Thymus syriacus Essential Oil Extract: Potential Antileishmanial Activity Induced by an Apoptotic-like Death

Background: Chemotherapy continues to be the cornerstone for the management of leishmaniasis. The preferred medications are pricey and have a number of unfavorable side effects. These restrictions make it necessary to produce novel antileishmanial chemicals, and plants have opportunities in this respect. Objectives: This study aimed to evaluate the antileishmanial properties of Thymus syriacus essential oil and its mechanisms of action. Results: Our findings demonstrated that Thymus syriacus essential oil, rich in thymol, exhibited potent antileishmanial activity, with an IC50 value of approximately 1 µg/mL against L. tropica promastigotes. Furthermore, the cell cycle arrest at the sub-G0-G1 phase supported the theory that the leishmanicidal effect was mediated by apoptosis. Methods: The essential oil was characterized using gas chromatography–tandem mass spectrometry. Antileishmanial activity against L. tropica promastigotes was assessed, with mechanisms confirmed via flow cytometry. Conclusions: These results confirm the potential of Thymus syriacus essential oil as a promising therapeutic candidate for the treatment of leishmaniasis.