USE OF SILYBUM MARIANUM (L.) GAERTN. OIL TO STRENGTHEN THE SKIN'S BARRIER FUNCTION

Description

DOMAINE TECHNIQUE DE L'INVENTION

[0001] The present invention relates to the use of an oil derived from achenes of Milk thistle (L.) Gaertn. and / or the use of cosmetic compositions comprising such an oil, as well as a cosmetic method for preventing the reduction and / or strengthening the epidermal barrier function. STATE OF THE ART

[0002] The scientific name Milk thistle(L.) Gaertn. refers to a plant belonging to the Asteraceae family, an annual or biennial with a robust stem that can reach more than a meter in height. Its large, shiny, alternate leaves, without stipules, are marbled with white and edged with hard, pointed spines. The flowers are grouped in terminal heads, often solitary. They are surrounded by large, spiny bracts with very sharp tips. The tubular, five-lobed flowers are purplish-purple in color. The fruits are shiny, black or marbled yellow achenes, topped with a pappus with ring-shaped, toothed bristles at their base. The main common name for this plant is Milk Thistle. This plant particularly likes dry, sunny locations, often on acidic, dry, and stony soils.Its geographical distribution is concentrated around the Mediterranean, but it is also present in Europe, Western Asia, as well as North America and Australia or even New Zealand. It grows in gardens but is more dominant in uncultivated fields, in pastures, along the edges of paths and among rubble.

[0003] The achene (often incorrectly called seed in the literature) of Milk thistle (L.) Gaertn. and its preparations are traditionally used orally in the symptomatic treatment of functional digestive disorders attributed to hepatic origin.

[0004] The main active ingredient of the achene of Milk thistle(L.) Gaertn. is silymarin, which is a mixture of several flavonolignans. Silymarin contains predominantly (at least 95% by weight) a mixture of the following four flavonolignans: silybin, isosilybin, silychristin, and silydianin (Kuki et al., Chromatographia 2012, 75, 175-180). The achenes contain up to 3% by weight of silymarin. They also consist of oil (15-30% by weight), mucilages, and proteins.

[0005] Silymarin has been the subject of numerous studies ( in vitro, in vivo and clinical studies) having demonstrated its antioxidant, hepatoprotective, digestive, and anti-inflammatory properties. Currently, extracts of achenes from Milk thistle (L.) Gaertn. titrated in silymarin are present in several pharmaceutical preparations intended for the treatment of various hepatic and biliary disorders, such as Legalon ®< .

[0006] The antiproliferative effect of silybin was studied in a model of HepG2 cells derived from hepatocellular carcinoma. It was shown that silybin induced a significant increase in the synthesis of certain ceramides that can act as second messengers in different apoptotic processes (Zappavigna et al., Int. J. Mol. Sciences 2019, 20, 2190). An increase in ceramide synthesis was also demonstrated in the same cell model by silybins A and B and synthetic derivatives, 3-O-galloyl silybin A and 3-O-galloyl silybin B (Boojar et al., Iranian J. Pharmaceutical Res. 2016, 15(3), 421-433).

[0007] The achenes of Milk thistle (L.) Gaertn. generally contain 15-30% oil. Removing the oil from the achenes (deoiling) is a preliminary step to silymarin extraction. Milk thistle(L.) Gaertn. is therefore a co-product of silymarin production (Zhu et al., Biochemidice and Pharmacotherapy 2018, 100, 191-197). Milk thistle (L.) Gaertn. is therefore devoid of silymarin or contains undetectable traces of it. This is confirmed by the analysis of the polyphenol fraction of milk thistle oil, which does not reveal the presence of any silymarin constituent (Meddeb et al., Antioxidants, 2018, 7, 95; Zarrouk et al., Current Pharmaceutical Design, 2019, 25, 1791-1805).

[0008] Unrefined oil from Milk thistle(L.) Gaertn. is essentially composed of triglycerides of unsaturated fatty acids, the majority of which are linoleic acid (30 to 60%) and oleic acid (15 to 30%). Its high content of unsaturated fatty acids allows it to be included in anti-cholesterol diets and to be used in the prevention of cardiovascular diseases (El-Mallah et al., Grasas y Aceites 2003, 54(4), 397-402). The oil also contains saturated fatty acids: palmitic acid (5 to 15%), stearic acid (3 to 8%), arachidic acid (1 to 4%) and behenic acid (1 to 4%). The crude oil obtained by cold pressing also contains phytosterols (beta-sitosterol in particular) and tocopherols (α-tocopherol and γ-tocopherol in particular) (Dabbour et al., Pakistan Journal of Nutrition 2014, 13(2), 67-78).

[0009] The oil of Milk thistle (L.) Gaertn. is mainly used in the culinary field.

[0010] Furthermore, studies on the antioxidant and hepatoprotective properties of Milk thistle (L.) Gaertn., administered orally, were carried out in life on rats or mice (Hermenean et al., Open Life Sci. 2015, 10-225-236; Zhu et al., Pharmacogn Mag 2014, 10(Sup 1), S92-S99).

[0011] Several studies in the tube Or in vitro highlight the antioxidant and cytoprotective properties of oil of Milk thistle (L.) Gaertn. obtained by cold pressing or solvent extraction (Dabbour et al., 2014; Harrabi et al., Lipids in Health and Disease 2018, 17, 82; Meddeb et al., Antioxidants 2018 7, 95).

[0012] A clinical study highlights the anti-aging effect on aged skin and by repeated topical application of 2 cosmetic formulations containing 1% of Milk thistle(L.) Gaertn. Improvements in facial wrinkles, dermal density, elasticity, and skin tone were observed after twice-daily applications for 2 weeks. However, these formulations contain multiple active ingredients such as palmitoyl peptides, vitamin E, jojoba oil, avocado oil, glycosphingolipids, and sodium hyaluronate (Hahn et al., Experimental and Therapeutic Medicine 2016, 12, 1171-1176).

[0013] The use of oil Milk thistle (L.) Gaertn. as biofuel is also considered (Takase et al., Ultrasonics Sonochemistry 2014, 21, 1752-1762).

