the stress hormone).

[0154] It is also known that sunlight has a beneficial effect on people's mood, making them feel more relaxed (less stressed), with an overall sense of well-being. Therefore, we sought to determine whether the oily extract according to the invention, applied to the skin, could confer this relaxing and well-being effect after application, without sun exposure (the oily extract would thus have a sun-mimicking effect, providing overall well-being). Protocol: The in vivo study protocol is that described in Examples 2c) and 3. At T0 and T56, saliva samples (approximately 1 mL) were collected and then frozen at -20°C. An ELISA assay was performed on these samples. A spectrophotometer reading (450 nm) was taken for each sample. The results are expressed as the mean percentage (MOY) (n = 19 for the population receiving the cream containing the oily ingredient; n = 22 for the population receiving the placebo cream).

[0155] Results: Table 8

[0156] [Table 8]

[0157] Conclusion: The oily ingredient demonstrated its ability to decrease average cortisol levels by more than 50%, unlike the group receiving topical application of the placebo cream, whose average cortisol levels decreased by only 25%. The oily ingredient, containing T. obliquus extract, therefore promotes well-being and relaxation.

[0158] Example 5: Increased protection against UV rays (Solar Protection Filter booster activity, also known as 'SPF booster effect')

[0159] Protocol: An in vitro test based on ISO 24443:2021 for the in vitro determination of the sun protection factor (SPF), reflecting the level of protection against UVB and UVA rays, was carried out as follows: 30 mg of an organic or mineral base, the compositions of which are given in Examples 7d) and 7e), and comprising the oily ingredient including T. obliquus extract as described in Example 1a) (1.5% or 3%) or MOT oil (1.5% or 3%) as a control, was applied to the rough face of sandblasted polymethyl methacrylate (PMMA) plates (1.2 mg / cm²). 2), using a pre-saturated base coat applied with a bare finger to obtain the most homogeneous film possible. Measurements were then taken by UV-2600 spectrophotometry (Shimatzu) or Lambda 1050+ spectrophotometry (PerkinElmer) equipped with an integrating sphere between 290 nm and 400 nm. The average of the absorbance readings was calculated to obtain the SPF and UVA sun protection indices (Table 9) according to the calculations established by ISO 24443:2021 (https: / / www.iso.org / fr / standard / 75059.htm).

[0160] • The average SPF index (SPF / nv / f roThe SPF value is obtained as follows: the spectrum of the standard UV solar radiation source (UV-SSR source) (S(A)) is multiplied by the sensitivity value of the corresponding erythematous action spectrum (E(A)) at that wavelength to obtain the effective solar burn energy at that wavelength. The resulting effective solar burn irradiance is integrated over the wavelength range of 290 to 400 nm. The sunscreen transmission values ​​at each wavelength are multiplied by the effective erythemal energy at that wavelength and integrated over the same interval to obtain the effective erythemal energy transmitted through the test. The ratio of these two integrals corresponds to the in vitro SPF value.

[0161] • The PFUV A index (Average UVA index in Table 9) is calculated in the same way as for the SPF / index nv / f roThe intensity spectrum of the UVA radiation source (L(Å)) (xenon arc lamp) is multiplied at each wavelength by the action spectrum value of the persistent pigment darkening (PDD) and by the wavelength range (d(Å) = 1 nm). The resulting effective irradiance is integrated over the wavelength range of 320 nm to 400 nm. The same calculation is performed, incorporating the average transmission of the oily ingredient layer or MCT oil as a spread control as described previously (T(Å)). The resulting irradiance is integrated over the range of 320 to 400 nm. The ratio of the two integrals corresponds to the PFUV A index.

[0162] Calculations:

[0163] [Math]

[0164] [Math2]

[0165] Where E(A) is the erythematous action spectrum, S(A) is the standard solar spectrum, T(A) is the average transmission of the oily ingredient or spreadable MOT oil, d(A) is the wavelength range (1 nm), P(A) is the action spectrum of the persistent darkening pigment (PPD), and L(A) is the spectrum of the UVA radiation source (xenon arc lamp). The average SPF and UVA index are expressed as a percentage relative to the corresponding control for the organic or mineral base.

[0166] Results: Table 9

[0167] [Table 9]

[0168] Conclusion: The oily ingredient comprising the T. obliquus extract according to the invention increased the SPF and UVA protection ratings of organic and mineral sunscreens. For mineral filters, the SPF rating increased by 27% at a concentration of 1.5% and by 64% at a concentration of 3%, while the UVA rating increased by at least 21% at a concentration of 1.5%. For organic filters, the SPF rating increased by 7% at a concentration of 1.5% of the oily ingredient according to the invention and by 58% at a concentration of 3%. Similarly, the UVA rating increased by 5% and 64%, respectively, at a concentration of 3% of the oily ingredient.The oily ingredient containing Tetradesmus obliquus extract is therefore effective in increasing the protective effect provided by the sunscreens present in mineral and organic sunscreen bases (it is said to act as an SPF booster) and can be effectively incorporated into a cosmetic sunscreen formulation. Due to its SPF-boosting effect, the use of the oily ingredient according to the invention makes it possible to reduce the amount of sunscreens in the formulation for an equivalent effect.

