ELECTROCATALYTIC REDUCTION OF ARTEMETHER BY HEMIN

Artemether is an important widely used derivative of artemisinin. On a glassy carbon electrode, artemether undergoes an entirely irreversibl e reduction at ca. -1.18 V. Hemin can catalyze the reduction of arteme ther as it catalyzes that of artemisinin. In the presence of concentra tions of hemin as low as 8 x 10(-8) M, the reduction happens at -0.54 V, reducing the cathodic overpotential ca. 640 mV. Ethylenediaminetetr aacetic acid (EDTA)-Fe(III) complex also catalyzes the reduction of ar temether while reducing the cathodic overpotential about 680 mV; but a concentration of at least 4 x 10(-4) M was required. Experiments sugg ested artemether might undergo the identical antimalarial mechanism as artemisinin. All these further confirm the important role of hemin in the mechanism of action of artemisinin-type drugs.