The purpose of this study was to determine the chemical composition of oregano essential oil, minimal inhibitory concentration (MIC) and to assess its antimicrobial efficiency against Enterococcus faecalis.
Gas Chromatography and Mass Spectrometry (GC-MS) was used to determine the chemical composition of essential oil from oreganum vulgare. Broth dilution and agar diffusion method was used to evaluate the MIC. For Broth dilution, 100 μL of different concentration of oil (6.25, 12.5, 25.0, 50.0, and 100 μg/ml) was tested. Agar diffusion method was utilized to evaluate the antimicrobial efficiency of different concentration of oil (25.0, 50.0, and 100 μg/mL) against E. faecalis.
GC-MS analysis revealed that oregano essential oil contained carvacrol (41.2%), γ-terpinene (12.68%), p-cymene (9.47%), α-terpinene (1.19%) as the major compounds and β–caryophyllene (0.83%), β-linalool (0.67%), β–bisabolene (0.601%), α-pinene (0.6%), β-pinene (0.5%), terpinen-4-ol (0.41%), borneol (0.4%), 3-thujene (0.4%), spathulenol (0.4%), myristicin (0.25%), and apiol (0.14%). The results of the present study reported Oregano essential oil possess antimicrobial activity against E. faecalis. The MIC was 25 μg/ml and the minimum bacterial concentration (MBC) was 50 μg/ml.