Composition for improving brain function

Abstract

[Problem] To provide a novel composition having a brain function-improving effect. [Solution] The problem is achieved by a brain function-improving composition characterized by containing a sulfated polysaccharide. The sulfated polysaccharide is preferably rhamnan sulfate.

Description

[Technical Field]

[0001] The present invention relates to a composition for improving brain function. [Background technology]

[0002] Dementia is not a specific disease name, but refers to a condition in which brain function (cognitive function) deteriorates due to some kind of disease or disorder, causing memory loss and interfering with daily life and work. In recent years, even mild symptoms that do not interfere with daily life or work have come to be diagnosed as mild cognitive impairment (MCI). Everyone experiences a decline in memory and forgetting people's names as they age. This condition is caused by the aging of the brain and is different from dementia. In contrast, forgetfulness due to dementia is caused by the destruction of nerve cells in the brain and is different from aging. As dementia progresses, people forget entire experiences and are unable to recall them even when given hints.

[0003] In Japan, the number of dementia patients is increasing year by year, and it is estimated that there are currently more than 3 million dementia patients. As a therapeutic agent for dementia, anticholinesterase inhibitors are used to treat Alzheimer's dementia, but they only somewhat suppress the progression of symptoms, and no definitive therapeutic agent is available. Recent research has revealed that foods and food-derived components are effective in maintaining, developing, and improving brain function. For example, it has been revealed that an oral composition containing chlorogenic acid extracted from coffee beans (Patent Document 1) and a substance extracted from garlic skin (Patent Document 2) are effective in improving brain function. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-39797 [Patent Document 2] Japanese Patent Publication No. 2021-153571 Summary of the Invention [Problem to be solved by the invention]

[0005] As the increase in dementia patients has become a major social problem, new compositions that are effective in improving brain function have been sought. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel composition having the effect of improving brain function. [Means for solving the problem]

[0006] As a result of extensive research, the present inventors have discovered that sulfated polysaccharides have the effect of improving brain function, and have basically completed the present invention. Thus, the composition according to the present invention is characterized by containing sulfated polysaccharides and exhibiting the effect of improving brain function. In the above invention, the sulfated polysaccharide is preferably rhamnan sulfate. The compositions of the present invention are preferably for oral administration. The dosage of rhamnan sulfate is preferably 10 mg to 1000 mg per day, more preferably 30 mg to 500 mg, and even more preferably 50 mg to 300 mg. Furthermore, the composition of the present invention can be provided as a food composition for improving brain function. Here, brain function mainly refers to cognitive function, and preferably includes the neurocognitive index (NCI), reaction time, overall attention, cognitive flexibility, executive function, and logical thinking. Diseases associated with decreased brain function include, for example, depression, schizophrenia, and autism.

[0007] The composition is provided by combining an effective amount of rhamnan sulfate for improving brain function with a pharmaceutically acceptable carrier or additive. This composition is provided as a drug or quasi-drug. The pharmaceutical composition is used internally or externally. This pharmaceutical composition can be used in the form of an oral preparation, an injection such as an intravenous injection, a subcutaneous injection, an intradermal injection, an intramuscular injection, and / or an intraperitoneal injection, a transmucosal application preparation, a transdermal application preparation, or the like. In particular, since rhamnan sulfate is effective when administered orally or transdermally, it is preferably used as an oral preparation, a transmucosal application preparation, or a transdermal application preparation. The dosage form of the pharmaceutical composition can be appropriately set, and examples thereof include solid preparations such as tablets, granules, capsules, powders, and dustings, liquid preparations such as solutions and suspensions, ointments, and semi-solid preparations such as gels. Although many factors that cause brain function decline are known, the present invention is particularly effective against the decline in brain function caused by diabetes. Therefore, the composition for improving brain function according to the present invention is preferably for the decline in brain function caused by diabetes. In this case, it is preferable that the improvement of brain function is due to an increase in blood nicotinamide concentration. In addition, a composition for improving pancreatic function according to another invention preferably contains rhamnan sulfate and protects the pancreas by increasing blood nicotinamide concentration. The present inventors have found that ingesting rhamnan sulfate increases blood nicotinamide concentration. Therefore, it has been found that rhamnan sulfate can protect the pancreas.

