Anti-anxiety composition

Abstract

The purpose of the present invention is to provide an anti-anxiety composition for humans and a method for preventing or improving anxiety symptoms. The present invention pertains to an anti-anxiety composition for humans that comprises L-ergothioneine or a salt thereof as an active ingredient.

Description

[Technical Field]

[0001] The present invention relates to an anti-anxiety composition. The present invention also relates to a method for preventing or ameliorating anxiety symptoms. [Background technology]

[0002] Anxiety is an unpleasant emotion such as vague fear with no clear target. If anxiety continues for some reason, it can cause problems in daily life and social life. Anxiety symptoms are seen in mental disorders such as anxiety disorders, but even people who have not been diagnosed with a mental illness can feel anxious due to stress in daily life.

[0003] Ergothioneine is an amino acid found in mushrooms and the like, and naturally exists in the L-form. Patent Document 1 describes that in a forced swimming test and a tail suspension test, mice fed with Pleurotus cornucopiae powder containing L-ergothioneine showed a significantly shorter immobility time than mice fed a normal diet. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-193844 Summary of the Invention [Problem to be solved by the invention]

[0005] When anxiety persists for a long period of time and interferes with daily life, anti-anxiety drugs may be used for treatment. However, due to concerns about side effects of anti-anxiety drugs, safer substances with anxiolytic effects are desired. Patent Document 1 describes that depressive symptoms were evaluated using the immobility time of mice in the above-mentioned forced swimming test and tail suspension test as an index, and the antidepressant effect of L-ergothioneine was confirmed. However, Patent Document 1 only shows the depressant effect in depression model animals, and the anxiolytic effect of L-ergothioneine in humans has not been investigated. It is difficult to predict whether anxiety symptoms will be prevented or improved when humans ingest L-ergothioneine based on the shortening of immobility time of mice in the above-mentioned forced swimming test and tail suspension test.

[0006] An object of the present invention is to provide an anti-anxiety composition for humans, and a method for preventing or ameliorating anxiety symptoms. [Means for solving the problem]

[0007] As a result of extensive research aimed at solving the above problems, the present inventors have found that ingestion of L-ergothioneine provides an anti-anxiety effect.

[0008] That is, although not limited thereto, the present invention relates to the following anti-anxiety compositions and the like. [1] An anti-anxiety composition for humans containing L-ergothioneine or a salt thereof as an active ingredient. [2] The composition described in [1] above, which suppresses activation of glutamate receptors. [3] The composition according to [1] or [2] above, which is an oral composition. [4] The composition according to any one of [1] to [3] above, which is a food or drink. [5] The composition according to any one of [1] to [4] above, wherein the content of L-ergothioneine or a salt thereof is 2 to 50 mg in terms of L-ergothioneine per daily intake for an adult. [6] A method for preventing or ameliorating anxiety symptoms, comprising administering L-ergothioneine or a salt thereof to a human. [7] Use of L-ergothioneine or a salt thereof for preventing or ameliorating anxiety symptoms in humans. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an anti-anxiety composition for humans. According to the present invention, it is possible to provide a method for preventing or ameliorating anxiety symptoms. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a graph showing the change in state anxiety score (Δ state anxiety (points)) in the test food group and the control food group. [Figure 2] FIG. 2 is a graph showing the actual measured values ​​of glutamic acid identified by blood metabolome measurement at the pre-test and the 4-week test. [Figure 3] FIG. 3 shows the results of evaluating the inhibitory activity of L-ergothioneine on substrate binding to nicotinic acetylcholine receptors (nAChRs). [Figure 4] FIG. 4 shows the results of evaluating the inhibitory activity of L-ergothioneine on substrate binding to the α3β4 nicotinic acetylcholine receptor at five concentrations. DETAILED DESCRIPTION OF THE INVENTION

[0011] The anti-anxiety composition of the present invention is a composition for anti-anxiety in humans and contains L-ergothioneine or a salt thereof as an active ingredient. Hereinafter, the anti-anxiety composition of the present invention may also be simply referred to as the composition of the present invention.

