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Epidemiological studies have demonstrated that the intake of green tea is effective in reducing the risk of dementia. The most important component of green tea is epigallocatechin gallate (EGCG). Both EGCG and epigallocatechin (EGC) have been suggested to cross the blood–brain barrier to reach the brain parenchyma, but EGCG has been found to be more effective than EGC in promoting neuronal differentiation. It has also been suggested that the products of EGCG decomposition by the intestinal microbiota promote the differentiation of nerve cells and that both EGCG and its degradation products act on nerve cells with a time lag. On the other hand, the free amino acids theanine and arginine contained in green tea have stress-reducing effects. While long-term stress accelerates the aging of the brain, theanine and arginine suppress the aging of the brain due to their anti-stress effect. Since this effect is counteracted by EGCG and caffeine, the ratios between these green tea components are important for the anti-stress action. In this review, we describe how green tea suppresses brain aging, through the activation of nerve cells by both EGCG and its degradation products, and the reductions in stress achieved by theanine and arginine.

By comprehensively measuring changes in metabolites in the hippocampus of stress-loaded mice, we investigated the reasons for stress vulnerability and the effect of theanine, i.e., an abundant amino acid in tea leaves, on the metabolism. Stress sensitivity was higher in senescence-accelerated mouse prone 10 (SAMP10) mice than in normal ddY mice when these mice were loaded with stress on the basis of territorial consciousness in males. Group housing was used as the low-stress condition reference. Among the statistically altered metabolites, depression-related kynurenine and excitability-related histamine were significantly higher in SAMP10 mice than in ddY mice. In contrast, carnosine, which has antidepressant-like activity, and ornithine, which has antistress effects, were significantly lower in SAMP10 mice than in ddY mice. The ingestion of theanine, an excellent antistress amino acid, modulated the levels of kynurenine, histamine, and carnosine only in the stress-loaded SAMP10 mice and not in the group-housing mice. Depression-like behavior was suppressed in mice that had ingested theanine only under stress loading. Taken together, changes in these metabolites, such as kynurenine, histamine, carnosine, and ornithine, were suggested to be associated with the stress vulnerability and depression-like behavior of stressed SAMP10 mice. It was also shown that theanine action appears in the metabolism of mice only under stress loading.

Epidemiological and animal studies have demonstrated that ingestion of green tea enhances healthy life. However, caffeine in green tea can interfere with sleep. In this report, we examined the effect of green tea with lowered caffeine, low-caffeine green tea, on stress and sleep of the elderly. The participants (n = 10, mean age 89.3 ± 4.2 years) drank five cups/day of standard green tea for 1 week. Subsequently, they drank five cups/day of low-caffeine green tea for 2 weeks. Salivary α-amylase activity (sAA) was measured as a stress marker. Sleep stages were measured using a portable electroencephalography (n = 7, 6 female and 1 male). The level of sAA in the morning (sAAm) was significantly lower when the participants drank low-caffeine green tea than standard green tea. While the levels of sAAm were different among individuals, lower sAAm correlated with a higher quality of sleep. In those participants whose sAAm was lowered by the ingestion of low-caffeine green tea, some sleep parameters improved. Daily ingestion of low-caffeine green tea may be a beneficial tool for improving the quality of sleep of the elderly via the suppression of stress, although further research is required to fortify this hypothesis.

Epidemiological and animal studies have shown that the ingestion of green tea enhances a healthy life. However, caffeine in green tea can interfere with sleep. On the other hand, theanine, the major amino acid in green tea, blocks the effect of caffeine. We examined the interaction among tea components and sleep using green tea with a lowered caffeine content (LCGT). Sleep stages measured in participants, which consisted of elderly and middle-aged individuals, showed that early morning awakening was improved in many participants who ingested LCGT. The ratio of slow-wave sleep (sleep quality) was higher in the middle-aged participants who consumed a higher amount of LCGT. Salivary α-amylase activity (sAA), a stress marker, was significantly lower when the participants drank LCGT than standard green tea. Moreover, in the elderly, a lower sAA was correlated with higher sleep efficiency. These results suggest that daily ingestion of LCGT enhances sleep quality.

Chronic stress can impair the health of human brains. An important strategy that may prevent the accumulation of stress may be the consumption of functional foods. When senescence-accelerated mice prone 10 (SAMP10), a stress-sensitive strain, were loaded with stress using imposed male mouse territoriality, brain volume decreased. However, in mice that ingested theanine (6 mg/kg), the main amino acid in tea leaves, brain atrophy was suppressed, even under stress. On the other hand, brain atrophy was not clearly observed in a mouse strain that aged normally (Slc:ddY). The expression level of the transcription factor Npas4 (neuronal PAS domain protein 4), which regulates the formation and maintenance of inhibitory synapses in response to excitatory synaptic activity, decreased in the hippocampus and prefrontal cortex of stressed SAMP10 mice, but increased in mice that ingested theanine. Lipocalin 2 (Lcn2), the expression of which increased in response to stress, was significantly high in the hippocampus and prefrontal cortex of stressed SAMP10 mice, but not in mice that ingested theanine. These data suggest that Npas4 and Lcn2 are involved in the brain atrophy and stress vulnerability of SAMP10 mice, which are prevented by the consumption of theanine, causing changes in the expression of these genes.

