Cosmetic use of azelaic acid to increase cellular longevity

Abstract

The present invention relates to the use, in particular cosmetic use, of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to increase the longevity of skin cells.

Description

[0001] Description

[0002] Title: Cosmetic use of azelaic acid to increase cellular longevity

[0003] Technical field

[0004] The present invention relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to increase the longevity of skin cells.

[0005] The present invention also relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to prevent and / or treat sign(s) of skin aging, in particular to improve skin quality, texture and / or appearance, and / or to combat environmental stress; reduce skin roughness, and / or prevent and / or reduce fine lines and wrinkles; and / or improve skin suppleness, rebound and / or firmness; and / or improve skin resilience, luminosity and / or health.

[0006] In particular, the present invention relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to prevent or reduce mitochondrial dysfunctions and / or stimulate mitochondrial energy metabolism, and / or increase the maximum respiration of skin cells.

[0007] Prior art

[0008] Aging is characterized by a gradual decline in physiological functions, which originates at the cellular level. Longevity, defined as the ability of a cell to maintain its integrity and functions over an extended period of time, depends on the integrity of various cellular processes.

[0009] The cellular processes involved in longevity are constantly challenged by a multitude of stressors, leading to a gradual deterioration and the appearance of cellular and tissue damage. The skin, the organ most exposed to environmental factors (UV rays, pollution, etc.), undergoes accelerated aging, called extrinsic aging, in addition to age-related intrinsic aging. These processes adversely affect the cells of the epidermis, dermis and skin appendages, as well as the extracellular matrix.

[0010] Mitophagy is a crucial process for maintaining cellular health, in particular in skin cells. It removes damaged or dysfunctional mitochondria, which can otherwise accumulate damage and contribute to cellular aging. By stimulating mitophagy, the regeneration of healthy mitochondria is promoted, which is essential for maintaining the vitality and longevity ofskin cells. Thus, by acting on mitophagy, it is possible to directly influence cellular aging, delaying the signs of aging and improving the overall quality of the skin.

[0011] There is therefore a need for a new cosmetic active agent capable of increasing the longevity of skin cells.

[0012] There is also a need for a new cosmetic active agent capable of preventing or reducing mitochondrial dysfunctions and / or of stimulating mitochondrial metabolism in skin cells. There is additionally a need for a new cosmetic active agent capable of increasing the maximum respiration of skin cells.

[0013] There is also a need for a new cosmetic active agent capable of increasing the process of mitophagy in skin cells.

[0014] There is also a need for a new cosmetic active agent capable of preventing and / or treating one or more signs of skin aging, chosen in particular from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of skin elasticity and / or tone.

[0015] There is also a need for a new cosmetic active agent capable of improving the skin quality, texture and / or appearance, and / or combating environmental stress; and / or reducing skin roughness, and / or preventing and / or reducing fine lines and wrinkles; and / or improving skin suppleness, rebound and / or firmness.

[0016] In this context, it is also important to develop new cosmetic compositions with a better carbon footprint, in particular by promoting the use of starting materials that are renewable and / or that have a good naturality index and / or that are of natural origin and more particularly of plant origin, while reducing the use of compounds of petrochemical origin.

[0017] The present invention aims to protect the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to stimulate the mitophagy process, thus allowing the removal of the non-functional mitochondria responsible for skin cell disorders. By acting on this process, azelaic acid improves cellular longevity, proper functioning and health of the skin.

[0018] Disclosure of the invention

[0019] The aim of the present invention is to solve at least one abovementioned technical problem. Indeed, the inventors have demonstrated that azelaic acid improves the mitochondrial network and metabolism by stimulating maximum mitochondrial respiration. This actionoptimizes energy production in response to cellular requirements. Azelaic acid also promotes the expression of the PINK1 and Parkin key genes, involved in mitophagy, and stimulates the fusion of damaged mitochondria with lysosomes, thus ensuring the effective removal thereof.

[0020] Summary of the invention

[0021] As mentioned above, the present invention thus relates to the use, in particular cosmetic use, of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to increase the longevity of skin cells.

[0022] It also relates to the use, in particular cosmetic use, of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to prevent and / or treat one or more signs of skin aging, in particular to:

[0023] - improve skin quality, texture and / or appearance, and / or to combat environmental stress; and / or

[0024] - reduce skin roughness, and / or prevent and / or reduce fine lines and wrinkles; and / or - improve skin suppleness, rebound and / or firmness; and / or

[0025] - improve skin resilience, luminosity and / or health.

[0026] In particular, said sign of skin aging being chosen from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of elasticity, lack of resilience, lack of luminosity, loss of health and / or lack of tone of the skin.

[0027] According to a particular embodiment, said use makes it possible to prevent or reduce mitochondrial disorders and / or stimulate mitochondrial metabolism in skin cells.

[0028] According to a particular embodiment, said use makes it possible to increase the maximum respiration of the skin cells.

[0029] According to a particular embodiment, said use makes it possible to increase the process of mitophagy in the skin cells.

[0030] According to one embodiment, azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, is present in a composition, in particular in a cosmetic composition, also comprising a physiologically acceptable medium.

[0031] In particular, azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, is present in said composition in a content greater than or equal to 0.01%by weight, greater than or equal to 0.1% by weight, better still greater than or equal to 0.5% by weight relative to the total weight of the composition.

[0032] In particular, the composition is topical, and in particular:

[0033] (i) liquid, preferably chosen from creams, emulsions, lotions, dispersions, solutions, gels, balms and serums; or

[0034] (ii) solid, preferably selected from masks and sticks.

[0035] According to another aspect, the invention relates to a non-therapeutic cosmetic process for caring for keratin materials, in particular the skin, comprising the topical application to these keratin materials of a composition, in particular a cosmetic composition, comprising azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, and a physiologically acceptable medium.

[0036] Description of the figures

[0037] Figure 1 represents the profile of mitochondrial respiration. It shows the variation of the oxygen consumption rate (OCR) in pmol as a function of time in minutes for the various steps of the respiration and taking into account sequential injections.

[0038] Figure 2 shows the variation of the oxygen consumption rate (OCR) in pmol as a function of time in minutes of the cells in the absence of azelaic acid (black circle control curve), in the presence of 22 pg / ml azelaic acid (gray circle curve), in the presence of 67 pg / ml azelaic acid (triangle curve) or in the presence of 200 pg / ml azelaic acid (star curve).

