Synthesis and anti-parasitic activity of a novel quinolinone-chalcone series

A series of novel quinolinone-chalcone hybrids and analogues were designed, synthesized and their biological activity against the mammalian stages of Trypanosoma brucei and Leishmania infantum evaluated. Promising molecular scaffolds with significant microbicidal activity and low cytotoxicity were identified. Quinolinone-chalcone 10 exhibited anti-parasitic properties against both organisms, being the most potent anti-L. infantum agent of the entire series (IC50 value of 1.3 ± 0.1 μM). Compounds 4 and 11 showed potency toward the intracellular, amastigote stage of L. infantum (IC50 values of 2.1 ± 0.6 and 3.1 ± 1.05 μM, respectively). Promising trypanocidal compounds include 5 and 10 (IC50 values of 2.6 ± 0.1 and 3.3 ± 0.1 μM, respectively) as well as 6 and 9 (both having IC50 values of <5 μM). Chemical modifications on the quinolinone-chalcone scaffold were performed on selected compounds in order to investigate the influence of these structural features on antiparasitic activity.