Promising Antileishmanial Activity of Essential Oil: In Vitro and In Silico Studies.

The present study aimed to evaluate the leishmanicidal potential of the essential oil (EO) of () and to investigate its molecular mechanism of action by qPCR. Furthermore, in silicointeraction study of the major EO compounds with the enzyme cytochrome P450 sterol 14α-demethylase (CYP51) was also performed. EO was analyzed by gas chromatography-mass spectrometry (GC-MS). Results showed that α-pinene (26.44%), -cadinol (26.27%), caryophyllene Oxide (7.73 ± 1.04%), and α-Cadinene (3.79 ± 0.12%) are the major compounds of EO. However, limited antioxidant activity was observed, as this EO was ineffective in neutralizing DPPH free radicals and in inhibiting β-carotene bleaching. Interestingly, it displayed effective leishmanicidal potential against promastigote (IC of 6.79 and 5.25 μg/mL) and amastigote (IC of 8.04 and 7.32 μg/mL) forms of and , respectively. Molecular mechanism investigation showed that EO displayed potent inhibition on the thiol regulatory pathway. Furthermore, a docking study of the main components of the EO with cytochrome P450 sterol 14α-demethylase (CYP51) enzyme revealed that -cadinol exhibited the best binding energy values (-7.5 kcal/mol), followed by α-cadinene (-7.3 kcal/mol) and caryophyllene oxide (-7 kcal/mol). These values were notably higher than that of the conventional drug fluconazole showing weaker binding energy (-6.9 kcal/mol). These results suggest that EO could serve as a potent and promising candidate for the development of alternative antileishmanial agent in the treatment of leishmaniasis.