关键词: 杨梅酮, 电化学, pH, 紫外可见光谱

Abstract: The electrochemical mechanism of redox and stability of myricetin were investigated using cyclic voltammetry and electronic absorption spectra.Two oxidation reactions and two reduction reactions were achieved in B-R buffer solution.The oxidation reactions were both due to oxidation of 4′-OH on ring B and 3-OH on ring C within a one electron one proton process.The reduction reactions both correspond to the transformation of 4-carbonyl group on ring C to intermediate radical,and intermediate radical to hydroxyl group within a one electron one proton process,respectively.The redox of myricetin is pH dependent because of deprotonation,resulting in an increase of the antioxidant ability upon formation of the deprotonated forms.The final oxidation product of myricetin without electroactivity adsorbs on the electrode surface,and blocks transfers of electron.With increase of pH(7.45~12.00),Ⅰand Ⅱ bonds of electronic absorption spectra of myricetin are red-shifted due to the deprotonation and the degradation of myricetin increases.The time of storage affects intensity of degradation of myricetin.

Key words: myricetin, electrochemistry, pH, electronic absorption spectra