Experimental diabetes treated with trigonelline: effect on β cell and pancreatic oxidative parameters.

Oxidative stress in diabetes coexists with a reduction in the antioxidant status, which can further increase the deleterious effects of free radicals. Trigonelline is the major component of Mirabilis jalapa L., which has been used to treat diabetes in China. The present study was designed to evaluate the beneficial effects of trigonelline against hyperglycemia, hyperlipidemia, β cell damage and antioxidant of pancreas in diabetic rats. Diabetic rats were induced by intraperitoneal injection 35 mg/kg streptozotocin and a high-carbohydrate/high-fat diet. Rats were divided into four groups: normal control, diabetic control, trigonelline-treated diabetic, and glibenclamide-treated diabetic. After 4-week treatment, blood glucose, serum insulin, total cholesterol (TC), and triglyceride (TG) levels, insulin content in pancreas, and oxidative stress parameters in pancreatic homogenate were assayed. Pancreas was examined by hematoxylin/eosin staining. Trigonelline significantly decreased blood glucose, TC, and TG levels of diabetic rats. Pancreas-to-body weight ratio, insulin level, insulin sensitivity index, insulin content in pancreas, malonaldehyde and nitric oxide contents, and superoxide dismutase, catalase, glutathione and inducible nitric oxide synthase activities were altered in diabetic rats, and were near control levels treated with trigonelline. These findings suggest that trigonelline has beneficial effect for diabetes through decreasing blood glucose and lipid levels, increasing insulin sensitivity index and insulin content, up-regulating antioxidant enzyme activity and decreasing lipid peroxidation.