In vitro Antihyperglycemic and Chelating Potential of Selected Ayurvedic Medicinal Plants

Seven medicinal plants used in folk medicine to relieve various diseases including diabetes, were investigated for antihyperglycemic activities. Two types of extracts for each plant were processed by decoction and by soaking in an aqueous-acetone mixture. The inhibitory activities were tested on α-amylase and α-glucosidase along with chelating activity. The aqueous-acetone extracts of Feretia apodanthera and Ozoroa insignis exerted strong inhibition on α-glucosidase (96.51±0.14 and 96.44±0.68 %, respectively) but lower inhibition on α-amylase (21.60±1.69 and 93.85±6.58 %, respectively) and displayed a weak chelating activity as compared to the respective standards acarbose and ethylenediaminetetraacetic acid. Subsequent column fractionation resulted in selectively strong inhibition of α-glucosidase. The inhibitory activities of α-amylase and α-glucosidase were weakly correlated (R=0,389) and both were inversely correlated with metal chelating activity (R=-0.731 and R=-0.809, respectively). Volatile compounds, 1-nonadecene and 1-heptadecene identified by GC-MS were related to the inhibitory activities of α-amylase and α-glucosidase enzymes. This potent inhibition of sugar degrading enzymes may help to manage the hyperglycemia occurring in type 2 diabetes.