Antidiabetic potential of Rhodiola sachalinensis root extract in streptozotocin-induced diabetic rats

In this study, we examined the antidiabetic effect and probable mechanisms of Rhodiola sachalinensis root extract (RS). The extract was examined by thin-layer chromatographic analysis, and the main compound was determined to be a polysaccharide. In streptozotocininduced diabetic rats, RS showed significant hypoglycemic activity by lowering blood glucose (at doses of 200 and 400 mg/kg for 40 days). The levels of serum total cholesterol and triglycerides in RS-treated diabetic rats were lower than in control diabetic rats. A significant increase in the serum insulin levels of diabetic rats following RS treatment was also observed. Furthermore, RS treatment decreased malondialdehyde levels, while increasing superoxide dismutase, catalase and glutathione peroxidase activities of the liver and kidney of diabetic rats. At the same time, RS did not show any significant toxicity in LD(50) and single-cell gel electrophoresis assays. These results indicate that RS has hypoglycemic and hypolipidemic activities and is an effective scavenger of free radicals that inhibits lipid peroxidation. The antioxidant and pancreatic beta-cell-protective activities of RS may be the main mechanisms of the observed antidiabetic effect of RS.