JP7638653B2 - Tea polyphenols as a brain function improver - Google Patents

Description

Application of Article 30, paragraph 2 of the Patent Act On September 17, 2020, Yoshitake Baba, Hayato Inagaki, Sae Nakagawa, Toshiyuki Kaneko, Makoto Kobayashi, and Takanobu Takihara published an embodiment of the invention made by Yoshitake Baba and Takanobu Takihara in Molecules 2020, 25(18), 4265; https://doi.org/10.3390/molecules25184265.

The present invention relates to a brain function improver that contains tea polyphenols, and a composition that contains the same, particularly a food and drink composition, etc.

In recent years, as the aging of the population progresses, cognitive impairment of the brain associated with aging has become a social issue, and various researches are being conducted on foods, ingredients, etc. that are effective in preventing or improving cognitive impairment. The presence or absence of cognitive impairment in humans can be diagnosed by cognitive function tests (screening tests), and various cognitive function tests have been proposed. Therefore, in the evaluation of cognitive function, an appropriate test is appropriately selected from known cognitive function tests depending on the purpose of the test and performed. Patent Document 1 proposes improving cognitive function using a composition containing docosahexaenoic acid, uridine, etc., and describes the use of a mini-mental state test as a standard test for evaluating cognitive ability.

Other known methods for testing cognitive function include the Hasegawa Dementia Scale-Revised and the Cognitrax test, and Patent Document 2 describes a method for evaluating the effectiveness of green tea ingredients for mild cognitive impairment using the Cognitrax test.

Patent Document 3 discloses that green tea leaf powder containing theanine and catechin is effective in maintaining cognitive function in healthy individuals or improving mild cognitive impairment through the Cognitrax test. On the other hand, Non-Patent Document 1 describes that epigallocatechin gallate can regulate cerebral blood flow parameters in the frontal lobe of healthy adults, but is unrelated to cognitive function.

JP 2015-143248 A JP 2020-038156 A JP 2020-037540 A

Wightman et al., "Epigallocatechin gallate, cerebral blood flow parameters, cognitive performance and mood in healthy humans: a double-blind, placebo-controlled, crossover investigation", Hum Psychopharmacol. 2012 Mar;27(2):177-86.

However, because brain functions are extremely complex and various functions interact with each other, there is a demand for drugs, supplements, and food and beverage products, such as beverages and tea leaf products, specifically functional foods, that are specialized for improving specific brain functions.

The present invention was made in consideration of the above problems, and aims to provide a novel brain function improver or a composition containing the same, in particular a food and drink composition.

Cognitive function testing methods differ not only in sensitivity and specificity, but also in the cognitive functions evaluated due to differences in the evaluation method. For example, the Revised Hasegawa Dementia Scale and the Mini-Mental State Examination, which evaluate cognitive function by adding up the results of individual items such as reciting numbers backwards and calculation problems, have biases in the test content and point allocation, and the types of dementia that are easy to detect (Alzheimer's type, cerebrovascular type, etc.) are different. It has also been reported that abnormalities are difficult to detect in subjects with mild symptoms of cognitive decline.

The Cognitrax test differs from the conventional Revised Hasegawa Dementia Scale and Mini-Mental State Examination in that it can individually assess areas of impaired function.

The inventors discovered that matcha and each of the components contained in it contribute to improving cognitive functions differently, even when assessed using the same Cognitrax test, and thus completed the present invention.

That is, the present invention includes the following inventions.
[1]
A brain function improving agent comprising tea polyphenols as an active ingredient, the brain function being evaluated by a Cognitrax test.
[2]
The brain function improving agent according to [1], wherein the tea polyphenol is a catechin.
[3]
The brain function improving agent according to [2], wherein the catechins include one or more selected from the group consisting of epigallocatechin gallate (EGCG), epicatechin gallate (ECG), gallocatechin gallate (GCG), catechin gallate (CG) and epicatechin (EC).
[4]
The brain function improving agent according to [3], wherein the tea polyphenols contain epigallocatechin gallate and the epigallocatechin gallate content is 40% by mass or more.
[5]
The brain function improver according to any one of [1] to [4], further comprising 1% by mass or less of caffeine.
[6]
The brain function improving agent according to any one of [1] to [5], wherein the brain function is sustained attention, reaction speed, or impulsivity as evaluated by the sustained processing test in the Cognitrax test, or working memory or sustained attention as evaluated by the 4-part sustained processing test.
[7]
The brain function improving agent according to [6], wherein sustained attention, reaction speed or impulsivity, or working memory or sustained attention is a brain function not assessed by the Revised Hasegawa Dementia Scale or the Mini-Mental State Examination.
[8]
The brain function improving agent according to any one of [1] to [7], wherein the effective amount of catechin is 100 to 400 mg per day.
[9]
The brain function improving agent according to [8], wherein the effective amount of catechin is a single dose.
[10]
The brain function improving agent according to any one of [6] to [9], wherein the improvement in sustained attention, reaction speed, or impulsivity is a reduction in the number of incorrect responses in the sustained processing test of the Cognitrax test compared to when matcha is administered.
[11]
The brain function improving agent according to any one of [6] to [10], wherein the sustained processing test is an examination of the time required to respond when a specific letter is displayed while letters are displayed randomly.
[12]
The brain function improving agent according to any one of [6] to [11], wherein the improvement in working memory or connectivity attention is a decrease in mean correct response time in the 4-part sustained processing test of the Cognitrax test compared to when matcha is administered.
[13]
The brain function improving agent according to [12], wherein the 4-part sustained processing test is a test of memory for two pictures prior to randomly displayed pictures.
[14]
A composition comprising the brain function improving agent according to any one of [1] to [13].
[15]
The composition according to [14], which is in the form of a beverage, food, supplement or medicine.
[16]
The composition according to [14] or [15], which is in the form of a liquid, powder, tablet or capsule.
[17]
The composition according to any one of [14] to [16] for improving working memory or sustained attention as assessed by the 4-part sustained processing test of the Cognitrax test.

