Abstract:

To understand the relationship between structure and antioxidant activity of flavonols, cyclic voltammetry and UVvisible spectroelectrochemical method in situ were used to investigate electro-oxidation mechanisms of myricetin and dihydroquercetin through the comparison with electrochemical-chemical mechanism of quercetin. Results indicated that 5＇-OH at the B-ring of myricetin hindered the subsequent chemical transformation to a certain extent, while C－C saturated bond at 2,3 positions in dihydroquercetin completely stopped the subsequent transformation step, thus leading to the decrease in antioxidant activity. These findings suggest that the subsequent chemical transformation provide very important contribution to antioxidant activity of flavonols.

Key words: antioxidant activity, cyclic voltammetry, UV-visible spectrum, myricetin, dihydroquercetin