Variations in essential oil compositions and biological activities of Artemisia annua L. (sweet wormwood) at different growth periods

The current study is purposed to examine the yields, chemical compositions, antioxidant and antimicrobial properties of Artemisia annua L. essential oils obtained at pre-flowering, initial flowering and post-flowering growth stages. The main constituent of the essential oils in pre-flowering stage was camphor (47.88%). At initial flowering, composition of the essential oil changed drastically. Artemisia ketone increased from 4.62% to 55.31% and camphor decreased to 11.50% resulting in an artemisia ketone chemotype essential oil. In post-flowering stage, both camphor and artemisia ketone did not change significantly compared to initial flowering. These changes of the essential oil compositions caused various alterations in antioxidant and antimicrobial activities. Antioxidant and antibacterial activities of the essential oils were slightly increased in parallel with artemisia ketone. On the other hand, the decrease in the camphor content executed a negative impact on antifungal activities. Correlation analysis revealed that artemisia ketone was slightly more antioxidant and more potent antibacterial while camphor was found to be more effective on investigated fungal strains.