Sesame lignans, which are biologically active compounds present in sesame seeds and oil, are known to have neuroprotective effects in several models of brain dysfunction. However, the effects of sesame lignans on age-related brain dysfunction are not clear and were thus investigated in the present study using a senescence-accelerated mouse (SAMP10). Two-month-old male SAMP10 mice were administrated a basal diet with 0% or 0.05% sesame lignans for two months, or with 0%, 0.02%, or 0.05% sesame lignans for 10 months and subjected to step-through passive avoidance tasks and forced swim tests. Reactive carbonyl species (RCs) were evaluated as markers of oxidative stress using a recently developed comprehensive analytical method. Both learning time in passive avoidance tasks and immobile time in forced swim tests became longer with aging (p &lt, 0.05). However, the administration of sesame lignans significantly ameliorated age-related effects in both tests (p &lt, 0.05). Age-related increases in RCs such as 4-hydroxy-2-nonenal in the cerebral cortex and liver were reduced in mice fed sesame lignans. These results suggest that sesame lignans can prevent age-related brain dysfunction via anti-oxidative activity.

The stress-reducing effect of matcha, a high-quality fine-powdered green tea, has recently been clarified by animal experiments and clinical trials. However, the effect of matcha added to confectioneries is not clear. One aim of this study was to evaluate the relationship between matcha components and their stress-reducing effect in mice that were loaded with territorially-based stress. Adrenal hypertrophy, a marker of stress, was significantly suppressed in stress-loaded mice that had ingested matcha components, displaying a caffeine and epigallocatechin gallate to theanine and arginine (CE/TA) ratio of 2 or less. Another aim was to evaluate, in humans, the stress-reducing effect of matcha in cookies using test-matcha (CE/TA = 1.79) or placebo-matcha (CE/TA = 10.64). Participants, who were fifth year pharmacy college students, consumed 4.5 g of matcha in three pieces of cookie daily for 15 days. Salivary α-amylase activity, a stress marker, was significantly lower in the test-matcha group than in the placebo group. These results indicate that the CE/TA ratio of tea components is a key indicator for the suppression of stress. Moreover, matcha with a CE/TA ratio of 2 or less displays a stress-reducing effect, even if it is included in confectionery products. Such products may also benefit individuals who have no habit of drinking matcha as a beverage.

Unhealthy diet promotes progression of metabolic disorders and brain dysfunction with aging. Green tea extracts (GTEs) have various beneficial effects and alleviate metabolic disorders. GTEs have neuroprotective effects in rodent models, but their effects against brain dysfunction in models of aging fed unhealthy diets are still unclear. Here, we showed that GTEs attenuate high-fat (HF) diet-induced brain dysfunction in senescence-accelerated mouse prone-8 (SAMP8), a murine model of senescence. SAMP8 mice were fed a control diet, HF diet, or HF diet with 0.5% GTEs (HFGT) for four months. The HF diet reduced memory retention and induced amyloid &beta, 1&ndash, 42 accumulation, whereas GTEs attenuated these changes. In HF diet-fed mice, lipid oxidative stress, assessed by malondialdehyde levels, was increased. The levels of proteins that promote synaptic plasticity, such as brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD95), were reduced. These alterations related to brain dysfunction were not observed in HFGT diet-fed mice. Overall, our data suggest that GTEs intake might attenuate brain dysfunction in HF diet-fed SAMP8 mice by protecting synaptic plasticity as well as via anti-oxidative effects. In conclusion, GTEs might ameliorate unhealthy diet-induced brain dysfunction that develops with aging.

Since aging is the most important risk factor for dementia, measures to slow the onset of brain aging are an important strategy for preventing dementia. Accumulation of oxidative damage is considered to be a major cause of aging. Catechins in green tea (GTCs) have powerful antioxidative activity. Ingestion of GTCs suppressed oxidative damage, brain atrophy and cognitive decline in aged mice. Age-related cognitive decline was significantly suppressed in mice when middle-aged mice started to drink green tea catechins. Middle-aged people are thus expected to be able to suppress brain aging by ingestion of GTCs. In addition, numerous people are stressed under various conditions. Brain aging was accelerated and lifespan shortened in experimental animals that were chronically and psychosocially stressed. Theanine, an amino acid in green tea, suppressed stress-induced aging. However, the anti-stress effect of theanine is blocked by catechins and caffeine that are main components in green tea. Daily drinking of several cups of green tea is considered to suppress brain aging. In addition, theanine-rich green tea or green tea with a lowered level of caffeine is expected to suppress stress and stress-induced aging.

The young leaves of green tea become lighter in color than usual when protected from sunlight by a shading net for about two weeks while growing. These leaves are called &ldquo, shaded white leaf tea&rdquo, or SWLT. In the eluate of SWLT, the amount of amino acids (361 mg/L) was significantly higher than that in regular tea (53.5 mg/L). Since theanine and arginine, the first and second most abundant amino acids in SWLT, have significant antistress effects, we examined the antistress effect of SWLT on humans. SWLT or placebo green tea (3 g) was eluted with room-temperature water (500 mL). Participants consumed the tea for one week prior to pharmacy practice and continued for 10 days in the practice period. The state-trait anxiety inventory, an anxiety questionnaire, tended to be scored lower in the SWLT group than the placebo, but other stress markers showed no differences. The effect of the difference in SWLT components examined with mice showed that aspartic acid and asparagine, which are abundant in SWLT, counteracted the antistress effects of theanine and arginine. Large amounts of caffeine also interfered with SWLT&rsquo, s antistress effect. Thus, SWLT, which is high in caffeine and amino acids, suppressed depressant behavior in mice.

Green tea is the most popular beverage in Japan and Asian countries. Theanine, the major amino acid in green tea, has a significant antistress effect on animals and humans. However, this effect is blocked by caffeine and gallate-type catechins [e.g., epigallocatechin gallate (EGCG)], two other main components of tea. Caffeine is also known to affect sleep. We made green tea with a lowered caffeine content, low-caffeine green tea (LCGT), in which elution temperature was set at low temperature to suppress the elution of EGCG. The antistress effect of each component in LCGT indicates that theanine, arginine (Arg), and epigallocatechin (EGC) cooperatively suppress the counter-effect of EGCG and caffeine in mice. The level of salivary α-amylase activity, which is a stress marker, is significantly lowered and some sleep parameters are improved after the ingestion of LCGT by humans. The daily ingestion of LCGT is suggested to be a useful way to improve daily problems caused by stress, as well as sleep, ranging from young to elderly people.

