Composition for increasing lactate level in brain

Abstract

To provide a composition for increasing lactate levels in the brain.SOLUTION: A composition for increasing lactate levels in the brain contains quercetin or a glycoside thereof as an active ingredient.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition for increasing the amount of lactic acid in the brain and the like.

Background Art

[0002] It is said that the brain has an energy metabolism regulatory function called the astrocyte-neuron lactate shuttle (ANLS). ANLS is a mechanism by which glucose in the blood is taken up by brain cells called astrocytes, converted into lactic acid, and supplied to nerve cells, thereby maintaining brain function. In ANLS, glycogen, a polymer of glucose, also plays an important role. Astrocytes convert excess glucose into glycogen and store it in the cytoplasm, and it is thought that when the brain is activated, glycogen is converted into lactic acid and supplied to nerve cells. In fact, studies using rats have reported that inhibiting the breakdown of glycogen in the brain results in the inability to supply lactic acid to nerve cells and causes disorders in brain function (Non-Patent Document 1).

[0003] Quercetin is a type of flavonol and is contained in plants such as onions, either as it is or as a glycoside. Quercetin is known to affect energy metabolism. For example, studies using streptozotocin-induced diabetic model rats have reported that the administration of quercetin or quercetin glycoside improved glucose metabolism (Non-Patent Documents 2 and 3).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Increasing the amount of lactate in the brain is useful for maintaining brain functions. As a method for increasing the amount of lactate in the brain, it is conceivable to improve (activate) ANLS. However, in Non-Patent Documents 2 and 3, the effects of quercetin or its glycosides on ANLS and the amount of lactate in the brain have not been examined. The effects of quercetin or its glycosides on ANLS and the amount of lactate in the brain have not been reported so far.

[0006] An object of the present invention is to provide a composition for increasing the amount of lactate in the brain.

Means for Solving the Problems

[0007] As a result of intensive studies to solve the above problems, the present inventors have found that quercetin (quercetin aglycone), quercetin sulfate conjugate, and quercetin glucuronide conjugate generated in the body when quercetin or its glycoside is ingested have an effect of improving ANLS. Based on such findings, the present inventors have completed the present invention.

[0008] That is, although not limited to the following, the present invention relates to the following composition for increasing the amount of lactate in the brain. [1] A composition for increasing the amount of lactate in the brain, containing quercetin or its glycoside. [2] The composition according to [1] above, which increases the amount of lactate in the brain by improving the astrocyte-neuron lactate shuttle (ANLS). [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, which is used for improving brain function or suppressing brain function decline. [6] The composition according to any one of [1] to [5] above, which is labeled with at least one function selected from the group consisting of "improving ANLS", "activating ANLS", "activating lactate production in the brain", "increasing the amount of lactate in the brain", "improving brain function", "suppressing brain function decline", and "improving cognitive function".

Advantages of the Invention

[0009] According to the present invention, a composition for increasing the amount of lactic acid in the brain can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] The composition for increasing the amount of lactic acid in the brain of the present invention contains quercetin or its glycoside as an active ingredient. The composition for increasing the amount of lactic acid in the brain of the present invention may also be referred to as the composition of the present invention hereinafter.

[0012] In the present specification, "quercetin" means quercetin, which is also called vitamin P and belongs to the flavonol which is a kind of polyphenol. Quercetin is a compound represented by the following formula (1).

[0013]

Chemical formula

[0014] In the present invention, the "quercetin glycoside" means a glycoside of the above quercetin, and specifically, it is a general term for a series of compounds in which one or more sugars are glycosidically bonded to the hydroxyl group at the 3-position of quercetin. The quercetin glycoside is a compound represented by the following general formula (2). The quercetin glycoside may be one kind of compound or two or more kinds of compounds.

[0015]

Chemical formula

[0016] (X)n in the above general formula represents a sugar chain. X represents a sugar (monosaccharide), and n is an integer of 1 or more.

