Biological activity evaluation of the oils from Laurus nobilis of Tunisia and Algeria extracted by supercritical carbon dioxide.

Isolation of essential oil from dried and ground leaves of Laurus nobilis L. from Algeria and Tunisia were obtained with two different methods: by means of classical hydrodistillation (HD) and by using carbon dioxide in the supercritical state (SFE). The effect of extraction pressure on the yield and composition of the L. nobilis volatile oil is examined. The best extraction conditions were as follows: pressure, 9.0 MPa; temperature, 323.15 K; 4 h of extraction and carbon dioxide flow, Phi = 1.2 kg h(-1). Waxes were entrapped in the first separator set at 9.0 MPa and 263.15 K. The oil was recovered in the second separator working at 2.0 bar and 288.15 K. GC/MS analysis of the leaves' volatile oil revealed that it mainly consisted of: 1,8-cineole, linalool, alpha-terpinyl acetate, methyl eugenol and sabinene. The comparison with the hydrodistilled oil did not reveal any big difference. The collection of samples at different extraction times during supercritical extraction allowed us to monitor the change of the oil composition. On the matrice exhaust owing to a SFE at 9.0 MPa, one further extraction at 323.15 K and 24.0 MPa was performed to obtain a mixture of compounds with higher molecular weight. Finally, the antibacterial and antifungal activity of the various extracts has been assayed.