Tea is one of the most consumed beverages in the world. Green tea, black tea, and oolong tea are made from the same plant Camellia sinensis (L.) O. Kuntze. Among them, green tea has been the most extensively studied for beneficial effects on diseases including cancer, obesity, diabetes, and inflammatory and neurodegenerative diseases. Several human observational and intervention studies have found beneficial effects of tea consumption on neurodegenerative impairment, such as cognitive dysfunction and memory loss. These studies supported the basis of tea&rsquo, s preventive effects of Parkinson&rsquo, s disease, but few studies have revealed such effects on Alzheimer&rsquo, s disease. In contrast, several human studies have not reported these favorable effects with regard to tea. This discrepancy may be due to incomplete adjustment of confounding factors, including the method of quantifying consumption, beverage temperature, cigarette smoking, alcohol consumption, and differences in genetic and environmental factors, such as race, sex, age, and lifestyle. Thus, more rigorous human studies are required to understand the neuroprotective effect of tea. A number of laboratory experiments demonstrated the benefits of green tea and green tea catechins (GTCs), such as epigallocatechin gallate (EGCG), and proposed action mechanisms. The targets of GTCs include the abnormal accumulation of fibrous proteins, such as A&beta, and &alpha, synuclein, inflammation, elevated expression of pro-apoptotic proteins, and oxidative stress, which are associated with neuronal cell dysfunction and death in the cerebral cortex. Computational molecular docking analysis revealed how EGCG can prevent the accumulation of fibrous proteins. These findings suggest that GTCs have the potential to be used in the prevention and treatment of neurodegenerative diseases and could be useful for the development of new drugs.

The expected prevalence of Alzheimer's disease (AD), the most common neurodegenerative disease triggered by aging, has become a critical problem. Although the cause is clear, accumulation of amyloid-β (Aβ), we still cannot totally cure this disease. Hence, it is essential to prevent the symptoms that have appeared. A number of studies have reported that soybean supplementation prevents cognitive dysfunction. Besides being a rich source of vegetable proteins, soybean contains other functional ingredients such as phytoestrogens, oligosaccharides, and dietary fibers. Especially, recent studies suggested greater functions with green soybean. Comprehensive analysis of gene expression in the brains of mice that ingested soybean using high-density oligonucleotide microarray suggests that an increase of an endogenous Aβ-chaperone, lipocalin-type prostaglandin D2 synthase (Ptgds), leads to suppressed Aβ accumulation, resulting in the prevention of cognitive dysfunction. Here we will review relevant patents and estimated effective components and underlying mechanisms of soybeans, suggested by comparing effects of green and yellow soybean breeds to mice.

In this study, we developed the stable isotope dilution hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC-MS/MS) technique for the accurate, reasonable and simultaneous quantification of glutamic acid (Glu), glutamine (Gln), pyroglutamic acid (pGlu), γ-aminobutyric acid (GABA) and theanine in mouse brain tissues. The quantification of these analytes was accomplished using stable isotope internal standards and the HILIC separating mode to fully correct the intramolecular cyclization during the electrospray ionization. It was shown that linear calibrations were available with high coefficients of correlation (r2 > 0.999, range from 10 pmol/mL to 50 nmol/mL). For application of the theanine intake, the determination of Glu, Gln, pGlu, GABA and theanine in the hippocampus and central cortex tissues was performed based on our developed method. In the region of the hippocampus, the concentration levels of Glu and pGlu were significantly reduced during reality-based theanine intake. Conversely, the concentration level of GABA increased. This result showed that transited theanine has an effect on the metabolic balance of Glu analogs in the hippocampus. Copyright © 2015 John Wiley & Sons, Ltd.

Caffeine, one of the main components in green tea, can interfere with sleep and block the effect of theanine. Since theanine, the main amino acid in tea leaves, has significant anti-stress effects in animals and humans, we examined the effects of green tea with lowered caffeine content, i.e., low-caffeine green tea (LCGT), on stress and quality of sleep of middle–aged individuals (n = 20, mean age 51.3 ± 6.7 years) in a double-blind crossover design. Standard green tea (SGT) was used as the control. These teas (≥300 mL/day), which were eluted with room temperature water, were consumed over a period of seven days after a single washout term. The level of salivary α-amylase activity (sAA), a stress marker, was significantly lower in participants that consumed LCGT (64.7 U/mL) than in those that consumed SGT (73.9 U/mL). Sleep quality was higher in participants that consumed a larger quantity of LCGT. In addition, a self-diagnostic check for accumulated fatigue was significantly lower in those participants that consumed LCGT than SGT. These results indicate that LCGT intake can reduce stress in middle-aged individuals and improve their quality of sleep. The reduction in caffeine is suggested to be a valid reason for enhancing the anti-stress effect of green tea.

Theanine, an amino acid in tea, has significant anti-stress effects on animals and humans. However, the effect of theanine was blocked by caffeine and gallate-type catechins, which are the main components in tea. We examined the anti-stress effect of green tea with lowered caffeine, low-caffeine green tea, on humans. The study design was a single-blind group comparison and participants (n=20) were randomly assigned to low-caffeine or placebo tea groups. These teas (≥500 mL/d), which were eluted with room temperature water, were taken from 1 week prior to pharmacy practice and continued for 10 d in the practice period. The participants ingested theanine (ca. 15 mg/d) in low-caffeine green tea. To assess the anxiety of participants, the state-trait anxiety inventory test was used before pharmacy practice. The subjective stress of students was significantly lower in the low-caffeine-group than in the placebo-group during pharmacy practice. The level of salivary α-amylase activity, a stress marker, increased significantly after daily pharmacy practice in the placebo-group but not in the low-caffeine-group. These results suggested that the ingestion of low-caffeine green tea suppressed the excessive stress response of students. This study was registered at the University Hospital Medical Information Network (ID No. UMIN14942).