[0017] The sugars that constitute the sugar chain represented by X, which is glycosidically bonded to quercetin, are, for example, glucose, rhamnose, galactose, glucuronic acid, etc., preferably glucose and rhamnose. Also, n is not particularly limited as long as it is 1 or more, but is preferably 1 to 16, more preferably 1 to 8. When n is 2 or more, the X moiety may consist of one type of sugar or may consist of a plurality of types of sugars. In other words, when n is 2 or more, (X)n may be a sugar chain consisting of one type of sugar or may be a sugar chain consisting of a plurality of types of sugars. The quercetin glycosides in the present invention include those obtained by treating existing quercetin glycosides with an enzyme or the like to effect sugar transfer. Specifically, the quercetin glycosides referred to in the present invention include rutin, enzymatically treated rutin (enzymatic treatment product of rutin), quercitrin, isoquercitrin, etc. In the present invention, it is particularly preferable to use enzymatically treated rutin as the quercetin glycoside. Preferred examples of enzymatically treated rutin include isoquercitrin obtained by enzymatically treating rutin to remove the rhamnose sugar chain moiety, isoquercitrin obtained by treating isoquercitrin with a glycosyltransferase and having a sugar chain consisting of 1 to 7 glucoses bonded thereto, and those having a mixture thereof as the main component. In one aspect, as the quercetin glycoside, a compound in which 1 or more (preferably 1 to 8) glucoses are glycosidically bonded to the 3-position hydroxyl group of quercetin (for example, isoquercitrin, glycosides in which 1 to 7 glucoses are bonded to isoquercitrin), etc. are preferable. The ingested quercetin glycoside is absorbed into the body after the sugar is cleaved in the intestinal tract to become an aglycone (quercetin). Thereafter, it undergoes conjugation such as sulfate conjugation or glucuronide conjugation and migrates into the blood. Also, it is known that a certain amount of aglycone is detected in the blood without undergoing conjugation.

[0018] In the present invention, quercetin or its glycoside may be used alone or two or more compounds may be used. When two or more compounds are used, for example, quercetin and one or more quercetin glycosides may be used, or two or more quercetin glycosides may be used.

[0019] In the present invention, there are no particular restrictions on the origin and production method for obtaining quercetin or its glycoside. For example, plants rich in quercetin or its glycoside include buckwheat, fava beans, capers, apples, tea, onions, grapes, broccoli, spinach, raspberries, loquats, cranberries, Opuntia, leafy vegetables, citrus fruits, etc., and quercetin or its glycoside can be obtained from these plants. In the present invention, as long as the effects of the present invention can be achieved, extracts derived from natural products such as the above-mentioned plants, etc., with the content of quercetin or its glycoside increased by operations such as concentration and purification, for example, concentrates or purified products of extracts containing quercetin or its glycoside can be used. Known methods can be adopted for the concentration method or the purification method. In one aspect of the present invention, purified or isolated quercetin or its glycoside may be used. Chemical synthetic products can also be used for quercetin or its glycoside.

[0020] Quercetin or its glycoside is a compound contained in natural products and food and beverages and has been ingested. Therefore, from the perspective of safety, it is considered that there are few problems with, for example, daily intake of quercetin or its glycoside. According to the present invention, a composition for increasing the amount of lactic acid in the brain containing a highly safe substance as an active ingredient can be provided.

[0021] As shown in the following examples, quercetin, the sulfate conjugate of quercetin, and the glucuronide conjugate of quercetin increased the amount of glycogen in astrocytes. In addition, quercetin increased the amount of lactate secreted by astrocytes under conditions of glucose deficiency in the brain. Astrocytes convert glycogen to lactate and supply it to neurons when the amount of glucose in the brain decreases. From the above, ingestion of quercetin or its glycoside can improve ANLS and increase the amount of lactate in the brain. To maintain brain function, a constantly stable energy source supply is necessary. Therefore, an increase in the amount of lactate in the brain is effective in improving or suppressing the decline of brain function. The composition of the present invention can be preferably used, for example, to increase the amount of lactate in the brain when the amount of glucose in the brain decreases. Improvement of ANLS promotes lactate secretion by astrocytes and increases the amount of lactate in the brain.

