Biochemical Theory
The regulation theory considers a polyphenol antioxidant’s ability to scavenge free radicals and up-regulate certain metal chelation reactions. Various reactive oxygen species, such as singlet oxygen, peroxynitrite and hydrogen peroxide, must be continually removed from cells to maintain healthy metabolic function. Diminishing the concentrations of reactive oxygen species can have several benefits possibly associated with ion transport systems and so may affect redox signaling.
The “deactivation” of oxidant species by polyphenolic antioxidants (POH) is based, with regard to food systems that are deteriorated by peroxyl radicals (R•), on the donation of hydrogen, which interrupts chain reactions:
R• + POH → R-H + PO•
Phenoxyl radicals (PO•) generated according to this reaction may be stabilized through resonance and/or intramolecular hydrogen bonding, as proposed for quercetin, or combine to yield dimerisation products, thus terminating the chain reaction:
PO• + PO•→ PO-OP
Read more about this topic: Polyphenol Antioxidant
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