[0008] In the food industry, rhamnan sulfate can be used as a food ingredient in various foods to provide food compositions. In this way, food compositions labeled for improving brain function can be provided. Examples of food compositions include general foods, foods for specified health uses, foods with nutrient functions, foods with functional claims, foods for hospital patients, and supplements. Additionally, rhamnan sulfate can be used as a food additive. Examples of food compositions include beverages (soft drinks, alcoholic beverages, carbonated drinks, dairy drinks, fruit juice drinks, tea, coffee, energy drinks, concentrated drinks, etc.), powdered drinks (powdered juice, powdered soup, etc.), sweets (candy (throat lozenges), cookies, biscuits, gum, gummy candies, chocolate, etc.), bread, cereal, seasonings, etc.

[0009] In the case of foods for specified health uses, foods with nutrient functions, and foods with functional claims, they can also be provided in the form of capsules, lozenges, syrups, granules, powders, etc. Foods for specified health uses are foods containing functional health ingredients that affect physiological functions, etc., and can be labeled as suitable for specific health uses with the permission of the Commissioner of the Consumer Affairs Agency. In this invention, the foods are sold with a label indicating a specific use, such as an effect of improving brain function. Foods with nutrient functions are foods used to supplement nutritional components (vitamins, minerals), and display the function of the nutritional components. To be sold as a food with nutrient functions, the amount of nutritional components contained in the recommended daily intake must be within the specified upper and lower limits, and not only nutritional function labeling but also warning labeling is required.

[0010] Foods with functional claims are foods that display scientifically based functionality at the responsibility of the business operator. Information on the basis of safety and functionality is submitted to the Commissioner of the Consumer Affairs Agency before sale. The present invention contains rhamnan sulfate as an active ingredient and is used as a food for specified health uses, a food with nutrient functions, or a food with functional claims for healthy individuals and individuals with mild cognitive impairment (MCI) (including those with mild symptoms). The present invention contains rhamnan sulfate as an active ingredient and is used as a food with functional claims for improving brain function (particularly, a food with functional claims for improving cognitive function) for humans. [Effects of the Invention]

[0011] According to the present invention, a novel composition for improving brain function can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a flowchart showing the tracking of test participants in Test 1 according to the present embodiment. [Figure 2] 7A and 7B are bar graphs showing the scores for which significant differences were observed between the subject group and the placebo group. (A) shows the mean ± standard deviation of the actual data, and (B) shows the mean ± standard deviation of the difference data (the same applies to Figures 3 to 7). These graphs show the results of the NCI standardized score data. [Figure 3] 1 is a graph showing the results of standardized score data of reaction time. [Figure 4] 10 is a graph showing the results of standardized score data for overall attention. [Figure 5] 1 is a graph showing the results of cognitive flexibility standardized score data. [Figure 6] 1 is a graph showing the results of standardized score data for executive function. [Figure 7] 10 is a graph showing the results of standardized score data for logical thinking.

[0013] [Figure 8] 1 is a bar graph showing the body weights of mice in Experiment 2. 1% MD indicates administration of 1% sugar-containing water (1% maltodextrin), RS100 indicates administration of 100 mg / kg rhamnan sulfate, RS300 indicates administration of 300 mg / kg rhamnan sulfate, and RS1000 indicates administration of 1000 mg / kg rhamnan sulfate. In the graph, "ns" indicates no significant difference, "*" indicates significance at a 5% level (p<0.05), "**" indicates significance at a 1% level (p<0.01), "***" indicates significance at a 0.1% level (p<0.001), and "****" indicates significance at a 0.01% level (p<0.0001) (the same applies to the following figures). [Figure 9] 1 is a bar graph showing the results of measuring blood glucose levels. [Figure 10] 1 is a bar graph showing the results of measuring locomotor activity. [Figure 11]1 is a bar graph showing task completion times in an eight-arm maze test. [Figure 12] 1 is a bar graph showing the number of errors in the eight-arm maze test. [Figure 13] 1 is a bar graph showing the results of a rotarod test. [Figure 14] 1 is a bar graph showing the results of comparing the thickness of the hippocampal neuronal layer CA1. [Figure 15] These are micrographs showing the results of immunostaining brain pathological tissue sections using an anti-AGE antibody. From the upper left to the right, representative samples are shown for the Control group and the 1% MD group, and from the lower left to the right, the 1% MD+RS100 group, the 1% MD+RS300 group, and the 1% MD+RS1000 group (the order of the photographs is the same in Figure 16). [Figure 16] FIG. 1 is a micrograph showing the results of immunostaining a brain tissue section using an anti-Iba1 antibody. DETAILED DESCRIPTION OF THE INVENTION

