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Method of assessment of antioxidant status in vivo
Author(s) -
Eich Natalie,
Rabovsky Alexander,
Cuomo John
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a144-c
Subject(s) - antioxidant , chemistry , uric acid , isoprostane , oxidative stress , lipid peroxidation , vitamin c , vitamin e , isoprostanes , in vivo , ex vivo , ferric reducing ability of plasma , biochemistry , food science , in vitro , antioxidant capacity , biology , microbiology and biotechnology
Currently there are two major ways to estimate antioxidant status of plasma: 1) antioxidant capacity of plasma (FRAP, ORAC, TEAC, etc) and 2) oxidative stress biomarkers (lipid peroxides, MDA, isoprostanes, etc). There are difficulties that hamper both of these approaches. Antioxidant capacity of plasma is mostly dependent on the amount of uric acid and proteins that are present and the addition of antioxidants changes this value very little or not at all. Oxidative stress biomarkers are usually present in plasma at very small concentrations and are at the limit of detection (if not below). This new method includes two steps: 1) ex vivo free radical oxidation of plasma and 2) measurement of markers of lipid peroxidation, 8‐isoprostanes. By utilizing this principle we are able to measure effect of water soluble antioxidants, substances associated with lipoproteins, and fat‐soluble antioxidants incorporated in lipoprotein structure and all possible synergistic interactions between them. It has been shown in an in vitro experiment that the addition of various antioxidants to plasma significantly reduced the amount of free‐radical induced 8‐isoprostanes. In a human single dose supplementation clinical study with vitamin C, vitamin E, and grape seed & green tea extracts (on separate days) 8‐isoprostane formation was also significantly reduced compared to baseline. FRAP value was also measured and no effect was shown for the same samples. When uric acid is enzymatically removed from plasma prior to oxidation, the measurable effect of antioxidant supplementation is amplified.