Investigation of Calcium Channel Blockers as Antiprotozoal Agents and Their Interference in the Metabolism ofLeishmania (L.) infantum

Abstract

Leishmaniasis and Chagas disease are neglected parasitic diseases endemic in developing countries; efforts to find new therapies remain a priority. Calcium channel blockers (CCBs) are drugs in clinical use for hypertension and other heart pathologies. Based on previous reports about the antileishmanial activity of dihydropyridine-CCBs, this work aimed to investigate whether thein vitroanti-Leishmania infantumand anti-Trypanosoma cruziactivities of this therapeutic class would be shared by other non-dihydropyridine-CCBs. Except for amrinone, our results demonstrated antiprotozoal activity for fendiline, mibefradil, and lidoflazine, with IC50values in a range between 2 and 16 μM and Selectivity Index between 4 and 10. Fendiline demonstrated depolarization of mitochondrial membrane potential, with increased reactive oxygen species production in amlodipine and fendiline treatedLeishmania, but without plasma membrane disruption. Finally,in vitrocombinations of amphotericin B, miltefosine, and pentamidine againstL. infantumshowed in isobolograms an additive interaction when these drugs were combined with fendiline, resulting in overall mean sum of fractional inhibitory concentrations between 0.99 and 1.10. These data demonstrated that non-dihydropyridine-CCBs present antiprotozoal activity and could be useful candidates for futurein vivoefficacy studies against Leishmaniasis and Chagas’ disease.