Original Articles
Florence Allanto, Salome Kpovi
Abstract
To investigate the effect of the harvest daytime of the Cymbopogon citratus (cd) Stapf (Cc) and Cymbopogon schoenantus (L). Spreng (Cs) leaves on the yields, composition, antitrypanosomal activity and cytotoxicity of their essential oils (EOs), volatile compounds of Cc and Cs leaves collected at three different times (7 am, 1 pm, 7 pm) on the same plants were extracted and analysed by GC/FID and GC/MS, tested on Trypanosoma brucei brucei (Tbb) and their cytotoxicity evaluated in vitro on CHO and WI38 cells. Cs leaves contained more EO (1.88%-2.25%) than Cc ones (0.71%-0.82%). We observed qualitative and quantitative differences in the chemical composition of essential oils of Cc and Cs over the day. The main compounds were geranial, neral and β-pinene in all Cc EOs and piperitone, (+)-2-carene and elemol in all Cs EOs, regardless of the harvest daytime. This daytime variation of the chemical composition mainly influenced the antitrypanosomal activities of the Cc EOs which were more trypanocidal than Cs ones. Oils from Cc collected at 7 am and 7 pm were the most active with selectivities higher than 5 compared to WI38 but not compared to CHO, as Cc EOs were more toxic against CHO cells. These EOs needs further toxicological studies. Cs EOs were not cytotoxic (IC50 >50 μg/mL), and did not show significant difference in activities between the collection times (IC50=16.74-47.40 μg/mL). These activities seemed to be explained by synergy or antagonism between compounds.