Preventive, therapeutic, or ameliorative agents for inflammatory skin diseases

Abstract

This invention provides a preventive, therapeutic, or ameliorative agent for inflammatory skin diseases. The preventive, therapeutic, or ameliorative agent for inflammatory skin diseases of this invention uses an oil containing 40% or more α-linolenic acid and 25% or more diglycerides as its active ingredient.

Description

Technical Field

[0001] This invention relates to a preventive, therapeutic, or ameliorative agent for inflammatory skin diseases such as atopic dermatitis. Prior Technology

[0002] Atopic dermatitis (AD) is a skin disease characterized by inflammation, caused by either genetic or environmental factors. Recent research has clarified that the development of atopic dermatitis is related to both immunological abnormalities and defects in the skin barrier function. The skin barrier function is primarily supported by the stratum corneum or the sebum film covering its surface. These layers function normally to prevent moisture loss and to protect against the invasion of various irritants or substances from the external environment. However, in atopic dry skin, a common symptom in atopic dermatitis patients, the skin barrier function is impaired. This leads to a vicious cycle where environmental allergens or irritants invade, causing eczema, worsening, and triggering itching, resulting in a chronic and refractory condition. Abnormalities in skin barrier function are also significant in patients with psoriasis vulgaris or other similar skin conditions. Therefore, the key to treating atopic dermatitis is to suppress inflammation while simultaneously normalizing the skin barrier function to alleviate symptoms.

[0003] Alpha-linolenic acid (C18:3, ALA) is a highly unsaturated omega-3 fatty acid that is abundant in linseed oil or perilla seed oil. Alpha-linolenic acid has been reported to have anti-atherosclerotic, antihypertensive, and anti-allergic effects. Furthermore, the transepidermal water evapotranspiration (TEWL) values ​​of dry and sensitive skin improved by consuming linseed oil have been reported (Non-Patent Literature 1). On the other hand, reports indicate that oils containing high concentrations of diglycerides have physiological effects such as inhibiting the increase of triglycerides (neutral fats) in the blood after eating and having less accumulation in the body. For example, Patent Document 1 reports an oil composition in which 15-90% by weight of the structural fatty acids are ω3 unsaturated fatty acids with less than 20 carbons, and the weight ratio of cis-ω3 unsaturated fatty acids to (cis-ω6 unsaturated fatty acids + saturated fatty acids + trans unsaturated fatty acids) is 1-6, and the content of diglycerides is 60-100% by weight. This oil composition has excellent visceral fat burning and body fat burning properties. However, it is not yet known that oils containing a high amount of diglycerides, which are a structural fatty acid, are useful for the prevention or treatment of inflammatory skin diseases such as atopic dermatitis.

[0004] (Patent Document 1) Japanese Patent Application Publication No. 2002-138296

[0005] (Non-patent literature 1) Jean-Marc Maurette. OCL. 2008, 15(4), 257-261 Summary of the Invention

[0006] That is, the present invention relates to any of the following 1) to 12). 1) A preventive, therapeutic or ameliorative agent for inflammatory skin diseases, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass. 2) A skin barrier function improver, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass. 3) A food for the prevention or improvement of inflammatory skin diseases, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass. 4) A food product for improving skin barrier function, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass. 5) An oil for use in the manufacture of a preventive, therapeutic or ameliorative agent for inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 6) An oil used for the prevention, treatment or improvement of inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 7) A non-therapeutic use of an oil for the prevention, treatment or improvement of inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 8) An oil for use in the manufacture of a skin barrier function improver, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 9) An oil used to improve skin barrier function, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 10) A non-therapeutic use of an oil for improving skin barrier function, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. 11) A method for the prevention, treatment or improvement of an inflammatory skin disease, wherein an oil comprising fatty acids of 40% or more alpha-linolenic acid and 25% or more diglycerides is applied to or used on a subject. 12) A method for improving skin barrier function, wherein an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass is applied to or used on a subject. Simple Explanation of the Diagram

[0007] Figure 1 is a chart showing the changes in dermatitis score (AD). Figure 2 is a chart showing the changes in the thickness of the auricle. Figure 3 is a graph showing the changes in transepidermal water evapotranspiration (TEWL). Figure 4 is a chart showing the analysis results of cytokine expression at the site of dermatitis. Implementation

[0008] This invention relates to providing a preventive, therapeutic, or ameliorative agent for inflammatory skin diseases.

[0009] The inventors evaluated the effectiveness of a diglyceride-containing oil with a high content of α-linolenic acid in a mouse model of atopic dermatitis. The results showed that in mice fed a diet supplemented with a diglyceride-containing oil with a high content of α-linolenic acid, dermatitis scores and ear thickening were inhibited, as was the increase in transepidermal water evapotranspiration (TEWL). Furthermore, the increase in various cytokines associated with inflammatory skin diseases was also inhibited. This suggests that the oil may be useful in preventing or treating inflammatory skin diseases such as atopic dermatitis.

[0010] According to the present invention, a medicine, food, etc., is provided that is effective in preventing, treating, or improving inflammatory skin diseases by inhibiting dermatitis and improving the skin barrier function.

[0011] In this invention, "oils and fats" refers to ester compounds of fatty acids and glycerol, including one or more of monoacrylic acid glycerol, diacrylic acid glycerol, and triacrylic acid glycerol. There are no particular restrictions on the type of oils and fats; any type is acceptable as long as it can be used as an edible oil.

[0012] The oil used in this invention is an oil in which the content of α-linolenic acid in the fatty acids constituting the oil is 40% by mass or more, and the content of diglycerides is 25% by mass or more. Hereinafter, in this specification, "oil in which the content of α-linolenic acid in the fatty acids constituting the oil is 40% by mass or more, and the content of diglycerides is 25% by mass or more" is sometimes simply referred to as "the oil of this invention".

