Stability and oxidation products of hydrolysable tannins in basic conditions detected by HPLC/DAD-ESI/QTOF/MS.

Introduction: Hydrolysable tannins occur in plants that are used for food or medicine by humans or herbivores. Basic conditions can alter the structures of tannins, that is, the oxidation of phenolic groups can lead to the formation of toxic quinones. Previously, these labile quinones and other oxidation products have been studied with colorimetric or electron paramagnetic resonance methods, which give limited information about products.