Aspidosperma-aspidosperma-type bisindole alkaloids from Voacanga africana

Four new aspidosperma-aspidosperma-type bisindole alkaloids 1-4 were isolated from the seeds and root bark of Voacanga africana (Apocynaceae) and their structures were determined by spectroscopic analysis. Among them, voacandimine A (2) featured a linkage mode new to dimeric monoterpenoid indole alkaloids.