Figure 1.

Mitochondrial generation of ROS and antioxidant mechanism of action. Mitochondrial-driven oxidative stress derived from suboptimal function at the level of complex I, complex III and complex IV enzymatic activities of the mitochondrial respiratory chain. Reactive oxygen species may damage different cell structures and molecules including lipids, b-oxidation cycle compounds or nucleic acids such as mitochondrial DNA. Non-enzymatic antioxidants, including polyphenols, carotenes and vitamins, and endogenous enzymatic antioxidants, including superoxide dismutase, catalase and glutathione peroxidase, exert protective mechanisms by scavenging the ROS towards redox equilibrium. ADP, adenosine diphosphate; Aox, antioxidant; ATP, adenosine triphosphate; CI, complex I; CII, complex II; CIII, complex III; CIV, complex IV; CV, complex V; Gpx, glutathione peroxidase; mtDNA, mitochondrial DNA; ROS, reactive oxygen species; SOD, superoxide dismutase.