[0014] Next, embodiments of the present invention will be described with reference to the drawings. However, the technical scope of the present invention is not limited to these embodiments, and the invention can be embodied in various forms without changing the gist of the invention. <Preparation of rhamnan sulfate> Any naturally occurring rhamnan sulfate can be used. In this embodiment, rhamnan sulfate obtained by hot water extraction from Monostroma nigra was used. Dried seaweed was washed with water and extracted with hot water. The resulting hot water extract was filtered to obtain an extract (Rhamnox 100) containing rhamnan sulfate as the main component (60% to 90% (average about 70%)). This was used as the sample of the present invention. The sulfated polysaccharides (e.g., rhamnan sulfate) that can be used in the present invention can be prepared by various methods other than the above. Furthermore, the raw material is not limited to Ulva pertusa, but also Ulva ribbon, etc. can be used.

[0015] <Test 1: Test on healthy subjects> <Test Method> 1. Subjects (1) Eligibility criteria The enrollment criteria for subjects were healthy Japanese people (both males and females) between the ages of 40 and 65. The exclusion criteria were as follows: those currently undergoing treatment for or with a history of malignant tumors, heart failure, or myocardial infarction; those with an implanted pacemaker or implantable cardioverter defibrillator; those undergoing treatment for arrhythmia, liver damage, kidney damage, cerebrovascular disease, rheumatism, diabetes, dyslipidemia, hypertension, or other chronic diseases; those who regularly consume foods for specified health uses, foods with functional claims, or other foods or beverages that are thought to have functionality; those who regularly consume seaweed or products containing ingredients derived from seaweed; those who regularly use medicines (including herbal medicines) or supplements; those with allergies (to medicines or foods related to the test food); those who are pregnant, breastfeeding, or intend to become pregnant during the study period; those who have participated in other clinical trials in the 28 days prior to the date of consent acquisition or those who plan to participate in such trials during the study period; those who are smokers; and those who the principal investigator deemed to be unsuitable for this study.

[0016] (2) Management of subjects The subjects' physical condition was ascertained through interviews when they visited the hospital. During the test period, participants were required to record daily whether they had taken the test food and whether they had their period (women only) in a diary designated by the contract clinical trial organization. The diary was submitted by mail every week, and if there was a diary that had not been submitted at the time of the final examination, they were required to bring it with them when they visited the hospital and submit it. The diary for the final examination was submitted at the time of the visit. If it could not be submitted at the time of the visit, it was completed on the spot. Subjects were asked to strictly adhere to the following points during their participation in the study: (a) consume the test food according to the prescribed usage and dosage, (b) consume the test food so that the intake rate is 80% or more, (c) avoid overeating and drinking and do not change their previous lifestyle habits from the day of obtaining the consent form until the final test (the test 8 weeks after intake), (d) refrain from drinking alcohol or engaging in excessive exercise from the day before each test until the end of the test on the day, (e) refrain from eating or drinking for 6 hours before blood sampling (this included not consuming the test food, although only water was permitted; functional water and tea were not allowed), (f) if any changes in their physical condition occurred during the study period, immediately contact the contracted clinical trial organization and ask for instructions on how to proceed, and (g) avoid, as much as possible, consuming foods for specified health uses, foods with functional claims, or other foods or beverages that may have functional properties during the study period.