[0012] L-ergothioneine is a type of amino acid. The salt of L-ergothioneine is not particularly limited as long as it is a pharmacologically acceptable salt or a salt acceptable for use in foods and beverages, and may be either an acidic salt or a basic salt. Examples of acidic salts include inorganic acid salts such as hydrochloride, sulfate, nitrate, and phosphate; and organic acid salts such as acetate, citrate, maleate, malate, oxalate, lactate, succinate, fumarate, and propionate. Examples of basic salts include alkali metal salts such as sodium salt and potassium salt; and alkaline earth metal salts such as calcium salt and magnesium salt.

[0013] L-ergothioneine or its salts may be chemically synthesized or extracted and purified from natural sources. L-ergothioneine is found in large amounts in the Golden / Yellow Oyster mushroom (scientific name: Pleurotus cornucopiae var. citrinopileatus), a mushroom of the Pleurotus genus in the family Pleurocystis. L-ergothioneine is also found in mushrooms such as white button mushrooms, crimini mushrooms, and portabella mushrooms (Agaricus bisporus), grey oyster mushrooms (Pleurotus ostreatus), shiitake mushrooms (Lentinula edodes), maitake mushrooms (Grifola Frondosa), reishi mushrooms (Ganoderma lucidum), Yamabushitake mushrooms (Hericium erinaceus), willow matsutake mushrooms (Agrocybe aegerita), chanterelles (Cantharellus cibarius), porcini mushrooms (Boletus edulis), and morels (Morchella esculenta). When obtaining L-ergothioneine from a natural product, it is preferable to extract it from Pleurotus cornucopiae. L-ergothioneine or a salt thereof can also be produced by microbial fermentation. An extract containing L-ergothioneine or a salt thereof produced by microbial fermentation, or a product purified from such an extract, may be used. Extraction and purification from natural products can be carried out by known methods. L-ergothioneine or a salt thereof may be isolated.

[0014] L-ergothioneine or its salts are compounds that are found in natural products and foods and beverages and are consumed as food. Therefore, from a safety perspective, L-ergothioneine or its salts are thought to pose few problems, even when taken over a long period of time.

[0015] Anti-anxiety includes at least one of preventing anxiety symptoms and ameliorating anxiety symptoms. The anti-anxiety composition of the present invention can be used to prevent or ameliorate anxiety symptoms in humans, and is preferably used to ameliorate such symptoms. Anxiety symptoms include anxiety symptoms caused by stress, for example, temporary (short-term) anxiety symptoms caused by stress. In one embodiment, the composition of the present invention can be preferably used to prevent or ameliorate anxiety symptoms in humans experiencing stress, and is more preferably used to ameliorate such symptoms. The stress may be mental (psychological) stress. Anxiety can be divided into two types: state anxiety and trait anxiety. State anxiety refers to temporary anxiety felt in a specific situation. Generally, the stronger the stress and the longer the exposure to stress, the greater the state anxiety. Temporary anxiety symptoms caused by stress include anxiety symptoms of state anxiety. Trait anxiety refers to a tendency to become anxious due to a subject's personality, rather than the temporary anxiety felt in a specific situation, as in state anxiety. The composition of the present invention is preferably used for preventing or ameliorating anxiety symptoms of state anxiety in humans.

[0016] Anxiety symptoms are either emotional symptoms of anxiety or mental (cognitive) symptoms of anxiety. Emotional symptoms of anxiety include, for example, a sense of unease, fear, tension, worry, heartache, loneliness, etc. Emotional symptoms of anxiety may be one or more of these. Mental (cognitive) symptoms of anxiety include, for example, poor memory, lethargy, irritability, mental stress, mental agitation, and decreased positive thinking, etc. Mental symptoms of anxiety may be one or more of these. In one embodiment, the composition of the present invention can be used for preventing or ameliorating one or more anxiety symptoms such as anxiety, fear, tension, worry, heartache, loneliness, memory loss, lethargy, irritability, stress, mental agitation, decreased positive thinking, etc. In one embodiment, the composition of the present invention is preferably used for preventing or ameliorating (preferably ameliorating) temporary anxiety symptoms such as tension, fear, heartache, loneliness, decreased positive thinking, irritability, stress, and mental agitation that are caused by stress or in a person experiencing stress.