[0039] Figure 3 shows the variation in the relative gene expression level for PINK1 (left graph) and Parkin (right graph) for various groups of cells represented by the columns, from left to right: control group (no UVB radiation, no azelaic acid), “model” group (UVB radiation, no azelaic acid) and “AZA” group (UVB radiation, azelaic acid).

[0040] Figure 4 shows the variation in relative red fluorescence intensity for various groups of cells represented by the columns, from left to right: “untreated” control group (no UVB radiation, no azelaic acid), “UV” group (UVB radiation, no azelaic acid) and “azelaic acid” group (UVB radiation, azelaic acid).Detailed description

[0041] The term “cosmetic” means a composition that is compatible with keratin materials, in particular the skin, mucous membranes and skin appendages. The composition according to the invention is non-therapeutic.

[0042] The composition according to the invention notably comprises a “physiologically acceptable” medium, that is to say a medium compatible with all keratin materials, in particular the skin.

[0043] Thus, a composition according to the invention has a pleasant color, odor and feel and does not give rise to any unacceptable discomfort, i.e. tingling, tautness or redness, that is liable to discourage the user from applying this composition. Needless to say, a person skilled in the art will take care to choose a physiologically acceptable medium such that the advantageous properties of the cosmetic active agent(s) of the invention are not, or are not substantially, adversely affected.

[0044] The pH of a composition, in particular a cosmetic composition, used according to the invention, may in particular be between 4 and 7.5, notably between 4.5 and 7, and in particular between 4.7 and 6.5.

[0045] The cosmetic uses described in the present text are non-therapeutic uses.

[0046] The term "keratin materials" is in particular intended to denote the skin, mucous membranes, fibers, eyelashes and skin appendages.

[0047] The term “the skin” means all the skin of the body, and preferably the skin of the face, the scalp, the neckline, the neck, the arms and forearms, the eyelids, around the mouth or behind the ears, the hollow of the elbow, the back of the knees, the hands, the wrists and the ankles, or even more preferably the skin of the face (in particular the forehead, the nose, the cheeks and the chin), the neckline and the neck.

[0048] The term “treating” or “treatment” means any action that aims to improve the comfort or the well-being of an individual; this term thus equally covers attenuating, relieving and curing.

[0049] The term “reducing” or “reduction” is understood in the context of the present invention to mean the reduction of the risk or probability of occurrence of a given phenomenon, in particular with respect to a “normal” situation, that is to say in the absence of application of the composition according to the invention.In the context of the present invention, the terms "preventing" and "prevention" denote the reduction, to a lesser degree, of the risk or probability of occurrence of a given phenomenon. Thus, "preventing the signs of skin aging" is understood to mean preventing or delaying the appearance of the signs of aging in the skin.

[0050] "Signs of aging" is understood to mean any modifications in the external appearance of the skin due to aging, whether chronobiological and / or photoinduced, such as, for example, wrinkles and fine lines, wizened skin, flaccid skin, thinned skin, lack of skin elasticity and / or tone.

[0051] The term "increasing" or "increase" is understood in the context of the present invention to mean the fact of increasing or improving a certain characteristic or property, in particular with respect to a "normal" situation, that is to say in the absence of application of azelaic acid according to the invention. For example, it is understood in the context of the present invention that "increasing the maximum respiration of skin cells" means an increase in this intracellular activity in the presence of azelaic acid, with respect to skin cells that have not received azelaic acid.

[0052] "Cellular longevity" is understood to mean the ability of cells to maintain their functions and viability over time, despite environmental or metabolic damage and stresses. This longevity depends on specific biological mechanisms that protect cells from aging, premature death or dysfunction. However, cellular aging is inevitable and is associated with progressive changes in cellular structure and functions.

[0053] In that which follows and unless otherwise indicated, the limits of a range of values are included within that range, notably in the expressions "between..." and "ranging from ... to

[0054] Moreover, the expression "at least one" used in the present description is equivalent to the expression "one or more" .

[0055] Azelaic acid

[0056] The present invention relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, as described above.

[0057] Azelaic acid has been widely studied for its antibacterial, exfoliating, depigmenting and antioxidant properties, notably in the treatment of acne. However, its potential for improving tissue longevity, particularly in the skin, remains unexplored. Recent studies, such as the oneby Thach TT et al. (Front Physiol. 2020 Apr 17; 11 :329), highlighted the advantage of azelaic acid for stimulating autophagy and mitochondrial biogenesis in muscles, thus suggesting its potential role in the proper functioning of this organ.

[0058] Nevertheless, no benefit to the mitochondrial network of the skin has been described to date. The term “ organic or mineral base salts" means salts of bases or alkaline agents as defined below, such as alkali metal or alkaline-earth metal hydroxides, such as sodium hydroxide or potassium hydroxide, aqueous ammonia, amines or alkanolamines, or else salts of “basic” amino acids such as lysine or arginine.

[0059] Azelaic acid, or nonanedioic acid, having the empirical formula C9HI6O4, is the compound of formula (I) below:

[0060]

[0061] Azelaic acid is a dicarboxylic acid derived from cereals (wheat, rye and barley) and / or extracted from plants, for instance tall oil acid (INCI name). It has excellent moisturizing, antimicrobial and anti-inflammatory properties, allowing it to combat skin irregularities such as acne, rosacea and / or fine lines.

[0062] Azelaic acid is typically in the form of a white powder.

[0063] Uses

[0064] The present invention relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to increase the longevity of skin cells.

[0065] According to another embodiment, the invention relates to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, for preventing and / or treating sign(s) of skin aging, in particular one or more signs of skin aging chosen from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of elasticity, lack of resilience, lack of luminosity and / or lack of tone of the skin.

[0066] These parameters are well known in the field of skin cosmetics, and are generally representative of the health and quality of the skin.

[0067] Methods and protocols for measuring these parameters are known in the art.The present invention relates in particular to the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to:

[0068] - improve skin quality, texture and / or appearance, and / or to combat environmental stress; and / or

[0069] - reduce skin roughness, and / or prevent and / or reduce fine lines and wrinkles; and / or - improve skin suppleness, rebound and / or firmness; and / or

[0070] - improve skin resilience, luminosity and / or health.

[0071] According to a particular embodiment, skin firmness and elasticity can be measured instrumentally, by imaging analysis, with manual tests, by indirect methods based on biomarkers or by clinical study protocols.

