Application of thin-layer chromatography to rank the efficacies of five antioxidants in red wine

Abstract

The potential health benefits of wine are frequently attributed to the antioxidant properties of its phenolic constituents. In this study, the antioxidant efficacies of five phenolic components of a red wine were assessed in the presence of hydrogen peroxide (H2O2) and metal ions ([Fe3+], [Fe2+], [Cu2+]), using functional thin-layer chromatography (TLC). The pH of the red wine sample was adjusted to 2.0 without prior extraction. Chromatographic separation was performed using silica gel 60 F254 TLC plates with toluene-ethyl acetate-formic acid 30:25:5 (ν/ν) as mobile phase. Five phenolic components (one flavonol and four phenolic acids) were identified. In independent experiments, the red wine was challenged with a range of oxidant systems comprising H2O2, redox-active metals (Fe3+ and Cu2+), and hydroxyl radical generators (Fe2+-H2O2 and Cu2+-H2O2). The results showed that all phenolic compounds gradually diminished in a concentration- and time-dependent manner. All systems tested showed that quercetin, c...