[0017] Human anxiety symptoms can be evaluated, for example, using the STAI State-Trait Anxiety Inventory (STAI). In the Examples described below, anxiety symptoms were evaluated using the STAI State-Trait Anxiety Inventory. In the STAI Y-1 state anxiety test, 20 items, including "feeling calm," "at ease," "tense," "stressed," "easygoing," "upset," "worried that something bad will happen," "contented," "fearful," "comfortable," "confident," "irritable," "hesitant," "relaxed," "satisfied," "worried," "confused," "settled," and "happy," are rated on a four-point scale ranging from "not at all true" to "very true." In one embodiment, the anti-anxiety composition of the present invention can be used to prevent or ameliorate anxiety symptoms of state anxiety evaluated by the STAI State-Trait Anxiety Inventory.

[0018] As shown in the examples below, ingestion of L-ergothioneine reduced the state anxiety score assessed by the STAI State-Trait Anxiety Inventory. This indicates that ingestion of L-ergothioneine improved anxiety symptoms. L-ergothioneine or a salt thereof has an anxiolytic effect and can be used as an active ingredient for preventing or ameliorating anxiety symptoms. Furthermore, ingestion of L-ergothioneine reduced blood glutamate levels compared to when not ingestion was performed. Glutamate is an excitatory neurotransmitter in the central nervous system. Furthermore, psychological stress has been reported to enhance glutamate signaling in the brain, and inhibiting glutamate receptor activation is expected to have an anti-psychotic stress effect. Lowering blood glutamate levels can inhibit glutamate receptor activation. In addition, L-ergothioneine has the effect of inhibiting the binding of substrates to nicotinic acetylcholine receptors such as α3β4 nicotinic acetylcholine receptors and α2α4 nicotinic acetylcholine receptors. For example, α3β4 nicotinic acetylcholine receptors are expressed in the brain, and inhibiting the binding of substrates to the receptors suppresses glutamate signals in the brain. Attenuating glutamate signals in the brain by inhibiting the activation of glutamate receptors, etc., can produce anxiolytic effects. Although the mechanism by which L-ergothioneine exerts the above-mentioned anxiolytic effect is unclear, it is presumed that the effect is exerted by suppressing activation of glutamate receptors through the action of lowering blood glutamate concentration and / or the inhibitory action of nicotinic acetylcholine receptors (e.g., α3β4 nicotinic acetylcholine receptors). The composition of the present invention can suppress activation of glutamate receptors and can be used for such purposes.

[0019] In one embodiment, the anti-anxiety composition of the present invention can be used to prevent or ameliorate conditions or diseases for which prevention or amelioration of anxiety symptoms is effective, such as anxiety disorders and adjustment disorders. Prevention includes preventing the onset, delaying the onset, reducing the incidence, reducing the risk of onset, etc. Improvement includes making the subject recover, alleviating symptoms, reducing the frequency of symptoms, improving symptoms, delaying progression, preventing, etc.

[0020] The compositions of the present invention can be used for either therapeutic (medical) or non-therapeutic (non-medical) purposes, the latter being a concept that does not include medical procedures, i.e., human surgery, treatment, or diagnosis. The anti-anxiety composition of the present invention can be provided in the form of a drug, for example, but is not limited to this form. The drug can be provided as a composition itself, or as a composition containing the drug. In one aspect, the anti-anxiety composition of the present invention for humans can also be referred to as an anti-anxiety drug for humans. From the viewpoint of fully achieving the effects of the present invention, the composition of the present invention is preferably an oral composition. Examples of oral compositions include foods and beverages, oral medicines, and quasi-drugs, and are preferably foods and beverages or oral medicines, and more preferably foods and beverages.