[0013] The content of α-linolenic acid in the fatty acids of the oil constituting the present invention is 40% by mass or more, and from the viewpoint of physiological effects, it is preferably 45% by mass or more, more preferably 50% by mass or more, and even more preferably 52% by mass or more; and from the viewpoint of oxidative stability, it is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. The content of α-linolenic acid in the fatty acids constituting the oil is 40% to 80% by mass, preferably 45% to 80% by mass, more preferably 50% to 80% by mass, and even more preferably 50% to 70% by mass, further preferably 52% to 70% by mass, and further preferably 52% to 60% by mass. Furthermore, the fatty acid content in this specification refers to the content converted to free fatty acids.

[0014] In this invention, the structural fatty acids constituting the oils, other than α-linolenic acid, are not particularly limited and can be any type of saturated or unsaturated fatty acid. From the perspective of flavor and industrial productivity of oils, the content of unsaturated fatty acids in the fatty acids constituting oils is preferably 60% to 100% by mass, more preferably 70% to 100% by mass, further preferably 75% to 99% by mass, and even more preferably 80% to 98% by mass. From the perspective of physiological effects, the number of carbon atoms in unsaturated fatty acids is preferably 14 to 24, more preferably 16 to 22.

[0015] Regarding the content of linoleic acid (C18:2) in the fatty acids that constitute oils, from the point of view of industrial production, it is preferably 5% by mass or more, more preferably 10% by mass or more; and from the point of view of physiological effects, it is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less. The content of linoleic acid (C18:2) in the fatty acids that constitute the oil is preferably 5% by mass or more and 40% by mass, more preferably 10% by mass or more and 30% by mass, and even more preferably 10% by mass or more and 20% by mass.

[0016] Furthermore, regarding the content of oleic acid (C18:1) in the fatty acids that constitute oils, from the point of view of industrial production, it is preferably 10% by mass or more; and from the point of view of physiological effects, it is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. The content of oleic acid (C18:1) in the fatty acids that constitute oils is preferably 10% by mass or more and 50% by mass, more preferably 10% by mass or more and 40% by mass, and even more preferably 10% by mass or more and 30% by mass.

[0017] Regarding the total content of saturated fatty acids in the fatty acids constituting oils, from the viewpoint of appearance, physiological effects, and industrial productivity of oils, it is preferably 6.0% by mass or less, more preferably 5.5% by mass or less, and even more preferably 5.0% by mass or less; furthermore, from the viewpoint of industrial productivity, it is preferably 0.5% by mass or more. The total content of saturated fatty acids in the fatty acids constituting the oil is preferably 0.5% by mass or more and 6.0% by mass, more preferably 0.5% by mass or more and 5.5% by mass, and even more preferably 0.5% by mass or more and 5.0% by mass. There is no particular limitation on the type of saturated fatty acid, but it is preferred to be saturated fatty acid with 14 to 24 carbons, more preferably saturated fatty acid with 16 to 22 carbons, and even more preferably saturated fatty acid with 16, 18, or 20 carbons.

[0018] The content of diglycerides in the oil of the present invention is 25% by mass or more, and from the viewpoint of effectively presenting effects and physiological effects, it is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 83% by mass or more, and even more preferably 84% by mass or more; and preferably 96% by mass or less, even more preferably 95% by mass or less, and even more preferably 94% by mass or less. The content of diglycerides in the oil is preferably 25% by mass or more and 96% by mass, more preferably 30% by mass or more and 96% by mass, further preferably 50% by mass or more and 96% by mass, further preferably 50% by mass or more and 95% by mass, further preferably 55% by mass or more and 95% by mass, further preferably 60% by mass or more and 95% by mass, further preferably 65% ​​by mass or more and 95% by mass, further preferably 65% ​​by mass or more and 94% by mass, further preferably 70% by mass or more and 94% by mass, further preferably 80% by mass or more and 94% by mass, further preferably 83% by mass or more and 94% by mass, and further preferably 84% by mass or more and 94% by mass.

[0019] In this invention, the fatty acids constituting diacylglycerol can be either saturated or unsaturated fatty acids. If the content of α-linolenic acid in the fatty acids constituting diacylglycerol is 40% by mass or more, the effect is effectively achieved, which is preferred in this respect. Regarding the content of α-linolenic acid in the fatty acids constituting diglycerides, from the same point of view, it is preferably 45% by mass or more, more preferably 50% by mass or more, and even more preferably 52% by mass or more; and from the point of view of oxidative stability, it is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less. The content of α-linolenic acid in the fatty acids constituting diglycerides is 40% to 80% by mass, preferably 45% to 80% by mass, more preferably 50% to 80% by mass, and even more preferably 50% to 70% by mass, further preferably 52% to 70% by mass, and further preferably 52% to 60% by mass.

[0020] The oils and fats of the present invention may also contain triglycerides. From the point of view of the industrial production of oils and fats, the content is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more; and preferably 75% by mass or less, more preferably 72% by mass or less, more preferably 50% by mass or less, and even more preferably 25% by mass or less. The triglyceride content in the oil is preferably 1% to 75% by mass, more preferably 2% to 75% by mass, further preferably 2% to 72% by mass, further preferably 5% to 72% by mass, further preferably 5% to 50% by mass, and further preferably 5% to 25% by mass. Furthermore, from the perspective of flavor and industrial productivity of oils, the content of monoglycerides in oils is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1.51% by mass or less; more preferably more than 0% by mass. The content of monoglycerides in oils can also be 0% by mass. From the perspective of the industrial productivity of oils and fats, it is preferable that the fatty acid composition of triglycerides, diglycerides, and monoglycerides is the same.

