Effects of Selected Terminalia and Ficus Species in the Inhibition of α-Amylase and α- Glucosidase Enzymes

Abstract

Some Ficus and Terminalia species are relevant in the management of diabetes mellitus but their antidiabetic principles and mechanism of action are yet to be investigated. This study was aimed at investigating the inhibitory potential of ten ethnobotanically selected Ficus and Terminalia species against α-amylase and α-glucosidase enzymes. The methanol extracts of ten selected plants from Ficus and Terminalia genera were tested for their inhibitory activity against porcine pancreatic α-amylase and α-glucosidase from Saccharomyces cerevisiae using colorimetric assay. Acarbose was used as the standard. Percentage inhibition was determined and IC50 value was calculated by analyzing dose-response data using non-linear regression with the aid of GraphPad prism® (7). The result showed that six plant extracts inhibited α-amylase enzyme while all the ten extracts displayed inhibition against glucosidase enzyme in a concentration-dependent manner. Terminalia mollis, F. capensis, and F. vogelli leaf extracts showed significant (p<0.05) inhibitory activity on α-amylase enzyme with IC50 of 344.47±4.66, 343.73±6.13; and 1630.67±2.85 µg/mL, respectively, compared to other extracts. A significant inhibitory activity of these extracts was also observed against α-glucosidase enzyme with IC50 of 6.482±0.61, 11.36±1.01, and 78.47±1.94 µg/mL, respectively, compared to acarbose IC50 2584±9.61 µg/mL. The results from this investigation justify the folkloric usage of these plants for the management of diabetes mellitus. Hence, further investigation is ongoing to isolate and characterize the antidiabetic principles from T. mollis, and F. capensis methanolic leaf extracts.