RESUMO
Objective: To study the chemical constituents from the roots of Astragalus englerianus, and to determine their anti-oxidative activities. Methods: The compounds were isolated and purified by silica gel, RP18, and Sephadex LH-20 column chromatography, then their structures were elucidated on the basis of spectral data and physicochemical properties, and anti-oxidative activities were tested by DPPH method. Results: Twenty-nine compounds were obtained from the ethyl acetate fraction of the methanol extract from the roots of A. englerianus and identified as isoliquiritigenin (1), 4'-hydroxy-2, 4-dimethoxychalcone (2), xenognosin (3), formononetin (4), calycosin (5), prunetin (6), (3R)-vestitol (7), liquiritigenin (8), (6aR, 11aR)-medicarpin-3-O-β-D-glucopyranoside (9), olean-12-en-3β, 22β, 24-triol (10), friedelin (11), β-sitosterol (12), stigmasterol (13), 7β-hydroxysitosterol (14), 7-oxositosterol (15), 3β-sitosteryl (9'Z)-9'-heptadecenoate (16), stigmast-4-en-3-one (17), 5α, 8α-epidioxy-ergosta-6, 9, 22E-trien-3β-ol (18), 5α, 8α-epidioxy-ergosta-6, 22E-dien-3β-ol (19), D-2-O-methylinositol (20), octacosanol (21), methyl stearate (22), eicosanoic acid (23), heneicosanoic acid (24), oleic acid (25), linoleic acid (26), α-linolenic acid (27), tripalmitin (28), and trilinolein (29). The ethyl acetate soluble portion, compounds 1 and 3 showed DPPH free radical scavenging activity with IC50 values of (66.0 ± 1.8), (64.3 ± 0.4), and (57.1 ± 1.2) μg/mL, respectively. Conclusion: This is the first report on the compounds 2, 3, 6, 10, 11, 14-22, and 28 from the plants of Astragalus Linn., and all the compounds are obtained from A. englerianus for the first time. A. englerianus is found to possess the potent anti-oxidative activity.