Abstract: The peroxy bond in dihydroartemisinin (DHA) is the most essential part for its anti-malarial and anti-tumor effect. The cleavage of the peroxy bond can affect its pharmacological activity. An electrochemical method was used to investigate the breakage of the peroxy bond in dihydroartemisinin induced by electrocatalysis of EDTA-Cu(Ⅱ). The effect of acidity and scan rate on this catalytic system was studied. The mechanism of the reaction at the electrode surface was also discussed. There was an irreversible reduction peak at-0.681V (vs SCE) for DHA in aB-Rbuffer solution containing 20% ethanol (pH=7.2). The reduction potential shifted about 94 mV toward the positive direction, and the reduction current increased in the solution containing 5.0×10-4mol/L DHA and 5.0×10-6mol/L EDTA-Cu(Ⅱ). Compared with EDTA-Fe(Ⅲ) and hemin, EDTA-Cu(Ⅱ) showed an obvious electrocatalytic effect to DHA in this system. These results indicated that EDTA-Cu(Ⅱ) can induce the cleavage of the peroxy bond of DHA and affect the pharmacological activity of DHA.

Key words: dihydroartemisinin, ethylene diamine tetraacetic acid disodium, copper, peroxy bond, cleavage, electrocatalytic reduction