[0021] The composition of the present invention may contain any additives and any components in addition to L-ergothioneine or a salt thereof, as long as the effects of the present invention are not impaired. These additives and components can be selected depending on the form of the composition, and those that can generally be used for foods and beverages, pharmaceuticals, quasi-drugs, etc. can be used. When the composition of the present invention is made into a food or beverage, pharmaceutical, quasi-drug, etc., the production method thereof is not particularly limited, and it can be produced by a general method.

[0022] For example, when the composition of the present invention is made into a food or beverage, various foods and beverages can be prepared by blending L-ergothioneine or a salt thereof with ingredients that can be used in foods and beverages (e.g., food ingredients, food additives used as needed, etc.). The foods and beverages are not particularly limited, and examples include general foods and beverages, health foods, health drinks, functional foods, foods for specified health uses, health supplements, foods and beverages for patients, etc. The health foods, functional foods, foods for specified health uses, health supplements, etc. can be made into various dosage forms, such as fine granules, tablets, granules, powders, capsules, chewable tablets, syrups, liquids, and liquid diets.

[0023] When the composition of the present invention is used as a pharmaceutical or quasi-drug, for example, L-ergothioneine or a salt thereof can be blended with a pharmacologically acceptable carrier and, if necessary, additives to produce a pharmaceutical or quasi-drug in various dosage forms. Such carriers, additives, etc. may be any pharmacologically acceptable carriers that can be used in pharmaceuticals or quasi-drugs, and may include, for example, one or more of excipients, binders, disintegrants, lubricants, antioxidants, colorants, etc. The pharmaceutical or quasi-drug may be administered orally or parenterally, with oral administration being preferred from the viewpoint of more fully achieving the effects of the present invention. When the composition of the present invention is used as a pharmaceutical or quasi-drug, it is preferably an oral pharmaceutical or quasi-drug. Dosage forms for oral administration include liquids, tablets, powders, fine granules, granules, sugar-coated tablets, capsules, suspensions, emulsions, chewable tablets, etc. Dosage forms for parenteral administration include injections and infusions.

[0024] The content of L-ergothioneine or a salt thereof in the composition of the present invention is not particularly limited and can be set depending on the form, etc. The content of L-ergothioneine or a salt thereof in the composition of the present invention is, for example, preferably 0.0001% by weight or more, more preferably 0.001% by weight or more, and preferably 90% by weight or less, more preferably 50% by weight or less, calculated as L-ergothioneine. In one aspect, the content of L-ergothioneine or a salt thereof in the composition is preferably 0.0001 to 90% by weight, more preferably 0.001 to 50% by weight, calculated as L-ergothioneine. In one aspect, when the composition of the present invention is used as a food or drink, a pharmaceutical product, a quasi-drug, or the like, the content of L-ergothioneine or a salt thereof is preferably within the above-mentioned range. The amount converted to L-ergothioneine or similar expressions means the amount of L-ergothioneine, or in the case of a salt of L-ergothioneine, the value obtained by multiplying the number of moles of the salt by the molecular weight of L-ergothioneine.

[0025] The composition of the present invention can be ingested or administered by an appropriate method depending on its form. From the viewpoint of more fully obtaining the effects of the present invention, the composition of the present invention is preferably ingested orally (administered orally). The intake amount (which can also be called the administration amount) of the composition of the present invention is not particularly limited, and may be an amount that provides an anxiolytic effect, and may be appropriately determined depending on the administration form, administration method, body weight of the subject, etc.