[0072] For example, instruments that can be used to measure skin firmness and / or elasticity include a Cutometer® (a device that uses mechanical suction to measure the deformability of the skin; it applies controlled suction and analyzes the speed at which the skin returns to its initial state), a Reviscometer® (a device that measures the mechanical properties of the skin using light reflection after a small deformation induced by a vibration) or a ballistometer (a ball hits the skin with a controlled force and the device measures the rebound speed of the ball to evaluate the firmness).

[0073] Viscoelastic methods make it possible to measure skin firmness and / or elasticity with imaging analysis. These include in particular the use of high-resolution ultrasound (for example via the DermaScan® device), 3D imaging (for example via the PRIMOS® device) or skin MRI which makes it possible to evaluate the density of the dermis.

[0074] Examples of manual methods for measuring skin firmness and / or elasticity are the “pinch test” (manual or instrumental measurement of the time taken for the pinched skin to return to its initial shape) and mechanical torsion (the skin is subjected to controlled torsion, and the resistance to movement as well as the return to the initial state are measured).

[0075] Indirect methods for measuring skin firmness and / or elasticity based on biomarkers are in particular skin biopsies, which analyze the density of collagen and elastin in the laboratory, and measurement of glycation by biochemical tests (glycated collagen fibers lose their elasticity).Skin roughness can be measured using instrumental methods, imaging analyses or tactile tests. Commonly used instruments include the roughness meter®, which analyzes the topography of the skin using a tactile sensor or structured light, and the Visioscan®, a device that captures high-resolution images in UV light to measure skin microreliefs. 3D imaging, for example via PRIMOS®, also makes it possible to obtain accurate data on skin roughness by creating a three-dimensional map of its surface. Tactile methods include manual evaluations performed by experts, where the surface of the skin is examined by touch to detect irregularities or rough patches.

[0076] Thus, according to a particular embodiment, the appearance of wrinkles and fine lines can be measured by 3D imaging, by measurement of skin replicas, by optical or laser profilometry, by in vivo confocal microscopy, by high-resolution digital photography or by sensory and clinical evaluations.

[0077] For 3D imaging, examples of devices that can be used include PRIMOS® (which uses a projection of structured light to capture a three-dimensional image of the skin) or Visia® Complexion Analysis (which analyzes wrinkles and fine lines in depth using photographs under standard, UV and polarized light).

[0078] The measurement of skin replicas consists in taking a silicone impression on the skin, which is then analyzed by microscopy or a scanner to measure the microreliefs.

[0079] Optical or laser profilometry consists of the projection onto the skin surface of a laser beam or optical light to measure the reliefs. It can be performed using a FOITS (Fast Optical In-vivo Topometry of human Skin) device.

[0080] In vivo confocal microscopy is a non-invasive analysis of skin structures in depth at the cellular level. It analyzes deep wrinkles and changes in the dermal matrix (collagen, elastin). Finally, high-resolution digital photography consists of capturing images of the skin for a qualitative evaluation of the wrinkles and fine lines. The analysis can be computer-aided to quantify wrinkle length and density.

[0081] Skin texture can be evaluated by topographic analyses and microrelief measurements. Instruments such as the SkinVisiometer® or the Skin Analyser® use optical or tactile techniques to quantify the evenness of the skin surface and the visible irregularities. Crosspolarized light imaging, carried out by systems such as Canfield Reveal®, makes it possible to evaluate the texture by visualizing the shadows and reflections caused by irregularities.Finally, measurements of local roughness by devices such as PRIMOS® or mechanical profilometry tests provide quantitative data on the physical properties of the skin texture, supplementing the visual or sensory observations.

[0082] The overall quality of the skin is evaluated by approaches combining visual analyses, advanced imaging and instrumental methods. Multispectral imaging, for example via VISIA® Complexion Analysis, makes it possible to characterize various parameters such as the complexion, pigment spots, porosity and texture. Colorimetric tests using devices such as Colorimeter® or Chroma Meter® objectively measure the uniformity of the complexion and detect discrete imperfections. In addition, clinical observations are often carried out by dermatologists or beauticians using standardized assessment grids to note criteria such as the luminosity, softness or general appearance of the skin.

[0083] According to a particular embodiment, the use of azelaic acid according to the invention prevents or reduces mitochondrial dysfunctions and / or stimulates mitochondrial energy metabolism.

[0084] Mitochondrial dysfunction involves a gradual impairment of the mitochondrial functions. Mitochondria, true powerhouses of the cell, control cell metabolism. However, with age and under the effect of oxidative stress, mitochondria suffer damage, and the mechanisms for eliminating damaged mitochondria (mitophagy process), and also the mechanisms for regenerating new mitochondria (mitochondrial biogenesis), are adversely affected. Deterioration of the mitochondria will have the direct consequence of modifying cell metabolism, increasing ROS production, and accelerating inflammatory processes. This vicious circle contributes to a state of chronic oxidative stress, harmful to cells, and accelerates skin aging.

[0085] According to a particular embodiment, the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, according to the invention, makes it possible to increase the maximum respiration of the skin cells.

[0086] This ability suggests that azelaic acid can mobilize cellular mechanisms in order to optimize mitochondrial respiration and generate energy production as needed.According to a particular embodiment, the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, according to the invention, makes it possible to increase the expression of the genes encoding the PINK1 and parkin key proteins in skin cells.

[0087] PINK1 is a 581 amino acid protein that contains a serine / threonine kinase domain, and a mitochondrial targeting peptide / signal / tag. The parkin protein plays a key role in regulating the quality of cellular proteins and organelles, notably in mechanisms of degradation of damaged or unnecessary proteins by the ubiquitin-proteasome system. It is particularly involved in maintaining mitochondrial homeostasis.

[0088] PINK1 and parkin are both involved in the mitophagy process.

[0089] According to a particular embodiment, the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, according to the invention, makes it possible to increase the mitophagy process in skin cells. Such activity induces the fusion of impaired mitochondria with lysosomes, thus ensuring the elimination of damaged mitochondria.

[0090] According to a particular embodiment, the use of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, according to the invention makes it possible, in skin cells, (i) to increase the maximum respiration, (ii) to increase the expression of genes encoding the PINK1 and parkin key proteins and (iii) to increase the mitophagy process.

[0091] The present text also describes azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, for its use in increasing the longevity of skin cells. Azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, is also described for its use in preventing and / or treating sign(s) of skin aging, in particular, one or more signs of skin aging chosen from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of elasticity, lack of resilience, lack of luminosity and / or lack of tone of the skin.

[0092] Such uses are also described in the present text.