[0014] The skin is made up of different tissues that form a vital barrier for the body against the external environment. This barrier protects the body against external aggressions, particularly chemical, mechanical or infectious, and as such a number of defense reactions against environmental factors and / or xenobiotics occur at its level.

[0015] The skin is made up of three main parts, the superficial one, the epidermis, the internal part, the dermis and a deeper layer, the hypodermis, which interact.

[0016] The human epidermis is composed of four to five distinct layers (depending on the anatomical site) and four types of cells: keratinocytes, which are the vast majority, melanocytes, Langerhans cells, and Merkel cells. Each of these cell types contributes, through its own functions, to the essential role played in the body by the skin, in particular the role of protecting the body from external aggressions. This property is called the barrier function.

[0017] Epidermal cells proliferate at its deepest layer, the basal layer, and differentiate during their migration towards the upper layers to successively form the spinous layer made up of several layers of polyhedral cells arranged on the germinative layers, the granular layer made up of flattened cells containing distinct cytoplasmic inclusions, the keratohyalin grains and finally the horny layer (or stratum corneum) which is the most superficial layer of the epidermis. The stratum corneum is made up of 20 to 30 layers of keratinocytes in the terminal stage of their differentiation called corneocytes. Corneocytes, the constituent elements of the stratum corneum, are dead, flat cells containing water and keratin. The architecture of the stratum corneum is classically likened to a brick wall. The bricks represent the corneocytes. The corneocytes are surrounded by a lipophilic "cement" made up of lipids. The barrier function is mainly ensured by the stratum corneumby its structure and composition. During the differentiation of keratinocytes, the phospholipids whose role is to develop the fluid structure of the cell membranes of the living layers of the epidermis, are gradually replaced by a mixture composed mainly of fatty acids, cholesterol and sphingolipids (ceramides). These lipids, which are organized into lamellar bilayers, form the intracellular cement of the stratum corneum. The supramolecular organization of intercorneocyte lipids plays a primordial role in establishing the physicochemical properties of stratum corneumand consequently in maintaining a physiological water gradient. The structure of these lipid bilayers has particular assembly properties, either hexagonal (gel state) or orthorhombic (crystalline system whose elementary cell is a rectangular parallelepiped), the latter being the majority (Bouwstra et al., Int. J. Cosmet. Sci., 2008, 30, 388). The orthorhombic state represents the densest conformation and a balance between these two states is necessary for optimal barrier properties. A disruption in the proportion of the three families of lipids of the stratum corneum leads to a modification of the orthorhombic and hexagonal states and consequently a modification of the barrier function. This lamellar bilayer structure alternates hydrophilic and lipophilic zones which condition the barrier function, the exchange of water between the organism and the external environment, as well as the hydration of the stratum corneum.

[0018] The latter was long considered a simple layer of dead cells without any real function. In reality, it is metabolically active and largely ensures the barrier function of the epidermis.

[0019] The epidermis is not supplied by any blood vessels and is only supplied by diffusion from the dermis.

[0020] The dermis provides the epidermis with solid support. The dermis is a connective tissue composed of different cell types, including fibroblasts, lymphocytes, and macrophages. Associated with these cells are collagen fibers and elastin, embedded in a gel called "ground substance." Collagen and elastin are synthesized by fibroblasts. Leukocytes, mast cells, and tissue macrophages are also found there. Finally, the dermis is crossed by blood vessels and nerve fibers, including free sensory fibers or those connected to sensors.

[0021] Cohesion between the epidermis and dermis is ensured by the dermo-epidermal junction. The balance of the skin barrier and mucous membranes depends on complex biological mechanisms involving numerous growth factors, hormones, enzymes and mediators within the epidermis and dermis.

[0022] Finally, the hypodermis is the deepest and thickest layer of the skin. It is a continuation of the dermis, with no real separation between the two tissues. The hypodermis constitutes a shock-absorbing cushion that acts as mechanical protection for the underlying structures. This fatty layer also helps insulate the body from thermal variations. While the dermis can be considered a water reserve, the fats stored within the adipocytes of the hypodermis constitute an energy reserve.

[0023] It is clear that the quality of the skin barrier and mucous membranes depends on complex endogenous biological mechanisms involving numerous growth and differentiation factors, adhesion molecules, hormones and lipid metabolism enzymes.

[0024] Thus, an alteration of the skin barrier and / or a break in the continuity of the skin surface can occur in the presence of external aggressions such as irritants (detergents, acids, bases, oxidants, reducers, concentrated solvents, toxic gases or fumes), mechanical stress (friction, shocks, abrasion, tearing of the surface, projection of dust, particles, shaving or hair removal), thermal or climatic imbalances (cold, dryness, radiation), or xenobiotics (undesirable microorganisms, allergens) or internal aggressions such as psychological stress. These aggressions cause lipid deficiencies, in particular for ceramides. These changes in lipid ratio will modify the organization of the lipid cement and lead to an alteration of the barrier function increasing the insensible water loss and a modification of the natural hydration factors.These changes will lead to dehydration of the skin as well as dry skin and can also worsen cases of atopic dermatitis, sensitive or reactive skin sensations.

[0025] This alteration of the skin barrier can notably result in skin discomfort, sensory phenomena and in particular unpleasant phenomena. This sensation of skin discomfort can manifest itself in particular by tingling, tightness, heating, itching. These sensations of skin discomfort are more frequent in the most exposed areas of the body, namely the hands, feet, face and scalp. They can occur in particular on areas subject to certain daily or frequently repeated hygiene gestures such as shaving, hair removal, cleansing with toiletries or household products, the application of adhesives with dressings or patches, the fixing of prostheses or in the case of sporting, professional or simply lifestyle-related gestures and the use of clothing, tools or equipment generating localized friction.They can also be amplified by psychological stress.

[0026] Alteration of the skin barrier can also promote the appearance of micro-chapping or micro-fissures, particularly on the hands, feet and lips.

