SELECTIVE TRYPANOCIDE ACTIVITY OF SOME SUBSTITUTED THIOSEMICARBAZONES OF CITRAL FROM BENIN CYMBOPOGON CITRATUS ESSENTIAL OIL AND THEIR TOXICITY AGAINST ARTEMIA SALINA LEACH.

Abstract

Extraction and analysis GC/FID and GC/MS showed that citral (neral + geranial) is the major compound of the essential oil of Benin Cymbopogoncitratus. This aldehyde was used as target for the hemi-synthesis in situ of the semicarbazone and substituted thiosemicarbazones. Their structures were confirmed by spectrometric analysis IR, 1H and 13C NMR. Their antiparasitic activities have been evaluated on Trypanosomabruceibrucei by determining their half-inhibitory concentrations (IC50). Among them, citral 4-phenyl-3-thiosemicarbazone (IC50 = 1.96 µM) and citralthiosemicarbazone (IC50 = 7.6 µM) showed a strong trypanocidal activity. Citral 2-methyl-3thiosemicarbazone (IC50 = 60.87 µM) showed a moderate activity. Citral 4-methyl-3-thiosemicarbazone (IC50 = 172.84 µM) and citralsemicarbazone (IC50 = 234.64 µM) were less actives. Toxicity test against Artemiasalina indicated that citral 4-phenyl-3-thiosemicarbazone is the most toxic compound (LC50 = 70.70 µM). The toxicities of other compounds are low. Citral 4-phenyl-3-thiosemicarbazone could have excellent anti-cancer properties. The selectivity index calculated from these data showed that all the molecules obtained are selective about the parasites Trypanosomabruceibrucei.