Analysis of the active fraction of Iranian Naja naja oxiana snake venom on the metabolite profiles of the malaria parasite by 1HNMR in vitro

Malaria is an important parasitic disease with high morbidity and mortality in tropical areas. Resistance to most antimalarial drugs has encouraged the development of new drugs including natural products. Venom is a complex mixture of active pharmaceutical ingredients. The purpose of this study was to investigate the antimalarial activity of purified fractions of Naja naja oxiana. Lyophilized venom was purified with a Sephacryl S-200 HR column and the fractions lyophilized and inhibitory concentration 50% against Plasmodium falciparum 3D7 in vitro obtained. The 4th fraction was run on a Mono Q column, and activity against P. falciparum was detected by lactate dehydrogenase assay and purity by SDS PAGE. Large scale culture of the parasite was carried out with and without the active fraction on the ring stage for 48 hr. The parasites were collected and lyophilized and analyzed by 1HNMR. Chemometrics studies were performed using MATLAB, differentiating metabolites were identified by Human Metabolic Database, and metabolic pathways by the Metaboanalyst online package. The active fraction from the ion exchange column had a 50% inhibitory concentration of 0.026 µg/ml on P. falciparum in vitro (P<0.001) with molecular weight of 63 kDa by SDS-PAGE and no hemolytic activity. Metabolomics studies on the two groups with and without the fraction identified 5 differentiating metabolites and a number of related pathways. The metabolites were succinic acid, l-glutamic acid, pyruvic acid, cholesterol, and NAD. The changes in the Krebs cycle and metabolism pathways of nicotinamide and pyruvate were noticeable.