Study of the plant growth stages effect on the color, content and composition of essential oil of Achillea wilhelmsii C. Koch. Case Study: Qushchi Ghat in West Azerbaijan province

Achillea wilhelmsii C. Koch. belongs to Asteraceae family, is widely found in different regions of Iran and used for treatment of different diseases. In this research, apical shoots of Achillea wilhelmsii at three different developmental stages includingvegetative (May), flowering (June) and end of flowering (July) stages were collected from natural habitat in 2016 from Qushchi region (Urmia) in West Azerbaijan peovince. Essential oil were obtained by water - distillation method (Clevenger apparatus) and were analyzed by GC and GC/MS. The results were showed that at different harvest times, the color, yield and the quality and quantity of essential oils were also different. The camphor (57.5%) and camphene (8.56%) were the main components of plant essential oil at the before flowering stage and their amount were reduced after flowering stage. In contrast, the eucalyptol (13.18%), borneol (18.91%), bicyclo heptanes (0.43%) and thujane (15.35%) had the highest amount at the end of flowering stage. Analysis of results were showed that plant essential oils have active ingredients of different quality and quantity at various growth stages and accordingly will have different pharmaceutical effects.