Antidiabetic effect of Cephalotaxus sinensis leaf extract (STP) in STZ-induced diabetic rats by its antioxidant activity

In previous study, we have reported the antihyperglycemic effect of Cephalotaxus sinensis leaf extract (STP) [1]. In this work, its protective action on pancreas and antioxidant activity in STZ-induced diabetic rats was investigated. Results showed that oral administration of STP had no effect on blood glucose and serum insulin in normal rats. However STZ-induced diabetic rats treated with STP showed significantly decreased fasting blood glucose and increased serum insulin level compared with the untreated diabetic control. Histopathology analysis showed that pancreases of diabetic rats treated by STP was more intact than that of untreated ones which indicates a protecting effect of STP on pancreas against STZ-induced injury. Further studies showed that serumal, pancreatic and hepatic superoxide dismutase (SOD) activities in STZ-induced diabetic rats treated by STP were significantly higher than that in untreated diabetic ones. At the same time, the corresponding MDA levels were much lower in STP-treated diabetic animals. In conclusion, Cephalotaxus sinensis leaf extract (STP) is a promising candidate for treatment of diabetes and has the potential for prevention and treatment of diabetic complications. The basis for its antidiabetic effect in STZ-induced diabetic rats is, among others, related to it antioxidant activities.