[0026] In one embodiment, when the composition of the present invention is orally ingested or administered to a human (adult) subject, the daily intake of L-ergothioneine or a salt thereof is preferably 2 mg or more, more preferably 5 mg or more, even more preferably 10 mg or more, and preferably 50 mg or less, more preferably 25 mg or less, and even more preferably 20 mg or less, in terms of L-ergothioneine. In one embodiment, when the composition of the present invention is orally ingested or administered to a human (adult) subject, the daily intake of L-ergothioneine or a salt thereof is preferably 2 to 50 mg, more preferably 5 to 25 mg, even more preferably 5 to 20 mg, and particularly preferably 10 to 20 mg, in terms of L-ergothioneine. The above amount is preferably ingested or administered once or more times a day, for example, once a day or in divided doses (e.g., 2 to 3 times a day). In one embodiment of the present invention, the composition of the present invention may be an oral composition for ingesting or administering the above amount of L-ergothioneine or a salt thereof per 60 kg body weight per day to a human. In one aspect, when the composition of the present invention is parenterally administered to a human (adult), the dosage of L-ergothioneine or a salt thereof is, for example, preferably 2 to 50 mg, more preferably 5 to 25 mg, even more preferably 5 to 20 mg, and particularly preferably 10 to 20 mg, per day in terms of L-ergothioneine. In one embodiment, for humans (adults), it is preferable to have the subject ingest or administer the above amount of L-ergothioneine or a salt thereof per 60 kg of body weight per day.

[0027] In one aspect, the composition of the present invention preferably contains 2 to 50 mg of L-ergothioneine or a salt thereof per daily intake for an adult, more preferably 5 to 25 mg, even more preferably 5 to 20 mg, and particularly preferably 10 to 20 mg of L-ergothioneine per daily intake for an adult.

[0028] It is expected that L-ergothioneine or a salt thereof will exhibit a more excellent anxiolytic effect when continuously ingested or administered. Therefore, in a preferred embodiment, the composition of the present invention is continuously ingested or administered. In one embodiment of the present invention, the composition of the present invention is preferably continuously ingested or administered for one week or more, more preferably two weeks or more.

[0029] The subject to which the composition of the present invention is ingested or administered (which can also be referred to as an administration subject) is a human. Examples of subjects to which the composition of the present invention is ingested or administered include humans who need or desire prevention or amelioration of anxiety, humans who need or desire prevention or amelioration of stress-induced anxiety symptoms, and humans experiencing stress. In one embodiment, the administration subject includes humans with anxiety symptoms. In one embodiment, the administration subject includes humans with symptoms such as decreased positive thinking ability, tension, irritability, anxiety, mental agitation, and heartache. In one embodiment of the present invention, preferred examples of the administration subject include humans with symptoms such as temporary decreased positive thinking ability, tension, irritability, anxiety, mental agitation, or heartache caused by stress. Further examples of the administration subject include humans who need or desire prevention or amelioration of anxiety disorders or adjustment disorders (e.g., humans with anxiety disorders or adjustment disorders). In one embodiment, the administration subject to the composition of the present invention may be a healthy subject. The composition of the present invention can also be used in healthy subjects, for example, for the purpose of preventing anxiety symptoms or preventing conditions or diseases for which prevention or amelioration of anxiety symptoms is effective.

[0030] The anti-anxiety composition of the present invention may be labeled with an indication of the functions exhibited by the anxiolytic effect, such as "improving anxiety," "reducing temporary mental stress," "reducing temporarily depressed mood to a more positive mood," "reducing temporarily depressed mood to a more positive mood," "reducing lively mood," "reducing temporarily depressed mood to a more motivated mood," or "reducing temporary loss of vitality and energy." In one aspect of the present invention, the composition of the present invention is preferably a food or drink to which the above-mentioned label is attached. The above-mentioned label may also be a label indicating that the composition is used to obtain the above-mentioned function. The above-mentioned label may be attached to the composition itself, or to a container or packaging of the composition.

[0031] The present invention also encompasses the following methods and uses. A method for preventing or ameliorating anxiety symptoms, comprising administering or having a human take L-ergothioneine or a salt thereof. Use of L-ergothioneine or a salt thereof for preventing or ameliorating anxiety symptoms in humans. When L-ergothioneine or a salt thereof is ingested or administered to a subject, anxiety symptoms can be prevented or improved. Preferably, L-ergothioneine or a salt thereof is orally ingested or administered to a human. The method may be a therapeutic method or a non-therapeutic method. The use may be a therapeutic use or a non-therapeutic use.

