Leishmania mexicana is one of the pathogens causing cutaneous leishmaniasis which is associated with patient morbidity. In our researches for new safe and effective treatments, thirty-seven essential oils (EOs) extracted from Vietnamese plants were screened in vitro for the first time on Leishmania mexicana mexicana(Lmm) promastigotes at the maximum concentration of 50 nL/mL. Active EOs were also analyzed for cytotoxicity on mammalian cell lines (WI38, J774) and their selectivity indices (SI) were calculated. Their composition was determined by GC-MS and GC-FID. Our results indicated that EOs extracted from Cinnamomum cassia, Zingiber zerumbet, Elsholtzia ciliata and Amomum aromaticum, possessed a moderate anti-leishmanial activity, with IC50 values of 2.92 ± 0.08, 3.34 ± 0.34, 8.49 ± 0.32 and 9.25 ± 0.64 nL/mL respectively. However, they also showed cytotoxicity with SI < 10. The most promising EO was extracted from Ocimum gratissimum, displaying an IC50 of 4.85 ± 1.65 nL/mL and SI > 10. It contained 86.5% eugenol, which was demonstrated to be effective on Lmm with IC50 of 2.57 ± 0.57 nL/mL and not toxic on mammalian cells, explaining the observed activity.
Keywords: Amomum aromaticum; Cinnamomum cassia; Elsholtzia ciliata; Leishmania mexicana mexicana; Ocimum gratissimum; Zingiber zerumbet; essential oils; eugenol.