[0022] The composition of the present invention is for increasing the amount of lactate in the brain, and preferably for increasing the amount of lactate in the human brain. The composition of the present invention preferably increases the amount of lactate in the brain by improving ANLS, and more preferably increases the amount of lactate in the brain by improving ANLS in humans.

[0023] The amount of glycogen and the amount of lactate secretion that characterize ANLS can be measured by known methods. In the case of cell experiments using astrocytes, the amount of intracellular glycogen and the amount of lactate secreted extracellularly can be easily measured using commercially available kits.

[0024] The composition of the present invention can be used for preventing or improving a condition or disease that can be expected to be prevented or improved by an increase in the amount of lactic acid in the brain. Neurons use lactic acid as an energy source. Therefore, an increase in the amount of lactic acid in the brain is effective in improving or suppressing the decline of brain function. In one aspect, the composition of the present invention can be used for improving or suppressing the decline of brain function. Examples of the condition or disease that can be expected to be prevented or improved by an increase in the amount of lactic acid in the brain include dementia, decline in cognitive function (e.g., memory function, attention function, etc.), depression, decline in mood, and the like. In one aspect, the composition of the present invention can be used for preventing or improving such a condition or disease. In one aspect, the composition of the present invention may be used for a subject in need of preventing or improving such a condition or disease. As used herein, prevention of a condition or disease includes preventing the onset of the condition or disease, delaying the onset of the condition or disease, reducing the incidence of the condition or disease, reducing the risk of onset of the condition or disease, and the like. Improvement of a condition or disease includes recovering the subject from the condition or disease, alleviating the symptoms of the condition or disease, delaying or preventing the progression of the condition or disease, and the like. Recovery includes at least partially recovering.

[0025] The composition of the present invention can be applied to either therapeutic or non-therapeutic uses. Non-therapeutic means a concept that does not include medical acts, that is, human surgery, treatment, or diagnosis. The composition of the present invention can be in the form of foods and drinks, pharmaceuticals, quasi-drugs, cosmetics, and the like. The composition of the present invention may itself be a food or drink, a pharmaceutical, a quasi-drug, a cosmetic, etc. used for increasing the amount of lactic acid in the brain, or may be a material or preparation, etc. used by being formulated in these. The composition for increasing the amount of lactic acid in the brain of the present invention can be provided, for example, in the form of an agent, but is not limited to this form. The agent can be provided as the composition itself, or as a composition containing the agent. In one aspect, the composition for increasing the amount of lactic acid in the brain can also be referred to as an agent for increasing the amount of lactic acid in the brain. The composition of the present invention may be either an oral composition or a parenteral composition, but is preferably an oral composition. Examples of oral compositions include food and drink products, oral pharmaceuticals, and quasi-drugs for oral use, preferably food and drink products or quasi-drugs for oral use, and more preferably food and drink products. Examples of parenteral compositions include parenteral pharmaceuticals, quasi-drugs for parenteral use, and cosmetics. Preferably, they are cosmetics or quasi-drugs for parenteral use.

[0026] The composition of the present invention can contain any additive or any component in addition to quercetin or its glycoside, as long as the effects of the present invention are not impaired. These additives and components can be selected according to the form of the composition, etc., and generally those that can be used in food and drink products, pharmaceuticals, quasi-drugs, cosmetics, etc. can be used. When the composition of the present invention is made into a food and drink product, a pharmaceutical, a quasi-drug, a cosmetic, etc., its production method is not particularly limited, and it can be produced by a general method.

