Evidence for hemin inducing the cleavage of peroxide bond of artemisinin (Qinghaosu): cyclic voltammetry and in situ FT IR spectroelectrochemical studies on the reduction mechanism of artemisinin in the presence of hemin

摘要

Cyclic voltammetry and in situ FT IR spectroelectrochemistry (SEC) were used to monitor the change of the peroxide group of artemisinin in the presence of hemin. On the glassy carbon electrode, artemisinin alone was reduced at potentials morenegative than -1.0 V in CH{sub}2Cl{sub}2; no well-defined reduction peak was observed. In the presence of a concentration of hemin as low as 10{sub}-7 M, artemisinin can be irreversibly reduced via hemin catalysis. In situ FT IR SEC experiments confirmedthe catalysis of hemin for the reduction of artemisinin. The changes of IR spectra for the peroxide bond of artemisinin at 1114 cm{sup}-1 clearly showed hemin inducing the cathodic cleavage of the peroxide bond. These results might contribute to anunderstanding of the antimalarial action of artemisinin.