Small-cell lung carcinoma releases progalanin. The released progalanin is activated via a nonclassical processing pathway, being processed into an active form of galanin (1-20) by plasmin in extracellular components. Plasmin is produced from plasminogen activators. To clarify the regulation of progalanin via plasminogen activation by urokinase and tissue-plasminogen activator (t-PA), we investigated the regulation mechanism for urokinase and t-PA expression and their effect on galanin activation. Additionally, we studied the effect of activated galanin on angiogenesis. To determine the effect of cell density, we measured the expression levels of urokinase and t-PA using real-time PCR and plasminogen/gelatin zymography in a cell culture. The urokinase expression increased under both high cell density and presence of cell membrane fractions. However, urokinase increments induced by conditioned medium were low. These results indicate that expression of plasminogen activators is regulated by cell membrane factors. We used tumor-bearing mice to clarify the expression of plasminogen activators and galanin activation. Real-time PCR showed that urokinase was substantially higher in the central parts of tumors compared to the periphery, and this was confirmed by plasminogen/gelatin zymography. To evaluate the biological effect of plasminogen activators on tumor growth, we used tranexamic acid as a plasminogen inhibitor. Tranexamic acid decreased galanin (1-20) and the hemoglobin content of tumors and suppressed tumor growth. Additionally, galanin had no effect on the hemoglobin content of tumors derived from cells lacking GALR2. These results demonstrate the regulation of urokinase expression in tumors through progalanin activation in extracellular compartments, and confirm that galanin plays a role in angiogenesis.

Over the last three decades, green tea has been studied for its beneficial effects, including anti-cancer, anti-obesity, anti-diabetes, anti-inflammatory, and neuroprotective effects. At present, a number of studies that have employed animal, human and cell cultures support the potential neuroprotective effects of green tea catechins against neurological disorders. However, the concentration of (−)-epigallocatechin gallate (EGCG) in systemic circulation is very low and EGCG disappears within several hours. EGCG undergoes microbial degradation in the small intestine and later in the large intestine, resulting in the formation of various microbial ring-fission metabolites which are detectable in the plasma and urine as free and conjugated forms. Recently, in vitro experiments suggested that EGCG and its metabolites could reach the brain parenchyma through the blood–brain barrier and induce neuritogenesis. These results suggest that metabolites of EGCG may play an important role, alongside the beneficial activities of EGCG, in reducing neurodegenerative diseases. In this review, we discuss the function of EGCG and its microbial ring-fission metabolites in the brain in suppressing brain dysfunction. Other possible actions of EGCG metabolites will also be discussed.

Purpose Theanine, an amino acid in tea, has significant anti-stress effect on experimental animals under psychosocial stress. Anti-stress effect of theanine on humans was evaluated in 5th-year university students during pharmacy practice. Method The study design was a single-blind group comparison and participants (n = 20) were randomly assigned to theanine or placebo groups. Theanine or placebo (lactose) tablets (200 mg, twice a day, after breakfast and lunch) were taken from 1 week prior to the pharmacy practice and continued for 10 days in the practice period. To assess the anxiety of the participants, the state–trait anxiety inventory test was carried out before the pharmacy practice. Salivary α-amylase activity (sAA) was measured as a marker of sympathetic nervous system activity. Results In the placebo-group, sAA in the morning (pre-practice sAA) was higher than in theanine-group during the pharmacy practice ( p = 0.032). Subjective stress was significantly lower in the theanine-group than in the placebo-group ( p = 0.020). These results suggest that theanine intake had anti-stress effect on students. Furthermore, students with higher pre-practice sAA showed significantly higher trait anxiety in both groups ( p = 0.015). Similarly, higher pre-practice sAA was correlated to shorter sleeping time in both groups ( p = 0.41 × 10 − 3 ). Conclusion Stressful condition increased the level of sAA that was essentially affected by individual trait anxiety. The low levels of pre-practice sAA and subjective stress in the theanine-group suggest that theanine intake suppressed initial stress response of students assigned for a long-term commitment of pharmacy practice.

Green soybean (Glycine max L.), which was used in this study, retains the green color of the seed coat cotyledon even after ripening, even though many soybean cultivars become yellow during maturation. We have reported that ingestion of green soybean extract (GSE) suppressed cognitive dysfunction and reduced amyloid β accumulation more than yellow soybean extract (YSE) in aged senescence-accelerated (SAMP10) mice, a mouse model of brain senescence. To clarify the mechanism by which GSE suppresses cognitive dysfunction, we examined the effect of GSE and YSE on neurite outgrowth in human neuroblastoma SHSY-5Y cells. GSE significantly increased cell number and neurite outgrowth at 5 ng/ml (as isoflavones, 30 pg/ml), but the effect of YSE was lower than that of GSE. Although isoflavone aglycones, genistein and daidzein increased the number of SH-SY5Y cells, the effect was only observed at a high concentration [0.05 μM (13 ng/ml)]. ICR mice were fed a diet containing 3% soybean extract for 3 weeks (3-4 g/kg; as isoflavones, ca. 20 mg/kg) to examine cognitive function. Learning and memory abilities, as evaluated by a step-through passive avoidance task, a Y-maze and a novel object recognition test, were significantly higher in mice that ingested GSE than control mice that were fed a normal diet. The expression of brain-derived neurotrophic factor (BDNF) in the hippocampus, as detected by western blot analysis, was higher in mice that ingested GSE than in control mice. This study suggests that the ingestion of GSE enhances learning and memory abilities in mice. The effect by which GSE improved cognitive function appears to be caused, in part, by increased neuritogenesis and BDNF expression.

