Modular Design of Mitochondrion-Targeted Iron Chelators Allows Highly Selective Antiparasitic Activity against Trypanosomes and Apicomplexan Parasites.

Parasitic protozoa exhibit a high demand for iron, with mitochondrial iron metabolism representing a vulnerable target for chemotherapeutic intervention. We recently demonstrated that mitochondrial targeting of the iron chelator deferoxamine (DFO) via triphenylphosphonium (TPP) conjugation enhances its antiparasitic efficacy. To expand upon this strategy, mitochondrially targeted derivatives of DFO and deferasirox (DFX) were synthesized and evaluated for their activity against important human parasites. The DFX derivative mitoDFX was effective against Trypanosoma spp. and Toxoplasma gondii with remarkable selectivity. The fact that mitoDFX is a promising anticancer agent, which is likely safe to use in the context of human health, highlights the potential for drug repurposing in parasitology. Structure-activity relationship (SAR) studies and iron distribution analyses in trypanosomes revealed that mitochondrial targeting of the compounds, rather than iron chelation per se, is the main driver of the antiparasitic effects, underscoring the critical role of phosphonium salts in bioactivity.