This article provides a succinct but limited overview of the protective and deleterious effects of reactive oxygen and nitrogen species in a clinical context. Reactive oxygen species include superoxide, hydrogen peroxide, single oxygen and lipid peroxides. Reactive nitrogen species include species derived from nitric oxide. This review gives a brief overview of the reaction chemistry of these species, the role of various enzymes involved in the generation and detoxification of these species in disease mechanisms and drug toxicity and the protective role of dietary antioxidants. I hope that the graphical review will be helpful for teaching both the first year medical and graduate students in the U.S. and abroad the fundamentals of reactive oxygen and nitrogen species in redox biology and clinical medicine.
Keywords: 4-HNE, hydroxynonenol; 8-OHdG, 8-hydroxy-2-deoxyguanosine; ATP, adenosine triphosphate; BH4, tetrahydrobiopterin; CAT, catalase; CGD, chronic granulomatous disease; CKD, chronic kidney disease; CO2, carbon dioxide; CO3–, carbonate radical; Cu2+, cupric ion; DOX, doxorubicin; EDRF, endothelial-derived relaxing factor; GPx, glutathione peroxidase; GSH, glutathione; GSSG, oxidized glutathione disulfide; GTP, guanosine triphosphate; H2O2, hydrogen peroxide; HOCl, hypochlorous acid; IC, intersystem crossing; Keap1, Kelch-like ECH-associated protein 1; LDL, low-density lipoprotein; LOOH, lipid hydroperoxide; LOO•, lipid peroxy radical; MC540, merocyanine 540; MPO, myeloperoxidase; MnSOD, manganese superoxide dismutase; NOS, •NO synthase; NOX, NADPH oxidase; O2•–, superoxide; ONOOCO2−, nitrosoperoxycarbonate; ONOOH, peroxynitrous acid; ONOO−, peroxynitrite; OS, oxidative stress; PDT, photodynamic therapy; Peroxynitrite; RNS, reactive nitrogen species; ROS, reactive oxygen species; Reactive oxygen species; Reperfusion injury; SOD, superoxide dismutase; Superoxide; XD, xanthine dehydrogenase; XO, xanthine oxidase; cGMP, cyclic GMP; eNOS, endothelial nitric oxide synthase or NOS-3; iNOS, inducible nitric oxide synthase or NOS-2; nNOS, neuronal nitric oxide synthase or NOS-1; sGC, soluble guanylyl cyclase; •NO, nitric oxide; •OH, hydroxyl radical.