Inhibition of α-glucosidase by Andrographis paniculata ethanol extract in rats

Abstract

In the current study, we investigated the effect of ethanol extract of Andrographis paniculata (Burm.f.) Nees (Acanthaceae) (AP) on α-glucosidase (EC 3.2.1.20) inhibition in both normal and streptozotocin-induced diabetic rats. Oral carbohydrate tolerance tests were performed in 18-h fasted rats with starch (3 g/kg), sucrose (4 g/kg), and glucose (2 g/kg) separately, in both normal and diabetic rats, 10 min after administration of 250 (D1), 500 (D2), 1000 (D3) mg/kg ethanol extract of AP, vehicle (control), and acarbose (Acar) 10 mg/kg, respectively. Blood samples were analyzed for blood glucose at 0, 30, 60, and 120 min after respective treatments and the peak blood glucose (PBG) and area under the curve (AUC) determined. Our results demonstrate that 500 mg, 1000 mg/kg ethanol extract of AP reduces and prolongs the PBG concentration, simultaneously decreasing AUC after starch and sucrose loading in normal and diabetic rats. Similarly, acarbose also reduced sucrose and starch induced blood glucose excursions, whereas it had no peak blood glucose suppressive effect after exogenous glucose load in both normal and streptozotocin-induced diabetic rats. The results suggest the possibility that the ethanol extract of AP may have PBG suppressive effect, post-carbohydrate challenge as evidenced by reduced PBG and AUC, which can be used effectively as a safer alternative to control postprandial hyperglycemia (PPH), especially in diabetic patients and borderline patients not properly controlled on diet alone. © 2006 Informa Healthcare.