Figure 1
From: Oxidative stress and the use of antioxidants in diabetes: Linking basic science to clinical practice

Generation of reactive species in diabetes. Highlighted in gray are some of the most important ROS and RNS in vascular cells. Oxygen is converted to •O2- via the activation of enzymatic and nonenzymatic pathways, which is then dismutated to H2O2 by SOD. H2O2 can be converted to H2O by catalase or glutathione peroxidase (GSH-Px) or to •OH after reaction with Cu or Fe. Glutathione reductase regenerates glutathione (GSH). In addition, •O2- reacts rapidly with •NO to form ONOO-.