青蒿素及其衍生物的电化学性质研究Ⅱ——氯化血红素存在下的青蒿素还原机理

Study on the Electrochemical Behaviors of Artemisinin(Qinghaosu) and Its Derivatives Ⅱ Reduction Mechanism of Artemisinin in the Presence of Hemin

用电化学方法研究了青蒿素与氯化血红素之间的相互作用。青蒿素在玻璃碳电极上于- 1.0 8V处能发生一个 2电子转移的不可逆还原。即使在低至 4 .0× 10 - 8mol/L氯化血红素存在下 ,青蒿素仍可被催化还原 ,阴极过电位降低了 6 0 0mV。配合物EDTA Fe(Ⅲ )具有类似氯化血红素的催化性质 ,它降低了QHS阴极过电位 590mV。在这个体系中 ,青蒿素在碳电极上的还原是一个借助于氯化血红素催化的还原过程 ,氯化血红素的存在降低了青蒿素还原活化能 ,促进了青蒿素的分解。

The interaction between artemisinin and hemin was investigated by electrochemical methods.Artemisinin was irreversibly reduced at -1.08?V via a two\|electron transfer at the glassy carbon electrode.In the presence of concentration of hemin as low as 4.0×10 -8 ?mol/L,artemisinin can be reduced via the hemin\|catalysis and its original cathodic peak at -1.08?V completely disappeared.The cathodic overpotential of artemisinin is decreased ca.600?mV.This process is verified by the fact that complex EDTA\|Fe(Ⅲ) can also promote the artemisinin reduction with decreasing the cathodic overpotential of artemisinin for 590?mV.These results show that the reduction of artemisinin at the glassy carbon electrode is a catalytic process with the aids of hemin.Hemin can greatly decrease the cathodic activation energy of the reduction of artemisinin and promote the decomposition of artemisinin.