The antistress effect of theanine (γ-glutamylethylamide), an amino acid in tea, was investigated using mice that were psychosocially stressed from a conflict among male mice in conditions of confrontational housing. Two male mice were housed in the same cage separated by a partition to establish a territorial imperative. When the partition was removed, the mice were co-housed confrontationally. As a marker for the stress response, changes in the adrenal gland were studied in comparison to group-housed control mice (six mice in a cage). Significant adrenal hypertrophy was observed in mice during confrontational housing, which was developed within 24 h and persisted for at least 1 week. The size of cells in the zona fasciculata of the adrenal gland, from which glucocorticoid is mainly secreted, increased (∼1.11-fold) in mice during confrontational housing, which was accompanied by a flattened diurnal rhythm of corticosterone and ACTH in blood. The ingestion of theanine (>5 μg ml(-1)) prior to confrontational housing significantly suppressed adrenal hypertrophy. An antidepressant, paroxetin, suppressed adrenal hypertrophy in a similar manner in mice during confrontational housing. In mice that ingested theanine, behavioural depression was also suppressed, and a diurnal rhythm of corticosterone and ACTH was observed, even in mice that were undergoing confrontational housing. Furthermore, the daily dose of theanine (40 μg ml(-1)) blocked the counteracting effects of caffeine (30 μg ml(-1)) and catechin (200 μg ml(-1)). The present study demonstrated that theanine prevents and relieves psychosocial stress through the modulation of hypothalamic-pituitary-adrenal axis activity.

Objective: We previously found that green tea catechins (GT-catechin) decrease oxidative damage to DNA and suppress brain dysfunction in aged senescence-accelerated mice (SAMP10). To clarify the effect of GT-catechin on suppression of brain dysfunction, we compare the effect on learning ability among several catechins and examined the essential intake period for prevention of brain dysfunction.Methods: Male SAMP10 mice were allowed free access to water containing epigallocatechin gallate (EGCG, 0.06 mg/ml), epigallocatechin (EGC, 0.03 mg/ml), GT-catechin (0.2 mg/ml), or green tea extract (0.66 mg/ml). Learning ability of mice was measured using a step-through passive avoidance task.Results: SAMP10 mice exhibit brain dysfunction with aging. However, learning ability was significantly higher in mice that drank GT-catechin and EGCG than same-aged control mice that drank water. EGCG was an important component, but EGC had no effect on learning ability. The learning ability was significantly improved in mice that ingested EGCG for > 5 months, and tended to improve in mice that ingested EGCG for 2 or 3 months. Next, the level of synaptophysin, a marker of presynapse, tended to be higher in mice that ingested EGCG but not in mice that ingested EGC. The levels of synaptophysin were significantly higher in mice ingested GT-catechin and green tea extract than control mice.Conclusion: The intake of EGCG, the major catechin in green tea, but not EGC, suppressed age-related brain dysfunction. The effective intake period of EGCG was > 5 months for suppression of brain dysfunction.

Increased oxidative stress is known to accelerate age-related pathologies. Beta-cryptoxanthin (β-CRX, (3R)-β,β-caroten-3-ol) is a potent antioxidant that is highly rich in Satsuma mandarin orange (mandarin), which is the most popular fruit in Japan. We investigated the antioxidative and anti-aging effects of β-CRX and mandarin using senescence-accelerated mice (SAMP10), which were characterized by a short lifespan, high generation of superoxide anions in the brain and poor learning ability with aging. β-CRX (0.5-5.0 µg/ml) or mandarin juice (3.8-38.0%) was added to drinking water of SAMP10 one to 12 months of age. β-CRX was dose-dependently incorporated into the cerebral cortex and the contents were similar to the concentration of β-CRX in the human frontal lobe. These mice also had higher learning ability. The level of DNA oxidative damage was significantly lower in the cerebral cortex of mice that ingested β-CRX and mandarin than control mice. In addition, the mice that ingested β-CRX (>1.5 µg/ml) and mandarin (>11.3%) exhibited a higher survival when 12 month-old, the presenile age of SAMP10, than control mice. These results suggest that β-CRX is incorporated into the brain and has an important antioxidative role and anti-aging effect.

Theanine, a major amino acid in green tea, exhibits a stress-reducing effect in mice and humans. Matcha, which is essentially theanine-rich powdered green tea, is abundant in caffeine. Caffeine has a strong antagonistic effect against theanine. The stress-reducing effect of matcha was examined with an animal experiment and a clinical trial. The stress-reducing effect of matcha marketed in Japan and abroad was assessed based on its composition. The stress-reducing effect of matcha in mice was evaluated as suppressed adrenal hypertrophy using territorially-based loaded stress. High contents of theanine and arginine in matcha exhibited a high stress-reducing effect. However, an effective stress-reducing outcome was only possible when the molar ratio of caffeine and epigallocatechin gallate (EGCG) to theanine and arginine was less than two. Participants (n = 39) consumed test-matcha, which was expected to have a stress-reducing effect, or placebo-matcha, where no effect was expected. Anxiety, a reaction to stress, was significantly lower in the test-matcha group than in the placebo group. To predict mental function of each matcha, both the quantity of theanine and the ratios of caffeine, EGCG, and arginine against theanine need to be verified.