[0017] (3) Dropout and Cancellation Rules Subjects who met any of the following criteria were considered to have dropped out of the study. Safety assessments were conducted on an individual basis: (a) when the study was discontinued for personal reasons; (b) when it was discovered that the subject was not following the instructions of the investigator or study organizer; (c) when there was a significant deviation from the compliance requirements set out in the protocol; or (d) when the investigator deemed it appropriate to drop the subject. In addition, subjects who met any of the following criteria were discontinued: (a) when a serious adverse event occurred and the investigator determined that the subject's participation in the study should be discontinued, (b) when the investigator determined that it would be difficult for the subject to continue the study due to objective symptoms, or (c) when the investigator determined that it would be difficult to continue the study for other reasons. In addition, the trial was to be discontinued if any unexpected serious adverse events occurred or if any serious violations or non-compliance with ethical guidelines or the protocol occurred.

[0018] 2. Test food The test food group used a seaweed-derived extract (containing rhamnan sulfate), and the placebo group used a placebo that did not contain the seaweed-derived extract. 3. Exam Period The subjects were asked to take the test food or placebo for eight weeks. Cognitive function was assessed twice: before and after the intake period. 4.Dose The following is the procedure: Test food group: Take one capsule per day Placebo group: Take one capsule daily However, the daily dose was to be taken on the same day, and if a dose was forgotten, it was to be taken as soon as remembered. The test foods were stored at room temperature, avoiding direct sunlight, high temperatures and humidity. The test food was manufactured by Konan Chemical Co., Ltd. The test food was indistinguishable in appearance, shape, color, odor, and taste. The composition of the test food (per capsule) is shown in Table 1. "Rhamnox 100" refers to an extract of Rhamnox acutus, the main component of which is rhamnan sulfate (approximately 70%). Each capsule of the test food (containing 120 mg of Rhamnox 100) contains approximately 90 mg of rhamnan sulfate. "Max 1000" refers to dextrin.

[0019] [Table 1]

[0020] 5.Measurement items The following items were measured as cognitive function tests. (1) Using Cognitrax, 10 types of tests were administered (verbal memory test, visual memory test, finger tapping test, SDC test, Stroop test, attention shifting test, sustained processing test, facial expression recognition test, logical thinking test, and four-part sustained processing test). (2) The survey items used were standardized scores for overall memory and standardized scores for other cognitive domains (Neurocognitive Index (NCI), verbal memory, visual memory, cognitive function speed, reaction time, overall attention, cognitive flexibility, processing speed, executive function, social cognition, logical thinking, working memory, sustained attention, simple attention, and motor speed). (3) Evaluation methods included screening and pre-intake tests, and tests 8 weeks after intake. (4) Physical measurements included height, weight, body fat percentage, and body temperature. BMI was calculated by dividing weight (kg) by the square of height (m). The test was conducted as a screening test before intake and an 8-week post-intake test. However, height was measured only at the information session.

[0021] (5) In addition, as part of the physical examination, blood pressure (systolic blood pressure, diastolic blood pressure) and pulse rate were measured. In addition, urine tests (protein, glucose, urobilinogen, bilirubin, ketone bodies, pH, occult blood) and peripheral blood tests (white blood cell count, red blood cell count, hemoglobin, hematocrit value, platelet count, MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), MCHC (mean corpuscular hemoglobin concentration), white blood cell picture (neutrophil rate, lymphocyte rate, monocyte rate, eosinophil rate, basophil rate, neutrophil count, lymphocyte count, monocyte count, The following were measured: eosinophil count, basophil count, AST (GOT), ALT (GPT), γ-GT (γ-GTP), ALP, LD (LDH), LAP, total bilirubin, direct bilirubin, indirect bilirubin, cholinesterase (ChE), total protein, urea nitrogen, creatinine, uric acid, CK, calcium, serum amylase, total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides (TG: neutral fat), glycoalbumin, serum iron (Fe), sodium (Na), potassium (K), chloride (Cl), inorganic phosphorus (IP), glucose, hemoglobin A1c (HbA1c: NGSP), and nonspecific IgE.

[0022] (6) Subject recruitment, allocation, and double-blinding The number of screening cases was 15, the target number of cases was 10, and the actual number of cases was 12. Participants were recruited through a monitor recruitment site operated by a contract clinical trial organization. The 12 people were divided into two groups of six people each and assigned to either the test food group or the placebo group. All subjects were assigned to the study on the same day after the target number of enrolled cases was reached. Random numbers were generated on a computer, and a randomization list was created using a completely random method with predetermined variables as factors. Study participants were enrolled based on the randomization list. The allocation ratio was 1:1. The study was conducted using a double-blind method. Blinding was achieved by using indistinguishable test foods. The person in charge of shipping the test foods at the contract clinical trial organization confirmed that the test foods were indistinguishable and entered and confirmed the screening test data, then communicated the identification number to the person in charge of allocation.

