Chemical constituents from the stems of Picrasma quassioides Bennet

The phytochemical studies on the stems of Picrasma quassioides Bennet led to the isolation of seven β-carboline alkaloids( 1 - 6 ), five cantin-6-one alkaloids( 7 - 11 ), two canthin-5, 6-dione( 12 , 13 ), three sesquiterpenes( 14 - 16 ), and one steroids( 17 ). Their structures were elucidated by the combination of spectroscopic analyses(ESI-MS, ¹H NMR and ¹³C NMR)and the comparisons with the reference. Compound 16 is a new natural product, and this is the first report for compounds 5 , 6 , 14 - 17 from the species P. quassioides.