[0027] For example, when the composition of the present invention is made into a food and drink product, components that can be used in food and drink products (for example, food materials, food additives used as necessary, etc.) are blended with quercetin or its glycoside to obtain various food and drink products. The food and drink products are not particularly limited, and examples include general food and drink products, health foods, health drinks, foods with functional claims, foods for specified health use, health supplements, foods for patients, etc. The above health foods, foods with functional claims, foods for specified health use, health supplements, foods for patients, etc. can be used in various dosage forms such as fine granules, tablets, granules, powders, capsules, chewable agents, dry syrups, syrups, liquids, beverages, enteral nutrition, etc. In one aspect, the composition of the present invention may be provided in the form of a beverage. The beverage is not particularly limited, but for example, tea-based beverages such as barley tea beverages, green tea beverages, blended teas, black tea beverages, oolong tea beverages, etc. are preferred.

[0028] When the composition of the present invention is used as a pharmaceutical or quasi-drug, for example, quercetin or its glycoside can be formulated with a pharmacologically acceptable carrier, additives added as necessary, etc. to obtain pharmaceuticals or quasi-drugs in various dosage forms. Such carriers, additives, etc. may be any pharmacologically acceptable ones that can be used in pharmaceuticals or quasi-drugs. Examples include one or more of excipients, binders, disintegrants, lubricants, antioxidants, colorants, etc. Forms of administration (ingestion) of pharmaceuticals or quasi-drugs include oral or parenteral (transdermal, transmucosal, enteral, injection, etc.) administration. When the composition of the present invention is used as a pharmaceutical or quasi-drug, it is preferably an oral (for oral administration) pharmaceutical or quasi-drug. Dosage forms for oral administration include solutions, tablets, powders, fine granules, granules, sugar-coated tablets, capsules, suspensions, emulsions, chewable tablets, etc. Dosage forms for parenteral administration include injections, drip infusions, external preparations for the skin (patches, creams, ointments, etc.), etc.

[0029] When the composition of the present invention is used as a cosmetic, quercetin or its glycoside can be formulated with a carrier, additives, etc. acceptable for cosmetics. The product form of the cosmetic is not particularly limited.

[0030] The content of quercetin or its glycoside contained in the composition of the present invention is not particularly limited and can be set according to its form and the like. The content of quercetin or its glycoside in the composition of the present invention is preferably, for example, 0.0001% by weight or more, more preferably 0.001% by weight or more, still more preferably 0.01% by weight or more, particularly preferably 0.1% by weight or more, in terms of quercetin conversion, and preferably 99.9% by weight or less, more preferably 95% by weight or less, still more preferably 80% by weight or less, particularly preferably 45% by weight or less. In one aspect, the content of quercetin or its glycoside is preferably 0.0001 to 99.9% by weight, more preferably 0.001 to 95% by weight, still more preferably 0.01 to 80% by weight, particularly preferably 0.1 to 45% by weight in the composition in terms of quercetin conversion. Further, in one aspect, when the composition of the present invention is a food or drink, the content of quercetin or its glycoside is preferably 0.0001 to 99.9% by weight, more preferably 0.001 to 95% by weight, still more preferably 0.01 to 80% by weight, particularly preferably 0.1 to 45% by weight in the food or drink in terms of quercetin conversion. The content of quercetin or its glycoside can be measured according to known methods, and for example, a high performance liquid chromatography (HPLC) method or the like can be used. In this specification, the amount in terms of quercetin or an expression similar thereto means the amount in the case of quercetin, and in the case of a quercetin glycoside, it means a value obtained by multiplying the number of moles of the glycoside by the molecular weight of quercetin.

[0031] The composition of the present invention is usually intended to be ingested or administered to a subject. The administration route of the composition of the present invention is not particularly limited, and it can be ingested or administered by an appropriate method according to its form. In one aspect, the composition of the present invention is preferably ingested orally (oral administration). The dosage (which can also be referred to as the ingestion amount) of the composition of the present invention is not particularly limited, and any amount can be used as long as the effect of increasing the amount of lactate in the brain can be obtained, and it can be appropriately set according to the administration form, administration method, body weight of the subject, and the like.

