Ascorbate is an outstanding antioxidant in human blood plasma.
AUTOR(ES)
Frei, B
RESUMO
We have shown recently that the temporal order of antioxidant consumption in human blood plasma exposed to a constant flux of aqueous peroxyl radicals is ascorbate = protein thiols greater than bilirubin greater than urate greater than alpha-tocopherol and that detectable lipid peroxidation starts only after ascorbate has been consumed completely. In this paper, we show that it is indeed ascorbate that completely protects plasma lipids against detectable peroxidative damage induced by aqueous peroxyl radicals and that ascorbate is the only plasma antioxidant that can do so. Plasma devoid of ascorbate, but no other endogenous antioxidant, is extremely vulnerable to oxidant stress and susceptible to peroxidative damage to lipids. The plasma proteins' thiols, although they become oxidized immediately upon exposure to aqueous peroxyl radicals, are inefficient radical scavengers and appear to be consumed mainly by autoxidation. Our data demonstrate that ascorbate is the most effective aqueous-phase antioxidant in human blood plasma and suggest that in humans ascorbate is a physiological antioxidant of major importance for protection against diseases and degenerative processes caused by oxidant stress.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=297842Documentos Relacionados
- Antioxidant defenses and lipid peroxidation in human blood plasma.
- Inactivation of kallikrein in human plasma.
- Transcobalamin II in human seminal plasma.
- UNESTERIFIED FATTY ACID IN HUMAN BLOOD PLASMA. II. THE TRANSPORT FUNCTION OF UNESTERIFIED FATTY ACID
- Growth response of yeast cells of Histoplasma capsulatum to citraed human blood plasma.