Relaxin-3 is a recently discovered member of the insulin superfamily and is a ligand for three orphan G-protein-coupled receptors: GPCR135, GPCR142 and LGR7 (leucine-rich repeat-containing G-protein-coupled receptor 7). GPCR135 mRNA is expressed in the pancreas, however, it is not known, whether the peptide affects pancreatic islet function. Reverse transcriptase (RT)-PCR and radioreceptor assay have shown that the relaxin-3 receptor (GPCR135) is expressed in pancreatic islets and rat insulinoma, but LGR7 is not expressed. Moreover, relaxin-3 has been revealed to inhibit the secretion of insulin from pancreatic islets. However, we can not detect relaxin-3 in small intestine and pancreas. These results suggest a novel role of relaxin-3 in the regulation of insulin release.

Ultraviolet (UV) irradiation induces significant changes to skin connective tissues as a result of the degradation of collagen, which is a major structural component of the extracellular matrix. This process may be mediated by matrix metalloproteinases (MMPs). In this study, we examined the protective effect of a polyphenolic flavone, luteolin, on the expression of two matrix metalloproteinases, MMP-1 and MMP-9, in UVA- and UVB-irradiated human dermal fibroblast cells. Luteolin is found in many medicinal plants as well as in a large number of vegetables, fruits and a variety of spices. It has a number of biological activities including anti-cancer, anti-oxidant, anti-inflammatory, antiallergic and immunomodulatory activities. Human dermal fibroblast (HDF) cells were treated with luteolin at 1-10 μM, then irradiated with UVA at 10 J/cm2 and UVB at 200 mJ/cm2. Cells and culture supernatant were harvested 24 h after irradiation. Our results show that luteolin at 1-10 μM dose-dependently suppressed the expression of MMP-1 and MMP-9 genes in UVA and UVB-exposed HDF cells, as measured by quantitative real-time reverse transcription–polymerase chain reaction (qRT-PCR). Luteolin was also found to reduce the production of MMP-1 protein in UVA and UVBexposed HDF cells detected by enzyme-linked immunosorbent assay (ELISA) in a dose-dependent manner. The release of MMP-9 was also reduced by luteolin in UVB-irradiated HDF cells in a dose-dependent manner. Our results indicate that luteolin can inhibit UV-induced MMP-1 and MMP-9 expression in HDF cells. Therefore, they may be potentially useful in the prevention and treatment of skin photoaging.

Senescence is an ageing process characterized by progressive and irreversible dysfunction of various physio- logical systems. Physiological senescence with advancing age is not a disease, but it affects the life-span and life-quality of elderly people. Brain functions such as cognition and motor skills, as with other organ systems, are impaired in almost all elderly people. Neuroprotective dietary components can play a key role in ensuring healthy ageing of the brain. Al- though the causative mechanisms of senescence are complex and not yet fully elucidated, enhanced oxidative stress is thought to be an important contributor. Dietary antioxidants from fruits and vegetables have preventative effects on oxida- tive stress. Catechin, a polyphenol found in green tea, has a potent antioxidative effect. Recently, catechin has been re- ported to protect against reduced ageing-related cognitive functions such as those associated with learning and memory, and ischemic brain damage. Catechin may act as a neuroprotective agent in progressive neurodegenerative disorders such as Parkinson's and Alzheimer's diseases. The neuroprotective effects and putative mechanisms of action of catechin and other antioxidants are examined and discussed in this review.

The high prevalence of dementia in aged individuals suggests that aging is the most important risk factor and that senescence further enhances dementia. We have searched for dietary factors that prevent brain senescence using a mouse model of age-related neurodegeneration (SAMP10). This mouse line is suitable for studying brain senescence because brain atrophy and cognitive dysfunction are observed with aging, similar to humans. The production of reactive oxygen species and oxidative damage are high in the brains of aged SAMP10. We found that green tea catechin and β-cryptoxanthin in Japanese mandarin oranges prevented brain atrophy and cognitive dysfunction. In addition, psychosocially chronically stressed mice exhibited a shortened life span and accelerated cognitive dysfunction. These deficiencies were prevented by the ingestion of theanine, an amino acid in tea, under stressed conditions. While a number of factors affect brain senescence, our results suggest that non-nutritive food components such as catechin, β-cryptoxanthin and theanine may be useful for preventing brain senescence.

Learning and memory functions decline with aging. Oxidative damage has been considered to be a cause of age-associated brain dysfunction because the brain is believed to be particularly vulnerable to oxidative stress. We investigated the influence of green tea catechins (GT-catechin), which have been reported to have antioxidative effects, on learning and memory using senescence-accelerated mice (SAMP10). The learning time for acquisition of avoidance response and the ratio of working memory in a Y-maze indicated that GT-catechin intake was effective for improvement of learning and memory functions in aged SAMP10 mice. In addition, we found that GT-catechin intake was effective for the suppression of cerebral atrophy in SAMP10 of 12-month-old mice. Levels of 8-oxodeoxyguanosine (8-oxodG) were suppressed in rhinencephalon and in liver of SAMP10 mice that had drunk catechin water. These results suggest that intake of GT-catechin over a long term partially improves oxidative damage and morphologic and functional alterations of the brain in aged SAMP10.

