ABSTRACT
Oxidative DNA modifications induced by reactive species and followed by repair occur continuously into cells. Lipid peroxidation, namely the reaction of reactive species with lipids leads to a wide range of products through complex processes. Protein modifications are caused by the reaction of proteins with free radicals, lipid peroxidation products or by glycosylation. The measurement of 8-hydroxy-2'-deoxyguanosine in urine represents a whole-body DNA oxidation assessment and there is a good agreement among laboratories on the concentration of this biomarker in urine. The major endogenous antioxidant enzymes against oxidation are superoxide dismutase, catalase, glutathione peroxidase and the peroxiredoxins. A multitude of substances have been used as antioxidant agents in redox biology research. The administration time point of an antioxidant during the day could greatly affect the results of a study. Performing a ‘functional’ categorisation of antioxidants, they are separated in reactive species scavengers, molecules that reduce reactive species generation and molecules that increase the production of antioxidants.