[0027] These feelings of skin discomfort affect everyone, especially those with sensitive or even intolerant skin. The concept of sensitive skin reflects the level of sensitivity of each individual's skin. While it is possible to have sensitive skin at any age, it is extremely common among babies and the elderly. Babies' skin is about one-fifth the thickness of adult skin. It is therefore extremely sensitive to chemical, physical, and microbial aggressions, as well as UV rays. The barrier function of adult skin, on the other hand, gradually weakens with age, in parallel with the slowing down of metabolic processes. Aging skin gradually leads to a lipid deficiency, which makes it more easily irritated by alkaline substances such as soap.

[0028] When the skin has a very low sensitivity threshold, that is to say that it reacts in an exacerbated manner to the slightest external aggression, we speak of intolerant skin, or even reactive intolerant skin. Intolerant skin is more vulnerable to external aggressions and is characterized by daily discomfort and strong irritability. Certain signs, more or less marked, allow it to be recognized. Intolerant skin on the face presents, for example, redness and tingling, it pulls, heats or itches, it can also cause burning sensations. Intolerant skin generally has an allergic background and is therefore particularly sensitive to the components of cosmetic care.

[0029] Sensitive skin is actually skin prone to tingling, heating, prickling, and itching, sometimes accompanied by redness. These feelings of discomfort appear in an exacerbated manner in reaction to stimuli that would not trigger irritation on so-called normal skin. This hypersensitivity of the skin results from a decrease in its tolerance threshold. The more sensitive the skin, the lower its tolerance threshold, and when the tolerance threshold is at its lowest, we speak of intolerant skin. This hypersensitivity can be explained by various factors, but the most important is an alteration of the barrier function of the epidermis. This phenomenon then promotes dehydration of the skin and, above all, the penetration of potentially irritating agents.

[0030] The skin is covered with a protective film, called the hydrolipidic film. It constitutes the outermost barrier, as well as the most fragile, and the most easily disrupted. It is largely composed of fatty substances excreted by the sebaceous glands and lipids resulting from the degradation of cells (squalene, waxes, triglycerides, free fatty acids, cholesterol esters) during the keratinization of horny cells, as well as hydrophilic compounds, such as water from sweat, glycerol, urea, natural skin moisturizing factors, salts, and metabolites of the skin flora. This surface film is very exposed and very sensitive to environmental stresses, hygiene habits, and the condition of the skin as well as exposure to UV radiation. The microbiota can significantly modify the composition of sebum, degrade triglycerides and modify the ratios of free fatty acids, particularly during stress or pathology.It is therefore important to preserve and even improve this skin barrier function, especially for the most sensitive skin.

[0031] There is still a need for agents to prevent a decrease in and / or strengthen the skin barrier function. SUMMARY OF THE INVENTION

[0032] Surprisingly and unexpectedly, the inventors have shown that the oil from achenes of Milk thistle (L.) Gaertn. induces cutaneous lipid synthesis, in particular endogenous ceramide synthesis, which, in addition to the nourishing and / or moisturizing effect on the skin, strengthens the epidermal barrier function or prevents a reduction in this epidermal barrier function, but also strengthens the protection of the skin against water loss and / or external aggressions.

[0033] According to a first aspect, the invention relates to the non-therapeutic cosmetic use of an oil derived from achenes of Milk thistle (L.) Gaertn. to increase total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0034] According to another aspect, the invention also relates to an oil derived from achenes of Milk thistle (L.) Gaertn, for its use in the prevention and / or treatment of skin irritations, by increasing total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0035] According to another aspect, the invention relates to a cosmetic composition comprising at least one oil derived from achenes of Milk thistle (L.) Gaertn and at least one cosmetically acceptable excipient, for use in the prevention and / or treatment of skin irritations, by increasing total ceramides in the skin in order to prevent a decrease and / or strengthen the epidermal barrier function Definitions

[0036] In the present invention, the plant Milk thistle (L.) Gaertn. may be abbreviated to Milk thistle.

[0037] By "organic solvent immiscible with oil from achenes of Milk thistle » , for the purposes of the present invention, an organic solvent is understood to mean an organic solvent which is not capable of mixing, or only partially, with the oil derived from achenes of Milk thistle, so that the mixture of organic solvent and oil from achenes of Milk thistle gives a heterogeneous mixture in which at least two distinct phases can be observed.

[0038] For the purposes of the present invention, the term "apolar solvent" means a solvent chosen, for example, from heptane, hexane, limonene, halogenated hydrocarbons (e.g., C 1 to C 3 chlorinated hydrocarbons such as chloroform or dichloromethane), supercritical CO 2 , a mixture of supercritical CO 2 and ethanol, and mixtures of these solvents. Mention may also be made of 100% bio-sourced solvents such as, for example, EcoXtract LIPOCOS (Supplier Pennakem Europa).

[0039] For the purposes of the present invention, the term "refining" means the steps of deodorization and / or decolorization and / or desolventization of the oil of Milk thistle.Indeed, crude oils contain a number of constituents responsible for unpleasant taste and odors and their poor preservation, which it may therefore be desirable to remove. For the purposes of the present invention, the term "deodorization" means a treatment aimed at eliminating the odor or taste of a vegetable oil. Deodorization can be carried out by heating the oil to a high temperature (e.g. between 150 and 300°C, in particular between 150 and 250°C or between 150 and 200°C), under vacuum, with injection of water vapor.

[0040] For the purposes of the present invention, the term "bleaching" means a treatment aimed at reducing the coloration of the vegetable oil. The color measurement can be carried out according to the Gardner measurement. The Gardner color scale is a scale for visual comparison of the color of clear and transparent liquids. Bleaching can be obtained by contacting the oil with a bleaching earth (which will absorb the pigments (e.g. carotene, chlorophyll, etc.) responsible for the coloring) and heating (e.g. between 60 and 100°C) which can be carried out under vacuum. Advantageously, a subsequent filtration step will separate the oil from the now used bleaching earth.

[0041] For the purposes of the present invention, the term "desolventization" means a treatment for removing the solvent present in an oil. Desolventization can be carried out by distillation by heating the mixture under vacuum and / or by steam distillation under vacuum.

