Abstract

The antibacterial activity of the essential oil of Laurus nobilis L. on human pathogenic bacteria by disc diffusion method via average inhibition zone was studied. The chemical composition of the essential oil of the leaves of L. nobilis L. (Lauraceae) were obtained by hydrodistillation method and analyzed by gas chromatography (GC) and gas chromatography mass spectrometry (GC/MS). Thirty three compounds, accounting for 95.75% of the total oil with 1.8% (v/w) oil yield were identified in the essential oil of the leaves. The major components were 1,8-cineole (25.7%), sabinene (8.7%) and α-pinene (5.25%). To study the antibacterial activity, the essential oil tested against 9 bacteria strains such as three Gram positive bacteria:Staphylococcus aureus, Staphylococcus epidermidis and Streptococcus faecalis and six Gram negative bacteria: Pseudomonas aeroginosa, Shigella flexneri, Klebsiella pneuomoniae, Salmonella typhi, Serratia marcescens and Escherichia coli were studied. Effect of theessential oil of L. nobilis on bacteria tested was more than that of tetracycline antibiotic. The results showed that the essential oil of L. nobilis had strong anti-bacterial effects.

Key words: Laurus nobilis L., human pathogenic bacteria, antibacterial activity, 1,8-cineole, gas chromatography mass spectrometry (GC/MS)