By essentially consuming only tea polyphenols, it is possible to improve brain function that could not be assessed by the Revised Hasegawa Dementia Scale or Mini-Mental State Examination.

The following describes in detail the embodiments or implementations of the present invention, but the present invention is not limited to these, and various modifications are possible without departing from the gist of the invention.

(brain function improver)
In one embodiment, there is provided a brain function improving agent comprising tea polyphenols, wherein the brain function is a brain function assessed by a Cognitrax test.

Dementia symptoms are diverse and include memory impairment, impaired judgment, disorientation, language disorder (aphasia), apraxia, agnosia, and impaired executive function. Mild cognitive impairment (MCI) is a gray zone stage between a healthy state and dementia. In other words, it is a state in which even if there is a problem with one of the cognitive functions (memory, decision-making, reasoning, execution, etc.), it does not interfere with daily life.

The Cognitrax test is a cognitive function testing technology developed by CNS Vital Signs, a US company (Gualtieri CT, Johnson LG: Reliability and validity of a computerized neurocognitive test battery, CNS Vital Signs. Arch Clin Neuropsychol 2006;21:623-643.), and has the following characteristics, for example:
-Measures a wide range of functional areas, including memory, attention, processing speed, and executive function, and the results are quantified and displayed in comparison with age-standard values.
- 10 types of tests are offered, and you can select the test depending on your testing purpose.
- By monitoring individual values over time, it is possible to detect changes in memory and cognitive function.
- Accurate and reliable measurements with millisecond sensitivity.
-Very low learning or ceiling effect.

The ten tests in the Cognitrax test are:
1. Verbal Memory Test (Verbal Memory (VBM))
2. Visual Memory Test (Visual Memory (VIM))
3. Finger Tapping Test (FTT)
4. SDC Test (Symbol Digit Coding (SDC))
5. Stroop Test (ST)
6. Shifting Attention Test (SAT)
7. Continuous Performance Test (CPT)
8. Perception of Emotion (POET)
9. Reasoning Test (NVRT)
10. Four Part Continuous Performance Test (FPCPT)

The brain function is preferably sustained attention, reaction speed or impulsivity as assessed by the sustained processing test in the Cognitrax test, or working memory or sustained attention as assessed by the four-part sustained processing test.

The sustained processing test measures sustained attention over long periods of time. In it, subjects are asked to respond only to the letter "B" that appears among randomly displayed letters on the screen, and to ignore all other letters. This allows the assessment of sustained attention, choice response speed, and/or impulsivity.

As used herein, "sustained attention assessed by the sustained processing test in the Cognitrax test" refers to a brain function that is a part of cognitive function, the ability to maintain a consistent reaction behavior during sustained or repetitive activities, and that cannot be assessed by the Hasegawa Dementia Scale-Revised or the Mini-Mental State Examination. In other words, "sustained attention assessed by the sustained processing test in the Cognitrax test" is different from attention assessed by the Hasegawa Dementia Scale-Revised or the Mini-Mental State Examination (e.g., the ability assessed by a calculation problem in which 7 is repeatedly subtracted from 100) or other cognitive functions.

As used herein, "reaction speed assessed by the sustained processing test in the Cognitrax test" refers to a part of cognitive function, such as reaction speed, such as the time it takes from when a question is presented to when a response is made (pressing a button), and refers to a brain function that cannot be assessed by the Revised Hasegawa Dementia Scale or the Mini-Mental State Examination, which do not assess reaction speed. In other words, "reaction speed assessed by the sustained processing test in the Cognitrax test" is different from the cognitive function assessed by the Revised Hasegawa Dementia Scale or the Mini-Mental State Examination.

As used herein, "impulsivity assessed by the sustained processing test in the Cognitrax test" refers to a part of cognitive function, in which when an uncontrollable impulse or impaired impulse control occurs, the desire manifests itself as behavior, resulting in unplanned, explosive, and impulsive behavior (impulsive behavior). This behavioral characteristic, i.e., the tendency to exhibit impulsive behavior, is a brain function that cannot be evaluated by the Revised Hasegawa Dementia Scale or Mini-Mental State Examination, which do not assess such tendencies. In other words, "impulsivity assessed by the sustained processing test in the Cognitrax test" is different from the cognitive function assessed by the Revised Hasegawa Dementia Scale or Mini-Mental State Examination.

