Chemical Composition and Antimicrobial Activity of Laurus nobilis L. Essential Oils from Bulgaria

Laurel, <i>Laurus nobilis</i> L. is an evergreen plant belonging to the Lauraceae family, native to Southern Europe and the Mediterranean area. This is the first report on the composition and bioactivity of laurel essential oil (EO) from Bulgaria. The oil yield was 0.78%, 0.80%, and 3.25% in the fruits, twigs, and leaves, respectively. The main constituents in the fruit EO were 1,8-cineole (33.3%), <i>α</i>-terpinyl acetate (10.3%), <i>α</i>-pinene (11.0%), <i>β</i>-elemene (7.5%), sabinene (6.3%), <i>β</i>-phellandrene (5.2%), bornyl acetate (4.4%), and camphene (4.3%); those in the twig EO were 1,8-cineole (48.5%), <i>α</i>-terpinyl acetate (13.1%), methyl eugenol (6.6%), <i>β</i>-linalool (3.8%), <i>β</i>-pinene (3.4%), sabinene (3.3%) and terpinene-4-ol (3.3%); and the ones in the leaf EO were 1,8-cineole (41.0%), <i>α</i>-terpinyl acetate (14.4%), sabinene (8.8%), methyl eugenole (6.0%), <i>β</i>-linalool (4.9%), and <i>α</i>-terpineol (3.1%). The antibacterial and antifungal properties of laurel EOs were examined according to the agar well diffusion method. The leaf EO showed antibacterial and antifungal activities against almost all strains of the microorganisms tested, whereas the twig EO was only able to inhibit <i>Staphylococcus aureus</i>. <i>Pseudomonas aeruginosa</i> ATCC 9027 and <i>Escherichia coli</i> ATCC 8739 were the bacterial strains that showed the highest resistance to the laurel EO. The results can benefit the EO industry and biopesticide development.