Supercritical CO2 extract and essential oil of bay (Laurus nobilis L.) - chemical composition and antibacterial activity

The present study deals with the supercritical carbon dioxide (SC-CO2) extraction and hydrodistillation (HD) of dried bay leaves (Laurus nobilis L.). The chemical composition and antibacterial activity of the SC-CO2 extract and essential oil (EO) from dried leaves of bay were compared to each other and literature data. Qualitative and quantitative analyses of the SC-CO2 extract and EO were performed using GC-FID and GC-MS analytical methods. A significant difference in the chemical composition of the SC-CO2 extract and EO was observed. The EO comprised high contents of monoterpcnes and their oxygenated derivates (98.4 %), principally 1,8-cineole (33.4 %), linalool (16.0 %) and alpha-terpinyl acetate (13.8 %), sabinene (6.91 %) and methyl eugenol (5.32 %). The SC-CO2 extract comprised twice less monoterpenes and their oxygenated derivates (43.89 %), together with sesquiterpenes (12.43 %), diterpenes (1.33 %) and esters (31.13 %). The major components were methyl linoleate (16.18 %), alpha-terpinyl acetate (12.88 %), linalool (9.00 %), methyl eugenol (8.67 %), methyl arachidonate (6.28 %) and eugenol (6.14%) An investigation of the antibacterial activity of bay SC-CO2 extract and EO was completed on different Staphylococcus strains using the broth macrodilution method. Staphylococcus intermedius strains were the most susceptible to both the SC-CO2 extract and EO (MIC = 640 mu g/ml).