[0042] For the purposes of the present invention, the term "C 1 to C 3 alcohol" means an alcohol R-OH whose chain R is a saturated, linear or branched hydrocarbon chain comprising 1 to 3 carbon atoms. It may be methanol, ethanol, n-propanol or isopropanol, in particular methanol, ethanol or isopropanol. Preferably, it will be isopropanol.

[0043] For the purposes of the present invention, the term "room temperature" means a temperature of from 15 to 40°C, preferably from 20 to 30°C, in particular around 25°C.

[0044] In this description, the term "approximately" means that the value concerned may be 10% lower or higher, in particular 5%, in particular 2%, more particularly 1%, than the indicated value.

[0045] For the purposes of the present invention, the term “topical application” means an application to the skin (including the scalp) and the mucous membranes.

[0046] For the purposes of the present invention, the term "epidermal barrier" means the cellular structures of the epidermis, in particular the tissue barrier formed by corneocytes and intercellular lipid cement.

[0047] For the purposes of the present invention, the term "epidermal barrier function" means the protective function of the epidermis, in particular against external aggressions, and the regulation of insensible loss of water and ions.

[0048] For the purposes of the present invention, the term "cosmetically acceptable" means that which is useful in the preparation of a cosmetic composition, which is generally safe, non-toxic and neither biologically nor otherwise undesirable and which is acceptable for cosmetic use, in particular by topical application to the skin. DETAILED DESCRIPTION OF THE INVENTION

[0049] According to a first aspect, the invention relates to the non-therapeutic cosmetic use of an oil derived from achenes of Milk thistle (L.) Gaertn. to increase total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0050] According to a particular embodiment, the invention relates to the non-therapeutic cosmetic use of an oil derived from achenes of Milk thistle (L.) Gaertn to strengthen the skin's protection against water loss and / or external aggressions.

[0051] According to a particular embodiment, the invention relates to the non-therapeutic cosmetic use of at least one oil derived from achenes of Milk thistle (L.) Gaertn to nourish and / or moisturize the skin, including the scalp, and / or mucous membranes.

[0052] According to a particular embodiment, the invention relates to the non-therapeutic cosmetic use of at least one oil derived from achenes of Milk thistle (L.) Gaertn to improve skin repair, by strengthening or restoring the barrier function.

[0053] According to a particular embodiment, the invention relates to the non-therapeutic cosmetic use of at least one oil derived from achenes of Milk thistle (L.) Gaertn to prevent and / or reduce tingling, itching, tightness, redness of the skin.

[0054] According to a particular embodiment, the invention also relates to an oil derived from achenes of Milk thistle(L.) Gaertn, for its use in the prevention and / or treatment of skin irritations, by increasing total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0055] Oil from achenes of Milk thistle will be used more particularly topically, notably by application to the skin.

[0056] In the context of the present invention, the oil derived from achenes of Milk thistle is obtained from the fruit (achene), the achenes can be whole or in pieces.

[0057] In the context of the present invention, the oil derived from achenes of Milk thistle can be obtained by pressing the achenes or by extracting the achenes with a non-polar solvent. In one embodiment of the present invention, the oil from achenes of Milk thistle can be obtained by pressing the achenes of Milk thistle,in particular by cold pressing, that is to say without heating, at room temperature, followed by a filtration step.

[0058] In a particular embodiment of the invention, the oil derived from achenes of Milk thistle is obtained by pressing the achenes of Milk thistle, followed by a filtration and then refining step.

[0059] In a particular embodiment of the invention, the oil derived from achenes of Milk thistle is obtained by pressing the achenes of Milk thistle, followed by a filtration step, then an extraction step with a polar to medium-polar extraction solvent to remove polar compounds from the oil, the polar to medium-polar extraction solvent comprising, in particular consisting of, a hydrotropic aqueous solution, subcritical water or an organic solvent immiscible with the oil from achenes of Milk thistlepossibly mixed with water, then possibly a desolventization step.

[0060] Advantageously, the polar to medium-polar extraction solvent comprises, in particular is constituted by, an organic solvent immiscible with the oil derived from achenes of Milk thistle possibly mixed with water.

[0061] The organic solvent immiscible with oil from achenes of Milk thistle could be in particular a C1 to C3 alcohol.

[0062] The polar to medium polar extraction solvent may be in particular a C1 to C3 alcohol, possibly mixed with water.

[0063] The organic solvent immiscible with oil from achenes of Milk thistle,in particular a C 1 to C 3 alcohol such as methanol, ethanol or isopropanol, may be used in a mixture with water, in particular in an organic solvent / water volume ratio of between 80 / 20 and 100 / 0, in particular of between 85 / 15 and 95 / 5, in particular of approximately 90 / 10.

[0064] The polar to medium polar extraction solvent may in particular be chosen from methanol, a methanol / water mixture, ethanol, an ethanol / water mixture, isopropanol and an isopropanol / water mixture.

[0065] According to a preferred embodiment, the polar to medium polar extraction solvent will be methanol, an ethanol / water mixture in a volume ratio of about 90 / 10 or an isopropanol / water mixture in a volume ratio of about 90 / 10, preferably an isopropanol / water mixture in a volume ratio of about 90 / 10.

[0066] The extraction step with a polar to medium polar extraction solvent of the oil from achenes of Milk thistle will be carried out in particular by mixing the oil from achenes of Milk thistle with the polar to medium polar extraction solvent for 1 to 12 hours and in particular at a temperature between 15 and 25°C, in particular around 20°C. The quantity of polar to medium polar extraction solvent used to carry out this extraction will advantageously be 0.5 to 3 g, in particular 1 to 3 g per 1 g of oil from achenes of Milk thistle.

[0067] An extraction phase and a lipid phase (residual oil devoid of its polar compounds, also called exhausted residual oil) will then be obtained at the end of this extraction. The lipid phase will be advantageously separated from the extraction phase and recovered. It can then be desolventized, in particular under vacuum, to remove the residual polar to medium-polar extraction solvent and obtain an oil from achenes of Milk thistle which is devoid of its polar constituents (free fatty acids, phytosterols, tocopherols).

