Antidiabetic effect of Gynura procumbens leaves extracts involve modulation of hepatic carbohydrate metabolism in streptozotocin-induced diabetic rats

Abstract

Gynura procumbens is an annual evergreen shrub found in Southeast Asia, especially Malaysia, Thailand and Indonesia, which is of considerable medicinal value. The present study aims to investigate the antidiabetic properties of G. procumbens leaves aqueous and ethanolic extracts and its possible underlying antihyperglycemic mechanisms of action involving liver carbohydrate metabolism in streptozotocin-induced diabetic rats. Experimental diabetes was induced via single intravenous injection of streptozotocin (55 mg/kg of body weight). G. procumbens leaves aqueous and ethanolic extracts were administered orally at 3 different doses (50, 100 and 150 mg/kg of body weight) for 42 consecutive days. Administration of G. procumbens leaves aqueous and ethanolic extracts significantly (P<0.05) reduced fasting blood glucose and HbA1c levels of diabetic rats after 42 days of treatment, in which ethanolic extract showed better improvement than aqueous extract in a dose-independent manner. Treatment of G. procumbens extracts also protected the diabetic rats from further body and liver weight loss, and showed slight increment on liver glycogen content in G. procumbens ethanolic extract-treated diabetic rats as well as significant (P<0.05) improvement on liver hexokinase, phosphofructokinase and fructose-1,6-bisphosphatase specific activities. However, administration of both extracts did not produce significant changes on plasma insulin concentration of diabetic rats when compared with diabetic controls. In conclusion, G. procumbens exerts its antidiabetic effect by promoting glucose metabolism via the glycolytic pathway and inhibiting hepatic endogenous glucose production via the gluconeogenic pathway.