Abstract
Partial reduction of molecular oxygen can generate reactive oxygen species (ROS),
including the hydrogen peroxide, and the radicals superoxide and hydroxyl. The formation
of ROS is a feature of many degenerative diseases, such as atherosclerosis and neurodegeneration,
Organisms contain a battery of defense mechanisms to prevent the formation of ROS,
to scavenge them, and to repair the damage they cause. Free radicals are also involved
in signal transduction pathways. For example, the free radical nitric oxide is involved
in signal transduction in both the cardiovascular and central nervous systems. The
interplay between nitric oxide and ROS has been a major focus recent studies, as nitric
oxide is an efficient radical scavenger. However, in some cases, such as in the formation
of peroxynitrite from nitric oxide and superoxide, the product is potentially more
deleterious that the parent radicals. This review describes the major chemical species
involved in oxidative stress and free radical biochemistry, and gives a brief overview
of their role in pathological conditions.
Keywords:
Oxidative stress - free radicals - superoxide - nitric oxide - lipid peroxidation