[0068] In a particular embodiment of the invention, the oil derived from achenes of Milk thistle is obtained by pressing the achenes of Milk thistle, then extraction with a polar to medium polar extraction solvent to remove polar compounds from the oil as detailed above, then desolventization as previously described, then deodorization.

[0069] In a particular embodiment of the invention, the oil derived from achenes of Milk thistle is obtained by pressing the achenes of Milk thistle, then extraction with a polar to medium polar extraction solvent to remove polar compounds from the oil as detailed above, then desolventization as previously described, then decolorization.

[0070] In a particular embodiment of the invention, the oil derived from achenes of Milk thistle is obtained by pressing the achenes of Milk thistle, then extraction with a polar to medium polar extraction solvent to remove polar compounds from the oil as detailed above, then desolventization as previously described, then deodorization and / or decolorization.

[0071] According to a second aspect, the invention relates to the non-therapeutic use of a cosmetic composition comprising at least one oil derived from achenes of Milk thistlewith at least one cosmetically acceptable excipient, to increase total ceramides in the skin in order to prevent a decrease and / or strengthen the epidermal barrier function.

[0072] According to a particular embodiment, the invention relates to the non-therapeutic use of a cosmetic composition comprising at least one oil derived from achenes of Milk thistle with at least one cosmetically acceptable excipient, to strengthen the protection of the skin against water loss and / or external aggressions.

[0073] According to a particular embodiment, the invention relates to the non-therapeutic use of a cosmetic composition comprising at least one oil derived from achenes of Milk thistle with at least one cosmetically acceptable excipient, to nourish and / or moisturize the skin, including the scalp, and / or the mucous membranes.

[0074] According to a particular embodiment, the invention relates to the non-therapeutic use of a cosmetic composition comprising at least one oil derived from achenes of Milk thistle with at least one cosmetically acceptable excipient, to improve skin repair, by strengthening or restoring the barrier function. According to a particular embodiment, the invention relates to the non-therapeutic use of a cosmetic composition comprising at least one oil derived from achenes of Milk thistle with at least one cosmetically acceptable excipient, to prevent and / or reduce tingling, itching, tightness, redness of the skin.

[0075] According to a particular embodiment, the invention relates to a cosmetic composition comprising at least one oil derived from achenes of Milk thistle(L.) Gaertn and at least one cosmetically acceptable excipient, for use in the prevention and / or treatment of skin irritations, by increasing total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0076] Advantageously, the oil from achenes of Milk thistle included in the cosmetic composition is prepared as described above.

[0077] In a particular embodiment, the cosmetic composition according to the invention comprises between 0.01 and 40% by weight relative to the total weight of the composition, in particular between 0.1 and 20% by weight, in particular between 0.1 and 10% by weight, more particularly between 0.1 and 5% by weight, even more particularly between 0.1 and 2% by weight, and even more particularly between 0.5 and 1% by weight of oil derived from achenes of Milk thistle relative to the total weight of the composition.

[0078] Preferably oil from achenes of Milk thistle is present in the cosmetic composition at a content of approximately 1% by weight relative to the total weight of the composition. According to a particular embodiment, the cosmetic composition according to the invention does not comprise the following ingredients named according to the INCI nomenclature: Enteromorpha compressa extract and / or Ocimum sanctum leaf extract. Thus, according to a particular embodiment, the cosmetic composition according to the invention does not comprise green algae extract and / or holy basil extract.

[0079] According to a particular embodiment, the cosmetic composition according to the invention does not comprise fruit extract of Momordica grosvenori and / or extract of Pseudopterogorgia elizabethae.

[0080] According to a particular embodiment, the cosmetic composition according to the invention does not comprise Defensil ®< which has the INCI name: Octyldodecanol (and) Echium Plantagineum Seed Oil (and) Helianthus Annuus (Sunflower) Seed Oil Unsaponifiables (and) Cardiospermum Halicacabum Flower / Leaf / Vine Extract (and) Tocopherol. Thus, according to a particular embodiment, the cosmetic composition according to the invention does not comprise a mixture of octyldodecanol, seed oil of Echium plantain (also called plantain leaf bugloss oil), the unsaponifiable fraction of sunflower oil, an extract (in particular of flowers / leaves / stems) of Cardiospermum Halicacabum (called heart pea vine, heart of India, or Poc-poc), and tocopherol. According to a particular embodiment, the cosmetic composition according to the invention does not comprise seed oil of Echium plantagineum,of the unsaponifiable fraction of sunflower oil, and / or of an extract (in particular of flowers / leaves / stems) of Cardiospermum Halicacabum.

[0081] According to a particular embodiment, the cosmetic composition according to the invention does not comprise green algae extract, holy basil extract, or fruit extract. Momordica grosvenori, extract of Pseudopterogorgia elizabethae, of seed oil Echium plantagineum, of the unsaponifiable fraction of sunflower oil, and / or of an extract (in particular of flowers / leaves / stems) of Cardiospermum Halicacabum.

[0082] According to another embodiment according to the invention, the cosmetic composition according to the invention comprises oil derived from achenes of Milk thistle as the only active ingredient useful for nourishing and / or moisturizing the skin, and more particularly useful for preventing a reduction and / or strengthening the epidermal barrier function.

[0083] The cosmetic compositions according to the invention are advantageously intended for topical application, in particular by application to the skin.

[0084] The cosmetic compositions according to the invention may thus be presented in the forms which are usually known for topical administration, that is to say in particular lotions, milks, emulsions, serums, balms, masks, creams, dispersions, gels, mousses or sprays.

[0085] Advantageously, it will be a balm and / or a milk.

[0086] The invention thus relates to cosmetic compositions according to one of the embodiments of the present invention, characterized in that they are presented in a form specific and suitable for topical application.