Background Chronic alcohol consumption may act as a cellular stressor for brain cells, as has been found for aging. In this study we examined one component of the cellular stress response (heat shock proteins) as a function of age and alcohol exposure. We have found that the level of constitutively expressed heat shock protein 70 (heat shock cognate 70, or Hsc70) increases in the aged rat brain. Among many heat shock proteins and molecular chaperones, Hsc70 might be important not only for the normal protein folding pathway but also for refolding of denatured proteins produced by mild and chronic stress. Methods Male Wistar rats that were 5.5 to 28.5 months old were fed a liquid diet that contained 5% (w/v) alcohol or a control diet for 6 weeks. The effects of alcohol consumption and aging on the expression of Hsc70 in the brain were investigated. The cytosol proteins in the 12,000 ×g supernatant fraction were heat-treated at 42°C for 1 hr. After the heat treatment, proteins that transferred from the soluble to insoluble aggregated fraction were estimated as heat-unstable proteins. Results In the 24- and 30-month-old rat brain, chronic consumption of alcohol increased levels of Hsc70 and heat-unstable proteins. On the other hand, those changes were not detected in the younger rat brain. Conclusion Chronic alcohol intake causes a stress response in the aged rat brain. It is thought that the increased level of Hsc70 is brought about by an increase of denatured proteins.

cope To understand the mechanism by which green tea lowers the risk of dementia, focus was placed on the metabolites of epigallocatechin gallate (EGCG), the most abundant catechin in green tea. Much of orally ingested EGCG is hydrolyzed to epigallocatechin (EGC) and gallic acid. In rats, EGC is then metabolized mainly to 5-(3’, 5’-dihydroxyphenyl)-γ-valerolactone (EGC-M5) and its conjugated forms, which are distributed to various tissues. Therefore, we examined the permeability of these metabolites into the blood-brain barrier (BBB), and nerve cell proliferation/differentiation in vitro. Methods and results The permeability of EGC-M5, glucuronide and the sulfate of EGC-M5, pyrogallol, as well as its glucuronide into the BBB were examined using a BBB model kit. Each brain- and blood-side sample was subjected to liquid chromatography tandem-mass spectrometry analysis. BBB permeability (%, in 0.5 h) was 1.9-3.7 %. In human neuroblastoma SH-SY5Y cells, neurite length was significantly prolonged by EGC-M5, and the number of neurites was increased significantly by all metabolites examined. Conclusion The permeability of EGC-M5 and its conjugated forms into the BBB suggests that they reached the brain parenchyma. In addition, the ability of EGC-M5 to affect nerve cell proliferation and neuritogenesis suggests that EGC-M5 may promote neurogenesis in the brain. This article is protected by copyright. All rights reserved

Galanin is a neuropeptide expressed in the central and peripheral nervous systems. Galanin is known to be biosynthesized in neural and endocrine cells, but little evidence exists for its synthesis in other cells. In this study, we explored galanin-releasing nonneural cells using radioimmunoassay, finding that some fibroblasts produced and released the galanin-like immunoreactive component (galanin-LI). The molecular weight of the galanin-LI obtained from the fibroblasts, as measured by gel filtration chromatography and Western blotting, was 14 kDa and suggested that the compound was progalanin. Peptide mass fingerprinting analysis identified the large form of galanin-LI as progalanin without its signal sequence. In addition, galanin-LI was located in the Golgi bodies and vesicle-like structures of the fibroblasts. Furthermore, the addition of brefeldin A, an inhibitor of transport from the ER, decreased the release of galanin-LI. In this study, we showed that the fibroblast, a nonneural and nonendocrine cell type, produced and released a galanin precursor, progalanin, without processing via Golgi bodies or secretory vesicles.

Progalanin is released from the small cell lung carcinoma line SBC-3A and converted to its active form by plasmin. To elucidate the role of progalanin activation in the extracellular compartment, matrix metalloproteinase (MMP) activity was studied in SBC-3A cells treated with progalanin siRNA, and angiogenesis was measured in tumor tissue originating from SBC-3A cell transplantation into mice. Progalanin siRNA caused downregulation of progalanin expression for approximately 8 days. MMP activity and angiogenesis were reduced in tumors induced by transplantation of progalanin siRNA-treated SBC-3A cells. In contrast, MMP-9 and MMP-2 activity and angiogenesis increased in tumors originating from progalanin siRNA-treated SBC-3A cells in the presence of galanin and progalanin. Furthermore, injection of tranexamic acid, a plasmin inhibitor, more markedly reduced MMP-9 and MMP-2 activity and angiogenesis in tumors originating from progalanin siRNA-treated SBC-3A cells and in tumor tissue originating from progalanin siRNA-treated SBC-3A cells in the presence of progalanin. The reduction of MMP-9 and MMP-2 activity with tranexamic acid was restored by galanin, but not by progalanin. Moreover, tranexamic acid reduced angiogenesis in control siRNA-treated SBC-3A cells. These results suggest that the activation of progalanin by plasmin in the extracellular compartment was involved in MMP-9 and MMP-2 activation and in angiogenesis in tumor tissue.

Oxidative stress, an imbalance between endogenous levels of oxygen radicals and antioxidative defense, increases with aging. However, it is not clear which of these two factors is the more critical. To clarify the production of oxygen radicals increases with age, we examined oxygen radical-dependent chemiluminescent signals in ex vivo brain slices using a novel photonic imaging method. The chemiluminescent intensity was significantly decreased by the membrane permeable superoxide dismutase (SOD)/catalase mimic, but not by Cu,Zn-SOD. Inhibitors for complex I, III, and IV of the mitochondrial electron transport chain transiently enhanced the chemiluminescent signal. The superoxide-dependent chemiluminescent intensity in senescence accelerated mouse (SAM) brain tissues increases with age. Moreover, the slope of the age-dependent increase was steeper in SAMP10, a strain characterized by a short lifespan and atrophy in the frontal cerebral cortex, than the senescence-resistant strain SAMR1, which has a longer lifespan. An increase in chemiluminescence with age was also observed in C57/BL6 mice, Wistar rats, and pigeons, although levels of chemiluminescence were lower in the pigeons than murines. The rate of age-related increases of superoxide-dependent chemiluminescence was inversely related to the maximum lifespan of the animals. The activity of superoxide dismutase was unchanged during the aging process in the brain. This suggested that superoxide production itself may increase with age. We speculated that reactive oxygen may be a signal to determine the aging process.

