Antimalarial activity of basic phospholipases A(2) isolated from Paraguayan Bothrops diporus venom against Plasmodium falciparum

Malaria is a parasitic infectious disease and was responsible for 400.000 deaths in 2018. Plasmodium falciparum represents the species that causes most human deaths due to severe malaria. In addition, studies prove the resistance of P. falciparum to drugs used to treat malaria, making the search for new drugs with antiplasmodial potential necessary. In this context, the literature describes snake venoms as a rich source of molecules with microbicidal potential, including phospholipases A(2) (PLA(2)s). In this sense, the present study aimed to isolate basic PLA(2)s from Paraguayan Bothrops diporus venom and evaluate their antiplasmodial potential. Basic PLA(2)s were obtained using two chromatographic steps. Initially, B. diporus venom was subjected to ion exchange chromatography (IEC). The electrophoretic profile of the fractions from the IEC permitted the selection of 3 basic fractions, which were subjected to reverse phase chromatography, resulting in the isolation of the PLA(2)s. The toxins were tested for enzymatic activity using a chromogenic substrate and finally, the antiplasmodial, cytotoxic potential and hemolytic activity of the isolated toxins were evaluated. The electrophoretic profile of the fractions from the IEC permitted the selection of 3 basic fractions, which were subjected to reverse phase chromatography, resulting in the isolation of the two enzymatically active PLA(2)s, BdTX-I and BdTX-II and the PLA(2) homologue BdTX-III. The antiplasmodial potential was evaluated and the toxins showed IC(50) values of: 2.44, 0.0153 and 0.59 μg/mL respectively, presenting PLA(2) selectivity according to the selectivity index results (SI) calculated against HepG2 cells. The results show that the 3 basic phospholipases isolated in this study have a potent antiparasitic effect against the W2 strain of P. falciparum. In view of the results obtained in this work, further research are necessary to determine the mechanism of action by which these toxins cause cell death in parasites.