SEASONAL VARIATION OF ESSENTIAL OIL YIELD AND COMPOSITION OF Juniperus phoenicea L. (Pinophyta; Cupressaceae) GROWN AT DJEBEL AMOUR REGION, ALGERIA

Yield and composition of the essential oil obtained by hydrodistillation from the aerial parts of Juniperus phoenicea(Cupressaceae) have been studied. Plant material has been harvested during three different vegetative stages (before flowering, flowering and after flowering) to look for some correlation between composition and vegetative stage. The yields of oils in different stages were in the order of: before flowering (0.24%), flowering (0.74%) and after-flowering (0.40%). The oils were analyzed by gas chromatography-mass spectrometry. In total, 30, 35 and 35 constituents were identified and quantified in the oil of before flowering, flowering and after flowering plants, representing 99.44, 99.93 and 99.48% of the oils, respectively. α-Pinene, α-phellandrene, linalool, and caryophyllene oxide were the main compounds in all samples. Monoterpenes were the main group of compounds in before flowering (59.88%), flowering (68.16%) and after flowering (69.39%) stages.