β-Carboline alkaloids from the leaves of Trigonostemon lii Y.T. Chang.

A phytochemical work on the alkaloid constituents from Trigonostemon lii Y.T. Chang was conducted to give six new β-carboline alkaloids, trigonostemines A-F (1-6) and eight known β-carboline alkaloids (7-14). Their structures were elucidated by extensive spectroscopic techniques including 2D NMR experiments and mass spectrometry. All of the compounds were evaluated for their cytotoxic activities against the HL-60, SMMC-7721, A-549, MCF-7, and SW480 human cancer cell lines. Trigonostemines A and B (1 and 2) exhibited stronger inhibitory activities than the positive control (cisplatin) in some cell lines.