[0087] The cosmetic compositions according to the invention, in addition to the oil derived from achenes of Milk thistle,and a physiologically acceptable medium, may also contain surfactants, complexing agents, preservatives, stabilizing agents, emulsifiers, thickeners, gelling agents, humectants, emollients, trace elements, essential oils, perfumes, colorants, matting agents, chemical or mineral filters, moisturizing agents, thermal waters, etc.

[0088] According to another aspect, the invention relates to a cosmetic composition comprising at least one oil derived from achenes of Milk thistle (L.) Gaertn and at least one cosmetically acceptable excipient, for use in the prevention and / or treatment of skin irritations, by increasing total ceramides in the skin to prevent a decrease and / or strengthen the epidermal barrier function.

[0089] Advantageously, the oil from achenes of Milk thistleis prepared as previously described and the cosmetic composition is as previously described.

[0090] The following examples illustrate the invention without limiting its scope. EXAMPLES Example 1: Preparation of oil from achenes of Milk thistle obtained by cold pressing

[0091] Cold pressing of achenes of Milk thistle then filtration on a filter press to obtain a first-pressed crude oil from achenes of Milk thistle (L.) Gaertn. Example 2: Preparation of oil from achenes of Milk thistle devoid of its polar compounds and refined

[0092] This process is done in 8 steps: Cold pressing of achenes of Milk thistle then filtration on a filter press to obtain a first-pressed crude oil from achenes of Milk thistle (L.) Gaertn. Extraction of crude oil first pressing from achenes of Milk thistleby an isopropanol / water mixture (90 / 10 v / v) with 1 weight of the isopropanol / water mixture for 1 weight of oil for 10 hours at 20°C Recovery of the lipid phase (exhausted residual oil) Desolventization of the exhausted residual oil: removal of the solvent by vacuum evaporation (distillation) then steam distillation under the following conditions: Stage 1 - distillation: Distillation temperature: 90°C Distillation time: 2 hours Vacuum: 2 mbar progressive Stage 2- stripping: Steam: approximately 7kg / h Stripping temperature: 90°C Stripping duration: 1 hour Vacuum: 2-20 mbar Decolorization of exhausted and desolventized residual oil under the following conditions: Natural bleaching earth: Tonsil ®< 210 FF Decolorization temperature: 80°C Decolorization duration: 45 minutes Vacuum: 10-20 mbar Filtration on filter press Deodorization under the following conditions: Deodorization temperature: 180°C Deodorization duration: 2 hours Stripping: steam (approximately 7kg / h) Vacuum: 2-20mbar Filtration on cartridge filter. Example 3: Effets d'huiles issues d'akènes de Silybum marianum sur la synthèse de lipides totaux et de ceramides sur une modèle d'épiderme reconstruit

[0093] The main function of the epidermis is to protect the body by forming a vital protective barrier against external aggressions and against the risk of dehydration. stratum corneum, the outermost layer of the skin, is largely responsible for the barrier function. This stratum corneumconsists of corneocytes embedded in a lipid matrix, the very specific organization of which depends on the lipid composition. The latter is composed of free fatty acids, cholesterol and ceramides. The lipids form multiple layers superimposed on each other. In vitro experiments have demonstrated that the specific lipid composition of the stratum corneum alone allows this particular arrangement of lipids in lamellar bilayers (De Jager et al., J. Lipid res. 2005, 46, 2649-2656). These lipids play a key role in the barrier function of the skin.

[0094] Ceramides constitute a lipid family of great biological importance because they allow the cohesion of the stratum corneum and, consequently, the formation of the skin barrier. Biochemically, they are sphingolipids resulting from the amidation of sphingosine with a fatty acid. They can be free or covalently bound to the proteins of the stratum corneum. Currently, 14 classes of ceramides have been identified and are named according to their chemical structure: ceramides can have a sphingosine (S), dihydrosphingosine (dS), phytosphingosine (P), or 6-hydroxysphingosine (H) base to which is linked an ω-hydroxy (EO or O), α-hydroxy (A) or non-hydroxy (N) fatty acid with an alkyl chain of variable length. EO ceramides have a unique structure because they have a very long ω-hydroxy-acid chain of more than 34 carbon atoms linked to a linoleic acid and will play a predominant role in the organization of the lamellar bilayers of the stratum corneum and consequently on the barrier function.

[0095] The quantification of ceramides provides information on the integrity or otherwise of the barrier function and provides an assessment of dermo-cosmetic products.

[0096] A wide variety of ceramides are included in the lipid composition of the stratum corneum. They alone represent approximately half of the intercorneocyte lipids. Ceramides play a key role in the organization of lamellar bilayers, particularly ultra-long chain esterified ceramides such as EOS, EOP, and EOH ceramides (Bouwstra et al., Biochim Biophys Acta 1996, 1300(3), 177-186). The importance of esterified ceramides, due to their very long carbon chains, has been demonstrated in the lamellar repeat distance and chain ordering (Kessner et al., Chem Phys Lipids, 2010, 163(1), 42-50). Moreover, the polar heads carried by ceramides, in particular CER EOS and CER EOP, exert a considerable influence on these structural properties required for a functional lipid matrix.

[0097] Non-esterified ceramides are predominant and are also important for the barrier function but also for the hydration and nutrition of the skin. Studies have shown that, during winter, states of skin dryness have been correlated with a decrease in total ceramide levels and more particularly with the levels of NP and NH ceramides (Ishikawa et al., J. Cosmet Dermatol 2013, 12(1), 3-11). In patients with atopic dermatitis, a significant decrease in total ceramide levels and more particularly with the levels of NP, NS and NH ceramides and an inverse correlation with the measurement of transepidermal water loss indicating an alteration of the barrier function has also been reported (Ishikawa et al., J Invest Dermatol, 2010, 130(10), 2511-2514).The decrease in ultra-long chain esterified ceramides as well as the shortening of the chain lengths of free fatty acids and ceramides in general leads to a change in the lipid organization towards a less dense state (Kessner et al., Skin Pharmacol Physiol 2008, 21(2), 58-74). This creates spaces in the lipid arrangement between corneocytes leading to a reduction in the skin barrier function and increased skin permeability. Thus, an increase in these specific lipids induces an improvement in the skin barrier function.

