Dihydrochalcone glucosides and antioxidant activity from the roots of Anneslea fragrans var. lanceolata

Bioassay-guided fractionation of the roots of Anneslea fragrans var. lanceolata led to the isolation of four dihydrochalcone glucosides, davidigenin-2'-O-(6 ''-O-4'''-hydroxybenzoyl)-beta-glucoside (1), davidigenin-2'-O-(2 ''-O-4'''-hydroxybenzoy1)-beta-glucoside (2), davidigenin-2'-O-(3 ''-O-4'''-hydroxybenzoy1)-beta-glucoside (3), and davidigenin-2'-O-(6 ''''-O-syringoy1)-beta-glucoside (4), and beta known compounds. The structures were identified by means of spectroscopic analysis. Davidigenin-2'-O-(6 ''-O-syringoyl)-beta-glucoside (4), 1-O-3,4-dimethoxy-5-hydroxy phenyl-6-O-(3,5-di-O-methylgalloyl)-O-glucopyranoside (5), lyoniresinol (10), and syringic acid (13) showed ABTS [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] cation radical scavenging activity, with SC50 values of 52.6 +/- 5.5, 26.0 +/- 0.7, 6.0 +/- 0.2, and 27.5 +/- 0.6 mu g/mL in 20 min, respectively. Lyoniresinol (10), isofraxidin (12), and syringic acid (13) also showed DPPH [1,1-dipheny1-2-picrylhydrazyl] radical scavenging activity, with SC50 values of 8.4 +/- 1.8, 51.6 +/- 2.2, and 4.3 +/- 0.7 mu g/mL in 30 min, respectively. (C) 2012 Elsevier Ltd. All rights reserved.