A Metabolomic Investigation of the Effect of Eosin B on Gameto-cyte of Plasmodium falciparum using 1HNMR Spectroscopy

Background: Recently eosin B was shown to have an effect on the asexual stage of Plasmodium falciparum and in this study, its activity against gametocytes and changes in the culture medium metabolites were investigated using an1HNMR-based metabolomics approach. Methods: In the Biochemistry Department of Pasteur Institute of Iran in 2017, parasites were cultured and gametocytogenesis induced by heparin and 5% hematocrit. Sexual stage parasites were tested by eosin B in 90 well plates and IC50 determined using Lactate Dehydrogenase assay. Gametocytes were treated by IC50 dose of eosin B and the medium collected in the two groups: with eosin B and controls and sent for 1HNMR spectroscopy. The spectra were analyzed on MATLAB interface and the altered metabolites in the culture medium and eosin-affected biochemical pathways were identified by Human Metabolome Database and Metaboanalyst website. Results: The results revealed eosin B had an effective gametocytocidal activity against P. falciparum. The significant metabolites changed in the medium were thiamine, Asp, Asn, Tyr, Lys, Ala, Phenylpyruvic acid, NAD+ and lipids. The main pathways identified were aminoacyl-tRNA biosynthesis, Phenylalanine, tyrosine and tryptophan biosynthesis, Alanine, aspartate and glutamate metabolism, Phenylalanine metabolism, Nicotinate and nicotinamide metabolism, and lysine degradation. Conclusion: Eosin B exhibited substantial gametocytocidal activity and affected important drug targets in the Plasmodium.