Polyphenols as Antioxidant/Pro-Oxidant Compounds and Donors of Reducing Species: Relationship with Human Antioxidant Metabolism
Celia María Curieses Andrés, José Manuel Pérez de la Lastra, Celia Andrés, Francisco J. Plou, Eduardo Pérez‐Lebeña
Abstract
In this review, we have focused mainly on the study of their antioxidant and pro-oxidant capacity, and the analysis of the oxidation of the catechol group to o-quinone. The redox balance established between the different oxidase and reductase enzymes generates reducing species, H+ and e−, and allows the oxidation of polyphenolic groups to quinones to be reversible. This continuous balance between these nucleophilic and electrophilic substances allows the activation of the NRF2/ARE axis, which regulates cellular antioxidant responses against oxidative stress, as well as cell proliferation. Understanding the ambivalent character of polyphenols, which can act simultaneously as antioxidants and pro-oxidants, will allow the design of specific therapies that can serve science and medicine in their tasks.