Figure 1.

Artemisinin 1 and current clinical derivatives: dihydroartemisinin (DHA) 2, artemether 3, and artesunate 4. The latter two are rapidly converted into DHA in vivo via metabolism or facile hydrolysis respectively. As a hemiacetal, DHA rearranges irreversibly under physiological conditions into the peroxyhemiacetal 5 that in turn rearranges to the inert deoxyartemisinin 6 (Haynes et al., 2007).