An example of an improvement in sustained attention, reaction speed, or impulsivity is a reduction in the number of incorrect responses in the sustained processing test of the Cognitrax test when administered matcha compared to matcha. Matcha, which is used as a comparison to confirm the effects of the brain function improver, is expected to contain approximately half the amount of tea polyphenols, particularly catechin, which are the active ingredients. For example, if the brain function improver contains 220 mg of epigallocatechin gallate, this is equivalent to 4 g of matcha, so the matcha used as the comparison will be approximately 2 g in total, and contain approximately 110 mg of epigallocatechin gallate.

The Four-Part Sustained Processing Test measures working memory and sustained attention. It consists of four parts: Part 1 tests simple reaction speed, Part 2 is a variation of the Sustained Processing Test, Part 3 tests memory for the previous picture, and Part 4 tests memory for the picture two pictures back.

As used herein, "working memory assessed by the four-part sustained processing test of the Cognitrax test" refers to a part of cognitive function, the memory function (function) temporarily required for the purpose of completing a task while the task is being performed, and the mechanism (structure) or system (structure) that supports it, in other words, the function of working memory, and is a brain function that cannot be assessed by the Revised Hasegawa Dementia Scale or Mini-Mental State Examination. In other words, "working memory assessed by the four-part sustained processing test of the Cognitrax test" is different from the working memory function and other cognitive functions assessed by the Revised Hasegawa Dementia Scale or Mini-Mental State Examination.

An example of an improvement in working memory or sustained attention is a reduction in the mean response time in the four-part sustained processing test of the Cognitrax test when administered matcha compared to matcha. Matcha, which is used as a comparison to confirm the effects of brain function improvers, is expected to contain about half the amount of tea polyphenols, particularly catechin, which are the active ingredients. For example, if the brain function improver contains 220 mg of epigallocatechin gallate, this is equivalent to 4 g of matcha, so the comparison would contain a total of about 2 g of matcha, and about 110 mg of epigallocatechin gallate.

As used herein, "sustained attention as assessed by the 4-part sustained processing test of the Cognitrax test" refers to a brain function that is a part of cognitive function, the ability to maintain a consistent reactive behavior during sustained or repetitive activities, and cannot be assessed by the Revised Hasegawa Brief Intelligence Scale or the Mini-Mental State Examination. In other words, "sustained attention as assessed by the 4-part sustained processing test of the Cognitrax test" is different from cognitive function as assessed by the Revised Hasegawa Brief Intelligence Scale or the Mini-Mental State Examination.

The tea polyphenols, which are the active ingredients of the brain function improving agent, may be derived from one or more types of tea selected from the group consisting of tea leaves, for example, unfermented tea, semi-fermented tea, fermented tea, and post-fermented tea. In addition, any one of these may be used alone, or two or more of these may be extracted, or a mixture of the extracts may be used.

Non-fermented teas include green teas such as Sencha, Bancha, Gyokuro, Kamairicha, Tencha, and Hojicha; semi-fermented teas include oolong teas such as Tieguanyin, Golden Katsura, Suisen, and Baozhongcha; fermented teas include black teas such as Darjeeling and Uba; and post-fermented teas include Pu-erh tea.

Furthermore, the tea polyphenols can be purified to increase the content of tea polyphenols, especially catechins, by purification methods such as solvent extraction, resin adsorption, and filtration such as ultrafiltration and reverse osmosis filtration to obtain tea polyphenols. Commercially available tea polyphenol preparations can also be used. For example, TheaFran 30A (manufactured by Itoen Co., Ltd.) is a tea polyphenol preparation in which green tea is subjected to hot water extraction and the extract is dried to have a catechin concentration of about 30%, and TheaFran 90S (manufactured by Itoen Co., Ltd.) is a tea polyphenol preparation in which an extract obtained by hot water extraction of green tea is separated and dried in an adsorption column using water and low and high concentration alcohols to have a tea polyphenol concentration of about 85 to 99.5%. Other commercially available tea polyphenol preparations include "Polyphenon" manufactured by Mitsui Norin Co., Ltd., "Sunphenon" manufactured by Taiyo Kagaku Co., Ltd., and "Sun Oolong" manufactured by Suntory Co., Ltd. TheaFran 90S is preferable because it contains 90% or more by mass of tea polyphenols.

It is preferable that the brain function improver is substantially free of tea-derived components other than tea polyphenols, such as theanine and caffeine. Theafuran 90S may contain up to 1% by mass of caffeine, but the caffeine contained in the brain function improver at about 1% by mass does not affect the effects of the brain function improver.

The tea polyphenol may be catechins. Catechins are polyphenols found in large quantities in plants such as tea plants. It is known that catechins are found in green tea leaves at about 8 to 20% by mass. The components contained in green tea leaves vary depending on the variety of tea plant, the cultivation method and cultivation environment, the time of plucking of tea leaves (first harvest, second harvest, etc.) and the part (buds, leaves, stems), and the processing conditions of tea leaves (steaming, rolling, drying, etc.). For example, in covered tea such as gyokuro and tencha grown in a shaded environment, the proportion of epigallocatechin gallate in the catechins is high. From the viewpoint of efficiency, it is preferable to extract the active ingredient from tea leaves in which the content of the desired catechin compound has increased. Catechins can be isolated using known methods. Synthetic catechins may be used.

