Synthesis, characterization and anti-trypanosomal activity of R-(-)carvone and arylketones-thiosemi carbazones and toxicity against Artemia salina Leach

This work is focused on the synthesis and characterization of a series of N(4)- substituted thiosemicarbazones and the evaluation of their in-vitro anti-trypanosomal activity and toxicity. A series of thiosemicarbazones (1-4) and N(4)-phenyl-3-thiosemicarbazones (5-8) have been synthesized on R-(-)carvone, acetophenone, 4’-methylacetophenone and benzophenone by condensation reaction with good yields. All compounds were characterized by spectrometrical analysis methods infrared IR, nuclear magnetic resonance NMR (1H &13C) and mass spectrometry MS, confirming their structures respectively, and were evaluated for their invitro parasitic activity against the bloodstream form of the strain 427 of Trypanosoma brucei brucei using the “LILIT, Alamar Blue” method (Baltzet al., 1985; Hirumi et al., 1994; Räz et al.,1997). Their toxicity against brine shrimp larvae (Artemia salina Leach) was studied, according to the method of Michael et al. (1956) resumed byVanhaecke et al. (1981) and bySleet and Brendel (1983). Some of them have exhibited a strong trypanocidal activity, especially compounds 8, 3, 1 and 4 with their half-inhibitory concentrations (IC50) values equal to 8.48, 8.73, 39.71 and 67.17 micro-molar (µM) respectively. Except compounds 1 and 4whose half-lethal concentration (LC50) values were20.58 and 33.72 µM respectively and then toxics, all synthesized compounds showed negligible toxicity against Artemia salinaL. (LC50> 280 µM) and good selectivity (S) (SI “index” =1)