Essential oil Composition and Antioxidant Properties of Artemisia sieberi Besser in Two Enclosure and Grazed Sites at Three Phenological Stages

The use of plants for treatment and food returns to ancient times. This study was conducted to examine the essential oil composition and antioxidant activity of the essential oil of Artemisia sieberi Besser at 3 phenological stages and effect of grazing livestock on these properties. For this purpose, 5 shrubs from two sites (under grazing site and enclosure site) were selected randomly at 3 phenological stages. In laboratory operations, essential oil of the species was extracted in by SDE method. The results of GC/MS analysis indicated 45 compounds for grazed site with essential oil content 98.73%, and 42 compounds for enclosure site with essential oil content 98.54%. Also, α-tujune (21.63%), α-Pinene (19.53%), and Camphene (10.34%) were the main compounds in the enclosure site and α-tujune (23.70%), α-Pinene (20.33%), and Camphene (12.60%) were the main compounds in the grazed site. The results of screening antioxidant activity using two assays (DPPH and β-carotene-linoleic acid) showed that the free radical scavenging activity of essential oil (IC50 µg ml-1) in the first phenological stage (vegetative stage) was more than other phenological stages in two sites. Also, the inhibition of essential oil in the grazed sites had a significant difference with essential oil's inhibition in the enclosure site. Effect of grazing on the composition and properties of the essential oil of this species can be considered in the planning of livestock grazing management. We wish our future research on this plant leads to the finding of new natural antioxidant compounds.