Chemical Composition, Antimicrobial and Antioxidative Activity of Laurel, Sage, Rosemary, Oregano and Coriander Essential Oils

Abstract

Abstract The essential oils obtained from five commercial samples of Sicilian aromatic plants, laurel, sage, oregano, rosemary and coriander were analyzed by GC/MS and assayed for their antibacterial, antifungal and antioxidant activities. Twenty-five different genera of bacteria and one fungal species were used in this study as test organisms. The oils showed a high degree of inhibition against all the microorganisms tested. The highest and broadest activity was shown by the oil of oregano, while the oil of sage was the least effective. The antioxidant activity of the oils was measured by the modified Thiobarbituric Acid Reactive Species (TBARS) assay, using egg yolk and rat liver as oxidable substrate, in absence and in presence of the radical inducer 2,2'-azobis (2-amidinopropane) dihydrochloride (ABAP). The activities were compared with those of α-tocopherol and 2,6-di-tert-butyl-4-methylphenol (BHT, butylated hydroxytoluene). The oils showed different effectiveness, the oregano oil being endowed with the highest activity. Chemical components of the oils, lipid composition of die substrates and the increased amount of peroxyl radicals played a fundamental role in establishing the different antioxidant activities of the oils.