Artemisinin 300 CapsThujone free Artemisinin Supplement Pure artemisinin, the active constituent of the herb Artemisia annua (sweet wormwood). Pure artemisinin or Qinghaosu, the active constituent of the herb Artemisia annua (sweet wormwood). Good quality Artemisia annua contains 0. 3 0. 5% artemisinin, so pure artemisinin provides hundreds of times more of the active constituent artemisinin than the whole herb itself. Allergy Research Group introduced artemisinin to the