Structural and antitrypanosomal data of different carbasones of piperitone.

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, (1)H and (13)C NMR based spectrometric analysis. Their antiparasitic activities were evaluated in vitro on Trypanosoma brucei brucei (Tbb). The compound 3 (IC50=8.63±0.81 µM) and 4 (IC50=10.90±2.52 µM) exhibited antitrypanosomal activity, 2 had a moderate activity (IC50=74.58±4.44 µM) but 1 was void of significant activity (IC50=478.47 µM). The in vitro tests showed that all compounds were less cytotoxic against the human non cancer fibroblast cell line (WI38) (IC50>80 µM) while only 2 (IC50=21.16±1.37 μM) and 4 (IC50=32.22±1.66 µM) 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.