[0023] (7) Data collection and management The measurement data for physical measurements and physical examinations were entered into paper medical records by staff at the study institution. The study participants themselves filled out questionnaires, which were then collected by staff at the study institution. Paper-based measurement results (medical records and questionnaires) were obtained by the monitoring staff. The measurement results for urine tests and peripheral blood tests were obtained as ".txt" data (electronic data) from m-Line (http: / / www.medience.co.jp / mline / ), operated by LSI Medience Corporation. Data management was led by the contracted clinical trial organization. The .csv data collected by the monitoring staff and the electronic data obtained via m-Line were imported into Microsoft Access and saved at the contracted clinical trial organization. One staff member entered the paper-based measurement results into Microsoft Access. Two staff members checked the entered data for errors.

[0024] The medical institution conducting the trial, the institution with an ethical review committee, the contract clinical trial organization, and the sponsor have agreed to keep documents that should be kept at their respective institutions for two years after the end of the trial. When storing documents, they have been appropriately managed to prevent the leakage, mixing, theft, loss, etc. of personal information. Furthermore, once the storage period has expired, the documents will be anonymized and discarded. The biological samples (blood and urine) collected from the study participants were used for no other purpose than measurement, and after the measurement they were anonymized and disposed of as medical waste. The storage and disposal of the samples was outsourced to LSI Medience Corporation.

[0025] (8) Statistical methods The entire enrollment population set provided informed consent and was included in the study. The full analysis set (FAS) was the set of all registered populations, excluding cases that met one or more of the following criteria: (a) cases that did not receive the allocated intervention, (b) cases that did not meet the criteria for the target population (cases with a confirmed diagnosis of some disease or cases that met clearly defined, objectively assessable important inclusion / exclusion criteria), (c) cases that never received the intervention after allocation, and (d) cases with no post-allocation data. The per protocol analysis set (PPS) was a group obtained by excluding cases that met one or more of the following criteria in the FAS: (a) cases in which the intake rate of the test food was less than 80%, (b) cases in which behavior that significantly undermined the reliability of the study results, such as missing diary records, (c) cases in which it became clear that they met the exclusion criteria after study enrollment, (d) cases in which it was discovered that they had violated compliance during the study period, (e) cases in which they had consumed food or medicines during the study period that were expected to significantly affect the study results, (f) cases in which they had engaged in activities that were significantly different from their lifestyle at the time of study enrollment, and (g) cases in which there were other clear reasons that made it appropriate to exclude them.

[0026] The safety analysis population (SAF) was comprised of the entire enrolled population, excluding cases that met one or more of the following criteria: (a) cases that did not receive the allocated intervention, (b) cases that never received the intervention after allocation, and (c) cases for which safety endpoints were never measured after allocation. Demographic data for study participant background was compiled for the entire registered population set or other analysis datasets, and gender was compared between groups using the chi-square test, and other items were compared using the Student's t-test. For statistical analysis of efficacy endpoints, PPS was used as the analysis dataset for the primary outcome. Means and standard deviations were presented, and comparisons between groups were performed using ANCOVA with baseline as a covariate. When other tests, such as unpaired t-tests, were necessary from multiple perspectives, they were also used to evaluate efficacy. Next, the PPS was used as the analysis dataset for secondary outcomes. Means and standard deviations were shown, and actual measured values ​​were compared between groups using ANCOVA with baseline as a covariate. Changes from the screening test and pre-intake test were compared between groups using unpaired t-tests. If other tests were required from a multifaceted perspective beyond the above-mentioned analytical methods, they were also used to evaluate effectiveness.

