Chemical profile and biological properties of the essential oil of Rosemary leaves (Rosmarinus officinalis L.)

Rosemary leaf essential oil (RoEO) is extracted using steam distillation. The aim of study is to determine physicochemical characteristics of essential oil (EO), such as acid/saponification/esterification index, relative/absolute density, freezing point, and fragrance retention. The chemical composition of EOs was analyzed by gas chromatography-mass spectrometry (GC-MS) method and identified 50 volatile compounds, of which α-Pinene (33.76%), 1,8-Cineole (18.47%), and Levoverbenone (6.11%) constituted the highest proportions in EO. The antioxidant capacity (AC) of the EO was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging method with a half-maximum inhibitory concentration (IC50) of 425.473 mg/mL. In particular, antibacterial activity (AA) by the paper plate diffusion method for susceptibility testing to essential oil showed that RoEO strongly inhibited the growth of four tested bacterial strains (Staphylococcus aureus, Bacillus cereus, Salmonella typhimurium, and Escherichia coli). Perhaps, it is possible to apply RoEO in the food industry and other fields owing to the good properties of RoEO.