ABSTRACT
Atherosclerosis is the major process underlying CVD, and one line of current thinking implicates reactive oxygen species (ROS) in its pathogenesis. Many ROS exist in biology that are free radicals by themselves or can give rise to free radicals, i.e., the superoxide anion, hydrogen peroxide, the hydroxyl radical, singlet molecular oxygen, the nitroxyl radical and many others. Many ROS, particularly the hydroxyl radical, which can attack all biomolecules, are very active. Once formed, any free radical will most likely react with nonradicals, generating new free radicals; hence, free radical reactions tend to proceed as chain reactions. Some ROS have a useful role in biology. Others are accidental by-products of aerobic metabolism or the result of environmental stress and pose a constant threat to biomolecules. All organic molecules, lipids, proteins, nucleic acids, and carbohydrates, are potential targets for oxidative damage (14).
