Abstract: Taking leaves of Kava（Piper methysticum Forst. f.） as materials, six compounds were obtained from the EtOAc extract by a combination of column chromatography of silica gel,Sephadex LH-20 many times. Their structures were determined on the basis of ¹HNMR,¹³C NMR,²DNMR,UV,IR,and ESIMS spectra data and were identified as Desmethoxyyangonin,yangonin,11-methoxyyangonin,11-methoxy-5,6-dihydroyangonin,methysticin,dihydromethysticin. The cytotoxicity of six compoundswas tested by MTT assay,the result showed that yangonin and 11-methoxyyangonin were very strong cytotoxicity against A549 and NCI-H460 cells,while,11-methoxy-5,6-dihydroyangonin,methysticin and dihydromethysticin were very weak cytotoxicity against A549 and NCI-H460 cells.

Key words: leaves of Kava （Piper methysticum Forst. f.）, chemical constituents, cytotoxicity