[0032] In the above-mentioned methods and uses, L-ergothioneine or a salt thereof, and preferred embodiments thereof, are the same as those of the anti-anxiety composition of the present invention. In the above-mentioned methods and uses, it is preferable to have a subject ingest or administer L-ergothioneine or a salt thereof at least once a day, for example, once to several times (e.g., 2 to 3 times) a day. In one aspect, L-ergothioneine or a salt thereof can be used to prevent or ameliorate anxiety disorders, adjustment disorders, etc.

[0033] In the above-mentioned methods and uses, L-ergothioneine or a salt thereof may be used in an amount sufficient to obtain an anxiolytic effect (which may also be referred to as an effective amount). The preferred dosage and administration targets of L-ergothioneine or a salt thereof are the same as those of the anti-anxiety composition of the present invention described above. L-ergothioneine or a salt thereof may be ingested or administered as is, or as a composition containing it. For example, the composition of the present invention may be ingested or administered.

[0034] L-ergothioneine or a salt thereof can be used to produce foods and drinks, pharmaceuticals, quasi-drugs, etc. that are used for preventing or ameliorating anxiety symptoms. In one aspect, the present invention also encompasses the use of L-ergothioneine or a salt thereof to produce an anti-anxiety composition. The present invention also encompasses L-ergothioneine or a salt thereof for use in the prevention or amelioration of anxiety symptoms.

[0035] This specification also describes the following anti-stress compositions, methods for preventing or ameliorating stress, etc. An anti-stress composition for humans, comprising L-ergothioneine or a salt thereof as an active ingredient. A method for preventing or ameliorating stress, comprising administering L-ergothioneine or a salt thereof to a human. Use of L-ergothioneine or a salt thereof for preventing or ameliorating stress in humans. Anti-stress includes one or more of stress prevention and stress amelioration. As described above, L-ergothioneine or a salt thereof has the effect of suppressing activation of glutamate receptors, and therefore can be used to prevent or ameliorate stress. Stress prevention refers to reducing the level (degree) of stress to be experienced in the future below the normal level. Stress amelioration includes reducing the stress experienced, alleviating stress, etc. The stress may be mental stress. The preferred intake amount of L-ergothioneine or a salt thereof is the same as that of the anti-anxiety composition described above. Preventing or alleviating stress can contribute to preventing or alleviating conditions or diseases caused by stress. [Example]

[0036] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0037] Example 1 (Assessment of anxiety symptoms in humans) To evaluate the effects of an ergothioneine-containing supplement on anxiety symptoms and blood metabolome in humans, a placebo-controlled, randomized, double-blind, parallel-group comparative study was conducted in which adult men and women who experience daily stress (46 in the test food group, 46 in the control food group, a total of 92 people) were asked to take one capsule containing 20 mg of ergothioneine (test food) or one capsule without ergothioneine (control food) per day for four weeks.

[0038] Anxiety symptoms were assessed using the STAI State-Trait Anxiety Inventory. Blood metabolome was measured using a capillary electrophoresis-time-of-flight mass spectrometer (CE-TOF-MS) owned by Human Metabolome Technologies, Inc. Before the start of the study (before the start of test or control food intake), the anxiety symptoms of candidate subjects were assessed using the STAI State-Trait Anxiety Inventory, and subjects with high state anxiety scores (92 adult men and women mentioned above) were selected as subjects. Additionally, the blood metabolome of the selected subjects was measured as a pre-test. After consuming the test or control food for 4 weeks, the subjects' anxiety symptoms and blood metabolome were measured again (week 4 test).