[0027] For statistical analysis of safety endpoints, SAF was used in the analysis dataset as the primary safety endpoint. Occurring side effects and adverse events were tabulated for each study participant. The incidence rates of side effects and adverse events were tabulated by group, and the 95% confidence intervals for the incidence rates by group and the differences in incidence rates between groups were calculated. The incidence rates of side effects and adverse events in each group were also compared using chi-square tests and other methods. As a secondary safety endpoint, the SAF was used in the analysis dataset. The proportion of cases in which urine test and peripheral blood test values ​​that were within the reference range at the screening and pre-intervention test fell outside the reference range after the intervention was calculated, and comparisons were made between groups at each time point using the chi-square test. In addition, if other tests were necessary from a multifaceted perspective, they were also used to evaluate safety. For other safety evaluation items, data tables were compiled for each study participant. In addition, the principal investigator or a sub-investigator checked the safety evaluation items on an individual basis to confirm that no medically problematic changes occurred due to the intake of the test food. In addition, when other tests or stratified analyses were deemed necessary from a multifaceted perspective, such as at case study meetings, appropriate other tests or stratified analyses were performed. All statistical analyses were performed using two-sided tests, with a significance level of 5%. SPSS Statistics version 23 or higher was used, and other statistical software was used as necessary. This study focused on the primary outcome, and multiplicity that occurs in secondary outcomes set as multiple hypotheses was not taken into consideration.

[0028] <Test Results> The following abbreviations and full names were used: ITT: Intention to treat, PPS: Per protocol set, SAF: Safety analysis population, VISIT 1: Screening and pre-intake test (baseline), VISIT 2: Test 8 weeks after intake, Change: Change from screening and pre-intake test at the test 8 weeks after intake, Mean: Mean value, SD: Standard deviation, SE: Standard error, 95% CI- and 95% CI+: 95% confidence interval. Figure 1 shows a flowchart of the follow-up of study participants. This study targeted healthy Japanese men and women aged 40 to 65 years. Of the 23 people who agreed to participate in the study, 12 who met the eligibility criteria were enrolled in the study, with six people assigned to the test food group and six to the placebo group. All participants completed the study, and no one violated the compliance requirements. The analysis datasets were the PPS and SAF, which were determined at the time of study planning, and consisted of 12 people each. The characteristics of the study participants are shown in Table 2.

[0029] [Table 2] The mean and SD of the cognitive function tests, the intergroup differences and their SE, 95% CI-, 95% CI+, and statistical analysis results are shown in Tables 3 and 4.

[0030] [Table 3]

[0031] [Table 4]

[0032] As shown in Tables 3 and 4, no significant differences were observed between the test food group and the placebo group in the standardized scores for overall memory, verbal memory, visual memory, cognitive function speed, social cognition, working memory, sustained attention, simple attention, motor speed, and processing speed. In contrast, significant differences (P<0.05) were observed between the subject and placebo groups in the standardized NCI scores, standardized reaction time scores, standardized overall attention scores, standardized cognitive flexibility scores, standardized executive function scores, and standardized reasoning scores. Specifically, the differences were P=0.004, P=0.049, P=0.043, P=0.019, and P=0.042, respectively, in VISIT 2. A trend toward improvement was also observed in the difference in reasoning scores (P=0.070). Figures 2 to 7 show (A) bar graphs showing the mean ± standard deviation of the actual data, and (B) bar graphs showing the mean ± standard deviation of the differential data for the NCI standardized scores, standardized reaction time score, standardized overall attention score, standardized cognitive flexibility score, standardized executive function score, and standardized logical thinking score. Furthermore, no significant differences were observed in the incidence of side effects, adverse events, or secondary safety evaluation items among the subject groups. In addition, when the results of individual anthropometric and physical examination data were reviewed, it was confirmed that no medically problematic changes occurred due to the intake of the test food.