[0093] A method is also described for increasing the longevity of skin cells comprising at least one step of administering azelaic acid, an organic or inorganic base salt thereof, a solvate thereof,or mixtures thereof, or a composition comprising azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, and a physiologically acceptable medium, in an individual in need thereof.

[0094] A method is also described for preventing and / or treating sign(s) of skin aging, in particular one or more signs of skin aging chosen from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of elasticity, lack of resilience, lack of luminosity and / or lack of tone of the skin, comprising at least one step of administering azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, or a composition comprising azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, and a physiologically acceptable medium, in an individual in need thereof.

[0095] In particular, an individual in need thereof is a healthy individual, i.e. an individual who is not ill, and wishes to improve the quality of their skin. Thus, skin considered according to the present invention is healthy skin. The term "healthy skin" is understood to mean skin which does not have any lesions and / or infections.

[0096] According to a particular embodiment, the administration of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, or of a composition according to the invention is a topical administration.

[0097] Cosmetic compositions

[0098] According to one embodiment, the azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, used according to the invention is present in a composition, in particular in a cosmetic composition, comprising a physiologically acceptable medium.

[0099] According to a particular embodiment, the azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, may be present in a composition, in particular in a cosmetic composition, in a content greater than or equal to 0.01% by weight of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, more preferentially greater than or equal to 0.1% by weight, better still greater than or equal to 0.5% by weight relative to the total weight of the composition.

[0100] In particular, the azelaic acid, an organic or mineral base salt thereof, a solvate thereof, or mixtures thereof is present in a total content ranging from 0.01% to 20% by weight, moreparticularly from 0.1% to 15% by weight, better still from 0.3% to 10% by weight, even better still from 0.5% to 5% by weight relative to the total weight of the composition.

[0101] Aqueous phase

[0102] A composition according to the invention may comprise an aqueous phase and / or a fatty phase.

[0103] An aqueous phase of a composition used according to the invention comprises in particular water and optionally a water-soluble organic solvent and is preferably single-phase.

[0104] According to a preferred embodiment, a composition according to the present invention has a water content of between 10% and 98% by weight, preferably between 25% and 90% by weight, and more preferentially between 35% and 85%, relative to the total weight of the composition.

[0105] According to the present invention, a “water-soluble organic solvent' denotes a compound that is liquid at room temperature and water-miscible (miscibility with water of greater than 50% by weight at 25°C and atmospheric pressure).

[0106] The water-soluble solvents that can be used in a composition of the invention may be volatile.

[0107] Among the water-soluble solvents that can be used in a composition according to the invention, mention may be made most particularly of lower monoalcohols containing from 1 to 5 carbon atoms, such as ethanol and isopropanol, polyols and also alkylene carbonates. According to an embodiment variant, the aqueous phase of a composition according to the invention may comprise at least one C2-C32polyol.

[0108] Preferably, a composition according to the invention comprises from 0.01% to 30% by total weight of at least one polyol relative to the total weight of the composition; more preferentially, the composition comprises from 0.1% to 20% by weight, even more preferentially from 0.5% to 10% by weight of at least one polyol, even better still from 0.7% to 5% by weight of at least one polyol, relative to the total weight of the composition. For the purposes of the present invention, the term “polyol” means any organic molecule including at least two free hydroxyl (OH) groups.

[0109] A polyol that is suitable for use in the invention may be a compound of alkyl type with a linear, branched or cyclic, saturated or unsaturated hydrocarbon chain, bearing at least two -OH functions on the alkyl chain. Preferably, a polyol that may be used in the compositionaccording to the invention is a compound of the linear alkyl type bearing on the alkyl chain at least two -OH functions, preferably from 2 to 6 hydroxyl -OH groups, more preferentially 2 or 3 hydroxyl groups.

[0110] The polyol(s) that are advantageously suitable for the formulation of the cosmetic compositions according to the present invention is (are) that or those notably containing from 2 to 16 carbon atoms, preferably 3 to 10 carbon atoms and more preferentially from 3 to 8 carbon atoms.

[0111] The polyol(s) that may be used according to the present invention is (are) chosen from linear polyols containing from 3 to 8 carbon atoms; mention may notably be made of:

[0112] - diols, such as propylene glycol, butylene glycol, pentylene glycol; and

[0113] - triols, such as glycerol (glycerin),

[0114] and mixtures thereof.

[0115] According to a very preferred embodiment, the polyol is chosen from triols such as glycerol. The aqueous phase of a composition according to the invention may also comprise any water-soluble or water-dispersible compound that is compatible with an aqueous phase, such as stabilizers, gelling agents, film-forming polymers, thickeners, surfactants, and mixtures thereof.

[0116] Fatty phase

[0117] As mentioned above, a composition according to the invention may comprise at least one fatty phase.

[0118] For the purposes of the invention, a "fatty phase" is understood to mean all of the lipophilic components included in a formulation, whether they are liquid, semi-solid or solid at room temperature. This includes in particular oils, butters, waxes, and also fatty acids, lipid esters and other fatty substances, used for the formulation of the compositions of the invention. In particular, a composition according to the invention may comprise from 5% to 95% by weight and preferably from 10% to 80% by weight of fatty phase, relative to the total weight of the composition.

[0119] The fatty phase of a composition according to the invention may in particular comprise at least one oil, in particular a cosmetic oil.Oils

[0120] The term “oil” means a water-immiscible non-aqueous compound that is liquid at room temperature (20°C) and at atmospheric pressure (760 mmHg).

[0121] A fatty phase that is suitable for preparing the compositions, notably cosmetic compositions, according to the invention may comprise hydrocarbon-based oils, silicone oils, fluoro oils or non-fluoro oils, or mixtures thereof.

[0122] The oils may be volatile or non-volatile.

[0123] The fatty phase can comprise at least one volatile or non-volatile hydrocarbon oil and / or one volatile and / or non-volatile silicone oil and / or one volatile and / or non-volatile fluoro oil. For the purposes of the present invention, the term “ hydrocarbon-based oil” means an oil mainly containing hydrogen and carbon atoms.

[0124] The term “ silicone oil” means an oil comprising at least one silicon atom and notably at least one Si-0 group.

[0125] The term "fluoro oil” means an oil comprising at least one fluorine atom.

[0126] The oils may optionally comprise oxygen, nitrogen, sulfur and / or phosphorus atoms, for example in the form of hydroxyl or acid radicals.