As used herein, "catechins" refers to one or more catechins selected from the group consisting of four epicatechins (epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC), epigallocatechin gallate (EGCG)) and four non-epicatechins (catechin (C), gallocatechin (GC), catechin gallate (CG), gallocatechin gallate (GCG)).

The active ingredient may be a combination of two or more of the catechins. For example, the catechin is preferably one or more selected from the group consisting of epigallocatechin gallate (EGCG), epicatechin gallate (ECG), gallocatechin gallate (GCG), catechin gallate (CG) and epicatechin (EC). Among these catechin compounds, when epigallocatechin gallate (EGCG) is used alone or in combination with other catechin compounds, an active ingredient containing more epigallocatechin gallate (EGCG) than other catechin compounds is preferred. The content of epigallocatechin gallate (EGCG) in tea polyphenols is preferably 30% by mass or more, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

The brain function improver may be in the form of a powder. However, the dosage form of the brain function improver is not limited to powder and may be in other forms.

The brain function improver is enclosed in an appropriate container depending on the dosage form. In the case of a powder, it can be enclosed in a bag, box, or similar container. For example, the brain function improver may be enclosed in a package such as a tea bag, and examples of the shape of such a package include a square shape, a triangular pyramid shape (so-called Tetra Pak (registered trademark)), a rounded bag, and a double chamber type. The brain function improver may also be filled into a bag that is filled with water or hot water and dripped like coffee.

The container may be made of any material known to those skilled in the art. Examples include plastics and metals, and more specifically, polyester, nylon, polycarbonate, cellophane, polyethylene, polypropylene, aluminum, paper, cellulose fibers, natural fibers, polylactic acid, and the like. For example, the container may be made of a cloth filter made of synthetic fibers or the like, or may be made of a nonwoven fabric filter.

The container may comprise a laminate film. Preferably, such a laminate film comprises an internal aluminium layer.

The brain function improving agent can be administered to a subject suffering from or suspected of suffering from mild cognitive impairment, more specifically, to a human who needs to improve working memory or sustained attention. The age of the subject is not particularly limited, but is preferably middle-aged or elderly, aged 50 to 69 years.

When the brain function improving agent is substantially composed of tea polyphenols, the dosage of the brain function improving agent is adjusted so that the effective amount of tea polyphenols is, for example, about 250 to 1000 mg per day, preferably about 600 to 1000 mg, more preferably about 800 mg. When Theafuran 90S is used as an active ingredient, the effective amount of epigallocatechin gallate (EGCG) calculated from the effective amount of tea polyphenols described above is about 100 to 400 mg per day, preferably about 150 to 250 mg, more preferably about 200 mg. The above dosage may be a single dose once a day, or multiple doses two to three times a day. The above dosage may be increased or decreased as appropriate depending on the age, pathology, and symptoms of the subject.

It is preferable that tea polyphenols be added alone as an active ingredient to the brain function improving agent, but they may be combined with other active ingredients known to improve brain function as long as the effect of improving brain function is not impaired. However, theanine and caffeine, which are tea-derived ingredients, inhibit the brain function improving effect of tea polyphenols when combined with tea polyphenols, so it is preferable to exclude theanine and caffeine as much as possible.

(Composition)

In one embodiment, a composition is provided that includes a brain function improving agent.

The dosage form of the brain function improving agent or the composition containing it is not particularly limited, and the administration route can be appropriately determined by a person skilled in the art depending on the dosage form and the degree of brain function improving agent to be improved, and examples include oral administration or parenteral administration (intravenous, intraarterial, subcutaneous, intradermal, intramuscular, or intraperitoneal injection, transdermal, nasal, transmucosal, etc.). Oral administration is preferred.

The composition may contain an excipient in addition to tea polyphenols as an active ingredient. The excipient may be a solid excipient generally used in pharmaceutical preparations. Examples of the excipient include starches such as cornstarch, wheat flour, and rice flour, sugars such as lactose, sucrose, mannitol, sorbitol, and white sugar, dextrin, precipitated silica, gelatin, cellulose, and methylcellulose. One or more of these excipients may be appropriately selected and used.

The composition may be in the form of a powder.

A composition containing a brain function improver is prepared by adding fats and oils, seasonings, flavors, etc., as necessary, to tea polyphenols and, optionally, excipients and mixing them. The composition may be prepared and provided as a liquid, powder, capsule, or tablet, in which case it is easy to provide as a supplement, etc. As used herein, "liquid" refers to a liquid preparation based on a liquid medium such as water or oil, including syrups, etc. As used herein, "tablet" refers to not only tablets but also tablet dosage forms including pills. For tablets, the form may be such that the contents cannot be distinguished by taste, such as sugar-coated tablets. Capsules that are generally used for pharmaceuticals, etc., can be used, and both hard capsules and soft capsules can be used. Hard capsules can be prepared by filling a sample into a capsule coating formed using, for example, gelatin, hydroxypropyl methylcellulose, etc. Soft capsules can be obtained by sandwiching a sample between sheets of gelatin to which a plasticizer such as glycerin has been added, and then pressing and molding them.

