Cytotoxic Yohimbine-Type Alkaloids from the Leaves of Rauvolfia vomitoria.

Two new yohimbine-type monoterpene indole alkaloids, rauvines A and B, and six known derivatives were obtained from the leaves of R. vomitoria. The structures of rauvines A and B were determined by extensive spectroscopic analyses, C-NMR, and ECD calculations. This is the first time to determine the absolute configurations of yohimbine-type N-oxides by quantum chemistry calculations ( C-NMR and ECD calculations). All the isolates were tested for their cytotoxicity against five human cancer cell lines. Rauvine B showed moderate cytotoxicity on human MCF-7 breast, SWS80 colon, and A549 lung cancer cell lines with IC values of 25.5, 22.6, and 26.0 μM, respectively.