Flow injection analysis with luminol chemiluminescence detection for evaluation of quenching effects of grape seed extracts and polyphenolics against reactive oxygen species

A simple and rapid FIA method for measurement of quenching effects of grape seed extracts and polyphenolics against reactive oxygen species (ROS) was developed. This method is based on the determination of luminol chemiluminescence generated with ROS such as hydroxyl radical ((OH)-O-center dot), singlet oxygen (O-1(2)), peroxynitrite (ONOO-) and superoxide anion (O-2(-)). More than 1 sample/min could be measured with satisfactory precision. The total reagent amount in this method could be reduced to one tenth of that for our previous batch method. The grape seed extracts A and B were successfully evaluated by the proposed method. The EC50 of cyanidin as a representative polyphenolic against (OH)-O-center dot, O-1(2), ONOO center dot and O-2(-) were 50 +/- 4, 148 +/- 8, 36 +/- 4, and 95 +/- 8 ng/assay (n = 3), respectively. Except for chalcone, the other polyphenolics such as pelargonidin, delphinidin and trans-resveratrol also showed the high quenching effects against ROS.