Anti-diabetic activity of a polyphenol-rich extract from in KK-Ay mice with spontaneous type 2 diabetes mellitus

• Published in: Food & function 2018-01, Vol.9 (1), p.614-623
• Main Authors: Zheng, Sijian, Deng, Shihao, Huang, Yun, Huang, Mi, Zhao, Ping, Ma, Xinhua, Wen, Yanzhang, Wang, Qiang, Yang, Xinzhou
• Format: Article
• ISSN: 2042-6496; 2042-650X
• DOI: 10.1039/c7fo01460k

The present study investigated the anti-diabetic activity and potential mechanisms of the polyphenol rich extract from Phellinus igniarius (PI-PRE) in vitro and in vivo . Four main phenolic compounds of PI-PRE were purified and identified as 7,8-dihydroxycoumarin, 3,4-dihydroxybenzalacetone, 7,3′-dihydroxy-5′-methoxyisoflavone and inoscavin C by the off-line semipreparative liquid chromatography-nuclear magnetic resonance protocol. In vitro , PI-PRE stimulated GLUT4 translocation by 2.34-fold and increased glucose uptake by 1.73-fold in L6 cells. However, the selective AMP-activated protein kinase (AMPK) inhibitor, compound C, completely reversed the PI-PRE-induced GLUT4 translocation. In vivo , KK-Ay mice treated with PI-PRE for four weeks had lower fasting blood glucose levels, as well as other blood-lipid indexes, compared with the vehicle control group. Mechanistic studies showed that the expressions of p-AMPKα and GLUT4 were significantly increased by treatment with PI-PRE in L6 cells. In KK-Ay mice, the expression of p-AMPKα was enhanced in the liver and skeletal muscle, and the expression of GLUT4 was increased in skeletal muscle. These findings suggest that PI-PRE possesses potential anti-diabetic effects including improving glucose tolerance, reducing hyperglycemia, and normalizing insulin levels. These effects are partly due to the activation of GLUT4 translocation via the modulation of the AMPK pathway. The present study investigated the anti-diabetic activity and potential mechanisms of the polyphenol rich extract from Phellinus igniarius (PI-PRE) in vitro and in vivo .