Nebraska Redox Biology Center Educational Portal

Hydroxyl Radical

Hydroxyl radicals are short lived (usually 10-9s in a cell) and highly reactive type of ROS. Hydroxyl radicals are formed in atmosphere as result of radiation and in organism as result of hydroperoxides decomposition, as product of Fenton reaction and as a byproduct of immune system action [ 1, 2, 3, 4, 5 ].

Fe2+ + H2O2 → Fe3+ + OH- + .HO;

This radical is responsible for the oxidative damage of most biomolecules and can interact with most organic and inorganic molecules - DNA, proteins, lipids, amino acids, sugars, and metals. These reactions are characterized by high rate giving the reactivity and short life-span of hydroxyl radicals [ 1, 2, 3, 4, 5 ].

.HO + RH → H2O + R.;

Living organisms did not developed any enzymatic system for hydroxyl radicals detoxification. Mechanisms of scavenging are based on interaction with reactive thiols and other endogenous antioxidants such as uric acid, vitamin E, melatonin, ascorbic acid and flavonoids [ 5, 6, ].

Hydroxyl radical can be detected by methods such as EPR, UV spectroscopy and fluorescence spectroscopy [ 7, 8, 9, 10, 11, 12 ].

Example of fluorescent probes for hydroxyl radical detection.

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