title: Chemical studies of the antioxidant mechanism of tea catechins: radical reaction products of epicatechin with peroxyl radicals.
abstract: Tea catechins, an important class of polyphenols, have been shown to have antioxidant activity and are thought to act as antioxidants in biological systems. However, the mechanisms of their antioxidant reactions remain unclear. The objective of this study was to characterize the reaction products of epicatechin with peroxyl radicals generated by thermolysis of the azo initiator azo-bisisobutyrylnitrile (AIBN). Structural elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. Eight reaction products were isolated and identified using high-field 1D and 2D NMR spectral analysis. The observation of these compounds confirmed that the B-ring is the initial site for formation of reaction products in the peroxyl radical oxidant system.
authors.affiliation: Department of Food Science and Center for Advanced Food Technology, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520, USA. ssang@rci.rutgers.edu
authors.forename: Shengmin
authors.initials: S
authors.lastname: Sang
authors.forename: Shiying
authors.initials: S
authors.lastname: Tian
authors.forename: Hsin
authors.initials: H
authors.lastname: Wang
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Stark
authors.forename: Robert T
authors.initials: RT
authors.lastname: Rosen
authors.forename: Chung S
authors.initials: CS
authors.lastname: Yang
authors.forename: Chi Tang
authors.initials: CT
authors.lastname: Ho
mesh_terms: D000975:Antioxidants / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D002392:Catechin / Q000138:chemical synthesis / Q000737:chemistry* / Q000302:isolation & purification; D005609:Free Radicals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D010545:Peroxides; D013662:Tea; C049375:perhydroxyl radical; D002392:Catechin