ABSTRACT
This chapter provides basic information and background to set the stage for the subsequent chapters that address health or disease conditions in which reactive oxygen species (ROS) and oxidant stress play important roles. The major forms of ROS are described along with mechanisms that account for their production. For perspective, superoxide radical generated from redox cycling systems (e.g., the repetitive coupling of a given reduction and subsequent oxidation reactions) can vary several orders of magnitude when the reaction is examined in water (dielectric constant, Gê+70) versus in alcohol (dielectric constant, Gê+25) or in lipid micelles. Hydroxyl radicals are produced from the decomposition of hydrogen peroxides (often as the result of Fenton-type reactions or photolysis) or water (as a result of radiolysis).
