Abstract: To study chemical constituents of the flower of Eupatorium chinense,various chromatographic techniques,including normal phase silica gel column chromatography,preparative thin-layer chromatography,and preparative HPLC were used.Their structures were determined by various spectral data.Finally,nine compounds were isolated from the acetic ether extract of flower of E. chinense and the structures were identified as 3,11-dioxo-olean-12-ene(1),3β-(octanoyloxy)-11-oxoolean-12-en-28-oic acid(2),β-armyrin(3),kaempferol-3-O-β-D-galactoside(4),ethyl caffeate(5),5-Methyl-2-(1-methylethyl)phenyl-β-D-glucopyranoside(6),eupalinolide K(7),11-hydroxy-10,11-dihydro-euparin(8),dieupachinin E(9).Among them,compounds 1-7 were isolated from the flower of E. chinense for the first time.Compounds 1-3,belonging to oleanolic pentacyclic triterpenoids,were isolated for the first time from Eupatorium chinensis and presumed to be the characteristic constituent of the flower of Eupatorium chinensis. Moreover,the antimicrobial activity of compound 1-7 was tested and evaluated by Oxford cup method.The results showed that the tested compounds had different degrees of antimicrobial activity against bacteria or fungus.Compounds 1 and 4 had the best activity.The study was the first report about the chemical constituents of the flower parts of E. chinense.

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