Tsuruoka N.,Cerebos Pacific Ltd |
Beppu Y.,Suntory Business Expert Ltd |
Koda H.,Suntory Business Expert Ltd |
Doe N.,Kouiken Co. |
And 3 more authors.
PLoS ONE | Year: 2012
Diketopiperazines (DKPs) are naturally-occurring cyclic dipeptides with a small structure and are found in many organisms and in large amounts in some foods and beverages. We found that a chicken essence beverage, which is popular among Southeast Asians as a traditional remedy and a rich source of DKPs, inhibited the serotonin transporter (SERT) and suppressed serotonin uptake from rat brain synaptosomes, which prompted us to isolate and identify the active substance(s). We purified a SERT inhibitor from the chicken essence beverage and identified it as the DKP cyclo(L-Phe-L-Phe). Interestingly, it was a naturally occurring dual inhibitor that inhibited both SERT and acetylcholinesterase (AChE) in vitro. The DKP increased extracellular levels of the cerebral monoamines serotonin, norepinephrine, and dopamine in the medial prefrontal cortex and acetylcholine in the ventral hippocampus of freely moving rats when administered orally. Moreover, cyclo(L-Phe-L-Phe) significantly shortened escape latency in the water maze test in depressed mice previously subjected to a repeated open-space swimming task, which induces a depression-like state. Cyclo(L-Phe-L-Phe) also significantly improved accuracy rates in a radial maze test in rats and increased step-through latencies in a passive avoidance test in mice with scopolamine-induced amnesia. These animal test results suggest that cyclo(L-Phe-L-Phe), which is present abundantly in some foods such as chicken essence, may abrogate the onset of depression and, thus, contribute to preventing the development of Alzheimer's disease and other dementia, because senile depression is a risk factor for dementia. © 2012 Tsuruoka et al.
Hirota S.,Kagawa Nutrition University |
Adachi N.,Kagawa Nutrition University |
Gomyo T.,Kagawa Nutrition University |
Kawashima H.,Suntory Wellness Ltd. |
And 2 more authors.
Prostaglandins Leukotrienes and Essential Fatty Acids | Year: 2010
Arachidonic acid (ARA) is considered to be a minor contributor to the diet. Previous reports regarding the effect of ARA supplementation on the composition of long-chain polyunsaturated fatty acids (LCPUFA) in the blood of humans are extremely limited. In the present study, we conducted a crossover double-blind, placebo-control study. Twenty-three young Japanese women consumed one capsule containing triacylglycerol enriched with 80. mg ARA, equivalent to the amount in one egg, daily for 3 weeks. Blood samples were drawn before and after treatment periods, and the compositions of the LCPUFA in blood lipid fractions were measured. The supplementation of ARA increased the composition of ARA, but did not decrease the composition of n-3LCPUFA in erythrocyte phospholipids and plasma phospholipids, esterified cholesterol, and triacylglycerol. We found that dietary ARA increased the ARA level in all lipid fractions of the blood, even at a very low dose. © 2010 Elsevier Ltd.
Ono E.,Suntory Holdings Ltd |
Homma Y.,Tohoku University |
Horikawa M.,Suntory Institute for Bioorganic Research |
Kunikane-Doi S.,Tohoku University |
And 6 more authors.
Plant Cell | Year: 2010
We identified two glycosyltransferases that contribute to the structural diversification of flavonol glycosides in grapevine (Vitis vinifera): glycosyltransferase 5 (Vv GT5) and Vv GT6. Biochemical analyses showed that Vv GT5 is a UDP-glucuronic acid:flavonol-3-O-glucuronosyltransferase (GAT), and Vv GT6 is a bifunctional UDP-glucose/UDP-galactose:flavonol-3-Oglucosyltransferase/galactosyltransferase. The Vv GT5 and Vv GT6 genes have very high sequence similarity (91%) and are located in tandem on chromosome 11, suggesting that one of these genes arose from the other by gene duplication. Both of these enzymes were expressed in accordance with flavonol synthase gene expression and flavonoid distribution patterns in this plant, corroborating their significance in flavonol glycoside biosynthesis. The determinant of the specificity of Vv GT5 for UDP-glucuronic acid was found to be Arg-140, which corresponded to none of the determinants previously identified for other plant GATs in primary structures, providing another example of convergent evolution of plant GAT. We also analyzed the determinants of the sugar donor specificity of Vv GT6. Gln-373 and Pro-19 were found to play important roles in the bifunctional specificity of the enzyme. The results presented here suggest that the sugar donor specificities of these Vv GTs could be determined by a limited number of amino acid substitutions in the primary structures of protein duplicates, illustrating the plasticity of plant glycosyltransferases in acquiring new sugar donor specificities. © 2010 American Society of Plant Biologists.