The size and content of the capsules and tablets, as well as the number of servings per time, can be set so that the subject can take them without difficulty. In general, the intake conditions can be set so that the daily intake of tea polyphenols is about 250-1000 mg, preferably about 600 mg-1000 mg, and more preferably about 800 mg. When the brain function improving agent is substantially composed of tea polyphenols, the dosage of tea polyphenols is adjusted to, for example, about 250-1000 mg, preferably about 600 mg-1000 mg, and more preferably about 800 mg per day.

The composition is preferably provided in the form of a food or drink, particularly a food for specified health uses or a functional food. The composition is expected to be taken by subjects suffering from or suspected of having mild cognitive impairment, more specifically, by people who need to improve their working memory or sustained attention, and therefore the composition can be used to improve the brain function of such subjects, particularly working memory or sustained attention as assessed by the four-part sustained processing test of the Cognitrax test, and preferably brain function not assessed by the Revised Hasegawa Dementia Scale or the Mini-Mental State Examination.

The active ingredient, tea polyphenols, can be added to food and beverages by sprinkling or placing it on the surface of the food or beverage, or by mixing and dissolving it in the food or beverage.

As used herein, "food and beverage" refers to processed foods, beverages, fruits and vegetables, and other items that are consumed. Examples of beverages include, but are not limited to, milk beverages, lactic acid bacteria beverages, soy milk; tea beverages such as green tea, black tea, barley tea, roasted green tea, brown rice tea, and blended tea; soft drinks, nutritional beverages, sports drinks, fruit beverages, vegetable juices, dairy beverages, alcoholic beverages, jelly beverages, and carbonated beverages; and other beverages and energy supplements. In the case of tea beverages, it is preferable to reduce the caffeine or theanine content, or both, relative to the tea polyphenol content, or to eliminate the caffeine or theanine content, or both.

Examples of containers for filling the beverage include, but are not limited to, commonly used containers such as plastic bottles, cans, paper bottles, and other containers. It is preferable to use containers that can be sealed after filling.

Examples of foods include, but are not limited to, sweets such as cookies, biscuits, chocolate, cakes, puddings, ice cream, sherbet, waffles, wafers, pancakes, donuts, popcorn, castella cakes, caramel, candy, chewing gum, and Japanese sweets; breads such as white bread, sweet bread, and other breads; noodles such as udon, hiyamugi, somen, buckwheat, Chinese noodles, spaghetti, macaroni, rice vermicelli, and harusame; processed meat foods such as hamburger steaks, ham, bacon, and sausages; and instant foods such as curry, ramen, and soup.

Among food and beverage products, it is preferable to incorporate tea polyphenols into tea-related food and beverage products such as tea drinks, granulated tea, tea bags, and packed tea (leaf).

Alternatively, the composition may be prepared in the form of granules, emulsion, cream, etc., and provided as a food product such as a seasoning, sauce, or dressing. Such foods can be easily handled by providing them in small portions appropriately packaged according to the amount to be consumed per serving.

The number of times per day to be taken and the time of day to be taken (morning/afternoon, morning/afternoon/evening, relative to meals), the amount to be taken at one time, and the amount to be taken per day are appropriately set, so the green tea composition can be prepared in an easy-to-take form based on the set intake conditions. Tea polyphenols are preferably taken in the morning. The composition should be taken orally for about 10 weeks or more, preferably about 12 weeks or more.

The percentage of people whose symptoms progress from mild cognitive impairment to dementia is said to be about 10% per year, which means that after five years, about 40% will progress to dementia, so it is extremely important to prevent dementia by dealing with mild cognitive impairment early. Therefore, providing the market with green tea-related foods in a form that is effective in maintaining cognitive function or improving mild cognitive impairment is significant in terms of health and medical care.

(Treatment Method)
In one embodiment, there is provided a method for improving brain function in a subject, the method comprising administering to the subject a brain function improving agent comprising tea polyphenols, wherein the brain function is working memory or sustained attention as assessed by the 4-part sustained processing test of the Cognitrax test.

Those expected to receive the brain function improving agent are those who suffer from or are suspected of having mild cognitive impairment, more specifically, those who need to improve their working memory or sustained attention. There are no particular limitations on the age of the subjects, but they are preferably middle-aged or elderly, aged 50 to 69 years.

When the brain function improving agent is substantially composed of tea polyphenols, the dosage of the brain function improving agent is adjusted so that the effective amount of tea polyphenols is, for example, about 250 to 1000 mg per day, preferably about 600 to 1000 mg, more preferably about 800 mg. When Theafuran 90S is used as an active ingredient, the effective amount of epigallocatechin gallate (EGCG) calculated from the effective amount of tea polyphenols described above is about 100 to 400 mg per day, preferably about 150 to 250 mg, more preferably about 200 mg. The above dosage may be a single dose once a day, or multiple doses two to three times a day. The above dosage may be increased or decreased as appropriate depending on the age, pathology, and symptoms of the subject.

