Tackling emerging artemisinin resistance by modulating the defensive oxido-reductive mechanism of human malaria parasite by repurposing Nitrofurantoin

Abstract

AbstractOxidative stress mediated cell death has remained the prime parasiticidal mechanism of front line anti-malarial, artemisinin (ART). The emergence of resistantPlasmodiumparasites characterized by oxidative stress management due to impaired activation of ART as well as enhanced ROS detoxification has decreased its clinical efficacy. This gap can be filled by development of alternative chemotherapeutic agents to combat resistance defense mechanism. Interestingly, repositioning of clinically approved drugs presents an emerging approach for expediting anti-malarial drug development and resistance management. Herein, we evaluated the anti-malarial potential of Nitrofurantoin (NTF), a clinically used antibacterial drug, against intra-erythrocytic stages of ART-sensitive (Pf3D7) and resistant (PfKelch13R539T) strains ofPlasmodium falciparum(Pf), alone and in combination with ART. NTF exhibited growth inhibitory effect at sub micro molar concentration by arresting parasite growth at trophozoite stage. It also inhibited the survival of resistant parasites as revealed by ring survival assay. Concomitantly,in vitrocombination assay revealed synergistic association of NTF with ART. NTF was found to enhance the reactive oxygen and nitrogen species as well as induced mitochondrial membrane depolarization in parasite. Furthermore, we found that exposure of parasites to NTF disrupted their redox balance by impedingPfGlutathione Reductase activity, which manifests in enhanced oxidative stress, inducing parasite death.In vivoadministration of NTF, alone and in combination with ART inP. berghei ANKA infected mice blocked parasite multiplication and enhanced mean survival time. Overall, our results indicate NTF as a promising repurposable drug with therapeutic potential against drug sensitive as well as resistant parasites.