Effect of Ethanolic Extracts of Andrographis Paniculata on Type 2 Diabetes Mellitus and Insulin Resistant Rats

Most of the previous studies on anti-diabetic activity of Andrographis paniuclata including the studies performed by Kasmuri (2006) were concentrating on the effect of the plant on Type-I diabetes whereas more than 98% of diabetics in the affected population are of the type 2 (T2DM) nature. Therefore, the aim of the present study was to evaluate the effects of ethanolic extracts of Andrographis paniculata on T2DM and insulin resistance rats. In vitro alpha glucosidase and alpha amylase enzyme inhibitory experiments demonstrated that both 20%v/v and 95% v/v ethanolic extracts have appreciable alpha glucosidase and a weak alpha amylase inhibitory activity. This finding was further supported by acute in vivo alpha glucosidase inhibitory test in diabetic rats. The ethanolic extracts treatment at doses of 250, 500, and 1000mg/kg caused a reduction in peak blood glucose (PBG), and area under the curve (AUC) levels and thus could inhibit the rise in PBG when challenged with starch, and sucrose. Furthermore, chronic treatment for 21 days with 250, 500 and 1000mg/kg of 20%v/v ethanol extract and and 500, 1000mg/kg of 95% v/v ethanolic extracts reduced the fasting serum glucose levels of nicotinamide and streptozotocin-induced T2DM rats. There was a reduction in liver gluconeogenic enzyme level and an increase in liver glycolytic and lipogenic enzyme levels on treatment with 20%v/v ethanolic extract. The serum cholesterol, triglycerides, and free fatty acids were also reduced with both the extracts at all the doses. There was also a small increase in liver glutathione S hydroxylase (GSH), glutathione S transferase (GST), and