Melodinine V, an antitumor bisindole alkaloid with selective cytotoxicity from Melodinus henryi

Melodinine V (1) with a vincanol-eburenine skeleton, was isolated from Melodinus henryi. The structure was elucidated by extensive spectroscopic methods and further confirmed by the single crystal X-ray diffraction analysis. Melodinine V showed selective cytotoxic activities against human colon cancer cell line HT-29 and inhibited cell proliferation in a concentration-dependent manner. It induced cell cycle arrest at G1 phase and cellular apoptosis by increasing histone-associated DNA fragmentation in the treated HT-29 cells.