ELECTROCHEMISTRY OF CATECHOL-CONTAINING FLAVONOIDS

The electrochemical properties of four structurally related flavonoids , quercetin, quercetin-3-O-rhamnose (quercitrin), quercetin-3-O-rutino se (rutin) and luteolin were investigated. These flavonoids were shown to undergo homogenous chemical reactions following oxidation at a gla ssy carbon electrode. These reactions were studied using cyclic voltam metry and rotating ring-disk voltammetry. Both first-order and zero-or der processes were observed. The rate of the zero-order process was st rongly dependent on the substituent at the C-3 position of the flavono id. The rate of the first-order process was independent of substitutio n. Two products were observed using liquid chromatography. These produ cts did not correspond to previously reported products of enzymatic ox idation. The products were not stable under conditions for isolation.