Study on quantity and quality of essential oils of Artemisia sieberi Besser in grazed and ungrazed rangelands

The essential oil yield and chemical composition of the aerial parts of Artemisia sieberi Besser were investigated in two sites of grazed and ungrazed rangelands. Plant sampling was performed from 2 sites in Ahmadabad, located in Semnan province at the beginning of flowering stage in October 2010. The samples of inflorescences of plants were collected from 5 random points of each site. Then, air-dried parts of the plants were subjected to hydrodistillation using a Clevenger-type apparatus. Analysis and identification of chemical composition of the essential oils were performed by GC and GC/MS. There was no significant difference between the oil yields of Artemisia sieberi in 2 investigated sites. In ungrazed and grazed sites, the main components of essential oils were respectively, Camphor (48/03%), 1,8-Cineole (15/96%), Camphene (10/32%) and Camphor (51/82%), Camphene (10/86%), 1,8-Cineole (9/52%). According to the results, significant differences were recorded for Thuja-2,4(10)-diene (p<0.05) and α –Terpineol (p<0.01) between two studied sites. No significant differences were observed for the percentage of other componenets between 2 investigated sites. Also, comparison of the economic value of oil in one hectare with total area of the grazed and ungrazed rangelands showed that garzing caused a reduction in economic efficiency of oil.