Chemical constituents from traditional Chinese medicine Siegesbeckia pubescens

Column chromatography on silica gel was used to study the chemical constituents of traditional Chinese medicine Siegesbeckia pubescens. The chemical structures of the separated compounds were elucidated by spectroscopic data analyses. As a result, eighteen compounds were obtained and identified as 3, 4'-dimethoxy quercetin(1), 3, 3', 4'-trimethoxy quercetin(2), 3, 3'-dimethoxy quercetin(3), 7, 3', 4'-trimethoxy luteolin(4), ursolic acid(5), 2β,19α-dihydroxyursolic acid(6), 2β-hydroxyursolic acid (7), stigmasterol-7-one(8), 5α, 8α-epidioxy-24(R)-methyl-cholesta-6, 22-diene-3β-ol(9), β-sitosterol(10), 2, 6-di(3-hydroxy-4-methoxyphenyl)-3, 7-dioxacyclo [3. 3. 0] octane (11), aurantiamide acetate (12), 3-(m-hydroxyl-p-methoxy)-N-(2'-p-hydroxyl-phenethyl)-2E-acrylamide(13), p-hydroxy benzaldehyde (14), m-hydroxy-p-methoxy benzaldehyde (15), 3, 4, 5-trimethoxybenzoic acid(16), monoethyl malonate(17), and p-hydroxylcinnamic acid(18). Among them, compounds 1-9, 11-18 were isolated from this plant for the first time.