Antibacterial and leishmanicidal activities ofSyzygium aromaticumessential oil versus its major ingredient, eugenol

The essential oil ofSyzygium aromaticum(clove EO) and its major ingredients, eugenol, possess many biological activities such as antibacterial, antifungal, and antioxidant properties. Therefore, they have been widely used in traditional and contemporary medicine. In this study, the ingredients of clove EO were identified using GC-MS analysis. The antibacterial and leishmanicidal activities of the total essential oil and eugenol were also investigated. Eugenol (65.41%),trans-caryophyllene (12.6%), eugenol acetate (9.85%), caryophyllene oxide (3.00%), and alpha-humulene (1.73%) were identified as five major components of clove EO. Additionally, the obtained IC(50)s of clove EO, 177.66, 300.53, 362.94, and 248.08 mu g/mL, againstStaphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa, andKlebsiella pneumoniae, respectively, were lower than those of eugenol with IC(50)s of 320.80, 692.91, 591.82, and 445.87 mu g/mL. However, this difference was not significant, except againstE coli. Also, clove EO and eugenol showed proper leishmanicidal effects on promastigotes ofLeishmania tropica(180.24 and 233.52 mu g/mL) andLeishmania major(654.76 and 517.14 mu g/mL). Furthermore, there was no significant statistical difference between the anti-Leishmaniaeffect of EO and eugenol. Clove EO and eugenol showed proper antibacterial and leishmanicidal activities. However, the use of clove EO is preferable than eugenol because of the lower cost and straightforward preparation process.