Quantitative measurement of the total, peroxyl radical-trapping antioxidant capability of human blood plasma by controlled peroxidation. The important contribution made by plasma proteins.
Plasma obtained from fasted humans has been analysed for total radical-trapping antioxidant content by subjecting it to controlled peroxidation using the thermal decomposition of water-soluble azobis (2-amidinopropane hydrochloride) at 37 degrees C to produce peroxyl radicals at a known, steady rate. It is found that the total radical-trapping antioxidant content is rather similar for the 7 subjects that have been tested and, furthermore, it is 10-20-times larger than the effect attributable to vitamin E alone. Although it is shown that urate and ascorbate augment the contribution from vitamin E, their contributions (21-34 and 0-2%, respectively) still leave 57-73% of the total antioxidant content unaccounted for. Evidence is presented to show that this previously unrecognized large reserve of antioxidant capacity is attributable to the plasma proteins.
D000975:Antioxidants / Q000097:blood*; D001205:Ascorbic Acid / Q000097:blood; D001798:Blood Proteins / Q000378:metabolism*; D005609:Free Radicals; D006801:Humans; D008433:Mathematics; D010545:Peroxides / Q000097:blood*; D014527:Uric Acid / Q000097:blood; D014810:Vitamin E / Q000097:blood
D000975:Antioxidants; D001798:Blood Proteins; D005609:Free Radicals; D010545:Peroxides; D014810:Vitamin E; D014527:Uric Acid; D001205:Ascorbic Acid