There is an
increasing interest in the use of ascorbyl radical content (A•) in
biological tissues as an informative, non-invasive and natural indicator of oxidative
stress in the hydrophilic medium. It was also showed that A• steadystate concentration in tissues may be considered as an objective but not a
universal indicator characterizing oxidative stress intensity, since ascorbate
(AH¯) oxidation rate depends on AH¯ concentration, pH and
non-disproportionation mechanisms of A• decay. A basic kinetic
approach was applied to calculate A• steady state concentration in
the rat brain under physiological conditions.
Ascorbic acid is an especially
significant component, due to the fact that its low redox potential, allows it
to donate one single electron to almost any free radical occurring in a
biological system or to reduce oxidized biological radical scavengers, such as
α-tocopherol. The A• is the intermediate in the oxidation of AH¯ to
dehydroascorbate (DHA). It has an unpaired electron in a highly delocalized
π-system, giving stability to it as the terminal small-molecule antioxidant.
The concentration of A• is a dynamic value, which is determined by
the rates of generation and decay of this species.(Read more)
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