Department of Neurophysiology, School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
Tea Science Center, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
Nutrients. 2018 Oct 10;10(10):1468. doi: 10.3390/nu10101468.
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 ( = 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.
茶氨酸是绿茶中的主要氨基酸，具有减轻小鼠和人类压力的作用。抹茶是一种富含茶氨酸的粉状绿茶，富含咖啡因。咖啡因对茶氨酸有很强的拮抗作用。通过动物实验和临床试验研究了抹茶的减压效果。根据其成分评估了在国内外市场上销售的抹茶的减压效果。使用基于领地的负重应激评估了抹茶对小鼠的减压效果。抹茶中茶氨酸和精氨酸的高含量表现出很高的减压效果。然而，只有当咖啡因和表没食子儿茶素没食子酸酯（EGCG）与茶氨酸和精氨酸的摩尔比小于 2 时，才可能产生有效的减压效果。参与者（n=39）饮用了预期具有减压效果的测试抹茶或预计无效果的安慰剂抹茶。与安慰剂组相比，测试抹茶组的焦虑（对压力的反应）显著降低。为了预测每种抹茶的心理功能，需要验证茶氨酸的含量以及咖啡因、EGCG 和精氨酸与茶氨酸的比例。
