Pharmacological properties of new chalcones for treatment of leishmaniasis: in silico and in vitro studies

Abstract Leishmaniasis constitutes a complex of endemic and neglected diseases with high morbidity and mortality rates. Due to the toxicity, resistance profile and adverse effects of current drugs, science is looking for new therapeutic alternatives. Therefore, the objective of this study was to investigate in silico and in vitro tests the leishmanicidal potential of chalcones and verify their influence on the production of Reactive Oxygen Species (ROS). For the in silico tests, the PASS filter program was used. Murine macrophages (J774) and promastigotes and amastigotes of Leishmania braziliensis were used for in vitro tests. The selectivity index (SI) was calculated through the ratio between the 50% cytotoxicity concentration value (CC 50 ) and the 50% inhibitory concentration value (IC 50 ). Evaluation of ROS levels were obtained using the reagent 2'7'-dichlorodihydrofluorescein diacetate (H2DCFDA). The results indicated that one of the biological activities most associated with flavonoids is the antileishmanial activity. All chalcones tested did not show significant cytotoxicity and the chalcone that showed the best antileishmanial potency was compound 4 (FERAI), with a CI 50 of 9.75 ± 1.7 µM and 10.13 ± 1.7 µM for promastigotes and amastigotes of L. braziliensis , respectively. Macrophages treated with FERAI showed a reduction in infection and amastigotes number. FERAI has been shown to increase ROS levels, which is one of its possible mechanisms of action against the parasite. In view of the observed results, it is concluded that all compounds did not exhibit significant cytotoxicity and FERAI presented itself as a strong candidate for a new drug against leishmaniasis.