Alpha amylase inhibitory activities of extract of Annona squamosa Linn. Leaves in streptozotocin induced diabetic rats

Abstract

The leaves of Annona squamosa (AS) are reported to have anti-diabetic property, but its active principle and mechanism of action is not known. For further investigations, different extracts (hexane, chloroform, butanol, hexane washed methanol, total methanol extract and water decoction) of AS leaves were prepared, characterized and tested for their inhibitory property against activity of pancreatic α-amylase under in vitro and in vivo conditions. Hexane extract showed the lowest IC50 0.925 mg/mL and further tested for streptozotocin induced diabetes. Its hypoglycemic response was correlated with inhibitory activity with respect to α-amylase in pancreatic homogenate by using different doses and compared with standard drugs i.e., acarbose and glimepiride. It significantly reduced the raised glucose levels to 41.18±2.46 % at 100 mg/kg WB and 78.10±1.57% at 400 mg/kg WB. It also raised the serum insulin from 8.56±1.42 (experimental control) to 16.26±1.20 µU/mL at 400 mg/kg BW and simultaneously inhibited the activity of α-amylase to tune of 76.69±2.52% at 100 mg/kg WB and 86.67±2.30% at 400 mg/kg BW. In glimepiride treated rats, there was significant rise in serum insulin without inhibition of α-amylase and in case of acarbose treated rats; there was significant inhibition of α-amylase, without significant rise in serum insulin. Thus, it enhances the insulin secretion (acts as secretagogue) and also inhibits the pancreatic α-amylase in small intestine. Therefore, it could be used for the management of postprandial hyperglycemia in diabetes.