Modeling the decomposition mechanism of artemisinin

A theoretical study on artemisinin decomposition mechanisms is reported. The calculations have been done at the HF/3-21G and B3LYP/6-31G(d,p) theoretical levels, by using 6,7,8-trioxybicyclo3.2.2]nonane as the molecular model for artemisinin, and a hydrogen atom, modeling the single electron transfer from heme or Fe(II) in the highly acidic parasite's food vacuole, as inductor of the initial peroxide bond cleavage. All relevant stationary points have been characterized, and the appearance of the final products can be explained in a satisfactory way. Several intermediates and radicals have been found as relatively stable species, thus giving support to the current hypothesis that some of these species can be responsible for the antimalarial action of artemisinin and its derivatives.