Analysis of Antioxidant Compounds of Broad-Leaved Tree Leaves usingan Online LC-Radical Scavenging Ability Measurement System

Background: Antioxidant compounds have been reported to be effective in preventing and improving various diseases, including cancer and neurodegenerative diseases. In this study, an online liquid chromatography (LC) radical scavenging ability measurement system was used to explore the antioxidant compounds present in the leaf extracts of five broad-leaved tree species native to the Jeonnam region.<br/>Methods and Results: Ultraviolet (UV) absorption spectra and LC-mass spectrometry (LC-MS) analyses were performed on 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging active compound peaks identified in the measurement system. In Morus alba leaf extract, 3-caffeoylquinic acid, 4-caffeoylquinic acid, and isoquercitrin were identified as the major active compounds. In Eriobotrya japonica leaf extract, 5-caffeoylquinic acid, 3-caffeoylquinic acid, and epicatechin were identified. In Dendropanax morbiferus and Kalopanax septemlobus leaf extracts, 3-caffeoylquinic acid was identified as the major active compound, and in Crataegus pinnatifida leaf extract, epicatechin was identified as the major active compound.<br/>Conclusions: The online LC-radical scavenging ability measurement and compound analysis method used in this study can be applied to study the antioxidant activities in other plant materials. In particular, it can be a useful method for screening analyses in the early stages of research and development.