The timing of administration is not limited, but it is preferable to administer the drug in the morning. The administration period is about 10 weeks or more, and preferably about 12 weeks or more. Such long-term administration is particularly preferable when improving working memory or sustained attention as evaluated by the four-part sustained processing test.

As long as the effect of tea polyphenols in improving brain function is not impaired, it may be used in combination with drugs known to improve brain function.

The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited in any way by the following examples.

Preparation of brain function improver As a brain function improver, we used THEA-FLAN 90S (Itoen Co., Ltd., Tokyo), which contains tea polyphenols isolated from green tea extract. THEA-FLAN 90S contains more than 90% polyphenols, and the catechin content of THEA-FLAN 90S (482 mg) when taken per day was 336.4 mg and the caffeine content was 2.7 mg. The breakdown of catechins in THEA-FLAN 90S was 216.9 mg EGCG, 96.4 mg (-)-epicatechin gallate (ECG), 3.2 mg (-)-epigallocatechin (EGC), 1.7 mg (-)-epicatechin (EC), 12.5 mg (-)-gallocatechin gallate (GCG), 4.0 mg (-)-catechin gallate (CG), 1.0 mg (-)-gallocatechin (GC), and 0.8 mg (-)-catechin (C). The brown capsules of pork gelatin No. 1 were filled with THEA-FLAN 90S for use in this study. The placebo capsules were the same capsules filled with brown-colored cornstarch. Both the catechin capsules and the placebo capsules used cornstarch as an excipient. The capsules were manufactured by Sansho Pharmaceutical Co., Ltd. (Shizuoka Prefecture). Hereinafter, capsules filled with THEA-FLAN 90S will be simply referred to as catechin capsules.

Subjects were recruited from healthy Japanese men and women aged 50-69 years who self-reported cognitive decline. The MMSE-J was administered to 60 potentially eligible subjects.
Subjects were included if they met the following criteria:
1) You can reliably take 3 capsules per day for 12 consecutive weeks.
2) MMSE-J score is 24 or higher.
3) Being a non-smoker.

In addition, subjects who met any of the following criteria were excluded.
1) Currently taking any medication or receiving outpatient treatment.
2) Patients with a history or comorbidities of severe liver, kidney, endocrine, cardiovascular, gastrointestinal, pulmonary, hematological, or metabolic disease.
3) History of drug and/or food allergies.
4) Using health foods and/or supplements that may affect cognitive function.
5) Taking medications that may affect cognitive function.
6) People with extremely unbalanced dietary habits or extremely irregular lifestyle habits related to eating and sleeping.
7) People suspected of having insomnia.
8) People with a history of mental illness or alcoholism.
9) People who are currently participating in other clinical trials or have participated in other clinical trials within the past 3 months.
10) People with irregular employment schedules, such as night shifts.
11) Individuals who are deemed by the investigator to be unsuitable for this study.

Enrolled subjects were randomly assigned to the placebo or catechin group using a random number table, with age, sex, and MMSE-J score as allocation factors. Subjects performed both the serial sevens task and the backwards task on the MMSE-J, and assignment was based on the backwards task score. The randomization process was carried out by HUMA R&D CORP. (a contract research organization) in Japan.

Study design : This study was conducted with a double-blind, placebo-controlled, parallel-group design. Primary endpoints included MMSE-J and Cognitrax results. Secondary endpoints included serum levels of Aβ(1-40), Aβ(1-42), sAPPα, APP770, and BDNF.

Subjects were instructed to take three placebo or catechin capsules per day for 12 weeks, taking the capsules after breakfast. If they did not eat breakfast, they were instructed to take the capsules in the morning. Intake records were made on a computer using HUMA R&D CORP.'s Web input system. Subjects were not asked to limit their intake of other polyphenols (green tea, black tea, oolong tea, etc.) or to deviate from their usual diet. During the study period, subjects were prohibited from taking other health foods, supplements, or drugs that may affect cognitive function. In addition, they were instructed to avoid excessive exercise, dietary restrictions, binge eating, and heavy drinking. There were no specific restrictions on other types of health foods and supplements, but subjects were instructed to avoid taking these products as much as possible. If any of these products were taken, the type and amount were recorded on a record sheet. In addition, if they were taking medication, they were asked to record the name and dosage of the medication. Other than these restrictions, they were told to maintain their usual lifestyle. In addition, subjects recorded their intake status and the presence or absence of adverse events, respiratory infections, abdominal pain, etc. in a diary.

Mini-Mental State Examination (MMSE-J) was used in this study. The MMSE-J consists of 11 items, including orientation to time, orientation to place, memorization, attention and calculation, recall, naming, repetition, three-step command, reading, writing, and drawing, and the total score of these items is used for evaluation. In this study, two tests of attention and calculation were used from the above items, namely the backward spelling task and the serial sevens task. The score of the backward spelling task was used to assign subjects to the placebo or catechin group.

Cognitrax is a cognitive function testing service developed by the US company CNS Vital Signs (Morrisville, North Carolina) to measure both reaction time and number of responses. Test details are shown in Table 1.

