The effect of drying and distillation methods on essential oil content and composition of Satureja sahendica Bornm

Plant essential oils are used in a wide range of pharmaceutical، food، cosmetics and hygienic products. Satureja sahendica Bornm is an endemic aromatic plant in Iran. In traditional medicine، it has analgesic and anti-infection properties. Savory is used for treatment of chest discomfort، cough، wasting and rheumatic pain. Previous researches showed that the main compounds of Satureja Sahendica essential oil were ρ-cymene، thymol، carvacrol and γ-terpinene. Since different drying and distillation methods affect oil yield and composition of aromatic plants، in this study، to investigate the effect of drying methods، the aerial parts of Satureja Sahendica were collected from Agricultural Research farm in Qazvin، at full flowering stage. The plant materials were dried by different methods (oven 30°C، oven 40°C، oven 50°C and shade). The essential oils of each treatment were obtained by hydro- distillation in three replicates. The oils were analyzed by capillary GC and GC/MS. Oil yield and the percentage of main components were compared statistically by Duncan''s Multiple Range Test in SAS software. Results showed that oil yields، percentage of thymol and total phenolic compounds in essential oils were not different statistically in oven 30°C، oven 40°C and shade، but drying in oven 50°C produced lower oil yield. The percentage of thymol and total phenolic compounds was higher in oven 50°C. Statistical analysis showed that the oil yield obtained from hydro-distillation method (1/45%) was higher than that of the other two methods (at 1% level)، while the highest values of thymol and carvacrol were obtained by steam distillation (at 5% level).