Ferroquine (FQ or SR97193) is a unique ferrocene antimalarial drug candidate 
which just entered phase IIb clinical trials in autumn 2007. FQ is able to 
overcome the chloroquine (CQ) resistance problem, an important limit to the 
control of Plasmodium falciparum, the principal causative agent of malaria. 
However, as for other therapeutic agents such as chloroquine (CQ) and artemisin, 
its mechanism of action remains partially unknown. Most investigations have so 
far focused on comparing the activity of FQ to that of CQ in order to understand 
how the ferrocene core contributes to a stronger antiplasmodial activity. 
Studies have already shown that the ferrocene altered the shape, volume, 
lipophilicity, basicity and also electronic profile of the parent molecule and, 
hence, its pharmacodynamic behavior. However, few investigations have been 
undertaken to probe the real contribution of redox properties of the ferrocene 
(iron(II))/ferricinium (iron(III)) system in FQ as reported in this article. In 
our experimental and theoretical approach, we considered the redox profile of 
the ferrocene core of FQ in the specific conditions (acidic and oxidizing) of 
the parasitic digestive vacuole as a possible discriminating property from CQ in 
the antimalarial activity.