On the day of the blood biomarker test, subjects were on a diet from 6 hours before arriving at the hospital until the test was completed. Serum collection tubes were used to estimate BDNF levels, and disodium ethylenediaminetetraacetate tubes were used to measure Aβ(1-40), Aβ(1-42), sAPPα, and APP770. After collection, blood was centrifuged at 3000 rpm and dispensed into 1.5 ml Eppendorf tubes. Measurements were performed using the kits at the following dilution rates: Aβ(1-42) blood samples were diluted 4-fold with the HumanAmyloid-β(FL) Assay Kit-IBL; sAPPα blood samples were diluted 4-fold with the sAPPα(high sensitivity) Assay Kit-IBL; and APP770 blood samples were diluted 50-fold with the Human APP770 Assay Kit-IBL. Blood samples for BDNF were diluted 20-fold with the Human BDNF ELISA Kit (Quantikine-R&D Systems). Measurements below the range of the kit were excluded due to inaccuracy. Table 9 shows the number of samples analyzed for each biomarker. Measurements were performed by Skylight Biotech Co., Ltd.

Statistical analysis: Each value is presented as the mean ± standard deviation (SD). Normality was tested with the Shapiro-Wilk test. If no significant difference was found, a t-test was used, and if a significant difference was found, a Mann-Whitney U test was used. Statistical analyses were performed at baseline, during the single-dose study, and at week 12. Data were analyzed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA). To account for the multiplicity of tests, the significance level of differences between conditions was adjusted to p < 0.05/3 = 0.017 by Bonferroni correction.

Results: Finally, 52 patients were enrolled in the study. After allocation to each group, one patient in the placebo group and one patient in the catechin group violated the exclusion criteria. Three patients in the catechin group dropped out during the study period due to personal reasons. The final analysis included 25 patients in the placebo group (12 men, 13 women) and 22 patients in the catechin group (12 men, 10 women). The clinical characteristics of the patients in this study are shown in Table 2.

MMSE-J (Interactive Test)
The mean MMSE-J (backwards task) scores before the intervention (baseline) were 27.6±1.8 in the placebo group and 27.8±1.3 in the catechin group. The mean scores after the intervention were 28.0±2.0 in the placebo group and 28.0±1.7 in the catechin group. No significant differences were observed between the groups before and after the intervention.

Cognitrax Test (PC-based cognitive function test)
The cognitive tests of Cognitrax were conducted in the following order: Verbal Memory Test (VBM), Visual Memory Test (VIM), Finger-tapping Test (FTT), Symbol Digit-coding Test (SDC), Stroop Test (ST), Shifting Attention Test (SAT), Continuous Performance Test (CPT), Perception of Emotions Test (POET), Non-verbal Reasoning Test (NVRT), and 4-part Continuous Performance Test (FPCPT). After that, VBM and VIM were repeated, and the results of the first VBM and VIM test were used to evaluate immediate memory, and the results of the second VBM and VIM test were used to evaluate delayed memory. There was an interval of approximately 50 minutes between the first VBM/VIM and the second VBM/VIM. The performance of memory-related tasks was evaluated using the results of VBM and VIM (Table 3). Attention-related tasks were evaluated using the results of the ST, SAT, CPT, and FPCPT parts 1 and 2 (Table 4). Facial expression recognition-related tasks were evaluated using the results of the POET (Table 5). Working memory-related tasks were evaluated using the results of parts 3 and 4 of the FPCPT (Table 6). Visual information processing-related tasks were evaluated using the results of the SDC and NVRT (Table 7). Motor function-related tasks were evaluated using the results of the FTT (Table 8).

Administration of tea catechins did not significantly affect VBM or VIM results, either after a single dose or after chronic ingestion.
VBM, Verbal Memory test; VIM, Visual Memory test.
Values are shown as mean ± standard deviation.

After a single dose, the catechin group made significantly fewer errors in the Continuous Processing Test (CPT) compared with the placebo group. No significant differences were observed in other attention-related tests.
ST, Stroop Test; SAT, Shifting Attention Test; CPT, Continuous Performance Test; FPCPT, Four-Part Continuous Performance Test.
*p < 0.05/3 = 0.017 vs. placebo group. P values were calculated using the Mann-Whitney U test with Bonferroni correction. Values are presented as mean ± standard deviation.

Perception of positive (calm, happy) and negative (sad, anger) emotions was assessed using the Perception of Emotions Test (POET), which assesses positive and negative emotions combined and positive and negative emotions separately. Using the POET, no significant differences were found between the placebo and catechin groups in the facial expression recognition task, either after a single dose or after chronic tea catechin intake.
POET, Perception of Emotions test.
Values are shown as mean ± standard deviation.

After repeated administration of tea catechins, the mean time to respond correctly in FPCPT part 4, which tests memory for the previous two pictures, was significantly lower in the catechin group than in the placebo group. In FPCPT part 3, which tests memory for the previous picture, no significant difference was found between the placebo and catechin groups. Daily intake of tea catechins for 12 weeks significantly reduced the mean time to respond correctly in the four-part sustained processing test compared to placebo.
FPCPT, Four-Part Continuous Performance Test.
Values are presented as mean ± standard deviation. *p < 0.05/3 = 0.017 vs. placebo group. P values were calculated using the Mann-Whitney U test with Bonferroni correction.