[0169] Example 6: Protecting the skin against the effects of UV rays: reducing UV-induced inflammation

[0170] Since interleukin IL-8 levels in the stratum corneum are an indicator of local inflammation, IL-8 levels were measured as part of the in vivo study described above. At times T56 and T57 after UV-A exposure, skin samples were collected using patches (D-SQUAM patches, CuDerm) from the abdomen of the two population groups being monitored. Three patches were successively applied to the same skin area and placed in PBS buffer. After sonication for 10 minutes, the skin cells were centrifuged. Proteins were extracted from the supernatant using Tris-HCl buffer (pH 7.6) containing Triton X-100 (0.1% v / v). The protein content was measured by a colorimetric assay (bicinchoninic acid BCA assay). The measurement of the ILS level was carried out by ELISA assay and spectrophotometry (450nm) (Table 10).

[0171] Table 10: Maintenance of interleukin IL-8 levels after UV-A exposure [Table 10]

[0172] *Student's test: p-value = 0.0116

[0173] Conclusion: IL-8 levels did not significantly change between T56 and T57 in the group receiving the cream containing the oily ingredient according to the invention. In contrast, IL-8 levels increased significantly by more than 36% in just one day after UV-A exposure in the group receiving the placebo cream. The oily ingredient containing T. obliquus extract therefore reduces inflammation induced by UV-A rays. This oily ingredient thus helps to reduce skin disorders related to UV rays, and in particular the effects of photoaging.

[0174] Example 7: Formulations comprising an extract of Tetradesmus obliquus

[0175] The formulations are prepared by mixing the various ingredients using techniques well known to those skilled in the art until a homogeneous mixture is obtained. Percentages are expressed as a percentage of the total weight of the composition (w / w).

[0176] Example 7a) Body balm:

[0177] [Table 11]

[0178] Applied to the body, this balm has the ability to increase skin pigmentation while promoting an even skin tone. Example 7b) Mist containing sunscreens:

[0179] [Table 12]

[0180] Applied to the face or body, this mist helps protect the skin from UV rays by filtering them.

[0181] Example 7c) Nutraceutical composition in capsule form:

[0182] [Table 13]

[0183] This orally administered formula prepares the skin for tanning. It can also be used in combination with a sunscreen (commercial sunscreen) containing UV filters, thus boosting the sun protection provided by the UV filters in the sunscreen.

[0184] Example 7d): Organic sunscreen (Organic base used in example 5)

[0185] [Table 14]

[0186] Example 7e): Mineral sunscreen (Mineral base used in example 5)

[0187] [Table 15]

Claims

Demands 1. Cosmetic use of an extract of Tetradesmus obliquus or an oily ingredient containing it to increase the pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain the homogeneity of the complexion and / or to prepare the skin for tanning, and / or to promote relaxation and well-being.

2. Cosmetic use according to claim 1, characterized in that the extract is obtained by extraction in a solvent or mixture of solvents selected from water, acetone, butanone, hexane, ethyl acetate, methyltetrahydrofuran, 2-methyloxolane, heptane, an alcohol selected from ethanol, methanol, isopropanol, a natural or branched oil, a glycol, a polyol, an alcohol / water mixture, or glycol / water in a proportion of 99 / 1 to 1 / 99 (w / v), or by supercritical CO2 extraction.

3. Cosmetic use according to claim 1 or claim 2, characterized in that the extract is obtained by extraction in ethanol as the sole solvent.

4. Cosmetic use according to any one of claims 1 to 3, characterized in that the Tetradesmus obliquus extract is included in an oily ingredient comprising: From 0.5% to 5% by weight, or even more advantageously between 0.5% and 3.5% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient, From 0.05% to 1% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.06% to 0.25% by weight, and From 96% to 99.45% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and preferably coconut oil, relative to the total weight of the oily ingredient.

