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The essential oils obtained from Crithmum maritimum L. (marine fennel) and two samples of Foeniculum vulgare Miller (common fennel) were analysed by GC and GC-MS and assayed for their antioxidant and antibacterial activities. The antioxidant activity of the oils was evaluated by two lipid model systems: a modified thiobarbituric acid reactive species (TBARS) assay and a spectrophotometric detection of hydroperoxydienes from linoleic acid in a micellar system. The oils demonstrated antioxidant capacities, comparable in some cases to that of alpha-tocopherol and butylated hydroxytoluene (BHT), used as reference antioxidants. Concerning the antimicrobial tests the essential oils were assayed against twenty-five genera of bacteria, including animal and plant pathogens, food poisoning and spoilage bacteria. Oils from the two samples of F. vulgare showed a higher and broader degree of inhibition than that of C. maritimum.

The essential oil composition of Cananga odorata, Boswellia thurifera, Cymbopogon citratus, Marjorana hortensis, Ocimum basilicum, Rosmarinus ocinalis, Cinnamomum zeylanicum and Citrus limon was analysed by GC and GC±MS, and their antimicrobial and antioxidant activity tested. Twenty-®ve dierent genera of bacteria and one fungal species were used in this study as test organisms. These included animal and plant pathogens, food poisoning and spoilage bacteria and the spoilage fungus Aspergillus niger. The volatile oils exhibited considerable inhibitory eect against all the tested organisms. The oils also demonstrated antioxidant capacities, comparable with a-tocopherol and butylated hydroxytoluene (BHT). The method adopted in this study was the modi®ed thiobarbituric acid reactive species (TBARS) assay. The antioxidant activity was carried out under dierent conditions by using egg yolk and rat liver in the absence and presence of the radical inducer 2,2 H -azobis (2-amidinopropane) dihydrochloride (ABAP). #

The essential oils obtained from Origanum glandulosum Desf., collected in four different localities of the Sètif region (north-eastern Algeria), were analysed by GC-MS and assayed for their antioxidative effectiveness. The antioxidant capacity of the oils was measured by the modified thiobarbituric acid reactive species (TBARS) assay, using egg yolk as oxidizable substrate in presence of the radical inducer 2,2 0 -azobis-(2-amidinopropane) dihydrochloride (ABAP). The activity was compared with those of˛-tocopherol and 2,6-ditertbutyl-4-methyl phenol (BHT, butylated hydroxytoluene). The four oils were also endowed with a high degree of activity at the lowest concentration (100 ppm). This activity is to be ascribed to the high content of phenol components, viz. thymol and carvacrol, which strongly characterize the composition of these oils.