[0021] The oils and fats of this invention may also contain free fatty acids or their salts in the form of impurities. From a flavor perspective, the content of free fatty acids or their salts in the oils and fats is preferably 3% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less; and more preferably more than 0% by mass. The content of free fatty acids or their salts in the oils and fats may also be 0% by mass.

[0022] The oils and fats of this invention can be obtained by conventional methods, such as esterification of fatty acids from oils and fats with glycerol, and transesterification of oils and fats with glycerol (glycerolysis). If necessary, they can also be mixed with common edible oils and fats. Esterification and glycerol hydrolysis reactions can be broadly classified into chemical methods using chemical catalysts such as alkali metals or their alloys, oxides or hydroxides of alkali metals or alkaline earth metals, and alkoxides of alkali metals or alkaline earth metals; and enzymatic methods using enzymes such as lipases. From the perspective of controlling fatty acid composition, the preferred method is the esterification reaction of fatty acids (fractionated fatty acids) obtained by hydrolyzing fats and oils with glycerol, as described later.

[0023] In this invention, the source of the oil is not particularly limited as long as it is usable as an edible oil; it can be either vegetable oil or animal oil. Examples include: soybean oil, rapeseed oil, safflower oil, rice oil, corn oil, sunflower seed oil, cottonseed oil, olive oil, sesame oil, peanut oil, coix seed oil, wheat germ oil, perilla oil, linseed oil, perilla oil, chia seed oil, sacha inchi oil, walnut oil, kiwi seed oil, sage seed oil, grape seed oil, macadamia nut oil, hazelnut oil, pumpkin seed oil, camellia oil, tea seed oil, borage seed oil, palm oil, palm oil, palm stearin, coconut oil, palm kernel oil, cocoa butter, balsamic oil, shea butter, algae oil, and other vegetable oils; fish oil, seal oil, lard, tallow, milk fat, and other animal oils; or transesterified oils, hydrogenated oils, fractionated oils, and other oils. These oils can be used individually or in appropriate mixtures. From a usability standpoint, vegetable oils are preferred, and even more preferably, liquid oils with excellent low-temperature resistance. Furthermore, oils selected from one or more of the group consisting of perilla oil, linseed oil, and sesame oil are rich in α-linolenic acid and are therefore preferred. Moreover, liquid oils refer to oils that are liquid at 20°C after a cooling test according to the Standard Oil Analysis Test Method 2.3.8-27. Additionally, edible oils are preferably refined oils that have undergone a refining process.

[0024] Fatty acids from oils and fats can be obtained by hydrolyzing the oils and fats. Examples of methods for hydrolyzing oils and fats include: high-temperature, high-pressure (HTHP) decomposition and enzymatic decomposition. HTHP involves adding water to the oils and fats and then reacting them under high temperature and high pressure to obtain fatty acids and glycerol. Enzymatic decomposition involves adding water to the oils and fats and then using oil-hydrolyzing enzymes as catalysts to react them under low temperature conditions to obtain fatty acids and glycerol. Hydrolysis can be carried out using common methods.

[0025] After hydrolyzing the oil, it is preferable to fractionate the hydrolysis products to remove the solids. Examples of fractionation methods include: solvent fractionation, natural fractionation (drying fractionation), and wetting agent fractionation. Examples of methods for removing precipitated solids include: static separation, filtration, centrifugation, and separation by mixing a wetting agent aqueous solution with fatty acids.

[0026] The esterification reaction of fatty acids from oils and glycerol is superior in terms of flavor and other aspects if carried out using an enzymatic method under mild conditions. The amount of enzyme used can be appropriately determined based on the enzyme activity. From the point of view of improving the reaction rate, when using immobilized enzymes, the amount of enzyme used relative to the total mass of the esterification reaction raw materials is preferably 1 to 30% by mass, and more preferably 2 to 20% by mass. From the perspective of increasing reaction rate and inhibiting enzyme inactivation, the reaction temperature of esterification reaction is preferably 0~100℃, more preferably 20~80℃, and even more preferably 30~60℃; and from the perspective of industrial production, the reaction time is preferably within 15 hours, more preferably 1~12 hours, and even more preferably 2~10 hours. Examples of methods for contacting fatty acids and glycerol include: impregnation, stirring, and passing liquid through a column filled with immobilized lipase using a pump.

[0027] Following the esterification reaction, refining steps typically used for oils and fats can be performed. Examples of such steps include distillation, acid treatment, washing, decolorization, and deodorization.