Tomimori N.,Suntory Wellness Ltd. |
Tanaka Y.,Suntory Business Expert Ltd |
Kitagawa Y.,Suntory Business Expert Ltd |
Fujii W.,Suntory Business Expert Ltd |
And 2 more authors.
Biopharmaceutics and Drug Disposition | Year: 2013
A single-blind, placebo-controlled, parallel-group and multiple oral dose study was conducted in 48 healthy subjects to investigate the pharmacokinetics and safety of multiple oral doses of sesame lignans (sesamin and episesamin). Subjects were randomly divided into two groups. Each subject was administered 50 mg of sesame lignans (sesamin/episesamin = 1/1) or placebo once daily for 28 days. The pharmacokinetics of the sesame lignans were investigated using 10 of the 24 subjects in the sesame lignans group. No serious adverse events were observed in this study. Sesamin was absorbed with a peak plasma concentration at 5.0 h. The plasma concentration of the main metabolite, SC-1, reached a peak at 5.0 h and decreased rapidly with a terminal half-life of 2.4 h. Episesamin was also absorbed with a peak plasma concentration at 5.0 h and decreased with a terminal half-life of 7.1 h. The plasma concentration of the main metabolite, EC-1, reached a peak at 5.0 h and decreased rapidly with a terminal half-life of 3.4 h. The plasma concentrations of sesamin and episesamin reached a steady state by day 7. Sesame lignans were confirmed to be safe and tolerable in healthy subjects. The results of the pharmacokinetic study demonstrate that no accumulation was observed following multiple 50 mg doses of sesame lignans. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Tokuda H.,Suntory Wellness Ltd. |
Kontani M.,Suntory Wellness Ltd. |
Kawashima H.,Suntory Wellness Ltd. |
Kiso Y.,Suntory Wellness Ltd. |
And 2 more authors.
Neuroscience Research | Year: 2014
Hippocampal neurogenesis affects learning and memory. We evaluated in rats effects of ingestion of arachidonic acid (ARA) and/or docosahexaenoic acid (DHA) on age-related decreases in proliferating neural stem/progenitor cells (NSPCs) or newborn neurons (NNs). Rats were fed with ARA- and/or DHA-containing diet from 2 to 18 months old and then sacrificed 1 day or 4 weeks after 5-bromo-2-deoxyuridine (BrdU) injections at 2, 6 and 18 months. The numbers of NSPCs (SOX2+/BrdU+) and NNs (NeuN+/BrdU+) were determined immunohistochemically. The number of BrdU+ cells 1 day after BrdU injections decreased with age, but increased 65% after ARA ingestion compared to the control at 18 months. The SOX2+/BrdU+ cell ratio was unchanged by aging or ingestion of ARA or DHA. The number of NeuN+/BrdU+ cells 4 weeks after BrdU injections decreased with age, but increased 34% (yet not statistically significant) after DHA ingestion compared to the control at 18 months. These results indicate that ARA ingestion can ameliorate the age-related decrease in the number of NSPCs in rats. The functions of ARA and DHA in hippocampal neurogenesis appear to be different in aged rats; ARA may maintain an NSPC pool, whereas DHA may support NN production and/or survival. © 2014 Elsevier Ireland Ltd and the Japan Neuroscience Society.