Scavenging effects of phenolic compounds on reactive oxygen species

Phenolic compounds are widely present in plants and they have received considerable attention due to their antioxidant property. In this article we report the results of a study of the reactivity of 10 selected phenolics (sesamol, three phenolic acids, three flavonols, one flavone, and two flavanones) with superoxide anion radical (O2-•), hydroxyl radical (HO•) and singlet oxygen (1O 2). The following generators of reactive oxygen species were used: 18-crown-6/KO2/dimethylsulfoxide (DMSO) or hypoxanthine/xanthine oxidase as sources of O2-•, the Fenton reaction carried out in a sodium trifluoroacetate (pH 6.15) for HO•, and a mixture of alkaline aqueous H2O2 and cobalt ions for 1O2. We have employed chemiluminescence, electron spin resonance spin trapping, and spectrophotometry techniques to examine an antioxidative property. All tested compounds acted as scavengers of various reactive oxygen species. The reactivity indexes (β) for the reaction of the phenolic compounds with HO• were calculated. © 2007 Wiley Periodicals, Inc.