Abstract
Reactive oxygen species (ROS) are produced from molecular oxygen. ROS are the reduced forms of molecular oxygen and have high reactivity to biological components e.g. lipid, protein, and nucleic acid. ROS are considered to cause various diseases e.g. arteriosclerosis, myocardial infarction, cancer, and so on. A living body protects against ROS by antioxidant enzymes e.g. superoxide dismutase (SOD) and catalase. Natural antioxidants e.g. ascorbic acid (vitamin C) and α-tocopherol (vitamin E) also scavenge ROS. Recently, some novel artificial antioxidants are synthesized and are expected to a lead compound for drugs.