[0098] The aim of this study is to evaluate the impact of oil from achenes of Milk thistle on the synthesis of skin lipids, and in particular on the synthesis of ceramides, the major constituents of stratum corneumfrom a lipid point of view and to evaluate the nutritional effect for the treatment and improvement of barrier function. Ceramides, free fatty acids and cholesterol from stratum corneum are analyzed by high-performance thin-layer chromatography (HPTLC). This rapid technique is widely used to separate complex mixtures such as lipids (Fuchs et al., J. Chromatography A 2011, 1218(19), 2754-2774), the method used has been the subject of a scientific publication (Jamin et al., Eur J Mass Spectrum, 2019, 25(3), 278-290). The oil effect is evaluated on 3 batches of reconstructed epidermis with n=3 (triplicate) per experimental condition and per batch. After treatment with oil from achenes of Milk thistle, lipids of the stratum corneum are quantified by HPTLC to assess the impact of treatment on skin lipid synthesis. Method

[0099] The model used in this study is a reconstructed epidermis model derived from skin excisions from cosmetic surgery according to the method described by Frankart et al. (Frankart et al., Exp. Dermatol. 2012, 21(11), 871-875).

[0100] The cells (keratinocytes) are isolated from the skin excisions, then cultured before being seeded on culture inserts immersed in culture medium, then the culture inserts are placed at the air / liquid interface in an incubator at 37°C in a humidified atmosphere with 5% CO 2 , to form the stratum corneum.

[0101] It takes 14 days to reform a reconstructed epidermis with a surface area of ​​0.6cm 2. The culture medium is changed every 24 hours.

[0102] Three reconstructed epidermis are used per condition (control, oil from achenes of Milk thistle obtained by cold pressing, and positive control).

[0103] Control: Tween ®< 20 at 0.01% in phosphate buffer pH 7.4 (PBS); Oil from achenes of Milk thistle : 1st series of experiments: oil obtained according to example 1, tested at 1% in Tween ® 20 at 0.01% in phosphate buffer pH 7.4 (PBS); 2nd series of experiments: oil obtained according to example 2, tested at 1% in Tween ® 20 at 0.01% in phosphate buffer pH 7.4 (PBS); Positive control: Dexeryl ® cream.

[0104] On the 9th day of the protocol, the compounds to be tested are applied for the first time to the reconstructed epidermis (2mg for Dexeryl ® cream, 5µl of oil from achenes of Milk thistle obtained by cold pressing at 1% in Tween ®< 20 / PBS or 5µl of Tween ®< 20 / PBS for epithelium control). A 24-hour incubation is carried out. A second application (same conditions) is carried out on the 10th day, with a 48-hour incubation.

[0105] A third application (same conditions) is carried out on the 13th day, with 24 hours of incubation.

[0106] Finally, a fourth application (same conditions) is carried out on the 14th day (epithelium completely reconstructed), with 24 hours of incubation.

[0107] On the 15th day, the reconstructed epidermis are removed from the culture inserts, the stratum corneum is isolated using trypsin from the rest of the epidermis. The stratum corneum is then extracted using organic solvents (mixture of chloroform and methanol) in order to collect the lipids constituting it. These lipids are then concentrated under liquid nitrogen before analysis by HPLC

[0108] Ceramides, free fatty acids and cholesterol from stratum corneum are analyzed by HPTLC. The analytical conditions are detailed below, particularly in Table 1. Plate: Lichrospher ®< HPTLC Silica gel 60 F254S Deposit: 6 mm wide, dried under nitrogen flow Development: gradient: see Table 1 Post-derivatization: aqueous solution of copper sulfate (10% CuSO 4 , 8% H 3 PO 4 , 5% MeOH) Detection: λ scanner: 450 nm. [Table 1] Stages Chloroform Acetone MeOH / Eau / Acetic acid (97 / 3 / 1 v / v / v) Distance (mm) 1 81,5 4 14,5 20 2 81,7 4 14,3 30 3 82 4 14 42 4 83 4 13 46 5 84,5 4 11,5 54 6 85 4 11 57 7 86 4 10 59 8 87 4 9 67 9 88 4 8 75 10 90 5 5 83 11 100 0 0 90 Results

[0109] Dexeryl ® cream is known to increase lipid synthesis. Therefore, Dexeryl ® cream was chosen as a positive control and was applied to the reconstructed epithelia at 2 mg / epithelium.

[0110] Several classes of lipids are analyzed by HPTLC, free fatty acids, cholesterol derivatives (cholesterol oleate and cholesterol sulfate) and ceramides. 1 ère< experimental series

[0111] In this first series of experiments, the positive control (Dexeryl ® cream) induced, as expected, a synthesis of lipids, associated with an increase in free fatty acids, cholesterol derivatives and ceramides. These results validate the experimental conditions.

[0112] Oil from achenes of Milk thistle according to example 1 has no effect on the synthesis of free fatty acids, induces a slight decrease in total cholesterol (-4.3%) but this reduction does not reach the threshold of significance. On the other hand, the oil from achenes of Milk thistle according to example 1 significantly increases the synthesis of total ceramides (+ 36.1%). This result allows us to conclude that this oil from achenes of Milk thistle demonstrates a significant nourishing effect for the skin.

[0113] Ceramides are present as the dominant lipids in the stratum corneum,and play a crucial role in barrier function and therefore limit dehydration and water retention. Based on the important properties of ceramides, emphasis has been placed on different subclasses of ceramides, produced by the application of Milk thistle. Indeed, these ceramides were not present in the formulation, the ceramides found in the stratum corneum therefore correspond only to ceramides produced by the skin.