[0032] In one aspect, the dosage of quercetin or its glycoside is preferably 0.1 mg or more, more preferably 0.3 mg or more, still more preferably 1.0 mg or more, even more preferably 10 mg or more, even more preferably 50 mg or more, particularly preferably 55 mg or more, and most preferably 60 mg or more, in terms of quercetin, per day. Also, it is preferably 8000 mg or less, more preferably 4000 mg or less, still more preferably 1000 mg or less, even more preferably 500 mg or less, particularly preferably 200 mg or less, and most preferably 78 mg or less. In one aspect, the dosage of quercetin or its glycoside is preferably 0.1 to 8000 mg, more preferably 0.3 to 4000 mg, still more preferably 1.0 to 1000 mg, even more preferably 10 to 500 mg, and particularly preferably 10 to 200 mg, in terms of quercetin, per day. Also, in one aspect, the dosage of quercetin or its glycoside is preferably 50 to 500 mg, more preferably 55 to 500 mg, still more preferably 55 to 200 mg, even more preferably 55 to 78 mg, and particularly preferably 60 to 78 mg, in terms of quercetin, per day. In one aspect, it is preferable to ingest or administer the above amount, for example, once a day or divided into several times (for example, 2 to 3 times). In one aspect, it is preferable to orally ingest or administer the above amount of quercetin or its glycoside to a human. The above dosage of quercetin or its glycoside may be the dosage per 60 kg of body weight. In one aspect of the present invention, the composition of the present invention can be used to cause a human to ingest or administer the above amount of quercetin or its glycoside per day. In one aspect of the present invention, the composition of the present invention may be an oral composition for causing a human to ingest or administer the above amount of quercetin or its glycoside per day per 60 kg of body weight. The above dosage is preferably the dosage for an adult per day.

[0033] In one aspect, the composition of the present invention preferably contains 0.1 to 8000 mg of quercetin or its glycoside in terms of quercetin in the daily intake of humans. The content of quercetin or its glycoside in the daily intake is more preferably 0.3 to 4000 mg in terms of quercetin, even more preferably 1.0 to 1000 mg, still more preferably 10 to 500 mg, and particularly preferably 10 to 200 mg in terms of quercetin. Also, in one aspect, the composition of the present invention preferably contains 50 to 500 mg, more preferably 55 to 500 mg, even more preferably 55 to 200 mg, still more preferably 55 to 78 mg, and particularly preferably 60 to 78 mg of quercetin or its glycoside in terms of quercetin in the daily intake of humans. The above content of quercetin or its glycoside is preferably the content per adult daily intake.

[0034] The subject to which the composition of the present invention is ingested or administered (which may also be referred to as the administration subject) is not particularly limited. The administration subject is preferably a human or a non-human mammal, and more preferably a human. Examples of the administration subject include a subject that requires or desires an increase in the amount of lactic acid in the brain. In one aspect, examples of the administration subject include a subject having a condition or disease caused by or accompanied by a decrease in the amount of lactic acid in the brain. In one aspect, the composition of the present invention can also be used for a subject in a healthy state for the purpose of preventing or improving a condition or disease that can be expected to be prevented or improved by an increase in the amount of lactic acid in the brain.

[0035] The composition of the present invention can be used for subjects of a wide range of ages. Preferably, the composition of the present invention is administered to adults (for example, 18 years old or older). In one aspect, elderly and middle-aged subjects are preferred as the administration subject in the present invention. Generally, the elderly refers to humans 65 years old or older, and middle-aged refers to humans 45 years old or older and less than 65 years old. As the administration subject of the composition of the present invention, for example, humans 45 years old or older are preferred, and humans 55 years old or older and less than 80 years old are more preferred.