[0028] As described in the following examples, when the oil of the present invention was administered to mice with atopic dermatitis, the dermatitis score indicating the progression of atopic dermatitis and the thickening of the auricle were inhibited, and the increase in transepidermal water evapotranspiration (TEWL) was also inhibited. Furthermore, mRNA expression analysis of the skin at the dermatitis-inducing site was performed, and the results showed that in the group that ingested the oil of the present invention, the increase in expression of IL-4 (the main Th2 cytokine) and IL-1β, IL-6, TSLP, and IL-33 (cytokines secreted by naturally immune cells or keratinocytes) was inhibited. Regarding the aforementioned cytokines whose increased expression is inhibited by the oils of this invention, it has been reported that they not only contribute to atopic dermatitis, but also to the reduction of inflammatory response or barrier function in various inflammatory skin diseases such as seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, and erythema nodosum (References: Adalsteinsson JA, Kaushik S, et al. Exp Dermatol. 2020 May; 29(5):481-489, Lee HY, et al. Mediators Inflamm. 2013;2013:916497, Belge K, et al. F1000Prime Rep. 2014 Jan 2;6:4, Hanel KH, et al. Int J Mol Sci. 2013 Mar 26;14(4):6720-45, Polycarpou A, et al. Front Immunol. 2017 Mar 13;8:233). Therefore, the oils of the present invention can be used as a preventive, therapeutic or ameliorative agent for inflammatory skin diseases, or a skin barrier function improver (hereinafter also referred to as "preventive, therapeutic or ameliorative agent for inflammatory skin diseases, etc."), and can be used to prevent, treat or improve inflammatory skin diseases, or improve skin barrier function. Furthermore, they can be used to manufacture preventive, therapeutic or ameliorative agents for inflammatory skin diseases, etc. Here, "use" can refer to use on humans or non-human animals, and can be for therapeutic or non-therapeutic purposes. "Non-therapeutic" means excluding medical procedures, that is, excluding methods of performing surgery, treatment or diagnosis on humans. More specifically, it excludes the concept of methods of performing surgery, treatment or diagnosis on humans by physicians, medical practitioners, or persons under the instruction of physicians.

[0029] Examples of "inflammatory skin diseases" for which this instruction manual is applicable include: atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, and xerotica. Among these, it is suitable for atopic dermatitis. "Atopic dermatitis" refers to a chronic, progressive disease characterized by recurring exacerbations and remissions, accompanied by itching, as the primary lesion.

[0030] "Skin barrier function" refers to the function of preventing moisture from evaporating from the inside of the skin and preventing substances from penetrating the skin from the outside. This invention is suitable for improving the function of preventing moisture from evaporating from the inside of the skin (moisture penetration barrier function). By improving the skin barrier function, it is possible to treat or improve dry skin (sebaceous dermatitis), sebaceous eczema, and other conditions caused by a weakened skin barrier function.

[0031] "Prevention" refers to preventing or delaying the onset of an individual's disease or symptoms, or reducing the risk of developing an individual's disease or symptoms. "Improvement" refers to the improvement of a disease, symptom, or condition; the prevention or delay of the worsening of a disease, symptom, or condition; or the reversal, prevention, or delay of the progression of a disease or symptom. Furthermore, "treatment" includes not only the cure of the disease, but also the improvement of symptoms.

[0032] The preventive, therapeutic, or ameliorative agents for inflammatory skin diseases of the present invention can themselves be used as pharmaceuticals, quasi-medicines, cosmetics, foods, or feeds for the prevention, treatment, or amelioration of inflammatory skin diseases or for improving skin barrier function. They can also be used as materials or preparations formulated into such pharmaceuticals, quasi-medicines, cosmetics, foods, or feeds.

[0033] The pharmaceutical product (including quasi-pharmaceuticals, hereinafter the same) contains the oil of the present invention as an effective ingredient for the prevention, treatment or improvement of inflammatory skin diseases, or for improving skin barrier function. Furthermore, as long as the function of the effective ingredient is not lost, the pharmaceutical product may also contain pharmaceutically permissible carriers, or other effective ingredients, pharmacological components, etc., as needed. Pharmaceuticals can be administered in any form. Examples of administration forms include: oral solid dosage forms such as tablets (including chewable tablets), capsules, granules, powders, and lozenges; oral liquid dosage forms such as oral liquids and syrups; and non-oral dosage forms such as injections, suppositories, inhalers, transdermal absorbents, and topical preparations. Oral administration is preferred. The form and size can be adjusted according to the intended use. The formulations of the above-mentioned dosage forms may be appropriately combined with pharmaceutically permissible carriers, such as excipients, binders, expanders, disintegrants, surfactants, lubricants, dispersants, buffers, osmotic pressure adjusters, pH adjusters, emulsifiers, preservatives, stabilizers, preservatives, thickeners, flow improvers, flavoring agents, foaming agents, fragrances, coating agents, diluents, etc., or other active pharmaceutical ingredients, as needed, and prepared according to commonly used methods.

[0034] This cosmetic contains the oil of this invention as an effective ingredient for preventing or improving inflammatory skin diseases or for improving skin barrier function. Furthermore, as long as the function of the effective ingredient is not lost, the cosmetic may also contain carriers permitted by cosmetics, or other effective ingredients, pharmaceutical ingredients, cosmetic ingredients, etc., as needed. Preferred examples of cosmetics containing the oils of the present invention include: facial and body cosmetics (e.g., lotions, gels, creams, masks, etc.); cosmetics for makeup; facial or body bath products, etc. The formulations of the aforementioned cosmetics can be manufactured using common methods. Examples of permissible carriers for cosmetics include: various oils, surfactants, gelling agents, buffers, preservatives, antioxidants, solvents, dispersants, chelating agents, thickeners, UV absorbers, emulsion stabilizers, pH adjusters, pigments, and fragrances. Other active ingredients, pharmaceutical ingredients, and cosmetic ingredients include, for example, plant extracts, bactericides, moisturizers, anti-inflammatory agents, antibacterial agents, keratolytic agents, cooling agents, anti-seborrheic agents, cleansers, and cosmetic ingredients.

