Isolation of volatile and fixed oils from dried berries of Laurus nobilis L. from Tunisia have been obtained by supercritical fractioned extraction with carbon dioxide. Extraction experiments were carried out at a temperature of 40 °C and pressures of 90 and 250 bar. The extraction step performed at 90 bar produced a volatile fraction mainly composed of (E)-β-ocimene (20.9%), 1,8-cineole (8.8%), α-pinene (8.0%), β-longipinene (7.1%), linalool acetate (4.5%), cadinene (4.7%), β-pinene (4.2%), α-terpinyl acetate (3.8%) and α-bulnesene (3.5%). The oil yield in this step of the process was 0.9 % by weight charged. The last extraction step at 250 bar produced an odorless liquid fraction, in which a very small percentage of fragrance compounds was found, whereas triacylglycerols were dominant. The yield of this step was 15.0 % by weight. The most represented fatty acids of the whole berry fixed oil were 12:0 (27.6%), 18:1 n-9 (27.1%), 18:2 n-6 (21.4%), and 16:0 (17,1%), with the 18:1 n-9 and 18:2 n-6 unsaturated fatty acids in particular averaging 329 μg/mg of oil.

The essential oils and supercritical CO₂ extracts of wild Daucus carota L. subsp. carota from two different sites in Tunisia were investigated. The main components of the essential oil of the flowering and mature umbels with seeds from Sejnane were eudesm-7(11)-en-4-ol (8.2 – 8.5%), carotol (3.5 - 5.2%), sabinene (12.0 −14.5%), α-selinene (7.4 - 8.6) and 11-α-(H)-himachal-4-en-1-β-ol (12.7 – 17.4%), whereas the oils from Tunis were predominantly composed of elemicin (31.5 – 35.3%) and carotol (48.0 – 55.7%). The antimicrobial activity of the essential oils were assayed by using the broth dilution method on Escherichia coli ATCC 35218 and Staphylococcus aureus ATCC 43300, and clinical strains of Candida albicans and C. tropicalis 1011 RM. The MIC values obtained were all > 2.5% (v/v).

Species with fragmented populations and low population size often display low within-population genetic diversity and strong among-population differentiation. Laurus nobilis L. (Lauraceae), common laurel, has a scattered distribution throughout the Mediterranean, with only few autochthonous populations. Our goal was to elucidate if this species has range-wide genetic structure and if planted material can be traced back to its origin. Genetic diversity was investigated using 4 polymorphic nuclear microsatellites (nSSR) transferred from two species of Lauraceae. Sixty-six laurel trees were selected from 7 widely separated populations within the Mediterranean distribution area of the species. A total of 34 alleles (9 alleles per locus on average) were found. Mean genetic diversity within-population (Hs), was 0.558. Genetic differentiation among populations (GST = 0.243) was high compared to that of other angiosperms. Laurus nobilis can be separated into two main gene pools, one from western (Tunisia, Algeria and France) and the other from eastern Mediterranean (Turkey). The Algerian, Tunisian and French populations presented a strong genetic similarity, compatible with the fact that North African laurel populations could be recently introduced from north-western Mediterranean stock.

The compositions of the essential oils isolated from the aerial parts of tree Mediterranean populations of Laurus nobilis L. collected during the flowering phase on Tunisia, Algeria and France, were studied by GC and GC-MS. The analysis has allowed identifying 54 components. The main components were 1,8-cineole, α-terpinyl acetate (10-18.6%), methyl eugenol (10-22.1%), sabinene (1.2-8%), eugenol (1.2-11.7%) α-pinene (tr-4.5%) and β-pinene (0.4-4.2%). The monoterpene fraction was dominant in all the oils analysed and consisted mainly of oxygenated monoterpenes. The oils from the tree populations studied showed a clear chemical polymorphism. The principal component and the hierarchical cluster analyses separated the Laurus nobilis leaf essential oils into three groups.