variation in the essential oil composition of perovskia. atriplicifolia plant at different growth stages in taftan aera

Perovskia.atriplicifolia.benth is an extensive ethno medical tradition, the photochemistry of this plant has been the topic of several studies. the purpose of this research is investigating the variation in the essential oil composition of perovskia. atriplicifolia plant at the different growth stages from taftan mountain .the leaves of p. atriplicifolia were harvested before flowering, flowering, and after flowering stages.the essential oils were extracted by hydro distillation method which were analyzed by the gc & gc-ms techniques. oil yields (w/w%) related at three stages of plant growth were in the order of: before flowering (1.28), flowering (1.15),  and after flowering (1.03). in total 52, 62, and 43 components were identified using kovats indices and quantified in the oils of the before flowering, flowering and after flowering stages representing 92.0 %, 86.31%, and66.46 %   respectively. the higher percent of which: geranyl acetate, 1,8-cineole, δ-3-carene ,trans-caryophyllene, bornyl acetate ,camphene,valeranone,α-pinene,were the main compounds in all oil samples.total terpenoids were the main group of compounds in the before flowering (91.58 %), flowering (84.03 %) and after flowering stages (65.72 %) respectively. the before flowering stage essential oil is of the best quality.