Investigation on quality changes of damask rose essential oil during different ‎phenology stages in Oroumieh region

Damask rose (Rosa damascena Mill.) is one of the most valuable plant species from genus Rosa. Its essential oil is using in many industries, such as cosmetics, sanitary, and pharmaceutical. In present study, the chemical composition of damask rose essential oil was evaluated during different flower development stages: (1- flower bud 2- partially open flower 3- full open flower and 4- senescent flower) in Oroumieh region, during 2018. The damask rose essential oil was collected by distillation with water via Clevenger apparatus. The lowest and highest sap cell pH levels were observed at flower bud and senescent flower stages, respectively. Analysis of the chemical compositions of the essential oil was done by GC-MS technique and the most abundant compounds were nonadecane, heneicosane, citronellol, geraniol, and Z-5-nenadencene. The highest ratio of citronellol /geraniol was produced at the full open flower stage. The highest amount of a-pinene was produced in the flower bud stage and b-myrcene was produced solely in the flower bud stage. The highest amount of 2-phenyl ethanol alcohol, as well as eugenol and geranial compounds were exclusively produced at the full open flower stage; while docosane alkane was not produced at full open flower stage. The results manifested that due to the objective of using essential oils in cosmetic, health or pharmaceutical, different flower development stages can be selected for extraction.