Isolation and α-Glucosidase inhibitory activity of endophytic fungi from mahogany (Swietenia macrophylla King) seeds

Diabetes mellitus is a metabolic syndrome characterized by hyperglycemia. The major goal in the treatment of this disease is to achieve normoglycemia. One of medication used is α-glucosidase inhibitor that could reduce postprandial hyperglycemia with delay of digestion of carbohydrate. The ability of endophytic fungi to produce similar bioactive compounds to its host plant is potential source to get α-glucosidase inhibitory compounds. This research was aimed to isolate the endophytic fungi from Swietenia macrophylla King seeds, and to evaluate the inhibitory activity of α-glucosidase from fermentation culture of its isolate. Six endophytic fungi were isolated. Each isolate was fermented in submerged culture with Potato Dextrose Broth and yeast extract medium for 7 days, and then extracted with ethyl acetate and methanol. α-Glucosidase inhibitory activity of those extracts were assayed by spectrophotometric method using microplate reader. Five ethyl acetate extracts showed better activity than acarbose with smallest IC50 values was 73.64 μg/mL. The most active extract showed competitive inhibition. Chemical analysis indicated that the α-glucosidase inhibitor was flavonoid group.