Abstract: Nine compounds were isolated and purified from the roots of Eupatorium chinense L. by various chromatographic techniques such as column chromatography on silica gel,Sephadex LH-20 and preparative HPLC.Their structures were elucidated by physicochemical properties and NMR,and were identified as dammaradienyl acetate (1),(2R,3S)-5-acetyl-6-hydroxy-2-isopropenyl-3-ethoxy-benzodihydrofuran (2),stigmastero 1 (3),phthalic acid dibutyl ester (4),12,13-dihydroxyeuparin (5),5-acetyl-6-hydroxy-2-isopropenyl benzofuran (6),2,5-diacetyl-6-hydroxy benzofuran (7),ruscodibenzofuran (8),2-acetyl-5-(prop1-ynyl)-thiophen-3-O-β-D-glucopyranoside (9).Compounds 1,2,4 and 8 were isolated from the species for the first time,among which 2,4 and 8 were isolated from Eupatorium genus for the first time. In vitro antibacterial activity against 5 kinds of pathogenic bacteria was investigated by Oxford cup method,MIC was also measured by broth dilution method.All the tested compounds showed antibacterial activities at varying degree on five kinds of bacteria.Compound 1,6 and 8 showed strong inhibitory effect on Klebsiella pneumoniae with the MIC 0.98 μg/mL,0.98 μg/mL and 0.49 μg/mL respectively,compound 7 strongly inhibited Escherichia coli with MIC 3.91 μg/mL.Compound 1,2,6 and 7 showed strong inhibitory effect on Pseudomonas aeruginosa with the same MIC 7.81 μg/mL.The results indicated that the main active antibacterial ingredients may be related to 1 and benzofurans 2,6,7 and 8.

Key words: Eupatorium chinense L., chemical constituents, benzofurans, antibacterial activity