[0036] In the composition of the present invention, one or more of the use, the type of active ingredient, the effect, the method of use (for example, the method of ingestion, the method of administration), etc. may be indicated on the composition itself, the package, the container, or the instruction manual, etc. In the composition of the present invention, for example, one or more indications such as "ANLS", "astrocyte-neuron lactate shuttle", "astrocyte-neuron lactate shuttle", "intracerebral glycogen", "intracerebral lactate", "brain energy", "head glycogen", "head lactate", "head energy", "glycogen in astrocytes", "lactate secretion from astrocytes", etc. may be attached. Also, for example, "activate ANLS", "improve ANLS", "activate astrocyte-neuron lactate shuttle", "improvement of astrocyte-neuron lactate shuttle", "increase the amount of intracerebral glycogen", "activate lactate production in the brain", "increase the amount of lactate in the brain", "supply energy to the brain", "increase the amount of head glycogen", "activate head lactate secretion", "supply energy to the head", "increase the amount of glycogen in astrocytes", "activate astrocyte lactate secretion", "improve brain function", "suppress the decline of brain function", "improve cognitive function", "prevent dementia", "prevent depression", "improve the decline of mood", etc. One or more function indications may be attached. When the indication of the above function does not include the description of "ANLS" or "astrocyte-neuron lactate shuttle", it may be described that it is a function obtained by improving ANLS. In one aspect, the composition of the present invention is preferably a food or drink product with the above indication. Also, the composition of the present invention may be indicated to be used for obtaining the above function. The indication may be attached to the composition itself, or to the container, package, or instruction manual, etc. of the composition.

[0037] The present invention also includes the following methods and uses. A method for increasing the amount of intracerebral lactate by ingesting or administering quercetin or its glycoside. Use of quercetin or its glycoside for increasing the amount of lactic acid in the brain. When quercetin or its glycoside is ingested or administered to a subject, the amount of lactic acid in the brain can be increased. Preferably, quercetin or its glycoside is orally ingested or administered. The above method may be a therapeutic method or a non-therapeutic method. The above use may be a therapeutic use or a non-therapeutic use.

[0038] In the above method and use, quercetin or its glycoside, its preferred embodiments, etc. are the same as the composition of the present invention described above. In the above method and use, it is preferable to ingest or administer quercetin or its glycoside to the subject one or more times a day, for example, once to several times a day (for example, 2 to 3 times).

[0039] In the above method and use, an amount of quercetin or its glycoside that can obtain an effect of increasing the amount of lactic acid in the brain (which can also be referred to as an effective amount) may be used. The preferred dosage and administration subject of quercetin or its glycoside are the same as the composition of the present invention described above. Quercetin or its glycoside may be ingested or administered as it is, or may be ingested or administered as a composition containing the same. For example, the composition of the present invention may be ingested or administered.

[0040] Quercetin or its glycoside can be used for the manufacture of foods, beverages, pharmaceuticals, quasi-drugs, etc. used for increasing the amount of lactic acid in the brain. In one aspect, quercetin or its glycoside can be used for the manufacture of a composition for increasing the amount of lactic acid in the brain. In one aspect, the present invention also includes the use of quercetin or its glycoside for the manufacture of a composition for increasing the amount of lactic acid in the brain. The present invention also includes quercetin or its glycoside used for increasing the amount of lactic acid in the brain.

[0041] In this specification, a numerical range represented by a lower limit value and an upper limit value, that is, "lower limit value to upper limit value", includes those lower limit value and upper limit value. For example, the range represented by "1 to 2" means 1 or more and 2 or less, and includes 1 and 2. In this specification, the upper limit and the lower limit may be a range in any combination. All of the academic documents and patent documents described in this specification are incorporated herein by reference.

Example

[0042] Hereinafter, the present invention will be described in more detail by way of examples, but this does not limit the scope of the present invention. Those skilled in the art can variously change and modify the method of the present invention for use, and these are also included in the scope of the present invention.

