Chemical constituents from the roots of Aucklandia costus Falc. (Asteraceae)

Chemical constituents of Aucklandia costus Falc. (Asteraceae) have been extensively studied. However, its polar chemical constituents and their chemotaxonomic significance remain unclear. In this study, a phytochemical investigation of the n-butanol fraction of the roots of A. costus by various types of column chromatography (CC) (e.g., silica gel CC, D101 macroporous resin CC, Mitsubishi Chemical Industries CC, octadecyl-silica CC, and semi-preparative HPLC) led to the isolation of twenty-two compounds including five phenylpropanoids (1–5), nine lignans (6–14), one alkaloid (15), two alkynes (16 and 17), one chromone (18), two megastigmanes (19 and 20), one fructoside (21) and one sesquiterpenoid (22). Their structures were identified by analysis of their NMR and MS data and by comparing with those reported in the literature. The presence of these compounds in the n-butanol fraction of the roots of A. costus was supported by direct LC-MS detection and NMR analysis. Among them, compound 3 was isolated from the Asteraceae family for the first time, and compounds 4–5, 10, 11, 13–17 and 19 were firstly found in the genus Aucklandia. The identity of the investigated A. costus was confirmed morphologically. The chemotaxonomic significance of compounds 1–22 was discussed.