Toshiki Asano

Potential role of taurine in the prevention of diabetes and metabolic syndrome

Metabolic syndrome is characterized by the cluster of a number of metabolic abnormalities in the presence of underlying insulin resistance. The prevalence of metabolic syndrome has steadily increased in all populations worldwide. Taurine (2-aminoethanesulfonic acid) is a sulfur-containing amino acid that is involved in a variety of physiological functions. Clinical and experimental studies show that taurine intake may be beneficial in the prevention of metabolic syndrome including diabetes, obesity, dyslipidemia, and hypertension. This article reviews the effect of taurine on all of the components of metabolic syndrome. In addition, the possible mechanisms by which taurine prevents diabetes and metabolic syndrome are also discussed. Further study is needed to determine the role of taurine in the development of metabolic syndrome in humans, because there is presently limited clinical data available.

地黄の研究(第3報)地黄の修治法の違いによる成分変化と血液レオロジー改善作用との関連性

The relation between constituents and effects on hemorheology with processing of root of Rehmannia glutinosa was investigated. With the processing to dried or steamed root from crude root, the content of stachyose, which was the highest component in crude root, was decreased and the content of manninotriose was increased. Iridoid glycoside, catalpol, was gradually decreased with the processing. From these results, the content of carbohydrates and catalpol made it possible to estimate the quality of Rehmanniae Radix by processings. On the other hand, the change of pharmacological activities with the processing was investigated. The 50% ethanolic extract (BJ-ext) from steamed root of R. glutinosa increased erythrocyte deformability and erythrocyte ATP contents, inhibited polybrene-induced erythrocyte aggregation, and promoted an activity of fibrinolytic system. The extracts from crude or dried root had weak or no effect. The crude or dried root and steamed root of R. glutinosa showed the different pharmacological activities, and the quality of Rehamanniae Radix by processings may be estimated by investigation of correlation between the changes of constituents and improvable effects of hemorheology.

Effect of Zena F-III, a liquid nutritive and tonic drug, on the neurochemical changes elicited by physical fatigue in mice.

The effects of a liquid nutritive and tonic drug (NTD) on the neurochemical changes elicited by physical fatigue in mice were investigated in terms of the calcium-dependent dopamine synthesizing function of the brain. In this study, Zena F-III (Taisho Pharmaceutical Co., Ltd., Japan), one of the most popular NTDs in Japan, containing 15 crude drug extracts together with taurine, caffeine, and vitamins, and formulated based on the precepts of traditional Chinese medicine, was used. Male mice were forced to walk for 0-6 h at a speed of 3 m/min using a programmed motor-driven wheel cage. The serum and brain calcium levels in the mice were significantly increased following forced walking. The increase in brain calcium level began later and was more gradual than that in the serum calcium level, and reached its maximum value following forced walking for 3 h. The neostriatal dopamine level was also significantly increased, and locomotor activity significantly decreased following forced walking for 3 h. Prior oral administration of F-III (10 ml/kg) attenuated the increases in the serum and brain calcium levels, the increase in the brain dopamine levels, and the decrease in locomotor activity induced by forced walking. Taking into consideration these findings with our previous reports, it is suggested that physical fatigue leads to an increase in dopamine synthesis in the brain through a calcium/calmodulin-dependent system, thereby inducing behavioral changes, and that F-III inhibits this pathway and may alleviate overwork-induced physical fatigue.