[0127] Volatile oils

[0128] For the purposes of the invention, the term "volatile oil" means any oil that is capable of evaporating on contact with the skin in less than one hour, at room temperature and atmospheric pressure. The volatile oil is a volatile cosmetic compound that is liquid at ambient temperature, particularly having a non-zero vapor pressure, at ambient temperature and atmospheric pressure, particularly having a vapor pressure ranging from 0.13 Pa to 40 000 Pa (IO-3to 300 mmHg), in particular ranging from 1.3 Pa to 13 000 Pa (0.01 to 100 mmHg) and more particularly ranging from 1.3 Pa to 1300 Pa (0.01 to 10 mmHg).

[0129] The volatile oils may be hydrocarbon-based oils or silicone oils.

[0130] Among the volatile hydrocarbon-based oils containing from 8 to 16 carbon atoms, mention may be made notably of branched C8-Ci6alkanes, for instance C8-Ci6isoalkanes (also known as isoparaffins), isododecane, isodecane, isohexadecane and, for example, the oils sold under the trade names Isopar or Permethyl, branched C8-C16esters, for instance isohexyl neopentanoate, and mixtures thereof.Mention may also be made of volatile linear alkanes comprising from 8 to 16 carbon atoms, in particular from 10 to 15 carbon atoms, and more particularly from 11 to 13 carbon atoms, for instance n-dodecane (Cl 2) and n-tetradecane (Cl 4) sold by Sasol under the respective references Parafol 12-97 and Parafol 14-97, and also mixtures thereof, the undecanetridecane mixture, mixtures of n-undecane (Cll) and of n-tridecane (C13) obtained in examples 1 and 2 of patent application WO 2008 / 155059 from the company Cognis, and mixtures thereof.

[0131] Volatile silicone oils that may be mentioned include linear volatile silicone oils such as hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, tetradecamethylhexasiloxane, hexadecamethylheptasiloxane and dodecamethylpentasiloxane.

[0132] Volatile cyclic silicone oils that may be mentioned include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, cyclohexasiloxane and dodecamethylcyclohexasiloxane, in particular cyclohexasiloxane.

[0133] Use may also be made of volatile fluoro oils, such as nonafluoromethoxybutane, nonafluoromethoxybutane, decafluoropentane, tetradecafluorohexane, dodecafluoropentane, and mixtures thereof.

[0134] Non-volatile oils

[0135] The term "non-volatile" refers to an oil whose vapor pressure at room temperature and atmospheric pressure is non-zero and is less than 10'3mmHg (0.13 Pa).

[0136] The non-volatile oils may notably be chosen from non-volatile hydrocarbon, fluoro and / or silicone oils.

[0137] Non-volatile hydrocarbon-based oils that may notably be mentioned include:

[0138] linear or branched hydrocarbons of mineral or synthetic origin, such as petroleum jelly, poly decenes, hydrogenated polyisobutene such as Parleam, and squalane, and mixtures thereof,

[0139] non-volatile alkanes, preferably with a viscosity of less than 20 mPa.s at 20°C measured with a Rheomat RM100® viscometer from Lamy Rheology. The term “nonvolatile alkane” means a hydrocarbon cosmetic oil which is liquid at ambient temperature, notably having a vapor pressure at 20°C of less than 0.01 kPa, according to the definition of a Volatile Organic Compound (VOC) of article 2 of European Council Directive 1999 / 13 / ECof 11 March, 1992: “Any organic compound having at 293.15 K a vapor pressure of 0.01 kPa or more”. In particular, the non-volatile alkanes comprise from 10 to 30 carbon atoms, in particular from 12 to 26 carbon atoms, and more particularly from 15 to 19 carbon atoms, and preferably a mixture of alkanes containing from 15 to 19 carbon atoms, for example the products sold under the references Emogreen LI 9 and Emosmart L19 from SEPPIC, hydrocarbon oils of plant origin, such as glyceride triesters, which are generally fatty acid triesters of glycerol, the fatty acids of which may have varied chain lengths from 4 to 24 carbon atoms, it being possible for these chains to be saturated or unsaturated and linear or branched; these oils are notably wheatgerm oil, sunflower oil, grape seed oil, sesame oil, com oil, apricot oil, castor oil, shea oil, avocado oil, olive oil, soybean oil, sweet almond oil, palm oil, rapeseed oil, cottonseed oil, hazelnut oil, macadamia oil, jojoba oil, alfalfa oil, poppy oil, pumpkin oil, marrow oil, blackcurrant oil, evening primrose oil, millet oil, barley oil, quinoa oil, rye oil, safflower oil, candlenut oil, passionflower oil and musk rose oil; or else caprylic / capric acid triglycerides, such as those sold by the company Stearinerie Dubois or those sold under the names Miglyol 810, 812 and 818 by the company Dynamit Nobel, synthetic ethers containing from 10 to 40 carbon atoms, such as dicapryl ether, synthetic esters, such as oils of formula RICOOR2, in which Ri represents a residue of a linear or branched fatty acid containing from 1 to 40 carbon atoms, and R2represents a hydrocarbon chain, in particular branched chain, containing from 1 to 40 carbon atoms provided that Ri + R2is greater than or equal to 10, for instance Purcellin oil (cetostearyl octanoate), isopropyl myristate, isopropyl palmitate, alkyl benzoate having between 12 and 15 carbon atoms, such as the product sold under the trade name "Finsolv TN" or "Witconol TN" by Witco or "Tegosoft TN" by Evonik Goldschmidt, 2-ethylphenyl benzoate such as the commercial product sold under the name “X-tend 226” by ISP, isopropyl lanolate, hexyl laurate, diisopropyl adipate, isononyl isononanoate, oleyl erucate, 2-ethylhexyl palmitate, isostearyl isostearate, diisopropyl sebacate such as the product sold under the name “Dub DIS” by Stearinerie Dubois, octanoates, decanoates or ricinoleates of alcohols or of polyalcohols, such as propylene glycol dioctanoate; hydroxyl esters such as isostearyl lactate, diisostearyl malate; and pentaerythritol esters; citrates, such as the ester of C3-C22tricarboxylic acid and of Ci-C6alcohols with the INCI name Tiethyl Citrate, for example the product sold under the name Citrofol Al Extra by the company Jungbunzlauer; tartrates, such as linear dialkyl tartrates having 12 and 13 carbon atoms, for example those sold under thename Cosmacol ETI by the company Enichem Augusta Industriale, and also linear dialkyl tartrates having between 14 and 15 carbon atoms, for example those sold under the name Cosmacol ETL by the same company, and acetates,

