The Effect of the Extracts of Endophytic Fungi on Pancreatic α-Amylase Activity

Inhibitors of pancreatic α-amylase offer an effective strategy to lower the levels of postprandial hyperglycemia by control of starch breakdown. Among 86 fungal endophytes isolated from 15 medicinal plants Aspergillus terreus-AF104S, Aspergillus egypticus-HT166S and Penicillium sp.-CC200 exhibited strong pancreatic amylase inhibitory potential were selected. Endophytes were subjected to ethyl acetate extraction and tested for α-amylase inhibition, in order to assess and evaluate their inhibitory potential on pancreatic α-amylase. Analysis showed concentration dependent enzyme inhibition up to 83% with half inhibition (IC50) values for less 25 mg⋅mL, which is lower than acarbose as control. It was observed 3-fold increasing of Vmax and maintenance Km at control level in the presence of extracts A. terreus-AF104S and Penicillium sp.-CC200, while in presence of extract A. egypticus-HT166S Km was doubled, and Vmax was maintained at the control level. Kinetic studies allow proposing the competitive mode of α-amylase inhibition by extracts A. egypticus-HT166S and uncompetitive inhibition by extracts A. terreus-AF104S and Penicillium sp.-CC200.