An integrated antioxidant activity fingerprint for commercial teas based on their capacities to scavenge reactive oxygen species

Abstract

An integrated antioxidant activity fingerprint, based on on-line screening methods for three reactive oxygen species (ROS: superoxide anion radical, hydrogen peroxide, and hydroxyl radical) was developed to comprehensively evaluate the quality of 12 batches of commercial tea. High-performance liquid chromatography (HPLC) coupled with a chemiluminescent detector was used to determine the antioxidant characteristics of a selection of teas as bioactivity fingerprints. An HPLC-electrospray ionization-mass spectrometry analysis was used to determine the chemical profiles of the teas in the chromatographic fingerprints. All of the green teas (S01-S08) were better scavengers of the three ROS compared to the oolong teas (S09-S12). The main scavengers of the three ROS in green tea were 5-galloylquinic acid, (-)-epigallocatechin-3-O-gallate, and (-)-epicatechin-3-O-gallate, whereas in oolong tea, they were (-)-epigallocatechin-3-O-gallate and (-)-epigallocatechin. This study demonstrates that comprehensive fingerprinting is a potentially meaningful method for evaluating the quality of food products.

Keywords: Chemiluminescence; HPLC; Quality evaluation; Reactive oxygen species; Tea.