Effect of Wrightia tinctoria and Parthenocissus quinquefolia on blood glucose and insulin levels in the Zucker diabetic rat model.

The aim of this study is to evaluate the antidiabetic activity of two Indian Ayurvedic herbs using an oral glucose tolerance test and blood insulin levels to understand the mechanism of action using the Zucker diabetic rat model. Herbal extracts of Wrightia tinctoria and Parthenocissus quinquefolia at a dose of (250 mg/kg body weight) were used throughout the study. Following a glucose challenge of 2 gm/kg using oral gavage, a timed glucose tolerance test was used to determine the ability of these extracts to alter glucose levels in diabetic animal model. The glucose lowering activities of these extracts were then compared to the controls. Both tested herbal extracts have shown to exhibit significant (P < 0.05) hypoglycemic activity compared to the control. W. tinctoria and P. quinquefolia have an antidiabetic activity which reduced the blood glucose level in oral glucose tolerance test significantly compared with the control. To further understand their mechanism of action, blood insulin levels were also studied using an insulin Elisa assay. These studies revealed that the herbal extract of P. quinquefolia has direct correlation between glucose and insulin levels. However, W. tinctoria significantly lowered blood glucose levels (P< 0.05), while it did not show any correlation between blood glucose and insulin levels. Based on these findings, it can be concluded that hypoglycemic effects of W. tinctoria are more complicated than P. quinquefolia, and may involve other possible mechanism of action.