不同电极上血红素对青蒿素的电催化还原

 在含20%乙醇的Britton-Robinson缓冲液介质(pH=7.2)中,采用循环伏安法在玻碳电极和银电极上比较了血红素对青蒿素还原的催化作用. 由于血红素和青蒿素加合物的形成及血红素中Fe2+的催化作用,青蒿素在玻碳电极和银电极上的还原过电位分别降低了0.32和0.09 V,还原活化能分别降低了62.1和17.6 kJ/mol. 还比较了血红素和配合物EDTA-Fe3+对青蒿素的催化还原效果,结果表明,EDTA-Fe2+的催化作用远低于血红素. 进一步证实了血红素在青蒿素的药理研究中起着关键作用.

Electrocatalytic Reduction of Artemisinin by Hemin on Different Electrodes

Artemisinin is an effective antimalarial drug and hemin plays an important role in the antimalarial mechanism of artemisinin. In this work, the catalytic reduction of artemisinin induced by hemin at glassy carbon (GC) electrode and silver electrode was studied by cyclic voltammetry in Britton-Robinson buffer solution (pH 7 2) containing 20% ethanol. The comparison of the catalytic action was made between EDTA-Fe 3+ and hemin for the reduction of artemisinin. The results showed that the reduction overpotential of artemisinin induced by hemin decreased by 0 32 and 0 09 V, and the reduction activation energy decreased by 62 1 and 17 6 kJ/mol for GC electrode and Ag electrode, respectively. However, the EDTA-Fe 3+ complex had a very weak catalytic effect on the artemisinin reduction. The electrochemical experiments and UV-Vis absorption spectra of the interaction of artemisinin and hemin indicated that artemisinin may form an adduct with hemin, resulting in a decrease in the reduction activation energy and overpotential and an increase in the electron transfer rate. These results may be helpful in further understanding the mechanism of drug action of artemisinin.