Synthesis, characterization and biological activity of organometallic derivatives of the antimalarial drug mefloquine as new antischistosomal drug candidates.

We present the design, synthesis, characterization and biological evaluation of new ferrocenyl and ruthenocenyl derivatives of the organic antimalarial mefloquine, a drug also known for its antischistosomal activity. The two metallocenyl derivatives prepared (3 and 4) demonstrated comparable activity to mefloquine against adult-stage Schistosoma mansoni in vitro. Importantly, both compounds were found to have lower toxicity in all cell lines than mefloquine itself. Administration of a 200 mg kg-1 oral dose of 3 and 4 to S. mansoni-infected mice did not significantly reduce worm burden, contrary to mefloquine.