[0140] fatty amides, such as isopropyl N-lauroyl sarcosinate, for example the product sold under the trade name Eldew SL205 from Ajinomoto,

[0141] polyol esters and pentaerythritol esters, for instance dipentaerythrityl tetrahydroxy stearate / tetraisostearate,

[0142] fatty alcohols that are liquid at room temperature, with a branched and / or unsaturated carbon-based chain containing from 12 to 26 carbon atoms, for instance octyldodecanol, isostearyl alcohol, oleyl alcohol, 2-hexyldecanol, 2-butyloctanol, 2 -undecylpentadecanol, C12-C22 higher fatty acids, such as oleic acid, linoleic acid, linolenic acid, and mixtures thereof,

[0143] carbonates, such as dicaprylyl carbonate, for example the product sold under the name Cetiol CC by the company Cognis,

[0144] non-phenyl silicone oils, for instance caprylyl methicone, and

[0145] phenyl silicone oils, for instance phenyl trimethicones, phenyl dimethicones, phenyltrimethylsiloxydiphenylsiloxanes, diphenyl dimethicones, diphenylmethyldiphenyltrisiloxanes and 2-phenylethyl trimethylsiloxysilicates, dimethicones or phenyl trimethicone with a viscosity of less than or equal to 100 cSt, trimethylpentaphenyltrisiloxane, and mixtures thereof;

[0146] and also mixtures of these various oils.

[0147] Other faty substances

[0148] A fatty phase of a composition according to the invention may also comprise other fatty substances, mixed with or dissolved in an oil.

[0149] The other fatty substances which may be present in the fatty phase of a composition used according to the invention are, for example:

[0150] fatty acids including from 8 to 30 carbon atoms, such as stearic acid, lauric acid, palmitic acid and oleic acid;

[0151] waxes, other than glyceryl trihydroxystearate, such as lanolin, beeswax, carnauba or candelilla wax, paraffin waxes, lignite waxes or microcrystalline waxes, ceresin or ozokerite, or synthetic waxes, such as polyethylene waxes or Fischer-Tropsch waxes;silicone resins such as trifluoromethyl(Ci-C4)alkyl dimethicone and trifluoropropyl dimethicone;

[0152] silicone elastomers such as the products sold under the name KSG by the company Shin-Etsu, under the names Trefil or B Y29 by the company Dow Corning or under the name Gransil by the company Grant Industries;

[0153] a gum chosen from silicone gums (dimethiconol);

[0154] a pasty compound, such as polymeric or non-polymeric silicone compounds, esters of a glycerol oligomer, arachidyl propionate, fatty acid triglycerides and derivatives thereof;

[0155] and mixtures thereof.

[0156] As fatty substances, a composition according to the invention may comprise at least one fatty alcohol wax. Such waxes may be chosen from lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, lignoceryl alcohol, ceryl alcohol, montanyl alcohol, myricyl alcohol, and mixtures thereof.

[0157] As fatty substance, a composition according to the invention may in particular comprise at least one butter, in particular a plant butter.

[0158] The plant butters that are suitable for a composition according to the invention are preferably chosen from the group comprising avocado butter, cocoa butter, shea butter, kokum butter, mango butter, murumuru butter, coconut butter, apricot kernel butter, sal butter and urucum butter, and mixtures thereof, and in particular is shea butter.

[0159] These fatty substances may be chosen in a varied manner by those skilled in the art in order to prepare a composition having the desired properties, for example in terms of consistency or texture.

[0160] According to a preferred embodiment, a composition according to the invention comprises at least one non-volatile oil, preferably at least one non-volatile hydrocarbon oil, in particular chosen from linear or branched hydrocarbons of mineral or synthetic origin, non-volatile alkanes, hydrocarbon oils of plant origin, synthetic esters, fatty amides, carbonates, and also mixtures of these various oils, even better still chosen from synthetic esters, fatty amides, carbonates, and mixtures thereof.

[0161] According to a preferred embodiment, a composition according to the invention comprises a polar oil.In particular, such non-volatile hydrocarbon oils may be present in a composition according to the invention in a content ranging from 2.0% to 20.0% by weight and preferably from 2.0% to 15.0% by weight relative to the total weight of the composition.

[0162] According to a preferred embodiment, a composition according to the invention comprises at least one oil chosen from squalane, mixtures of alkanes containing from 15 to 19 carbon atoms, caprylic / capric acid triglycerides, alkyl benzoates containing between 12 and 15 carbon atoms, diisopropyl adipate, 2-ethylhexyl palmitate, diisopropyl sebacate, the ester of C3-C22 tricarboxylic acid and of Ci-C6alcohols having the INCI name Triethyl Citrate, isopropyl N-lauroyl sarcosinate, dicaprylyl carbonate, and mixtures thereof, even better still chosen from diisopropyl sebacate, isopropyl N-lauroyl sarcosinate, dicaprylyl carbonate. Preferably, a composition according to the invention comprises less than 2.0% by weight of silicone oil(s), in particular less than 1.0% by weight of silicone oil(s), preferably less than 0.5% by weight of silicone oil(s), relative to the total weight of the composition, and more preferentially is free of silicone oil(s).

[0163] Preferably, a composition according to the invention comprises a fatty phase containing at least one fatty substance.

[0164] According to a preferred embodiment, a composition according to the invention comprises at least one non-volatile hydrocarbon oil, and preferably at least one non-volatile ester oil.

[0165] Hydrophilic gelling agent / thickener

[0166] A composition according to the present invention may comprise at least one gelling agent (or thickener) that is hydrophilic, i.e. that is water-soluble or water-dispersible.

[0167] Examples of hydrophilic gelling agents that may be mentioned include modified or unmodified carboxyvinyl polymers, such as the products sold under the names Carbopol (CTFA name: carbomer) and Pemulen (CTFA name: Acrylates / C10-30 alkyl acrylate crosspolymer) by the company Goodrich; polyacrylamides; optionally crosslinked and / or neutralized 2-acrylamido-2-methylpropanesulfonic acid polymers and copolymers, for instance the poly(2-acrylamido-2-methylpropanesulfonic acid) sold by the company Hoechst under the name Hostacerin AMPS (CTFA name: Ammonium polyacryldimethyltauramide); crosslinked anionic copolymers of acrylamide and of AMPS, which are in the form of a W / O emulsion, such as those sold under the name Sepigel 305 (CTFA name: Polyacrylamide / C 13-14 Isoparaffin / Laureth-7) and under the name Simulgel600 (CTFA name: Aery 1 ami de / S odium acryloyldimethyltaurate copolymer / Isohexadecane / Polysorbate 80) by the company SEPPIC; polysaccharide biopolymers such as xanthan gum, guar gum, scleroglucan gum, alginates, modified celluloses; and mixtures thereof. The amount of gelling agents depends on the desired objective.

