Trypanocidal properties, structure–activity relationship and computational studies of quinoxaline 1,4-di-N-oxide derivatives

Main interactions between (2E)-1-(7-fluoro-3-methyl-quinoxalin-2-yl)-3-(3,4,5-trimethoxy-phenyl)-propenone and the active site of T.cruzi catPARP-1 homologous protein. [Display omitted] ► (2E)-1-(7-fluoro-3-methyl-quinoxalin-2-yl)-3-(3,4,5-trimethoxy-phenyl)-propenone is selectively active against proliferative cells (cancer and Leishmania) and inactive against murine peritoneal macrophages. ► (2E)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-quinoxalin-2-yl)-propenone is selectively active against Leishmania and inactive against the other proliferative cells. ► insilico studies show that these compounds could interact with the poly (ADP-ribose) polymerase protein of Trypanosoma cruzi. Pyrazole and propenone quinoxaline derivatives were tested against intracellular forms of Leishmania peruviana and Trypanosoma cruzi. Both series were tested for toxicity against proliferative and non-proliferative cells. The pyrazole quinoxaline series was quite inactive against T. cruzi; however, the compound 2,6-dimethyl-3-f-quinoxaline 1,4-dioxide was found to inhibit 50% of Leishmania growth at 8.9μM, with no impact against proliferative kidney cells and with low toxicity against THP-1 cells and murine macrophages. The compounds belonging to the propenone quinoxaline series were moderately active against T. cruzi. Among these compounds, two were particularly interesting, (2E)-1-(7-fluoro-3-methyl-quinoxalin-2-yl)-3-(3,4,5-trimethoxy-phenyl)-propenone and (2E)-3-(3,4,5-trimethoxy-phenyl)-1-(3,6,7-trimethyl-quinoxalin-2-yl)-propenone. The former possessed selective activity against proliferative cells (cancer and parasites) and was inactive against murine peritoneal macrophages; the latter was active against Leishmania and inactive against the other tested cells. Furthermore, insilico studies showed that both series respected Lipinski’s rules and that they confirmed a linear correlation between trypanocidal activities and LogP. Docking studies revealed that compounds of the second series could interact with the poly (ADP-ribose) polymerase protein of Trypanosoma cruzi.