concept recognizes the physiological effectiveness of the antioxidant defenses in
maintaining both oxidative stress and cellular damage at a minimum level in physiological
conditions (Boveris et al., 2008).
Lipid peroxidation is a chain reaction initiated by the hydrogen abstraction or addition of an
oxygen radical, resulting in the oxidative damage of polyunsaturated fatty acids (PUFA).
Since polyunsaturated fatty acids are more sensitive than saturated ones, it is obvious that
the activated methylene (RH) bridge represents a critical target site. The presence of a
double bond adjacent to a methylene group makes the methylene C-H bond weaker and
therefore the hydrogen in more susceptible to abstraction. This leaves an unpaired electron
on the carbon, forming a carbon-centered radical, which is stabilized by a molecular
rearrangement of the double bonds to form a conjugated diene which then combines with
oxygen to form a peroxyl radical. The peroxyl radical is itself capable of abstracting a
hydrogen atom from another polyunsaturated fatty acid and so of starting a chain reaction