Plant anticancer agents VII: Structural effects on cytotoxicity of bisindole alkaloids of voacamine type.

Structural effects on the cytotoxicity of bisindole alkaloids of the voacamine series were investigated with compounds isolated from various Tabernaemontana species and compounds synthesized specifically for this purpose. Activity is sensitive both to the position of attachment of the vobasane unit on the iboga moiety and to the presence of an N-methyl group on the vobasane unit.