Cathagines A-D, new bisindole alkaloids from Catharanthus roseus.

Four new bisindole alkaloids, cathagines A (1)-D (4) consisting of an aspidosperma and the fused tetracyclic 3-spirooxindole derived from an iboga type skeleton were isolated from the whole plant of Catharanthus roseus. The structures including absolute stereochemistry were elucidated on the basis of 2D NMR data and CD spectra. Cathagine B (2) showed moderate anti-malarial activity against Plasmodium falciparum 3D7.