Tryptanthrin derivatives as Toxoplasma gondii inhibitors--structure-activity-relationship of the 6-position.

A panel of derivatives of the natural product tryptanthrin was synthesized and screened for its in vitro activity against the intracellular parasite Toxoplasma gondii. We concentrated on the modification of the 6-keto group of tryptanthrin and prepared a series of oximes, hydrazones and alcohols based on tryptanthrin. We evaluated parasite growth inhibition and host cell cytotoxicity. Our results indicate that in particular alcohol analogs are promising candidates for further investigation.