[0035] This food contains the oils of this invention as an effective ingredient for preventing or improving inflammatory skin diseases or for improving skin barrier function. Food products include those claiming to prevent or improve symptoms of inflammatory skin diseases or improve skin barrier function, and for which labeling of this claim is permitted or applied for (such as foods for specific health uses, functional foods, and foods for special purposes). Examples of labeling include "has the function of helping to maintain skin moisture to relieve dryness" or "has the function of improving skin discomfort." Food products with permitted or applied-for functional labeling can be distinguished from ordinary foods. Food can be in solid, semi-solid, or liquid form (e.g., beverages). Examples include various food compositions (bread, cakes, noodles, pastries, frozen foods, ice cream, candies, rice seasonings, soups, dairy products, milkshakes, beverages, seasonings, etc.), and further examples include nutritional supplement compositions in the same form as the above-mentioned orally administered preparations (granules, powders, tablets, capsules, microcapsules, lozenges, etc., solid preparations). Various forms of food can be prepared by appropriately combining the oils of the present invention with any food materials, other active ingredients, or food-permitted additives (e.g., solvents, softeners, oils, emulsifiers, preservatives, acidulants, sweeteners, bittereners, pH adjusters, stabilizers, colorants, ultraviolet absorbers, antioxidants, humectants, thickeners, fixatives, dispersants, flow improvers, wetting agents, flavorings, seasonings, flavor modifiers), and following commonly used methods.

[0036] The feed may contain the oils of this invention as an effective ingredient for preventing or improving inflammatory skin diseases or for improving skin barrier function. As a form of feed, it is preferable to be granular, flake, paste, or liquid. Examples include: feed for livestock such as cattle, pigs, chickens, sheep, and horses; feed for small animals such as rabbits, rats, and mice; and pet food for dogs, cats, and birds. The feed can be prepared by appropriately combining the oil of the present invention with other feed materials, such as meat, protein, grains, bran, meal, sugar, vegetables, vitamins, minerals, gelling agents, shape retention agents, pH adjusters, seasonings, preservatives, and nutritional supplements, and by following common methods.

[0037] The content of the oil in the formulation of the present invention varies depending on the form of the formulation, and therefore cannot be generalized. For example, based on the total amount of the formulation, it is preferably 0.5% by mass or more, and more preferably 99.8% by mass or less.

[0038] The amount of oil or fat used in this invention can be the amount that achieves the effects of this invention. The amount of oil or fat used can vary depending on the type, weight, sex, age, condition, or other factors of the subject. In the case of oral administration (ingestion), the amount of oil or fat used in this invention is calculated as 0.3 to 15 g per adult (60 kg) per dose. The above-mentioned preparations can be administered or used according to any administration schedule, once a day to several times, repeatedly or continuously for more than 1 day, preferably more than 7 days, more preferably more than 14 days, and even more preferably more than 30 days.

[0039] The preventive, therapeutic, or ameliorative agents for inflammatory skin diseases of the present invention are preferably administered or used in the form of an oil-based composition. When the preventive, therapeutic, or ameliorative agents for inflammatory skin diseases are in the form of an oil composition, from the point of view of usability, the oil content of the present invention in the oil composition is preferably 90% by mass or more, more preferably 95% by mass or more; and preferably 100% by mass or less, more preferably 99.9% by mass or less.

[0040] From the perspectives of flavor, oxidative stability, and color inhibition, the oil composition preferably contains antioxidants. From the perspectives of flavor, oxidative stability, and color inhibition, the content of antioxidants in the oil composition is preferably 0.005% by mass or more and 1.0% by mass, more preferably 0.04% by mass or more and 0.75% by mass, and even more preferably 0.08% by mass or more and 0.5% by mass. As an antioxidant, there are no particular restrictions as long as it is used in food, but it is preferred to be selected from at least one of the following: natural antioxidants, lecithin, vitamin E, ascorbate palmitate, ascorbate stearate, butylated hydroxytoluene (BHT), and butylated hydroxymethoxybenzene (BHA).

[0041] Examples of recipients of the present invention for the prevention, treatment, or improvement of inflammatory skin diseases include: humans who require prevention, treatment, or improvement of inflammatory skin diseases, preferably atopic dermatitis; and humans who require improvement of skin barrier function. Examples of non-human animals include: apes, other primates, and other non-human mammals.

[0042] In relation to the above embodiments, the present invention further discloses the following features.

[0043] <1> An agent for the prevention, treatment or improvement of inflammatory skin diseases, wherein the active ingredient is an oil containing 40% or more α-linolenic acid and 25% or more diglycerides in the fatty acids constituting the oil.

[0044] <2> A skin barrier function improver, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass.

[0045] <3> A food product for the prevention or improvement of inflammatory skin diseases, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass.

[0046] <4> A food product for improving skin barrier function, wherein the active ingredient is an oil containing α-linolenic acid of 40% or more by mass and diglycerides of 25% or more by mass.

