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 <0.2 μg/mL. OM essential oil was found to have a MIC=3.13 μg/mL and a LD50=1.56 μg/mL. Conclusion All tested essential oils inhibited promastigotes of Leishmania tropica. OD essential oil demonstrated the highest anti-leishmanial activity. Amac Bitkilerden elde edilen dogal urunlerin leishmaniasis tedavisi icin yeni ve etkili bilesiklerin uretilmesine onculuk edecegi dusunulmektedir. Calismamizda, Kuzey Kibris’ta yetisen Origanum dubium (OD), Origanum majorana (OM), Salvia fruticosa (SF) ve Laurus nobilis (LN) bitkilerinden elde edilen ucucu yaglarin Leishmania tropica’ya karsi in vitro etkinlikleri arastirilmistir. Yontemler Calismamizda, Leishmania tropica susu (MHOM/TR/2012/CBCL-LT) kullanildi. Duz tabanli 96’lik plaklarda, tum kuyucuklara 100 μL RPMI-1640 ve ilk kuyucuklara 100 μg/mL ucucu yaglar eklenerek, seri dilusyonlari yapildi. Ardindan tum kuyucuklara Leishmania tropica promastigot suspansiyonundan pipetlendi ve inkube edildi. Hemositometre yontemiyle promastigotlarin sayisi incelendi. Bulgular OD yaginin minimum inhibitor konsantrasyonu (MIK)=0,2 μg/mL’de tum promastigotlari oldururken, en dusuk konsantrasyonlarda bile etkili oldugu gorulmustur. SF ve LN ucucu yaglarinin ikisinde de MIK=1,56 μg/mL, LD50=0,78 μg/mL olarak saptanmistir. SF’nin en dusuk konsantrasyonlarinin bile promastigot morfolojisini bozdugu gorulurken, Laurus nobilis’in ise 0,2 μg/mL’den sonraki konsantrasyonlarda etkisini kaybettigi belirlenmistir. OM ucucu yaginin MIK=3,13 μg/mL, LD50=1,56 μg/mL oldugu gorulmustur. Sonuc Kullanilan tum ucucu yaglarin Leishmania tropica promastigotlarini inhibe ettigi gorulurken, en yuksek anti-leishmanial etkinlik Origanum dubium ucucu yaginda bulunmustur.