Composition and chemical variability of Eucalyptus bosistoana essential oil from Algerian Sahara.

The composition of eight oil samples isolated from leaves of Eucalyptus bosistoana F. Muell., acclimatized in Tamanrasset (southern Algeria, Saharan climate), has been investigated by GC (retention indices), GC-MS and 13C NMR spectroscopy. T wo groups may be distinguished. The five samples of group I have their composition dominated by p-cymene (32.0-39.5%), cryptone (11.5-15.6%), 1,8-cineole (7.8-10.5%) and spathulenol (6.8-16.5%). The three oil samples of group II contained mainly 1,8-cineole (55.3-63.9%) and alpha-pinene (11.6-12.1%).

Chemical variability of Algerian Myrtus communis L.

The composition of 55 samples of essential oil isolated from the aerial parts of wild growing Myrtus communis L. harvested in 16 locations from East to West Algeria were investigated by GC (determination of retention indices) and (13) C-NMR analyses. The essential oils consisted mainly of monoterpenes, α-pinene (27.4-59.2%) and 1,8-cineole (6.1-34.3%) being the major components. They were also characterized by the absence of myrtenyl acetate. The compositions of the 55 oils were submitted to k-means partitioning and principal component analysis, which allowed the distinction of two groups within the oil samples, which could be subdivided into two subgroups each. Groups I (78% of the samples) and II were differentiated on the basis of the contents of α-pinene, linalool, and linalyl acetate. Subgroups IA and IB could be distinguished by their contents of α-pinene and 1,8-cineole. Subgroups IIA and IIB differed substantially in their contents of 1,8-cineole and limonene. All the samples contained 3,3,5,5,8,8-hexamethyl-7-oxabicyclo[4.3.0]non-1(6)-ene-2,4-dione (up to 4.9%).