[0047] <5> like <1> to <4> In any of the ingredients or foods described herein, the content of α-linolenic acid in the fatty acids constituting the oil is preferably 45% by mass or more, more preferably 50% by mass or more, and even more preferably 52% by mass or more; and preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 60% by mass or less; and preferably 40% by mass or more and 80% by mass or less, preferably 45% by mass or more and 80% by mass or less, more preferably 50% by mass or more and 80% by mass or less, and even more preferably 50% by mass or more and 70% by mass or less, and even more preferably 52% by mass or more and 70% by mass or less, and even more preferably 52% by mass or more and 60% by mass or less. <6> like <1> to <5> The content of linoleic acid (C18:2) in the fatty acids constituting the oil in any of the listed ingredients is preferably 5% by mass or more, more preferably 10% by mass or more; and preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less; and preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and even more preferably 10% by mass or more and 20% by mass or less. <7> like <1> to <6> The content of oleic acid (C18:1) in the fatty acids constituting the oil in any of the ingredients or foods described herein is preferably 10% by mass or more; more preferably 50% by mass or less, even more preferably 40% by mass or less, and further preferably 30% by mass or less; more preferably 10% by mass or more and 50% by mass or less, even more preferably 10% by mass or more and 40% by mass or less, and further preferably 10% by mass or more and 30% by mass or less. <8> like <1> to <7> In any of the preparations or food products described herein, the content of diglycerides in the oil is preferably 30% by mass or more, more preferably 50% by mass or more, further preferably 55% by mass or more, further preferably 60% by mass or more, further preferably 65% ​​by mass or more, further preferably 70% by mass or more, further preferably 80% by mass or more, further preferably 83% by mass or more, and further preferably 84% by mass or more; and preferably 96% by mass or less, more preferably 95% by mass or less, and further preferably 94% by mass or less; and preferably 25% by mass or more and 96% by mass or less, more preferably 30% by mass or more. The content is preferably 6% or less, and more preferably 50% or more and 96% or less, more preferably 50% or more and 95% or less, more preferably 55% or more and 95% or less, more preferably 60% or more and 95% or less, more preferably 65% ​​or more and 95% or less, more preferably 65% ​​or more and 94% or less, more preferably 70% or more and 94% or less, more preferably 80% or more and 94% or less, more preferably 83% or more and 94% or less, and more preferably 84% or more and 94% or less. <9> like <1> to <8> In any of the preparations or foods described herein, the content of α-linolenic acid in the fatty acids constituting diglycerides is preferably 40% by mass or more, more preferably 45% by mass or more, further preferably 50% by mass or more, and further preferably 52% by mass or more; also, preferably 80% by mass or less, more preferably 70% by mass or less, and further preferably 60% by mass or less; also, preferably 40% by mass or more and 80% by mass or less, more preferably 45% by mass or more and 80% by mass or less, further preferably 50% by mass or more and 80% by mass or less, and further preferably 50% by mass or more and 70% by mass or less, further preferably 52% by mass or more and 70% by mass or less, and further preferably 52% by mass or more and 60% by mass or less. <10> like <1> , <3> , <5> to <9> The inflammatory skin disease described in any of the above items is preferably atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, or dry skin, more preferably atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, or erythema nodosum, and even more preferably atopic dermatitis. <11> like <2> , <4> , <5> to <9> Of the agents or foods listed in any of the above, the one with better skin barrier function is the water penetration barrier function.

[0048] <12> An oil for use in the manufacture of a preventive, therapeutic or ameliorative agent for inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <13> An oil used for the prevention, treatment or improvement of inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <14> A non-therapeutic use of an oil for the prevention, treatment or improvement of inflammatory skin diseases, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <15> like <12> to <14> The oil or use described in any of the above, preferably for inflammatory skin diseases such as atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, or dry skin, more preferably atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, or erythema nodosum, and even more preferably atopic dermatitis.

[0049] <16> An oil for use in the manufacture of a skin barrier function improver, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <17> An oil used to improve skin barrier function, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <18> A non-therapeutic use of an oil for improving skin barrier function, wherein the oil comprises fatty acids having an α-linolenic acid content of 40% by mass or more and a diglyceride content of 25% by mass or more. <19> like <16> to <18> Of the oils or uses described in any one of them, the one with better skin barrier function is the water penetration barrier function. <20> like <12> to <19> The fat or use described in any of the above items, wherein the content of α-linolenic acid in the fatty acids constituting diglycerides is 40% by mass or more.

[0050] <21> A method for the prevention, treatment, or improvement of an inflammatory skin disease involves applying an oil containing 40% or more alpha-linolenic acid and 25% or more diglycerides to a target. <22> like <21> The methods described herein are preferably for inflammatory skin diseases such as atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, heat rash, folliculitis, infantile eczema, or dry skin, and more preferably for atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, or erythema nodosum, and even more preferably for atopic dermatitis.

[0051] <23> A method for improving skin barrier function involves applying or dispensing an oil containing 40% or more α-linolenic acid and 25% or more diglycerides to a target. <24> like <23> Of the methods described, the skin barrier function is better in terms of moisture penetration barrier function. <25> like <21> to <24> The method described in any one of them, wherein the content of α-linolenic acid in the fatty acids constituting diglycerides is 40% by mass or more. [Example]

[0052] Example 1 [Preparation of oils and special feeds] Flaxseed oil (manufactured by Archer Daniels Midland) was hydrolyzed using enzymes. The resulting fatty acids were then cooled and centrifuged to obtain fractionated fatty acids. 300 parts by weight of the obtained fractionated fatty acids were mixed with 47 parts by weight of glycerol, and an esterification reaction was carried out using a commercially available immobilized 1,3-selective lipase (Novozymes) as a catalyst. After filtration to separate the immobilized enzyme, the final product was subjected to molecular distillation, acid treatment, and washing with water to obtain processed oil. After deodorizing the processed oil, an antioxidant was added to prepare a diacryloylglycerol (DAG) oil (lin-DAG) from flaxseed oil.

[0053] We prepared DAG oil (lin-DAG) from linseed oil, linseed oil (lin-TAG, manufactured by Summit Oil Mill), and soybean oil (soy-TAG, manufactured by Nisshin OilliO Group Co., Ltd.) as a control, using the method described above. Furthermore, the same concentration of antioxidant was added to lin-TAG and soy-TAG, similar to lin-DAG. AIN-93G (Oriental Yeast Co., Ltd.), which is used as mouse feed, has its original soybean oil (7% by mass) and corn starch (3% by mass) removed. Then, 10% by mass of any of the above-mentioned oils is added to the resulting product to prepare three special feeds. The glycerol and fatty acid compositions of lin-DAG, lin-TAG, and soy-TAG are shown in Table 1. Furthermore, the C18:3 unsaturated fatty acid in the fatty acid composition of Table 1 is α-linolenic acid.

