Chemical studies on antioxidant mechanism of tea catechins: analysis of radical reaction products of catechin and epicatechin with 2,2-diphenyl-1-picrylhydrazyl.
Tea catechins, an important class of polyphenols, have been shown to have wide spectrum of antitumor activity believed to be due mainly to their antioxidative effect. In this study, the radical scavenging behavior of catechins on 2,2-diphenyl-1-picrylhydrazyl (DPPH) was studied. Two reaction products of (+)-catechin, and two reaction products of (-)-epicatechin were purified and identified. Their structures were determined on the basis of detailed high-field 1-D and 2-D NMR spectral analysis. Structure elucidation of these products can provide insights into specific mechanisms of antioxidant reactions. A possible mechanism of the formation of reaction products is suggested.
Sang
Shengmin
S
Department of Food Science and Center for Advanced Food Technology, Rutgers University, 65 Dudley Road, New Brunswick, NJ 08901-8520, USA. smsang@hotmail.com
Cheng
Xiaofang
X
Stark
Ruth E
RE
Rosen
Robert T
RT
Yang
Chung S
CS
Ho
Chi-Tang
CT
D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D001713:Biphenyl Compounds; D002392:Catechin / Q000737:chemistry / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010851:Picrates / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D013662:Tea; D002392:Catechin; C004931:1,1-diphenyl-2-picrylhydrazyl