[0168] More preferentially, the hydrophilic gelling agent is chosen from polysaccharide biopolymers such as scleroglucan gum.

[0169] According to one embodiment, the amount of hydrophilic gelling agents ranges for example from 0.01% to 10% and for example from 0.05% to 5% by weight, relative to the total weight of the composition.

[0170] Additional active agent! s)

[0171] A composition according to the invention may also comprise one or more additional active agents. These additional active agents are different from azelaic acid.

[0172] Needless to say, a person skilled in the art will take care to select one or more additional active agents such that the advantageous properties of the azelaic acid are not, or are not substantially, adversely affected.

[0173] Additional active agents that may be mentioned include, for example, moisturizers, depigmenting agents, desquamating agents, different antiaging agents, mattifying agents, cicatrizing agents, preserving agents such as antibacterial agents, UV-screening agents which are notably lipophilic, and mixtures thereof.

[0174] Preferably, a composition according to the invention comprises from 0.01% to 20% by total weight of at least one additional active agent, preferentially from 0.05% to 15% by weight, and preferentially from 0.1% to 10% by weight of at least one additional active agent relative to the total weight of the composition.

[0175] A composition according to the invention may contain one or more adjuvants commonly used in the cosmetic and dermatological fields; emollients; sequestrants; antioxidants; fillers; free-radical scavengers; essential oils; fragrances; film-forming agents; dyes; and mixtures thereof. The total amounts of these various adjuvants are those conventionally used in the fields under consideration. In particular, these amounts vary according to the desired aim and may range, for example, from 0.01% to 20% and preferably from 0.1% to 10% by weight relative to the total weight of the composition.Needless to say, a person skilled in the art will take care to select the optional adjuvant(s) added to a composition according to the invention such that the advantageous properties intrinsically associated with the composition in accordance with the invention are not, or are not substantially, adversely affected by the envisaged addition.

[0176] The amounts of these various adjuvants are those conventionally used in the fields under consideration. In particular, these amounts vary according to the desired aim and may range, for example, from 0.01% to 20% and preferably from 0.1% to 10% by weight relative to the total weight of the composition.

[0177] A composition according to the invention may be in any presentation form normally used in the cosmetics field, in particular in the skincare cosmetics field.

[0178] It may notably be in the form of an aqueous or aqueous-alcoholic solution, which may be gelled, a dispersion of the lotion type, which may be a two-phase dispersion, an oil-in-water or water-in-oil emulsion or a multiple emulsion, a gel, notably an aqueous gel, or even a dispersion of oils in an aqueous phase, notably using spherules, it being possible for these spherules to be polymeric particles or, better still, lipid vesicles of ionic and / or nonionic type. In particular, a composition according to the invention may be in the form of a gel, notably an aqueous gel. It may also be an anhydrous composition. The term “anhydrous composition” means a composition containing less than 10% by weight of water, in particular less than 5% by weight of water, more particularly less than 2% by weight of water or even less than 0.5% of water, and notably free of water, the water not being added during the preparation of the composition but corresponding to the residual water provided by the mixed ingredients. The composition may be of relatively fluid liquid consistency.

[0179] A composition according to the invention is in particular suitable for topical administration. Thus, a composition according to the invention may comprise all the constituents usually employed in the envisaged topical application and administration.

[0180] A composition according to the invention may advantageously be in the form of an emulsion, particularly obtained by dispersion of an aqueous phase in a fatty phase (W / O) or of a fatty phase in an aqueous phase (O / W), of liquid or semi-liquid consistency of the milk type, or of soft consistency, or else of a multiple emulsion (W / O / W or O / W / O). These compositions are prepared according to the usual known methods.More particularly, a composition according to the invention may be intended for topical application and may in particular be in the form of an emulsion, in particular an oil-in-water emulsion. In particular, such an emulsion is not intended to be rinsed off after application. A composition according to the invention is more particularly intended to be applied to skin. In particular, the skin is the skin of the face, scalp, neckline, neck, arms or forearms, or even more preferably the skin of the face (in particular of the forehead, nose, cheeks and chin), neckline and neck.

[0181] The composition according to the invention may alternatively be in the form of a face and / or body care or makeup product, and may be packaged, for example, in the form of a cream in a jar or a fluid in a tube or a pump bottle or a dropper bottle.

[0182] A composition according to the invention can be manufactured by any known process generally used in the cosmetics field.

[0183] The ingredients can be mixed before being formed into shape, in the order and under conditions readily determined by a person skilled in the art.

[0184] According to a particular embodiment of the invention, other agents intended to enhance the appearance and / or texture of the skin may also be added to the composition according to the invention.

[0185] In particular, a composition used according to the invention, in particular a topical composition, is:

[0186] (i) liquid, preferably chosen from creams, emulsions, lotions, dispersions, solutions, gels, balms and serums; or

[0187] (ii) solid, preferably selected from masks and sticks.

[0188] Cosmetic process

[0189] Finally, the present invention relates to a non-therapeutic cosmetic process for caring for keratin materials, in particular the skin, comprising the topical application to these keratin materials of a composition according to the invention.

[0190] The composition used in the uses and processes according to the invention may be as described elsewhere in the present text.

[0191] The cosmetic uses and processes considered according to the invention are non-therapeutic. The cosmetic uses and processes of the invention are more particularly performed by topically administering a composition according to the invention.Topical administration consists in externally applying cosmetic compositions to the skin according to the usual techniques for the use of these compositions.

[0192] By way of illustration, the cosmetic use or process according to the invention may be performed by topical, for example daily, application of at least one composition according to the invention, which may be formulated, for example, as a cream, gel, serum, lotion, emulsion or makeup-removing milk, in particular in gel form.

[0193] The application may be repeated for example 1 to 2 times daily over a day or more, and generally over an extended period of at least 3 days, at least 4 weeks, or even 4 to 15 weeks, with one or more periods of stoppage, if necessary.

[0194] According to one embodiment, the application is daily (once a day) and generally over an extended period of at least 3 days, at least 4 weeks, or even 4 to 15 weeks, with one or more periods of stoppage, if necessary.

