Evaluation ofα-Glucosidase Inhibitory Effect of 50% Ethanolic Standardized Extract ofOrthosiphon stamineusBenth in Normal and Streptozotocin-Induced Diabetic Rats

Abstract

In the present study, a 50% ethanolic extract ofOrthosiphon stamineuswas tested for itsα-glucosidase inhibitory activity.In vivoassays of the extract (containing 1.02%, 3.76%, and 3.03% of 3′hydroxy-5,6,7,4′-tetramethoxyflavone, sinensetin, and eupatorin, resp.) showed that it possessed an inhibitory activity againstα-glucosidase in normal rats loaded with starch and sucrose. The results showed that 1000 mg/kg of the 50% ethanolic extract ofO. stamineussignificantly (P<0.05) decreased the plasma glucose levels of the experimental animals in a manner resembling the effect of acarbose. In streptozotocin-induced diabetic rats, only the group treated with 1000 mg/kg of the extract showed significantly (P<0.05) lower plasma glucose levels after starch loading. Hence,α-glucosidase inhibition might be one of the mechanisms by whichO. stamineusextract exerts its antidiabetic effect. Furthermore, our findings indicated that the 50% ethanolic extract ofO. stamineuscan be considered as a potential agent for the management of diabetes mellitus.