Antibacterial Profile of Essential Oils Against Pathogen Bacteria

Abstract

The present study was performed to investigate the chemical composition and antibacterial activity of essential oils (EOs) from aromatic plants. Three EOs from clove, white thyme and oregano were evaluated against four pathogen bacterial strains (Staphyloccocus aureus, Escherichia coli, Salmonella enteritidis, Bacillus cereus) using agar dilution method, in order to obtain the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC).The Lamiaceae family EOs (white thyme and oregano) presented as main active compounds thymol (32,63% / 12,07%) and carvacrol (12,87% / 60,77%) but also p-cymen (25,44% / 14,85%), linalool (4,65% / 2,02%) and other chemical compound but in small amounts. The GC-MS analysis of clove oil identified seven chemical constituents, of these eugenol (53,94%) and isoeugenol (27,51%) were the major compounds.These essential oils showed an obvious antibacterial activity against the tested strains with an MIC and MBC in the ranges of 200-600 ppm and 400-1000 ppm, respectively. The most active essential oil was oregano oil with a MIC of 400 ppm for E. coli and 200 ppm for the rest of bacterial strains. Clove oil were less efective against tested bacteria and presented a MIC of 600 ppm for all the strains and a MBC between 800 - 1000 ppm. The result obtained permitted us to make a antibacterial profile of these essential oils, based on the chemical composition and the susceptibility of bacterial structure. In conclusion, these essential oils can be a good source of natural antibacterial agents.