Comparative Study of Dietary Flavonoids with Different Structures as α-Glucosidase Inhibitors and Insulin Sensitizers

This work was designed to comparatively investigate 27 dietary flavonoids that act as α-glucosidase inhibitors and insulin sensitizers. Based on the results of in vitro experiment of α-glucosidase inhibition, myricetin (IC50 = 11.63 ± 0.36 μM) possessed the strongest inhibitory effect, followed by apigenin-7-O-glucoside (IC50 = 22.80 ± 0.24 μM), and fisetin (IC50 = 46.39 ± 0.34 μM). A 3D-QSAR model of α-glucosidase inhibitors with good predictive capability (CoMFA, q2= 0.529, optimum number of components [ONC]= 10, R2= 0.996, F-value [F]= 250.843, standard error of estimation [SEE]= 0.064, two descriptors; and CoMSIA, q2= 0.515, ONC= 10, R2= 0.997, F= 348.301, SEE= 0.054, four descriptors) was established and indicated that meta-positions of ring B favored bulky and minor, electron-withdrawing, and hydrogen bond donor groups. The presence of electron-donating and hydrogen bond acceptor groups at position 4′ of ring B could improve α-glucosidase activity. Position 3 of ring C favored minor, electron-donati...