Salvianolic Acid B Ameliorates Hyperglycemia and Dyslipidemia in db/db Mice through the AMPK Pathway.

BACKGROUND/AIMS Salvianolic acid B (Sal B), a major polyphenolic compound of Salvia miltiorrhiza Bunge, has been shown to possess potential antidiabetic activities. However, the action mechanism of SalB in type 2 diabetes has not been investigated extensively. The present study was designed to investigate the effects of Sal B on diabetes-related metabolic changes in a spontaneous model of type 2 diabetes, as well as its potential molecular mechanism. METHODS Male C57BL/KsJ-db/db mice were orally treated with Sal B (50 and 100 mg/kg) or metformin (positive drug, 300 mg/kg) for 6 weeks. RESULTS Both doses of Sal B significantly decreased fasting blood glucose, serum insulin, triglyceride and free fatty acid levels, reduced hepatic gluconeogenic gene expression and improved insulin intolerance in db/db mice. High dose Sal B also significantly improved glucose intolerance, increased hepatic glycolytic gene expression and muscle glycogen content, and ameliorated histopathological alterations of pancreas, similar to metformin. Sal B treatment resulted in increased phosphorylated AMP-activated protein kinase (p-AMPK) protein expression in skeletal muscle and liver, increased glucose transporter 4 (GLUT4) and glycogen synthase protein expressions in skeletal muscle, and increased peroxisome proliferator-activated receptor alpha (PPARα) and phosphorylated acetyl CoA carboxylase (p-ACC) protein expressions in liver. CONCLUSION Our data suggest that Sal B displays beneficial effects in the prevention and treatment of type 2 diabetes at least in part via modulation of the AMPK pathway.