[0114] Table 2 below shows the percentage induction of ceramides produced after application of oil from achenes of Milk thistle according to example 1 compared to control. [Table 2] CER AH CER AP CER NH CER AS and EOH CER AdS and OH CER NP CER EOP CER NdS and NS CER EOS 15,3% 24,4% 25,8% 39,0% 45,3% 44,3% 63,7% 46,4% 32,0% P<0,01 P<0,05 P<0,05 P<0,05 P<0,01 P<0,05 P<0,01 P<0,001 P<0,05

[0115] Thus, the oil from achenes of Milk thistle,compared to untreated reconstructed epidermis (control), induces a statistically significant synthesis of all ceramides in this reconstructed epidermis model. It is interesting to note that the increase in the synthesis of ceramide CER EOS exceeds 30%, this ceramide being in reduced quantity in cases of eczema and atopic dermatitis, and playing an important role in the barrier function and in particular the organization of lamellar bilayers. Furthermore, ceramides involved in the lamellar organization of lipids in the stratum corneum, i.e. ultra-long chain esterified ceramides, such as EOS, EOH, and EOP ceramides, are significantly increased to at least 30%. Non-esterified ceramides are also increased, such as NP and NS ceramides, which are the majority ceramides at the stratum corneum.Ceramide NP is the major ceramide and contributes 8-13% to total ceramides (Van Smeden et al., J Lipid Res 2011, 52(6), 1211-1221). This ceramide plays an important role in the formation of lamellar bilayers along with ultra-long chain esterified ceramides, as well as ceramide AdS, which is also induced by topical application of achene oil. Milk thistle (Bouwstra et al., Biochim Biophys Acta 1996, 1300(3), 177-186). Ceramide NP with ceramide NH are also involved in skin dryness when the quantities of these ceramides decrease (Ishikawa et al., J Cosmet Dermatol 2013, 12(1), 3-11). Increasing the level of total ceramides and in particular ceramides which are major players in the barrier function such as ceramides EOS, NP and NS, by applying oil from achenes of Milk thistle, is very favorable for a strengthening effect on the epidermal barrier function. 2 here< experimental series

[0116] In this second series of experiments, the positive control (Dexeryl ® cream) induced, as expected, a synthesis of lipids, in particular cholesterol derivatives and total ceramides. It should be noted that the synthesis of lipids is less than that found in the first series of experiments. These results nevertheless validate the experimental conditions.

[0117] Under these conditions, the oil from achenes of Milk thistle according to example 2 increases the synthesis of total ceramides by around 13.6% compared to untreated reconstructed epidermis. These results therefore demonstrate a nourishing effect of this oil. As in the 1st series of experiments, the study focused on different classes of ceramides necessarily induced by the application of the products by the skin, since ceramides are absent from the formulations. The results obtained by the application of the oil from achenes of Milk thistleaccording to Example 2 are summarized in Table 3. Table 3 below shows the percentage induction of ceramides produced by the application of the oil from achenes of Milk thistle according to example 2. [Table 3] CER AH CER NH CER AdS and OH CER NP CER EOP CER NdS and NS CER EOS 5,9 25,8 30,5 12,7 12,8 20,7 25,7 NSS P<0,05 P<0,01 P<0,05 P<0,05 P<0,05 P<0,05

[0118] Oil from achenes of Milk thistle according to example 2 induces a statistically significant production of almost all ceramides, in particular ceramides which are major players in the barrier function.

[0119] All these results demonstrate that the oil from achenes of Milk thistle a nourishing effect but is also capable of inducing endogenous synthesis of ceramides and therefore improving the epidermal barrier function.

Claims

1. Non-therapeutic cosmetic use of an oil from Silybum marianum (L.) Gaertn. achenes to increase total ceramides in the skin in order to prevent a decrease and / or strengthen the epidermal barrier function.

2. Use according to claim 1, to strengthen the skin's protection against water loss and / or external aggressions.

3. Use according to claim 1, to nourish and / or moisturize the skin, including the scalp and / or mucous membranes.

4. Use according to claim 1, to improve skin repair by strengthening or restoring the barrier function.

5. Use according to claim 1, to prevent and / or reduce tingling, itching, tightness or redness of the skin.

6. Use according to any of claims 1 to 5, characterized in that the oil from Silybum marianum (L.) Gaertn. achenes is obtained by a process comprising a cold pressing step of Silybum marianum (L.) Gaertn. achenes, followed by a filtration step.

7. Use according to claim 6, characterized in that the filtration step is followed by a step of extraction with a polar to medium-polar extraction solvent to give an extraction phase and a lipid phase, separation of the extraction phase and the lipid phase, and recovery of the lipid phase.

8. Use according to claim 7, characterized in that the polar to medium-polar extraction solvent is a C1 to C3 alcohol.

9. Use according to any of claims 7 and 8, characterized in that the recovered lipid phase is then desolventized and, if desired, deodorized and / or decolorized.

10. Oil from Silybum marianum (L.) Gaertn. achenes for use in the prevention and / or treatment of skin irritation by increasing total ceramides in the skin in order to prevent a decrease and / or strengthen the epidermal barrier function .

11. Non-therapeutic use of a cosmetic composition comprising at least one oil from Silybum marianum (L.) Gaertn. achenes with at least one cosmetically acceptable excipient, to increase the total ceramides in the skin in order to prevent a decrease and / or strengthen the epidermal barrier function.

12. Use of a cosmetic composition according to claim 11, to strengthen the skin's protection against water loss and / or external aggressions.

13. Use of a cosmetic composition according to claim 11, for nourishing and / or moisturizing the skin, including the scalp and / or mucous membranes.

14. Use of a cosmetic composition according to claim 11, for improving skin repair by strengthening or restoring the barrier function.

15. Use of a cosmetic composition according to claim 11, for preventing and / or reducing skin tingling, itching, tightness or redness.

16. Use of a cosmetic composition according to any of claims 11 to 15, characterized in that it contains from 0.1 to 2% by weight of oil from Silybum marianum (L.) Gaertn. achenes, relative to the total weight of the composition.

17. Cosmetic composition comprising at least an oil from Silybum marianum (L.) Gaertn. achenes with at least one cosmetically acceptable excipient, for its use in the prevention and / or treatment of skin irritations by increasing the total ceramide content in the skin in order to prevent a decrease in and / or strengthen the epidermal barrier function.