Tea is derived from the leaves and buds of Camellia sinensis (Theaceae) plant, and is consumed worldwide. Green tea was discovered in the People's Republic of China approxi- mately 3,000 BC. Lu Yu (733-803) published a book that describes the history of tea, the techniques, and utensils used for manufacturing, the method of preparation, and drinking of tea in the People's Republic of China. Green tea contains various components with specific health- promoting effects and is believed to exert protective effects against diseases such as cancer, obesity, diabetes, hepatitis, and neurodegenerative diseases. Of the various tea components, the polyphenol catechins have been the subject of extensive investigation. Among the catechins, (−)-epigallocatechin gallate has the strongest bioactivity in most cases. Caffeine induces alert- ness, decreases the sensation of fatigue, and has a diuretic effect. Theanine and γ-aminobutyric acid can lower the blood pressure and regulate brain function. Vitamin C exhibits antiscorbutic activity, prevents cataracts, and may boost the immune system. Majority of the scientific evi - dence based on cellular and animal experiments as well as a number of human epidemiological and intervention studies indicate that green tea and (−)-epigallocatechin gallate have beneficial health effects against various diseases. However, conflicting results have also been reported. Since confounding factors could affect the results, future studies should be designed to elimi- nate such factors for better understanding of the benefits of green tea on human health. Genetic and environmental factors such as race, sex, age, and lifestyle may also influence the results of human studies. Although care should be taken to avoid the consumption of green tea and supplements with very high catechin content, recent findings suggest that habitual drinking of green tea promotes longevity.

The accumulation of oxidative damage is believed to contribute to senescence. We have previously found that the consumption of green tea catechins (GT-catechin), which are potent antioxidants, decreases oxidative damage to DNA and improves brain function in aged mice with accelerated senescence (SAMP10 mice). To investigate the mechanisms underlying the beneficial effects of GT-catechin, we measured the activities of antioxidative enzymes in the brains of aged SAMP10 mice. The activity of glutathione peroxidase (GPx), an essential enzyme for reduction of hydrogen and lipid peroxides, was significantly lower in aged mice than in younger ones. However, the decline in activity was prevented in aged mice that had consumed GT-catechin. The increased level of carbonyl proteins, a marker of oxidative damage in proteins, was also significantly reduced in aged mice that had consumed GT-catechin. The activities of superoxide dismutase and catalase were not decreased in aged mice. These results suggest that decreased activity of GPx importantly contributes to brain dysfunction in ageing SAMP10 mice. Furthermore, the intake of GT-catechin protected the decline in GPx activity and age-related oxidative damage in the brain.

We investigated whether or not three kinds of social stress (isolation, crowding, and confrontation) increase urinary excretion of biopyrrins, oxidative metabolites of bilirubin, in mice. Male BALB/c mice (4 weeks old) were housed 5 per cage for 10 days. After acclimatization, mice were exposed to the above mentioned three kinds of psychosocial stress. Mouse blood and urine samples were collected after 2, 7, and 30 days of stress. Serum levels of corticosterone and urinary levels of biopyrrins were determined by EIA and ELISA, respectively. Adrenal hypertrophy, significant increases in serum concentration of corticosterone and in urinary excretion of biopyrrins were observed in mice exposed to these types of social stress for 7 days. These levels decreased after 30 days, though they were still rather high compared to the control group. These results suggested that social stress causes oxidative stress and that biopyrrins could be useful biomarkers of psychosocial stress.

Almost all elderly people show brain atrophy and cognitive dysfunction, even if they are saved from illness, such as cardiac disease, malignancy and diabetes. Prevention or delay of brain senescence would therefore enhance the quality of life for older persons. Because oxidative stress has been implicated in brain senescence, we investigated the effects of green tea catechin (GT-catechin), a potential antioxidant, in senescence-accelerated (SAMP10) mice. The mouse is a model of brain senescence with short life span, cerebral atrophy and cognitive dysfunction. Mice were fed water containing 0.02% GT-catechin from 1- to 15-month-old. The mean dose was about 35 mg/kg/day. We found that daily consumption of GT-catechin prevented memory regression and DNA oxidative damage in these mice. GT-catechin did not prolong the lifetime of SAMP10 mice, but it did delay brain senescence. These findings suggest that continued intake of GT-catechin might promote healthy ageing of the brain in older persons.

Labeling with stable isotopes, typically deuterium (D), is powerful tool for studying the functional structure of biomolecules by NMR. Biosynthesis of certain deuterated proteins in microorganisms cultured in deuterium oxide (D(2)O) is an attractive strategy. However, the growth of almost all microorganisms is inhibited at high concentrations of D(2)O. We isolated a mutant of yeast that grows well in D(2)O. The expression of Hsp70 was enhanced in the mutant. The increased expression also endowed the yeast with cold-resistance. The mutant might be useful for biosynthesis of D-labeled biomolecules.

Here, we present a detailed comparison of the heat response, including the induction of heat-shock proteins, between H- and D-Chlorella

Isotope effects of deuterium on photosynthetic metabolism of carbon in Chlorella ellipsoidea were investigated

The effect of deuterium oxide (D2O) was examined on the cell growth of photoautotrophically growing Chlorella ellipsoidea. The growth rate was inversely proportional to the concentration of D2O in the medium up to 60 mol%. The growth in D2O medium at concentrations higher than 60 mol% was highly inhibited. However, the cells pre-cultured in 60 mol% D2O medium became able to grow even in practically 100 mol% D2O medium. Deuterium (D) was incorporated into cells proportionally to the concentration of D2O in the medium. The D/H ratio in the cells was lower than that of the cultivation medium. Chlorella cells cultured in practically 100 mol% D2O medium contained ca. 70 mol% D. Of the D incorporated into cells, about 20% was easily exchangeable with H, and the remaining 80% was unexchangeable.