[0033] <Test 2: Test using diabetic model mice> <Test Method> C57BL / 6J mice (7 weeks old) were fasted for 24 hours, then intraperitoneally administered 240 mg / kg body weight of 1.2% w / v nicotinamide (NA) solution, followed 15 minutes later by intraperitoneal administration of 100 mg / kg body weight of 1% w / v streptozotocin (STZ) solution. This procedure was repeated twice, one day apart, followed by a 4-month glucose loading regimen. The following five groups were prepared for the study. The control group was given a normal diet and clean water. The STZ group was given a high-fat diet and water containing 1% sugar (1% MD (Maltodextrin)). The STZ+RS group was given a high-fat diet and water containing rhamnan sulfate (100 mg / kg, 300 mg / kg, 1000 mg / kg). Each group consisted of six rats. After 4 months of glucose loading, the rats were weighed, blood glucose levels were measured, and behavioral pharmacological tests and brain pathological autopsies were performed. The behavioral pharmacological tests included spontaneous locomotor activity tests, an eight-arm maze test, and a rotarod test. In addition, pathological tissue sections of the brain were immunostained with anti-AGE and anti-Iba1 antibodies and examined pathologically.

[0034] In the spontaneous locomotor activity test, the amount of exercise was quantified as activity level, and the amount of exercise spontaneously exhibited was confirmed. The eight-arm maze test was conducted using an elevated maze with eight lanes arranged radially from a central platform. A reward was placed at the end of each lane, and the time it took to reach it was measured. This test evaluated memory-related cognitive functions. In this test, the time to complete the task was measured from the start up to a maximum of 600 seconds, and if the task was not completed within that time, the time was set to 600 seconds. In the rotor rod test, a mouse was placed on a rotating rod, and the speed of the rod was gradually increased to measure the time it took for the mouse to fall. This test assessed motor dysfunction in cognitive function and motor memory in behavior. Cognitive function was evaluated comprehensively based on the results of these three behavioral pharmacological tests. For statistical analysis, Dunnett's test was used for data on body weight, hippocampal blood glucose level, and behavioral pharmacology test, and chi-square test was used for data on AGE1 and Iba1.

[0035] <Test Results> Figure 8 shows the results of weight measurements for each group. Compared to the control group, the 1% MD group showed a significant increase in weight. Furthermore, although no significant difference was observed in the rhamnan sulfate-administered group, the 1% MD+RS100 group showed a tendency for weight to decrease compared to the 1% MD group. Figure 9 shows the results of measuring blood glucose levels in each group. Blood glucose levels were significantly higher in the 1% MD group compared to the control group. Furthermore, blood glucose levels were significantly lower in all groups administered rhamnan sulfate compared to the 1% MD group. The results of measuring spontaneous movement are shown in Figure 10. Although no significant difference was observed, spontaneous movement tended to decrease in the 1% MD group compared to the control group. Figure 11 shows the results of the task completion time in the eight-arm maze test, and Figure 12 shows the results of the number of errors in the eight-arm maze test. In terms of task completion time, all animals in the 1% MD group were unable to complete the task, taking 600 seconds, which was significantly longer than the control group. Furthermore, although no significant difference was observed, the 1% MD+RS100 and 1% MD+RS300 groups showed a tendency for task completion time to be shorter than the 1% MD group. In terms of the number of errors, the 1% MD group significantly increased compared to the control group. Furthermore, the 1% MD+RS100 group showed a significantly lower number of errors than the 1% MD group, with a risk level of 6.06%.

[0036] The results of the rotarod test are shown in Figure 13. The time to fall was significantly shorter in the 1% MD group compared to the control group. Furthermore, although no significant difference was observed, the RS group tended to have a longer time to fall compared to the 1% MD group. Figure 14 shows the results of comparing the thickness of the hippocampal neuronal layer CA1. The CA1 layer was significantly thinner in the 1% MD group compared to the control group, confirming hippocampal atrophy. Furthermore, the CA1 layer was significantly thicker in the 1% MD+RS100 and 1% MD+RS300 groups compared to the 1% MD group, demonstrating an improvement in atrophy. In addition to CA1, the thickness of CA2, CA3, and the dentate gyrus was also measured, and the results were similar to those for CA1.