[0195] According to one embodiment, the cosmetic treatment process according to the invention may comprise a single application.

[0196] The examples that follow illustrate the present invention without limiting the scope thereof. The starting materials are referred to by their chemical or INCI name. The amounts are indicated as weight percentages of starting materials relative to the total weight of the composition, unless otherwise mentioned.

[0197] In the examples, unless otherwise specified, the temperature is room temperature (25°C) and is expressed in degrees Celsius, and the pressure is atmospheric pressure.

[0198] Examples

[0199] Example 1 : Effect of azelaic acid on mitochondrial respiration

[0200] Protocol

[0201] Human epidermal keratinocytes of “normal” skin were seeded in a 96-well plate specific for the Seahorse apparatus and incubated in culture medium to confluence. The medium is then replaced by culture medium containing or not containing (control) azelaic acid and the cells are incubated for 24 hours before evaluation of mitochondrial respiration. Three different azelaic acid concentrations were tested: 22 pg / ml, 67 pg / ml and 200 pg / ml. All the experiments are carried out in triplicate (n=3).The Seahorse XF® technology (Agilent) measures the mitochondrial respiration in real time in a microchamber. It is measured from the oxygen consumption rate (OCR) of cells in real time, which is a key indicator of mitochondrial respiration. Three parameters were measured: - basal respiration,

[0202] - ATP production,

[0203] - maximum respiration, enabling the "spare capacity" (i.e. the reserve respiratory capacity) to be defined.

[0204] Various measurement cycles are performed as a function of the sequential injections of: - oligomycin which inhibits ATP synthase, in order to determine the production of ATP; - FCCP (carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone) which stimulates OCR and makes it possible to determine the spare respiratory capacity, defined as the difference between the maximum respiration value and basal respiration;

[0205] - rotenone and antimycin A which make it possible to shut down mitochondrial respiration in order to determine the non-mitochondrial respiration.

[0206] The mitochondrial respiration profile is represented in Figure 1.

[0207] The basal respiration corresponds to the oxygen consumption of the cells for normal energy activity. Its value is proportional to the metabolic activity of the cell.

[0208] The production of ATP is directly proportional to the energy requirements of the cells. The maximum respiration is directly proportional to the metabolic agility of the cell. The higher the value, the more reactive the system.

[0209] The reserve respiratory capacity measures the cell's capacity to respond to increased energy demand or to stress.

[0210] The results showed that azelaic acid makes it possible to increase the maximal mitochondrial respiration in the cells, compared to the control cells, for the three azelaic acid concentrations tested (see Figure 2).

[0211] Example 2: Measurement of PINK 1 and parkin mRNAs

[0212] Keratinocyte line HaCaT cells were cultured and then seeded in a 6-well plate.

[0213] The cells were optionally subjected to UVB exposure (50 mJ / cm2) in a PBS buffer.

[0214] The viability of the cells was then checked by MTT colorimetric assay.Azelaic acid was then added to the medium of theUKLK' group at a concentration of 200 pg / ml. This concentration is noncytotoxic. The treatment time was 24 h.

[0215] The expression of PINK1 and parkin mRNAs was measured by RT-qPCR after 24 hours of treatment, using appropriate primers.

[0216] The results showed that azelaic acid makes it possible to increase the expression of PINK1 and parkin in the cells, compared with the control cells (see Figure 3). It was also observed that the mitophagy process is reduced after UVB treatment.

[0217] Example 3 : Evaluation of the mitophagy process by fluorescence

[0218] Keratinocyte line HaCaT cells were cultured and then seeded in a 24-well plate.

[0219] They were then incubated with a dye for visualizing the mitophagy processes (MtPhagy ® dye) for 30 min.

[0220] The cells were then exposed to UVB rays (50 mJ / cm2), with the exception of the control group.

[0221] Azelaic acid was then added to the medium of the “azelaic acid” group at a concentration of 200 pg / ml. This concentration is noncytotoxic. The treatment time was 24 h.

[0222] The cells were then incubated again with a dye for visualizing the lysosomes (LysoDye®). They were then observed by fluorescence microscopy.

[0223] The results of these observations showed that, in the presence of azelaic acid, the relative red fluorescence intensity is equivalent to the relative red fluorescence intensity of the untreated group. These results suggest that azelaic acid makes it possible to reestablish the mitophagy process after exposure of the cells to UVB (see Figure 4).

Claims

Claims1. The use, in particular cosmetic use, of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to increase the longevity of skin cells.

2. The use, in particular cosmetic use, of azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, to prevent and / or treat sign(s) of skin aging, in particular to:- improve skin quality, texture and / or appearance, and / or to combat environmental stress; and / or- reduce skin roughness, and / or prevent and / or reduce fine lines and wrinkles; and / or - improve skin suppleness, rebound and / or firmness; and / or- improve skin resilience, luminosity and / or health.

3. The use as claimed in claim 1 or 2, said sign of skin aging being chosen from the group consisting of wrinkles, fine lines, wizened skin, flaccid skin, thinned skin, lack of elasticity, lack of resilience, lack of luminosity and / or lack of tone of the skin.

4. The use as claimed in any one of the preceding claims, said use making it possible to prevent or reduce mitochondrial dysfunctions and / or stimulate mitochondrial metabolism in skin cells.

5. The use as claimed in any one of the preceding claims, said use making it possible to increase the maximum respiration of skin cells.

6. The use as claimed in any one of the preceding claims, said use making it possible to increase the process of mitophagy in skin cells.

7. The use as claimed in any one of the preceding claims, wherein azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, is present in a composition, in particular in a cosmetic composition, also comprising a physiologically acceptable medium.

8. The use as claimed in claim 7, wherein azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, is present in said composition in an amount greater than or equal to 0.01% by weight, greater than or equal to 0.1% by weight, better still greater than or equal to 0.5% by weight relative to the total weight of the composition.

9. The use as claimed in claim 7 or 8, characterized in that the composition is topical, and in particular:(i) liquid, preferably chosen from creams, emulsions, lotions, dispersions, solutions, gels, balms and serums; or(ii) solid, preferably selected from masks and sticks.

10. A non-therapeutic cosmetic process for caring for keratin materials, in particular the skin, comprising the topical application to these keratin materials of a composition, in particular a cosmetic composition, comprising azelaic acid, an organic or inorganic base salt thereof, a solvate thereof, or mixtures thereof, and a physiologically acceptable medium.

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