Chemiluminescence assay for catechin based on generation of hydrogen peroxide in basic solution

We have determined that the catechin group in basic solution efficiently produces hydrogen peroxide; moreover, a highly sensitive analysis methodology was developed to measure catechin employing a peroxalate chemiluminescence detection system. Identification of hydrogen peroxide generated by catechin was determined by ESR as well as peroxalate chemiluminescence using catalase and SOD. As a result, catechin-generated superoxide by electron reduction to dissolved oxygen in basic solution, followed by production of hydrogen peroxide through dismutation reaction. This method could measure several tea catechins, (+)-catechin (CC),(-)-epigallocatechin-3-gallate (EGCg), (-)-epicatechin-3-gallate (ECG) and gallic acid, with measurement range from 10(-7) to 10(-3) Mol/l and sensitivity of 10(-8) mol/l. This method was also applied to the determination of total catechin levels in green tea, black tea and roasted green tea. (C) 2002 Elsevier Science B.V. All rights reserved.