[0054] [Table 1] Analysis Project lin-DAG lin-TAG soy-TAG Glyceryl ester composition MAG [%] 1.4 0.0 0.1 DAG [%] 84.3 2.5 1.4 TAG [%] 13.9 97.5 98.5 Fatty acid composition C14:0 [%] 0.0 0.1 0.1 C16:0 [%] 2.7 5.6 10.6 C16:1 [%] 0.1 0.1 0.1 C18:0 [%] 1.6 4.8 3.9 C18:1 [%] 23.2 19.9 24.8 C18:2 [%] 16.0 15.8 51.7 C18:3 [%] 54.8 52.5 7.1 C20:0 [%] 0.1 0.2 0.4 C20:5 [%] 0 0 0 C22:0 [%] 0.2 0.2 0.5 C22:6 [%] 0 0 0 other [%] 1.2 1.0 0.9

[0055] The analytical methods for the composition of glycerides and fatty acids are shown below. (i) Glyceryl ester composition of fats and oils Approximately 10 mg of the oil sample and 0.5 mL of a trimethylsilylating agent (“Silylating Agent TH”, manufactured by Kanto Chemical) were added to a glass sample bottle. After sealing, the mixture was heated at 70 °C for 15 minutes. 1.0 mL of water and 1.5 mL of hexane were added thereto, and the mixture was shaken. After standing, the upper layer was subjected to gas chromatography (GLC) analysis. <GLC Analysis Conditions> (Conditions) Apparatus: Agilent 6890 series (manufactured by Agilent Technologies) Integrator: Chem-Station B 02.01 SR2 (manufactured by Agilent Technologies) Column: DB-1ht 10 m × 0.25 mm × 0.2 μm (manufactured by Agilent J&W) Carrier gas: Helium at 1.0 mL / min Syringe: Split (1:50), T = 340 °C Injection volume: 1 μL Detector: FID (Flame ionization detector), T = 350 °C Oven temperature: Heated from 80 °C at 10 °C / min to 340 °C and then held for 15 minutes

[0056] (ii) Structural fatty acid composition of the oil Fatty acid methyl esters were prepared in accordance with the “Method for Preparation of Fatty Acid Methyl Esters (2.4.1.-1996)” in the “Standard Oil Analysis Test Methods” edited by the Japanese Oil Chemists' Society. For the obtained oil sample, determination was carried out in accordance with the American Oil Chemists' Society Official Method Ce 1f-96 (GLC method). <GLC Analysis Conditions> Column: CP-SIL88 50 m × 0.25 mm × 0.2 μm (VARIAN) ?Carrier gas: Helium at 1.0 mL / min Syringe: Split (1:50), T = 300 °C Injection volume: 1 μL Detector: FID, T = 300 °C Oven temperature: Hold at 150℃ for 5 min → Increase temperature by 1℃ / min → Hold at 160℃ for 5 min → Increase temperature by 2℃ / min → Hold at 200℃ for 10 min → Increase temperature by 10℃ / min → Hold at 220℃ for 5 min

[0057] The fatty acid composition of diglycerides in lin-DAG, lin-TAG, and soy-TAG is shown in Table 2.

[0058] [Table 2] Analysis Project lin-DAG lin-TAG soy-TAG Fatty acid composition C14:0 [%] 0 0 0 C16:0 [%] 2.5 6.9 13.4 C16:1 [%] 0.1 0 0 C18:0 [%] 1.4 4.8 5.5 C18:1 [%] 23.0 25.1 19.5 C18:2 [%] 16.0 21.7 50.5 C18:3 [%] 56.3 38.1 5.1 C20:0 [%] 0.1 0.5 0.9 C20:5 [%] 0 0 0 C22:0 [%] 0.1 0.8 1.3 C22:6 [%] 0 0 0 Others [%] 0.6 2.2 3.7

[0059] The analysis method of the fatty acid composition of diacylglycerol is as follows. After extracting the DAG component from each oil sample and derivatizing it, it is analyzed by gas chromatography (GLC method) under the following conditions. At this time, the measurement method is based on the official method Ce 1f-96 of the American Oil Chemists' Society (AOCS). Furthermore, the unsaturated fatty acid C18:3 in the fatty acid composition of Table 2 is α-linolenic acid. <GLC analysis conditions> Instrument: Agilent 7890B (manufactured by Agilent Technologies) Column: CP-Sil 88 for FAME 50 m×0.25 mm×0.2 μm (manufactured by Agilent Technologies) Carrier gas: Helium 1.0 mL / min Syringe: Split (1:50), T = 300 °C Injection volume: 1 μL Detector: FID, T = 300 °C Oven temperature: Hold at 150 °C for 5 min → Heat at 1 °C / min → Hold at 160 °C for 5 min → Heat at 2 °C / min → Hold at 200 °C for 10 min → Heat at 10 °C / min → Hold at 220 °C for 5 min

[0060] [Experiment Summary] (1) Thirty-two male NC / Nga mice were divided into four groups: a non-sensitized group (soy-TAG(-) group) and a transdermal sensitized group (soy-TAG(+) group, lin-TAG(+) group, and lin-DAG(+) group) (N=8 in each group). The transdermal sensitized mice were allowed to freely consume any one of the three special diets mentioned above. Meanwhile, the non-sensitized mice were allowed to freely consume a special diet containing soy-TAG. After 30 days, for the transdermal sensitized mice, 100 mg of Biostir AD ointment (Biostir Inc.) containing the allergen from house dust mites was evenly applied to the back of the neck and auricle of the mice. Four days after the first application of Biostir AD, 150 μL of 4% sodium dodecyl sulfate (SDS) aqueous solution was evenly applied to the back of the neck and auricle of mice to induce rough skin. Subsequently, 100 mg of Biostir AD ointment was applied evenly to the same area again. For non-sensitized mice, no Biostir AD ointment was applied, only SDS aqueous solution. This procedure was repeated twice a week for four more times to induce atopic dermatitis. Twenty-two days after the first application of Biostir AD ointment, mice were euthanized under isoflurane anesthesia and cardiac blood sampling to collect skin from the back of the neck, the site of dermatitis induction. Before the first application of Biostir AD ointment and 7, 14, and 21 days after application, visual evaluation of dermatitis scores, measurement of auricular thickness, measurement of transepidermal water evapotranspiration (TEWL) using a Tewameter (registered trademark) TM300 (Courage+Khazaka electronic GmbH), and analysis of the mRNA expression of various cytokines in the skin at the dermatitis-inducing site were performed.