5. Cosmetic composition for topical application to the skin and / or its appendages comprising, in a physiologically acceptable medium: (i) an oily ingredient comprising: From 0.5% to 5% by weight, or even more advantageously between 0.5% and 3.5% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient, From 0.05% to 1% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.06% to 0.25% by weight, and From 96% to 99.45% by weight of a vegetable oil, preferably a medium-chain triglyceride (MCT) oil and preferably coconut oil, relative to the total weight of the oily ingredient and (ii) possibly also at least one cosmetically acceptable excipient chosen in particular from additional oils such as vegetable oils, in particular argan oil, shea oil, jojoba oil, avocado oil, sweet almond oil, or any oil extracted from a plant or algae, including a microalga, in particular olive oil, rapeseed oil, linseed oil, sunflower oil, a medium-chain triglyceride (MCT) oil, C11-C13 alkanes, ester oils and mixtures thereof, preservatives, emulsifiers, emollients, surfactants, moisturizers, thickeners, shine enhancers, texturizing agents, film-forming agents, organic or mineral sunscreens, pigments, colorants, perfumes, biological additives, chelating agents, astringents, the polymers, reducing agents, pH regulating agents, humectants,Conditioning agents, and mixtures thereof.

6. Cosmetic composition according to claim 5, characterized in that it further comprises at least one UV filter selected from an organic UV filter, an inorganic UV filter, and mixtures thereof.

7. Cosmetic composition according to claim 5 or claim 6, characterized in that the oily ingredient is present in said composition in a content ranging from 0.1% to 10% by weight, advantageously from 0.25% to 5% by weight, preferably even 1.5% by weight relative to the total weight of the composition.

8. Cosmetic composition according to any one of claims 5 to 7, characterized in that the cosmetic composition is in a form suitable for topical application selected from a cream, lotion, gel, soap, spray, oil, oil-in-water or water-in-oil emulsion, aerosol, foam, ointment, serum, stick, powder, sunless tanning product, dry shampoo, shampoo, hair coloring solution, conditioner, skin or hair mask, leave-in hair treatment, hairspray and a composition encapsulated in the form of spheres, microspheres or liposomes.

9. Nutraceutical use of an extract of Tetradesmus obliquus or an oily ingredient containing it, to increase pigmentation of the skin and / or hair, advantageously of the hair, and / or to maintain evenness of complexion and / or to prepare the skin for tanning, and / or to promote relaxation and well-being.

10. Nutraceutical use according to claim 9, characterized in that the oily ingredient comprises: - From 8% to 79.85% by weight, advantageously from 20% to 50% by weight of Tetradesmus obliquus extract relative to the total weight of the oily ingredient, - From 0.15% to 1.25% by weight of vitamin E relative to the total weight of the oily ingredient, advantageously from 0.5% to 1% by weight, again advantageously from 0.5%, and - From 20% to 90% by weight and advantageously from 60% to 90% by weight of a vegetable oil, preferably a medium chain triglyceride (MCT) oil and preferably even more so a coconut oil, relative to the total weight of the oily ingredient.

11. Nutraceutical use according to claim 10 characterized in that the oily ingredient is present in the nutraceutical composition in a content ranging from 10% to 70% by weight, advantageously ranging from 20% to 50% by weight relative to the total weight of the nutraceutical composition.

12. Nutraceutical use according to claim 11, characterized in that the nutraceutical composition is presented in a form suitable for oral administration selected in particular from a capsule, a softgel, a tablet, a lozenge, an orodispersible tablet, an orodispersible granule, a pill, an orodispersible lozenge, a soft capsule, a syrup, an ampoule, and a suspension.

13. A cosmetic or nutraceutical skincare method for the skin and / or its appendages to increase skin pigmentation and / or appendages, advantageously hair pigmentation, and / or to maintain even skin tone and / or to prepare the skin for tanning, and / or to promote relaxation and well-being, comprising (i) the topical application to the skin and / or its appendages of an extract of Tetradesmus obliquus or an oily ingredient comprising it as defined in any one of claims 1 to 4, or of a cosmetic composition comprising it as defined in any one of claims 5 to 8, or (ii) the oral administration of an extract of Tetradesmus obliquus or an oily ingredient comprising it as defined in claim 10 or of a nutraceutical composition comprising it as defined in claim 11 or claim 12.

14. A cosmetic treatment method according to claim 13, characterized in that the Tetradesmus obliquus extract, the oily ingredient comprising it, or the cosmetic composition comprising said extract or said oily ingredient is applied topically to at least one area of ​​the body and / or face and / or the skin appendages, the body area being advantageously chosen from the décolletage, face, arms, shoulders, stomach, legs and the skin appendages being advantageously the hair.

15. Non-therapeutic cosmetic or nutraceutical use of a Tetradesmus obliquus extract or an oily ingredient comprising it, as defined in any one of claims 1 to 4 or claim 10, in combination with at least one UV filter present in the same composition or in a separate composition, as an agent to enhance the sun protection effect provided by the UV filter(s).

16. An oily ingredient comprising a Tetradesmus obliquus extract as defined in claim 4 or claim 10, or a topical cosmetic composition as defined in any one of claims 5 to 8, or a nutraceutical composition as defined in claim 11 or 12, for use in the prevention and / or treatment of the adverse effects of UV radiation on the skin and / or its appendages.

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