[0043] <Example 1> (Evaluation of the effect of increasing the amount of glycogen in astrocytes by quercetin, quercetin sulfate conjugate, and quercetin glucuronide conjugate) Human iPS cell-derived astrocytes (manufactured by FUJIFILM Cellular Dynamics, Inc.) were seeded in a 48-well plate and cultured in Astrocyte Growth Medium (manufactured by Lonza) at 37 ° C and 0.5% CO2 for 2 weeks. The cell density at the time of seeding was 2×10 4 cells / well.

[0044] After 2 weeks, the medium was replaced with Astrocyte Growth Medium prepared so that the final concentration of quercetin (quercetin aglycone, manufactured by Nacalai Tesque, Inc.) would be 0, 1, or 10 μM, and further cultured at 37°C and 0.5% CO2 for another 24 hours. After 24 hours, the entire amount of the medium was removed, and the cells were washed once with ice-cold phosphate-buffered saline (PBS). After washing, ice-cold ultrapure water was added, and the cells were left standing at -80°C for 30 minutes. After thawing at 37°C for 5 minutes, the cells were heated at 98°C for 10 minutes to inactivate the enzymes involved in glycogen metabolism. After heating, the cells were centrifuged at 18,000 g for 10 minutes at 4°C, and the amount of glycogen in the supernatant was measured using a Glycogen Colorimetric / Fluorometric Assay kit (manufactured by BioVision) (N = 3).

[0045] The protein concentration of the solution in which the amount of glycogen was measured was measured using Pierce (trademark) BCA Protein Assay Kits (manufactured by Thermo Fisher Scientific), and the measured value of the amount of glycogen was corrected by the amount of protein.

[0046] The results are shown in Fig. 1A. "Cont." in Fig. 1A is the group to which quercetin aglycone was not added (the final concentration in the medium was 0 μM). The vertical axis shows the amount of glycogen corrected by the amount of protein (glycogen (μg) / protein amount (mg)). The obtained values are shown as the mean ± standard error (N = 3). The significance test was performed by Dunnett's test (a test by multiple comparison assuming equal variance, p-value) using the analysis tool of Excel (*: p < 0.05, **: p < 0.01).

[0047] <Example 2> (Evaluation of the effect of increasing the amount of intracellular glycogen of quercetin sulfate conjugate or quercetin glucuronide conjugate) The glycogen amount increasing effect was evaluated in the same manner as in Example 1, except that quercetin was replaced with a quercetin sulfate conjugate (prepared based on the methods described in J. Nat. Prod., 2016, 79, 1808-1814 and J. Agric. Food Chem., 2012, 60, 3592-3598) or a quercetin glucuronide conjugate (manufactured by Cayman Chemical). The results are shown in Fig. 1B. "Cont." in Fig. 1B is the group to which neither the quercetin sulfate conjugate nor the quercetin glucuronide conjugate was added (the final concentration in the medium was 0 μM).

[0048] From the results of Examples 1 and 2, it was confirmed that the addition of quercetin, a quercetin sulfate conjugate, or a quercetin glucuronide conjugate significantly increased the amount of glycogen in human iPS cell-derived astrocytes.

[0049] <Example 3> (Evaluation of the effect of quercetin on increasing the lactate secretion amount of astrocytes) Human iPS cell-derived astrocytes (manufactured by FUJIFILM Cellular Dynamics, Inc.) were seeded in a 48-well plate and cultured in Astrocyte Growth Medium (manufactured by Lonza) at 37 °C under 0.5% CO2 for 2 weeks. The cell density at the time of seeding was 2×10 4 cells / well.