[0061] The dermatitis score (AD score) is evaluated based on the indicators in Table 3 below. Each indicator is evaluated on four items (0-3 points each): i) redness and bleeding, (ii) crust formation and dryness, (iii) edema, and (iv) abrasion and tissue loss. The total score obtained (0-12 points) is used as the final dermatitis score.

[0062] [Table 3] Score Redness and bleeding Scab formation and drying edema abrasions and tissue loss 0 Asymptomatic Asymptomatic Asymptomatic Asymptomatic 1 Localized redness was visible on the back, but there was no bleeding from continuous abrasions. There are visible scabs on the back, the skin is slightly whitened, and there is slight peeling of the stratum corneum. A certain thickness is visible on either the left or right side. Discontinuous abrasions are visible on the auricle, but no tissue loss is observed. 2 Scattered redness may be visible on the back, or there may be no bleeding accompanied by continuous abrasions. Scattered scabs are visible on the back, or there is obvious peeling of the stratum corneum. Both auricles show obvious thickness and a bulging appearance. Small, continuous abrasions were visible on the auricle, with no tissue loss observed. 3 The back is visibly red, or there may be bleeding accompanied by continuous abrasions. It is visible that there are scabs all over the back, or obvious signs of keratin peeling. Both auricles show obvious thickness, bulging, and warping, and feel firm to the touch. Continuous abrasions are visible on the auricle, and tissue loss is also evident.

[0063] The analysis of mRNA expression in the skin at the site of dermatitis was based on the following. Total RNA was extracted from skin samples collected from the back of the neck using the RNeasy Mini Kit (QIAGEN) according to the recommended operating instructions. cDNA was synthesized from the obtained total RNA using the SuperScript™VILO™ cDNA Synthesis Kit (Thermo Fisher Scientific) according to the recommended operating instructions. Subsequently, real-time PCR (Polymerase Chain Reaction) was performed using the obtained cDNA to analyze the mRNA expression of various cytokines present in the skin at the site of dermatitis. In this real-time PCR, Taqman™ Fast Universal PCR Master Mix (2×) (Applied Biosystems) and the inherent Taqman™ probes of each gene were used to prepare samples for detecting mRNA expression levels. The Taqman™ probes used in the expression analysis of various cytokine genes are shown in Table 4 below. RPLP0 was used as an intrinsic control.

[0064] [Table 4] Gene name Assay ID IL-4 Mm00445259_m1 IL-1β Mm00434228_m1 IL-6 Mm00446190_m1 TSLP Mm01157588_m1 IL-33 Mm00505403_m1 RPLP0 Mm00725448_s1

[0065] (2) Results As shown in Figures 1, 2, and 3, compared to the non-sensitized soy-TAG(-) group, the soy-TAG(+) and lin-TAG(+) groups that consumed special diets containing soy-TAG and lin-TAG showed increased dermatitis scores, auricular hypertrophy, and transepidermal water evapotranspiration (TEWL). However, in the lin-DAG(+) group that consumed special diets containing lin-DAG, dermatitis scores, auricular hypertrophy, and TEWL were significantly inhibited. Furthermore, as shown in Figure 4, it was confirmed that the expression of IL-4, IL-1β, IL-6, TSLP, and IL-33 was significantly inhibited in the skin at the site of dermatitis induced by the lin-DAG(+) group. Reports indicate that these cytokines contribute to the reduction of inflammatory responses or barrier function in various inflammatory skin diseases, including seborrheic dermatitis, contact dermatitis, psoriasis, abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, and xerotica. Therefore, the oils of this invention are considered useful for the prevention, treatment, or improvement of various inflammatory skin diseases, including atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, and xerotica.

Claims

1. An oil for use in the manufacture of a preventive, therapeutic or ameliorative agent for inflammatory skin diseases, wherein the oil comprises an α-linolenic acid content of 40% by mass or more, a diglyceride content of 60% by mass or more, and an α-linolenic acid content of 40% by mass or more in the fatty acids constituting the diglyceride.

2. As claimed in claim 1, the inflammatory skin disease is atopic dermatitis, seborrheic dermatitis, contact dermatitis, psoriasis, sebaceous abscess eczema, erythema nodosum, neonatal acne / acne-like eruption, miliaria, folliculitis, infantile eczema, or dry skin.

3. As requested in item 1 or 2, wherein the content of α-linolenic acid in the fatty acids constituting diglycerides is 45% by mass or more.

4. An use of an oil for manufacturing an oral skin barrier function improver, wherein the oil comprises an α-linolenic acid content of 40% by mass or more, a diglyceride content of 60% by mass or more, and an α-linolenic acid content of 40% by mass or more in the fatty acids constituting the diglyceride.

5. As requested in item 4, the skin barrier function is the moisture penetration barrier function.

6. As claimed in paragraphs 4 or 5, wherein the content of α-linolenic acid in the fatty acids constituting diglycerides is 45% by mass or more.

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