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

<i>Trapa natansi> 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 <i>T. natansi> 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.