STUDY ON THE ELECTROCHEMICAL BEHAVIORS OF ARTEMISININ (QINGHAOSU) ANDITS DERIVATIVES - II - REDUCTION-MECHANISM OF ARTEMISININ IN THE PRESENCE OF HEMIN

The interaction between artemisinin and hemin was investigated by elec trochemical methods. Artemisinin was irreversibly reduced at - 1.08V v ia a two - electron transfer process at glassy carbon electrode. In th e presence of hemin at concentration as low as 4.0 x 10(-8)mol/L, arte misinin can be reduced via the hemin - catalysis and its original cath odic peak st - 1.08V completely disappeared. The cathodic overpotentia l of artemisinin is decreased by ca. 600mV. This process is verified b y the fact that complex EDTA-Fe(III) can also promote the artemisinin reduction with decreasing the cathodic overpotential of artemisinin fo r 590mV. These results show that the reduction of artemisinin at glass y carbon electrode is,a catalytic process with the aid of hemin. Hemin can greatly decrease the cathodic activation energy of the reduction of artemisinin and promote the decomposition of artemisinin.