[0039] (Food for evaluation) Two types of food were used for evaluation, and they were indistinguishable in appearance, flavor, etc. Test food: Capsules containing the test substance (L-ergothioneine 20 mg) Control food: Capsules containing no test substance In addition to the test substance, the ingredients of each evaluation food product included dextrin, hydroxypropyl cellulose, carrageenan, potassium chloride, and titanium oxide. The control food was manufactured using the same ingredients as the test foods, except that it did not contain the test substance (L-ergothioneine).

[0040] The STAI Y-1 state anxiety test involves rating 20 items - "feeling calm," "feeling at ease," "feeling tense," "feeling stressed," "feeling at ease," "feeling upset," "feeling worried that something bad will happen," "feeling satisfied," "feeling scared," "feeling comfortable," "feeling confident," "feeling irritated," "feeling hesitant," "feeling relaxed," "feeling satisfied," "feeling worried," "feeling confused," "feeling stable," and "feeling happy" - on a four-point scale ranging from "not at all applicable" (1 point) to "feeling very much applicable" (4 points). Ratings are made by checking the items that the subject feels apply to them.

[0041] The average state anxiety score (points) of the subjects in the test food group was used as the state anxiety score for the test food group. The average state anxiety score (points) of the subjects in the control food group was used as the state anxiety score (points) for the control food group. In addition, for each group, the state anxiety score at the pre-test was subtracted from the state anxiety score at the 4-week test (score at the 4-week test - score at the pre-test) to calculate the change in state anxiety score (Δ state anxiety (points)). The change in state anxiety score at the pre-test (Δ state anxiety (points)) was set to 0.

[0042] Figure 1 is a graph showing the change in state anxiety scores (Δstate anxiety (points)) in the test food group and the control food group. State anxiety refers to temporary anxiety felt in a specific situation. As a result, the state anxiety score decreased more significantly in the test food group than in the control food group. In Figures 1 and 2, ■ (black square) indicates the test food group, and □ (white square) indicates the control food group. "Pre" on the horizontal axis indicates the time of the pre-test, and "Week 4" indicates the time of the fourth-week test. L-ergothioneine improved state anxiety scores, indicating that it has the effect of alleviating temporary anxiety symptoms caused by mental stress. In the above evaluation, the anxiety symptoms that were confirmed to improve with L-ergothioneine intake include tension, fear, pain, loneliness, decreased positive thinking ability, irritability, mental stress, and mental agitation.

[0043] Figure 2 is a graph showing the actual measured values ​​of glutamate identified by blood metabolome analysis at the pre-test and the 4-week test. Glutamate is an excitatory neurotransmitter in the central nervous system and is known to increase with psychological stress. Significance testing for differences between groups was performed using a two-sample t-test (*: p<0.05 vs. the control food group). As a result, blood glutamate concentrations were significantly reduced in the test food group. This suggests that L-ergothioneine exerts an anxiolytic effect by lowering glutamate concentrations, thereby inhibiting glutamate receptor activation and attenuating glutamate signaling.

[0044] <Example 2> (Evaluation of substrate binding inhibitory activity of nicotinic acetylcholine receptors) To evaluate the molecular target of L-ergothioneine's inhibition of glutamate signaling, an in vitro assay was performed on nicotinic acetylcholine receptors, which are involved in glutamate signaling. The in vitro assay was outsourced to Eurofins Panlabs. The assay was performed as follows.

[0045] Human α3β4 nicotinic acetylcholine receptor (α3β4 receptor) Human recombinant α3 / β4 nicotinic acetylcholine receptor (nAChR(α3β4)) expressed in Chinese hamster ovary CHO-K1 cells was used. 0.6 μg of cell membranes from these cells expressing nAChR(α3β4) was incubated with 0.05 nM [125I]epibatidine and L-ergothioneine (L-ergothioneine concentrations: 30 μM, 100 μM, 300 μM, 1000 μM, or 3000 μM) in Tris-HCl buffer (pH 7.4) at 25°C for 60 min. Nonspecific binding was estimated in the presence of 10 μM epibatidine. The cell membranes were filtered and washed, and the inhibitory activity of L-ergothioneine on substrate binding was assessed using the radioactivity of [125I]epibatidine.

