Melodinines Y 1 -Y 4 , four monoterpene indole alkaloids from Melodinus henryi .

Melodinines Y 1 -Y 4 (1-4), four undescribed alkaloids were isolated from Melodinus henryi . Their structures were elucidated by extensive NMR, mass spectroscopic analyses, theoretical NMR and electronic circular dichroism (ECD) calculations. Compounds 1 and 2 are the first examples of bisindole alkaloids possessing an eburnamine-leuconoxine combination. Compound 3 is a rare 2,3- seco pleiocarpamine type monoterpene indole alkaloid. Compound 1 showed cytotoxic activities against six human cancer cell lines with IC 50 values of 0.5-15.2 μM.