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This article reports data on four carbazones of piperitone: semicarbazone 1, thiosemicarbazone 2, 4-phenyl semicarbazone 3 and 4-phenyl thiosemicarbazone 4 prepared directly in situ from essential oil of Cymbopogon schoenantus, whose GC-FID and GC–MS analysis revealed piperitone as major component (68.20%). The structures of hemi-synthesized compounds were confirmed by high throughput IR, MS, 1H and 13C NMR based spectrometric analysis. Their antiparasitic activities were evaluated in vitro on Trypanosoma brucei brucei (Tbb). The compound 3 (IC50=8.63±0.81µM) and 4 (IC50=10.90±2.52µM) exhibited antitrypanosomal activity, 2 had a moderate activity (IC50=74.58±4.44µM) but 1 was void of significant activity (IC50=478.47µM). The in vitro tests showed that all compounds were less cytotoxic against the human non cancer fibroblast cell line (WI38) (IC50>80µM) while only 2 (IC50=21.16±1.37μM) and 4 (IC50=32.22±1.66µM) were cytotoxic against the Chinese Hamster Ovary (CHO) cells and toxic on Artemia salina (Leach) larvae. Piperitone 4-phenyl semicarbazone 3, the best antitrypanosomal compound, showed also a selectivity index (SI) higher than 7 on the larvae and the tested cells and therefore might be further studied as antitrypanosomal agent. Also, all compounds except 3 showed selectivity between the two tested cell lines (SI>2). This data reveals for the first time the antitrypinosomal properties of thiosemicarbazones, their cytotoxicity on mammalian cells as well as their activities against Tbb and A. salina Leach.

To ensure the safety of trypanocidal molecules of thiosemicarbazones hemi-synthesized in essential oil of Cymbopogon citratus , toxicology studies were conducted. These studies which were performed on rats “Wistar” had focused on our most active molecules: citral thiosemicarbazone, citral semicarbazone, citral 4-phenylthiosemicarbazone and the starting substrate which was the essential oil of Cymbopogon citratus . From these studies, it appears that citral semicarbazone, citral 4-phenylthiosemicarbazone and essential oil were no toxic as LD 50 > 2000 mg/kg. Citral thiosemicarbazone was slightly more toxic with a LD 50 = 315 mg/kg. The study of biochemical parameters revealed that the use of a high dose of the compounds may affect kidney function. A strong dose of essential oil of Cymbopogon citratus could affect liver function. It appears that the citral 4-phenylthiosemicarbazone is a very promising compound because it had an excellent antitrypanosomal activity and had very low toxicity (IC 50 = 1.96 μM; LD 50 > 2000 mg/kg). © 2019 International Formulae Group. All rights reserved. Keywords: Trypanocidal thiosemicarbazones, toxicology, essential oil, Cymbopogon citratus , biochemical parameters