Stopped-flow-optical Absorption and -ESR Detection of Rutin (Quercetin-3-O-rutinoside) B-ring Catechol Aroxyl Radicals Generated during Redox Reaction between Rutin and O-2(-center dot) Radical in DMSO

Stopped-flow-optical absorption and -electron spin resonance spectroscopies were employed to analyze the kinetic behaviors of short-lived intermediate radicals in redox reactions between electrochemically generated O2(-center dot) radicals and rutin (Rut(OH)(2)) in DMSO. The results of both studies indicate the formation of a rutin B-ring catechol-derived aroxyl (Rut(OH)O-center dot) radical in the presence of excess amounts of rutin.