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, ¹³ C-NMR, and ECD calculations. This is the first time to determine the absolute configurations of yohimbine-type N-oxides by quantum chemistry calculations (¹³ 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 IC₅₀ values of 25.5, 22.6, and 26.0 μM, respectively.