No significant differences were observed between the placebo and catechin groups in the SDC and NVRT.Catechin had no effect on visual information processing tasks after single or long-term administration.
SDC, Symbol Digit Coding Test; NVRT, Non-Verbal Reasoning Test.
Values are shown as mean ± standard deviation.

Using the FTT, no significant differences were found in the mean number of strokes for the right and left hands between the placebo and catechin groups. Catechin had no effect on motor function tasks after single administration or long-term intake.
FTT, Finger Tapping Test
Values are shown as mean ± standard deviation.

The first VBM and VIM performed indicate immediate memory, and the last indicates delayed memory. There was a time gap of approximately 50 minutes between the first and last VBM and VIM performed.

No significant differences were observed between the placebo and catechin groups in serum concentrations of amyloid-β1-40 or amyloid-β1-42, or the Aβ1-40/Aβ1-42 ratio. No significant differences were observed between the placebo and catechin groups in the secreted form of amyloid-β precursor protein α (sAPPα) or the level of amyloid-β precursor protein (APP) 770. In addition, no significant differences were observed between the placebo and catechin groups in serum concentrations of brain-derived neurotrophic factor (BDNF).

Values are shown as mean ± standard deviation.

Comparative Example: A randomized, double-blind, parallel-group comparative study similar to that described above was also conducted on catechin, caffeine, and matcha tea containing catechin. Samples were prepared in the same manner as capsules filled with catechin, and capsules were filled with theanine (50.3 mg), caffeine (72.5 mg), and catechin (171 mg) in amounts equivalent to 2 g of matcha tea. Of the catechins included, 110 mg was derived from epigallocatechin gallate.

As with catechin, this study recruited healthy Japanese men and women aged 50 to 69 years, and 62 subjects who did not meet the exclusion criteria were assigned to either the placebo or matcha group.

Subjects took nine capsules of either placebo or matcha green tea per day after breakfast for 12 weeks. As a result, the sustained processing test of the Cognitrax test did not show a reduction in incorrect responses (single administration) as was seen with catechin, and the four-part sustained processing test did not show a reduction in mean correct response time (12 weeks of administration) as was seen with catechin.

Claims (12)

A brain function improving agent containing tea polyphenols as an active ingredient, the tea polyphenols containing 40% by mass or more of epigallocatechin gallate (EGCG), the content of epigallocatechin gallate (EGCG) being greater than the content of other catechins, the other catechins further containing one or more selected from the group consisting of epigallocatechin gallate (EGCG), epicatechin gallate (ECG), gallocatechin gallate (GCG), catechin gallate (CG) and epicatechin (EC), and the catechins contained in the brain function improving agent are A brain function improver, the brain function of which is 1% by mass or less of phene, the brain function improver is substantially free of theanine, and the brain function is sustained attention, reaction speed or impulsivity as evaluated by the sustained processing test in the Cognitrax test, or working memory or sustained attention as evaluated by the 4-part sustained processing test (however, the total amount of epigallocatechin gallate (EGCG) and gallocatechin gallate (GCG) in the tea polyphenols is not 59-72% by mass, and the active ingredient is not epigallocatechin gallate (EGCG) alone ). The brain function improving agent according to claim 1 , wherein the content of epigallocatechin gallate (EGCG) in the tea polyphenols is 50% by mass or more, 60 % by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more . The brain function improving agent according to claim 1, wherein sustained attention, reaction speed or impulsivity, or working memory or sustained attention is a brain function not assessed by the Revised Hasegawa Dementia Scale or the Mini-Mental State Examination. The brain function improving agent according to claim 1 or 2, wherein the effective amount of epigallocatechin gallate is 100 to 400 mg per day. The brain function improving agent according to claim 4, wherein the effective amount of epigallocatechin gallate is a single dose. The brain function improving agent according to claim 1, wherein the improvement in sustained attention, reaction speed, or impulsivity is a reduction in the number of incorrect responses in the sustained processing test of the Cognitrax test compared to when matcha is administered. The brain function improving agent according to claim 1, wherein the sustained processing test is an examination of the time required to respond when a specific letter is displayed while letters are displayed randomly. The brain function improving agent according to claim 1, wherein the improvement in working memory or connectivity attention is a decrease in the mean correct response time in the four-part sustained processing test of the Cognitrax test compared to when matcha is administered. The brain function improving agent according to claim 1, wherein the four-part sustained processing test is a test of memory for two pictures prior to randomly displayed pictures. A composition for improving sustained attention, reaction speed or impulsivity as assessed by the sustained processing test in the Cognitrax test, or working memory or sustained attention as assessed by the 4-part sustained processing test, comprising the brain function improving agent according to any one of claims 1 to 9. The composition according to claim 10, in the form of a beverage, food, supplement or medicine. The composition according to claim 10 or 11, in the form of a liquid, powder, tablet or capsule.