The effects of different mesh sizes, methods and periods of distillation on essential oil content and composition of Pimpinella affinis Ledeb.

Limonene, trans-α-bergamoten, geijeren, elemicine and germacrene B are being used widely in the formulation of pharmaceutical products, cosmetics, hygienic applications, and aromatization. These compounds are found in essential oils of Pimpinella affinis Ledeb. (a species native to Iran and Turkey). In the present study, aerial parts of the plant were collected in flowering and maturity stages from Alborz Research Station of Karaj, and dried in room temperature. Three methods of oil extraction including hydro distillation, water & steam distillation and direct steam distillation were applied based upon Taguchi statistical method in three levels to determine the quantitative and qualitative effects of the parameters namely method, time and mesh on essential oil. Essential oil yields were calculated based on dry weight. Identification of the compounds and determination of compounds percentage were done by GC and GC/MS. Mean comparisons of essential oil yield showed that more content of limonene, trans-α-bergamoten and geijeren was obtained by mesh size 20 in hydro-distillation and steam distillation methods. Mesh size 40 and time 2.5 h gave the best result for elemicine and germacren B in steam distillation method. The maximum and minimum essential oil yield was respectively obtained by mesh size 20 and 14 in water & steam distillation method. Therefore, deseirable percentage and compounds of the essential oil could be achieved from Pimpinella affinis Ledeb. by selection of the condition of essential oil extraction.