[0037] Figure 15 shows the results of immunostaining brain pathological tissue sections using an anti-AGE antibody. AGE stands for advanced glycation end products, and it has been suggested that they may be involved as a causative substance in cognitive impairment. Inhibiting the production of these substances may potentially improve cognitive impairment. Compared to the control group, the 1% MD group had a significantly increased amount of AGE (Table 1). Meanwhile, administration of RS together with 1% MD appeared to inhibit the increase in AGE amount. With 1% MD RS100, the increase in AGE was significantly inhibited with a risk factor of 7.6% (Table 5). Thus, it is believed that rhamnan sulfate improves cognitive function by inhibiting the production of AGE. Figure 16 shows the results of immunostaining brain histopathological sections using anti-Iba1 antibodies. Iba1 stands for "ionized calcium-binding adapter molecule 1," a protein specifically expressed in microglia in the brain, and is also used as a microglial marker. Iba1 is known to be involved in inflammation in the brain, and inhibiting this molecule may improve brain inflammation (cognitive dysfunction). Compared to the control group, the 1% MD group showed a significant increase in Iba1 levels (Table 6). On the other hand, administration of RS with 1% MD significantly suppressed the increase in Iba1 levels in both groups (especially RS100, Table 6). These results suggest that rhamnan sulfate inhibits Iba1 production, thereby suppressing brain inflammation and improving cognitive function. These results indicate that administration of rhamnan sulfate (especially in the RS100 group) improves cognitive function in patients with diabetes, and that rhamnan sulfate also improves hippocampal atrophy caused by diabetes.

[0038] [Table 5]

[0039] [Table 6]

[0040] <Consideration> In the above-mentioned <Study 1>, healthy Japanese adult men and women aged 40 to under 65 were surveyed to examine the effects on dementia of 8 weeks of continuous intake of a food containing a seaweed extract containing rhamnan sulfate as an active ingredient. Cognitive function tests showed that the Neurocognitive Index (NCI), an index of overall cognitive function, was significantly higher in the test food group than in the placebo group after eight weeks of intake. The NCI is a score composed of 11 domains: overall memory, verbal memory, visual memory, cognitive function speed, reaction time, overall attention, cognitive flexibility, processing speed, executive function, simple attention, and motor speed. In this study, reaction time, overall attention, cognitive flexibility, and executive function were also significantly higher in the test food group than in the placebo group after eight weeks of intake. Standardized scores for cognitive function tests were calculated based on normative data for the same age, normalized to a mean of 100 points and a standard deviation of 15 points; higher scores indicate better performance. All standardized scores in the test food group tended to be higher than the mean for the same age group after intervention compared to the placebo group, suggesting that test food intake contributed to clinically significant improvements in cognitive function. There have been few previous studies examining the cognitive function-enhancing effects of rhamnan sulfate intake in healthy individuals, and its mechanism of action is unclear. However, because rhamnan sulfate has anticoagulant and thrombolytic properties, it may have the effect of improving blood flow.

[0041] Aging is a factor that leads to decreased cerebral blood flow, and previous studies have suggested a correlation between age-related decreases in cerebral blood flow and cognitive decline. Based on this, a possible mechanism of action for the cognitive improvement effect in this study is that rhamnan sulfate intake may have reduced blood flow inhibitors, thereby increasing cerebral blood flow and improving cognitive function. Another possible mechanism of action is that rhamnan sulfate has been shown to improve the intestinal environment, including promoting the intestinal flora-related nicotinamide metabolic system. Furthermore, it has been reported that the intestinal environment and nicotinamide / nicotinamide metabolites contribute to cognitive function improvement. Therefore, it is possible that rhamnan sulfate may contribute to improved brain and cognitive function by improving the intestinal environment and thereby increasing blood nicotinamide levels. In <Test 2>, a mouse model was used to confirm the effect of rhamnan sulfate on diabetic cognitive decline. The results showed that rhamnan sulfate was effective in improving diabetic cognitive decline and in ameliorating atrophy of the hippocampal neuronal layer. Rhamnan sulfate also protected the pancreas by increasing blood nicotinamide levels. Therefore, it was found that rhamnan sulfate could also be used as a composition for improving pancreatic function. As described above, according to this embodiment, a novel composition that is safe and has the effect of improving brain function can be provided.

Claims

1. A composition for improving brain function, characterized by containing rhamnan sulfate derived from Monostroma aestivum.

2. The composition for improving brain function according to claim 1, wherein the composition is for oral administration.

3. A food composition for improving brain function, comprising the composition for improving brain function according to claim 2.

4. 3. The composition for improving brain function according to claim 2, characterized in that it improves brain function by increasing blood nicotinamide concentration.

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