Structure-Activity Relationship (SAR) Studies of Oxidation of Some Flavonoids with Photochemically Generated t-BuO Radicals in t-BuOH-Water System through Kinetic ApproachAuthor(s): Vijaya Lakshmi G
As a dietary component, flavonoids are thought to have a variety of pharmacological and health-promoting properties both in vivo and in vitro systems. It is attributed to their high antioxidant capacity which in turn is associated with their free radical scavenging properties. In order to understand the mechanism of t-BuO radical scavenging properties of some flavonoids viz., quercetin (QU), apigenin (AP), daidzein (DA), genistein (GE), myricetin (MY) and kaempferol (KA), a kinetic study of photo-oxidation of these flavonoids with photochemically generated t-BuO radicals in t-BuOH-water (2:1 v/v) system was carried out. The initial rates of oxidation of flavonoids increased with [flavonoid], [t-BuOOH] and light intensity. The quantum yields () were considered from the initial rate of oxidation of flavonoid by t-BuO radicals and measured light intensity at 254 nm. The order on [flavonoid] and [t-BuOOH] was found to be fractional whereas order on light intensity was found one. The products of oxidation of flavonoids by t-BuO radicals were identified using LC-MS and FTIR analysis.