Abstract: The petroleum ether-soluble fraction of pooled ethanol extracts from the aboveground parts of Cirsium setosum (Willd.) MB was further fractionated by silica gel column chromatography, Sephadex LH-20 column chromatography and preparative HPLC. The resulting sub-fractions were structurally identified by one-dimensional, two-dimensional NMR and MS spectroscopies. Four steroids were obtained, including ergosta-4, 24 (28)-diene-3-one (1), stigmast-4-en-3-one (2), stigmasterol (3) and β-sitosterol (4). To the best of our knowledge, this is the first report showing the presence of Compounds 1 and 2 in the genus Cirsium and the presence of Compounds 1, 2 and 3 in Cirsium setosum (Willd.) MB. None of these identified compounds showed cytotoxic activity at a concentration of 1 × 10-5 mol/L as determined by in vitro MTT assay.

Key words: Cirsium setosum, isolation and purification, structural elucidation, steroids, cytotoxicity