Bioactive constituents from Dioscorea bulbifera L. rhizomes with antioxidant and α-glucosidase inhibitory properties.

The chemical profile of the rhizomes of Dioscorea bulbifera L. was systematically investigated. As a result, nineteen known compounds were isolated and structurally characterised, comprising emodin (1), piceid (2), quercetin (3), physcion (4), kaempferol (5), caffeic acid methyl ester (6), resveratrol (7), 3,4,5-trihydroxybenzoic acid (8), resveratrol-2''-O-galloylester (9), bisdemethoxycurcumin (10), resveratrol-O-E-phyllanthine (11), rhein (12), aloe-emodin (13), 5-methoxy-7-hydroxy-1(3H)-benzofuranone (14), questinol (15), vanillic acid (16), β-sitosterol (17), 3,4-dihydroxybenzoic acid (18), and diosgenin (19). All isolated compounds were evaluated for their α-glucosidase inhibitory and antioxidant activity. The results demonstrated that compounds 3, 5, 8, 9, and 18 exhibited antioxidant activity, with radical scavenging rates ranging from 84.19% to 97.73%, while 9, 11, 13, and 15 showed α-glucosidase inhibitory effects, with IC50 values ranging from 0.4556 to 1.3528 mg/mL. These findings indicate that the ethyl acetate fraction of D. bulbifera represents a promising source of multifunctional bioactive constituents and provides a chemical basis.