Anti-Hyperglycemic Properties of Crude Extract and Triterpenes fromPoria cocos

Abstract

Poria cocos, Bai Fu Ling in Chinese, is used in traditional Chinese medicine to treat diabetes. However, its claimed benefits and mechanism are not fully understood. This study aimed to investigate the effect and action ofP. cocoson type 2 diabetes. We first performed phytochemical analysis on the crude extract and factions ofP. cocos.P. cocoscrude extract at 50 mg/kg body weight or more significantly decreased blood glucose levels in db/db mice. Based on a bioactivity-directed fractionation and isolation (BDFI) strategy, chloroform fraction and subfractions 4 and 6 of theP. cocoscrude extract possessed a blood glucose-lowering effect. Dehydrotumulosic acid, dehydrotrametenolic acid, and pachymic acid were identified from the chloroform sub-fractions 4, 3, and 2, respectively. Dehydrotumulosic acid had anti-hyperglycemic effect to a greater extent than dehydrotrametenolic acid and pachymic acid. Mechanistic study on streptozocin- (STZ-) treated mice showed that the crude extract, dehydrotumulosic acid, dehydrotrametenolic acid, and pachymic acid ofP. cocosexhibited different levels of insulin sensitizer activity. However, theP. cocoscrude extract and triterpenes appeared not to activate PPAR-γpathway. Overall, the data suggest that theP. cocosextract and its triterpenes reduce postprandial blood glucose levels in db/db mice via enhanced insulin sensitivity irrespective of PPAR-γ.