In vitro Anti-Leishmanial Activity of Essential Oils Extracted from Plants Growing in Northern Cyprus Against Leishmania tropica

Objective Natural plant products are considered as a source of novel and effective compounds for the treatment of leishmaniasis. In this study, the in vitro activities of essential oils obtained from Origanum dubium (OD), Origanum majorana (OM), Salvia fruticosa (SF) and Laurus nobilis (LN) plants in Northern Cyprus were investigated against Leishmania tropica. Methods Leishmania tropica strain (MHOM/TR/2012/CBCL-LT) was obtained. RPMI-1640 was added to 96-well plates in 100 μL aliquots, 100 μg/mL essential oil was added to the first well of each row and serial 2-fold dilutions were performed. A promastigote suspension was pipetted into all wells, and the plates were incubated. The promastigotes were enumerated using a haemocytometer. Results OD essential oil was effective at killing all promastigotes at a minimum inhibitor height (MIC)=0.2 μg/mL and had high activity at the lowest concentrations. Both SF and LN oils had MIC=1.56 μg/mL and LD50=0.78 μg/mL. SF was observed to impair promastigote morphology at the lowest concentrations, while LN did not exert any effect at concentrations