Hanen Marzouki

Extraction and Separation of Volatile and Fixed Oils from Berries of Laurus nobilis L. by Supercritical CO2

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.

Seasonal and geographical variation of Laurus nobilis L. essential oil from Tunisia.

Yield and composition of the essential oil obtained by hydrodistillation from leaves of laurel coming from ten different sites in Tunisia were determined. From each locality, leaves were harvested during four different vegetative stages (October, production of seeds; January, dormancy; April, flowering; July, vegetative activity) to look for some cor- relation between composition and vegetative stage. All 40 essential oil samples produced similar GC profiles containing a total of 71 peaks. 60 Compounds were identified. 1,8-cineole was, in all samples, the main constituent among different compounds such as methyl eugenol, � -terpinyl acetate, sabinene and linalool. All essential oils considered were character- ized by a clear predominance of oxygenated compounds chiefly monoterpenes then phenylporpanoids and sesquiterpenes. The concentration of this class generally decreases during the period October - July; the values are in the range 67.5% - 86.1%. The yields of essential oil ranged between 0.65 and 2.2% by weight. With only one exception, the higher produc- tion of essential oil was obtained during the vegetative period. A seasonal variation in the yield and composition of essen- tial oil was revealed, while geographical variability was not pronounced and no chemotypes were observed among the samples of laurel leaf oil examined.

Influence of Extraction Methods on the Composition of Essential Oils of Achillea millefolium L. from Lithuania

Influence of Extraction Methods on the Composition of Essential Oils of Achillea millefolium L. from Lithuania In this study, flowering aerial parts of Achillea millefolium were used as a matrix for supercritical CO2 extraction (SFE) of volatile oil. The collected extracts were analyzed by GC-FID and GC-MS methods and their composition were compared with that of the essential oil isolated by hydrodistillation (HD). The composition of the essential oil obtained by hydrodistillation and SFE methods is widely different. Indeed, the SFE volatile oil had a pale yellow color whereas the HD oil had a blue color due to the presence of chamazulene (48.0% vs. 4.3%). Other important constituents of HD oil were (E)- caryophyllene (19.5 %) and γ-muurolene (13.1%). The CO2 supercritical extract was dominated by (E)-caryophyllene (26.0%), γ-muurolene (22.0%), and caryophyllene oxide (8.1%).

Fatty Acid Composition, Essential Oil and Antibacterial Activity of Berries of Laurus nobilis L.

Abstract Fruits of Laurus nobilis L. growing wild in different stations of Tunisia and Algeria were analysed for their fixed oil and essential oil composition. Fixed oil was extracted in Soxhlet apparatus by using hexane as solvent. The yield values were found approximatively the same for the fruit of the different stations. Fatty acids composition of the fixed oil was determined by using combined techniques of HPLC and GC. Fatty acids composition of L. nobilis were found as 54 % for satured fatty acids and 46 %for unsatured acids. Essential oils, isolated by hydrodistillation, from different parts of the berries (seeds and pericarp) of L. nobilis were analyzed by GC-MS and the main components were: 1,8-cineole, (E) β-ocimene, α-terpinyl acetate, α-pinene, β-pinene and β-longipinene. The yields in essential oil range between 0.6 - 1.2 % by weight for seeds and 0.8 -1 .1 % for pericarps. Study of the chemical composition indicate a small variability of the volatile oil and fixed oil between the different stations whereas big differences in the composition was observed for the seeds and pericarp.