Reactive oxygen species and antioxidants in living systems: an integrated overview

The brief overview is dedicated to the current understanding of the redox metabolism in the aerobic cells. The characteristic of oxygen radicals and information about the mechanisms of their generation are presented. The data on the role of reactive oxygen species (ROS) in the cellular signaling and the induction of oxidative stress were analyzed. The excessive ROS accumulation is dangerous for the cells, as oxygen radicals are able to interact with the biologically important molecules (DNA, proteins, lipids, etc.) and damage the cellular structures. The redox balance violation can be caused by negative effects of factors of various nature (abiotic, biotic, anthropogenic), but ultimately their effects are reduced to the occurrence of oxidative stress. In humans, oxidative stress provokes the development of various diseases, causes a decrease in performance, early aging, etc. This is opposed by the antioxidant system, which detoxifies oxygen radicals and suppresses the processes of the macromolecules oxidation. The article summarizes information about the main low molecular weight antioxidants and antioxidant enzymes, and role of the antioxidant system in maintaining the redox balance of the living cells. In conclusion, topical issues for further study and their portance for solving practical problems of ecology are noted.