Obtusifolin treatment improves hyperlipidemia and hyperglycemia: possible mechanism involving oxidative stress

Clinical research has confirmed the efficacy of several plant extracts in the modulation of oxidative stress associated with hyperlipidemia and hyperglycemia induced by obesity and diabetes. Findings indicate that obtusifolin has antioxidant properties. The aim of this study was to evaluate the possible protective effects of obtusifolin against oxidative damage in diabetic hyperlipidemia and hyperglycemia. In this study, the rats were divided into the following groups with eight animals in each: control, untreated diabetic, three obtusifolin (10, 30, and 90 mg/kg/day)-treated diabetic groups. Diabetes was induced by streptozotocin (STZ) in rats. STZ was injected intraperitoneally at a single dose of 60 mg/kg for diabetes induction. Obtusifolin (intraperitoneal injection) was administered 3 days after STZ administration; these injections were continued to the end of the study (4 weeks). At the end of the 4-week period, blood was drawn for biochemical assays. In order to determine the changes of cellular antioxidant defense systems, antioxidant enzymes including glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) activities were measured in serum. Moreover, we also measured serum nitric oxide (NO) and serum malondialdehyde (MDA) levels, markers of lipid peroxidation. STZ-induced diabetes caused an elevation (P < 0.001) of blood glucose, MDA, NO, total lipids, triglycerides and cholesterol, with reduction of GSH level and CAT and SOD activities. The results indicated that the significant elevation in the blood glucose, MDA, NO, total lipids, triglycerides and cholesterol; also the reduction of glutathione level and CAT and SOD activity were ameliorated in the obtusifolin-treated diabetic groups compared with the untreated groups, in a dose-dependent manner (P < 0.05, P < 0.01, P < 0.001). These results suggest that obtusifolin has antioxidant properties and improves chemically induced diabetes and its complications by modulation of oxidative stress.