Hypoglycemic Constituents Isolated from Trapa natans L. Pericarps

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• 作者：Hui-Chi Huang ; Chien-Liang Chao ; Chia-Ching Liaw ; Syh-Yuan Hwang ; Yao-Haur Kuo ; Tsu-Chung Chang ; Chih-Hua Chao ; Chao-Jung Chen ; Yueh-Hsiung Kuo
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2016
• 出版时间：May 18, 2016
• 年：2016
• 卷：64
• 期：19
• 页码：3794-3803
• 全文大小：608K
• 年卷期：0
• ISSN：1520-5118

文摘

Trapa natans L., called water chestnut or water caltrop, is a floating aquarium plant. Its fruits are widely used as food. Two new tannins, 1 and 2, one new neolignan, 14, one new norlignan, 17, and 20 known compounds, 3–13, 15, 16, and 18–24 were isolated from T. natans pericarps in this study. The 1, 2, 14, and 17 structures were elucidated using a chemical method and extensive spectral evidence. A series of hydrolyzable tannins, 1–8, a lignin, 13, a flavonoid, 16, a norlignan, 17, and phenolic compounds, 18, 20, 21, and 24 resulted in the enhanced glucose uptake activity in C2C12 myotubes. Compounds 4 and 5 significantly increased GLUT4 protein expression in C2C12 myotubes. In addition, 4 and 5 improved the phosphorylation of AMPK, AKT(S473), and AKT(T308). The involvement of AMPK and PI3K in the mechanism of action of compounds 4 and 5 was confirmed by use of AMPK and PI3K inhibitors, which completely suppressed the 4- and 5-mediated activities of glucose uptake in C2C12 myotubes. We also demonstrated that 4 and 5 could increase GLUT4 protein levels in plasma membranes.