[0050] After 2 weeks, the medium was replaced with Astrocyte Growth Medium prepared so that the final concentration of quercetin would be 0 μM or 10 μM, and the cells were further cultured at 37°C and 0.5% CO2 for 24 hours (for subsequent procedures, two groups were prepared for each of the 0 μM and 10 μM quercetin groups). As a comparison group, two groups were also prepared in which the medium was replaced with Astrocyte Growth Medium prepared to contain 10 μM of CP 316-819 (manufactured by Sigma-Aldrich Japan K.K.), which is known as a glycogenolytic enzyme. After 24 hours, for each of the two groups of 0 μM and 10 μM quercetin, the medium was replaced with Astrocyte Growth Medium prepared so that the final concentration of quercetin would be 0 μM or 10 μM, and glucose-free D-MEM (manufactured by Fujifilm Wako Pure Chemical Corporation) prepared so that the final concentration of quercetin would be 0 μM or 10 μM. For the CP 316-819-treated group, the medium was also replaced with Astrocyte Growth Medium prepared so that the final concentration of CP 316-819 would be 10 μM, and glucose-free D-MEM (manufactured by Fujifilm Wako Pure Chemical Corporation) prepared so that the final concentration of CP 316-819 would be 10 μM. Thereafter, for measurement of the amount of lactic acid, the cells were cultured for 4 hours while collecting the medium over time. After 4 hours, the amounts of glycogen and protein were measured in the same manner as in Example 1. The amount of lactic acid in the medium was measured using a Lactate Assay Kit-WST (manufactured by Fujifilm Wako Pure Chemical Corporation). The amounts of intracellular glycogen and lactic acid secretion were corrected by the amount of protein.

[0051] Figure 2A shows the results of evaluating the effect of quercetin on the amount of glycogen in astrocytes and its effect on glycogenolysis during energy deficiency. Figure 2B shows the results of evaluating the effect of quercetin on the amount of lactate secreted by astrocytes in the group where the medium was replaced with glucose-free D-MEM. In Figures 2A and 2B, "Cont." and "10uM CP" indicate the group without the addition of either CP 316-819 or quercetin, and the CP 316-819 treatment group, respectively. Also, "Glucose +" and "Glucose -" indicate the cases where the medium is Astrocyte Growth Medium and glucose-free D-MEM, respectively. The case where the medium is glucose-free D-MEM corresponds to the energy deficiency of astrocytes. The obtained values are shown as the mean ± standard error (N = 4). The significance test was performed using the analysis tools of Excel by Tukey-Kramer's test (test by multiple comparison assuming equal variance, p-value) and Dunnett's test (test by multiple comparison assuming equal variance, p-value) (*: p < 0.05, **: p < 0.01).

[0052] From the above results, it was shown that the amount of glycogen in human iPS cell-derived astrocytes significantly increased by adding quercetin was rapidly decomposed during energy deficiency. Also, it was shown that the amount of lactate secreted thereby significantly increased. For the comparative CP 316-819, it was found that the amount of glycogen in astrocytes increased, but the amount of lactate produced during energy deficiency decreased. [Industrial Applicability]

[0053] Since quercetin or its glycoside is contained in natural products and food and beverages and is a compound with dietary experience, the composition of the present invention can safely increase the amount of lactate in the brain. As a new means for improving brain function and suppressing its decline, the industrial applicability is high.

Claims

1. A composition for increasing the amount of lactic acid in the brain, containing quercetin or its glycoside as an active ingredient.

2. The composition according to claim 1, which increases the amount of lactic acid in the brain by improving the astrocyte-neuron lactate shuttle (ANLS).

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

4. The composition according to claim 1 or 2, which is a food or drink.

5. The composition according to claim 1 or 2, which is used for improving or suppressing the decline of brain function.

6. The composition according to claim 1 or 2, which is labeled with at least one function selected from the group consisting of "improving ANLS", "activating ANLS", "activating lactic acid production in the brain", "increasing the amount of lactic acid in the brain", "improving brain function", "suppressing the decline of brain function", and "improving cognitive function".

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