Study of phytochemical composition and antibacterial effects of Artemisia fragrans Willd. essential oil in different seasons

In the current study, the effect of seasonal variation on the type and percentage of phytochemical compounds of Artemisia fragrans</em> Willd. essential oil was investigated. Herbal samples were collected in 4 different seasons and then their essential oils were extracted by the Clevenger type apparatus. In the following, the essential oil compositions of each season was analyzed by GC-MS apparatus. In total, 50 different compounds were identified in four sentential oil. The major components of the essential oil were camphor, thujone, and 1,8-cineole in different seasons. Also, the results showed that monotreptans were the major class of essential oil compounds in September (91.87%), December (90.55%), May (96.32%) and July (95.4%). The highest amount of phenolics (5.49 mg GAE/g) and antioxidant capacity (28.98%) were observed in essential oil of Septebmer.   Antibacterial effects of the different essential oils using paper disc diffusion method were carried out on Escherichia coli</em>, Proteus vulgaris</em>, Klebsiella pneumonia</em>, Staphylococcus aureus,</em> and Bacillus subtilus</em>. Based on the results of the study, gram negative bacteria (E. coli</em>, Proteus vulgaris,</em> and K. pneumonia</em>) were more susceptible to artemisia essential oils in comparison with gram positive bacteria (S. aureus</em> and B. subtilus</em>). The results of this research can be useful in determining the best sampling date of this plant for pharmaceutical and antibacterial uses.