[0046] Human α4β2 nicotinic acetylcholine receptor (α4β2 receptor) Human recombinant α4 / β2 nicotinic acetylcholine receptors (nAChR(α4β2)) were used, expressed in human neuroblastoma-derived SH-SY5Y cells. Thirty micrograms of cell membranes expressing nAChR(α4β2) were incubated with 0.6 nM [3H]cytisine and L-ergothioneine (L-ergothioneine concentrations: 100 μM or 1000 μM) in Tris-HCl buffer (pH 7.4) at 4°C for 120 min. Nonspecific binding was estimated in the presence of 10 μM nicotine bitartrate. The membranes were filtered and washed, and the inhibitory activity of L-ergothioneine on substrate binding was assessed using the radioactivity of [3H]cytisine.

[0047] Human α7 nicotinic acetylcholine receptor (α7 receptor) Human recombinant α7 nicotinic acetylcholine receptor (nAChR(α7)) expressed in human neuroblastoma-derived SH-SY5Y cells was used. 20 μg of cell membranes from these cells was incubated with 0.4 nM [125I]α-Bungarotoxin and L-ergothioneine (L-ergothioneine concentrations: 100 μM or 1000 μM) in phosphate buffer (pH 7.4) at 37°C for 120 min. Nonspecific binding was estimated in the presence of 1 μM α-Bungarotoxin. The cell membranes were filtered and washed, and the substrate binding inhibitory activity of L-ergothioneine was assessed using the radioactivity of [125I]α-Bungarotoxin as an indicator.

[0048] Figure 3 shows the results of evaluating the substrate binding inhibitory activity of L-ergothioneine on nicotinic acetylcholine receptors (nAChRs). The concentration (μM) on the horizontal axis represents the concentration of L-ergothioneine. L-ergothioneine exhibited substrate binding inhibitory activity on the α3β4, α4β2, and α7 nicotinic acetylcholine receptors. We also confirmed that L-ergothioneine exhibited particularly strong substrate binding inhibitory activity on the α3β4 type (nAChR(α3β4)) of nicotinic acetylcholine receptors.

[0049] Figure 4 shows the results of evaluating the substrate binding inhibitory activity of L-ergothioneine at five concentrations of α3β4 nicotinic acetylcholine receptors. L-ergothioneine exhibited concentration-dependent activity, with a 50% inhibitory concentration of 1.11 mM. α3β4 nicotinic acetylcholine receptors are expressed in the brain, and their inhibition is known to suppress glutamate signaling. Therefore, it is speculated that L-ergothioneine also attenuates glutamate signaling by inhibiting nicotinic acetylcholine receptors such as α3β4 nicotinic acetylcholine receptors, thereby exerting the above-mentioned anxiolytic effects.

Claims

1. An anti-anxiety composition for humans, which contains L-ergothioneine or a salt thereof as an active ingredient and is used for preventing or ameliorating at least one anxiety symptom selected from the group consisting of anxiety, fear, tension, worry, and heartache.

2. The composition of claim 1, which inhibits activation of glutamate receptors.

3. The composition according to claim 1 or 2, which is an oral composition.

4. The composition according to any one of claims 1 to 3, which is a food or drink.

5. 5. The composition according to claim 1, wherein the content of L-ergothioneine or a salt thereof is 2 to 50 mg in terms of L-ergothioneine per daily intake for an adult.

6. A method for preventing or ameliorating anxiety symptoms, which comprises administering L-ergothioneine or a salt thereof to a human, wherein the anxiety symptom is at least one anxiety symptom selected from the group consisting of anxiety, fear, tension, worry, and heartache (however, this method excludes medical procedures on humans).

7. Use of L-ergothioneine or a salt thereof for preventing or ameliorating an anxiety symptom in a human, wherein the anxiety symptom is at least one anxiety symptom selected from the group consisting of anxiety, fear, tension, worry, and heartache (however, this use excludes medical procedures on humans).

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