Variations in Chemical Compositions and Biological Activities of Artemisia vulgaris L. (Common Mugwort) Essential Oils at Different Growth Stages

The current study is aimed to investigate the essential oil (EO) yields, chemical compositions, antioxidant and antimicrobial activities of Artemisia vulgaris L. EOs were isolated before flowering, initial flowering and post-flowering growth stages. Before the flowering stage, major constituents of the EO were alpha-thujone (30.68%) and beta-caryophyllene (22.05%). Parallel to plant development, sesquiterpene hydrocarbons (mainly beta-caryophyllene) decreased and an increase was recorded in oxygenated monoterpenes, especially in alpha-thujone. These significant changes in the EO compositions caused various alterations in antioxidant and antimicrobial activities. Antioxidant activities of EOs were drastically decreased as the amount of beta-caryophyllene dropped off from 22.05 to 7.92% and alpha-thujone increased from 30.68 to 47.41%. Spearman's correlation coefficients exhibited that alpha-thujone was quite weak against oxidative stress. In contrast to antioxidant activities, correlation analysis revealed that antimicrobial activities of EOs were enhanced with the increase of alpha-thujone.