Oxidative stress: Relations between the formation of reactive species and the organism's defense.

This work describes the mechanism of action of some reactive oxygen species (ROS) and reactive nitrogen species (RNS) in the oxidative stress of the human body, and their consequences on damage to DNA, RNA, proteins and lipids. It also illustrates the defense system of our organism against these ROS and RNS species. The action of nonenzymatic protection systems is reported, with emphasis on micromolecules like Q10 coenzyme, vitamin C, a-tocopherol, carotenoids and flavonoids. The importance of flavonoids is also emphasized, and their body protection mechanism is detailed.