Antioxidative Properties of Silymarin, 7-aminoflavone, Neohesperidin Dihydrochalcone and Trihydroxyethylenorutin Studied by the Electrochemical Methods

摘要

The electrooxidation of flavonoids has been investigated in non-aqueous solution at a platinumelectrode. The process of oxidation and its kinetics has been investigated using cyclic voltammetry(CV) and differential pulse voltammetry (DPV). The electrochemical oxidation of flavonoids is anirreversible reaction at a platinum electrode. For neohesperidin dihydrochalcone, silymarin, 7- aminoflavone and trihydroxyethylenorutin, the first step in the electrooxidation is the exchange of oneelectron during the oxidation of the hydroxyl group in ring B. The hydroxyl groups in ring A are likelyoxidised in a subsequent step. Neohesperidin dihydrochalcone oxidation was the easiest, andtrihydroxyethylenorutin was the hardest, which was confirmed by the half-wave potential (E1/2) of thefirst electrode step in the electrooxidation of the flavonoids. Structural investigations of the flavonoidswere conducted using FTIR spectroscopy. The voltammetric potentials were found to correlate wellwith computed highest occupied molecular orbital (HOMO) energies.