Antioxidant and α-Glucosidase Inhibitory Activities of Fisetin

Fisetin is a flavonoid widespread in vegetables, fruits and medicinal plants. The in vitro antioxidant and α-glucosidase inhibitory activities of fisetin were systemically investigated in this study. The DPPH and ABTS radical scavenging performance of fisetin was higher than that of BHA. In the ORAC and PSC assays, fisetin also exhibited strong antioxidant activity. The α-glucosidase inhibitory activity of fisetin (IC50, 9.38±0.35 μg/mL) was significantly superior to that of acarbose (IC50, 1.07±0.15 mg/mL). Its inhibition type was determined to be a mixed competitive and non-competitive inhibition mode. Molecular docking analysis suggested it could exert the α-glucosidase inhibitory role by forming hydrogen bonds with the TRP391, ASP392, ARG428 and ASP568 residues of α-glucosidase.