Cytotoxicity of modified indole alkaloids.

Indole alkaloids of the iboga series were structurally modified by incorporation of a 3,4-dimethoxybenzyl or -benzoyl unit so that they contained the N-O-O triangle required for antileukemic activity according to the triangulation hypothesis. The cytotoxicities of the modified alkaloids in the in vitro P-388 system were not significantly increased over the unmodified alkaloids, suggesting that the triangulation hypothesis does not apply in this series at least.