In Vitro and In Vivo Antileishmanial Activities of Pistacia vera Essential Oil

This study aims to evaluate the in vitro and in vivo antileishmanial activities of Pistacia vera essential oil and compare their efficacy with a reference drug, meglumine antimoniate (Glucantime®). This essential oil (0-100 µg/mL) was evaluated in vitro against the intracellular amastigote forms of Leishmania tropica (MHOM/IR/2002/Mash2) and then tested on cutaneous leishmaniasis of male BALB/c mice by Leishmania major (MRHO/IR/75/ER). In the in vitro assay, it could be observed that P. vera essential oil significantly (p < 0.05) inhibited the growth rate of amastigote forms (IC50 of 21.3 ± 2.1 µg/mL) in a dose-dependent response compared with the control drug. Meglumine antimoniate also demonstrated antileishmanial effects with an IC50 value of 44.6 ± 2.5 µg/mL for this clinical stage. In the in vivo assay, the results indicated that 30 mg/mL of the essential oil had potent suppression effects on cutaneous leishmaniasis in BALB/c mice (87.5% recovery), while 10 and 20 mg/mL of the essential oil represented the suppression effects as weak to intermediate. The mean diameter of the lesions decreased about 0.11 and 0.27 cm after the treatment of the subgroups with the essential oil concentrations of 10 and 20 mg/mL, respectively. In contrast, in the subgroup treated with the essential oil concentration of 30 mg/mL, the mean diameter of the lesions decreased about 0.56 cm. In the control subgroups, the mean diameter of the lesions increased to 1.01 cm. The main components of P. vera essential oil were limonene (26.21%), α-pinene (18.07%), and α-thujene (9.31%). It was also found that P. vera essential oil had no significant cytotoxic effect on J774 cells. The present study found that P. vera essential oil showed considerable in vitro and in vivo effectiveness against L. tropica and L. major compared to the reference drug. These findings also provided the scientific evidence that natural plants could be used in traditional medicine for the prevention and treatment of cutaneous leishmaniasis.