Which constituent is associated with Artemisia annua and antimalarial activity?

• A. Artemisinin
• B. Thujone
• C. Quercetin
• D. Saponins

Answer: (A)

Artemisinin is the constituent linked to Artemisia annua’s antimalarial activity. This compound is a sesquiterpene lactone with an endoperoxide bridge, a feature essential for its action. In the malaria parasite, artemisinin is activated by the iron in heme within the parasite’s digestive vacuole, generating reactive species that damage critical proteins and membranes and kill the parasite. Because of this potent activity, artemisinin and its derivatives are used in combination therapy to treat falciparum malaria. Other substances listed may be present in Artemisia species or plants in general, but they are not the primary antimalarial agent for Artemisia annua; thujone, for example, is linked more to neurotoxicity in some wormwood species, while quercetin and saponins are not the main antimalarial constituents.