Benzie, IFF, Chung, WY and Strain, JJ (1999) "Antioxidant'' (reducing) efficiency of ascorbate in plasma is not affected by concentration. JOURNAL OF NUTRITIONAL BIOCHEMISTRY, 10 (3). pp. 146-150. [Journal article]
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Ascorbate (vitamin C), an important dietary derived antioxidant, reportedly shows decreasing ``antioxidant efficiency'' with increasing concentrations in indirect radical trapping methods of antioxidant capacity. This study investigated the effect of concentration on antioxidant efficiency of ascorbate using a direct test of antioxidant capacity, the ferric reducing/antioxidant power rest (FRAP assay). Results showed that the antioxidant efficiency factor of ascorbate was 2 and was constant over a wide concentration range in both plasma and pure aqueous solution. However, the absolute amount of ascorbate lost per unit of time increased with concentration. Furthermore, ascorbate was less stable in plasma than in aqueous solutions of similar pH and less stable in ethylenediamine tetraacetic acid (EDTA) than in heparinized plasma. Results indicate that previously reported concentration-dependent changes in antioxidant efficiency of ascorbate may have been caused by loss of ascorbate prior to and during testing, and by methodologic characteristics of indirect peroxyl radical trapping tests of antioxidant capacity. Therefore, it is suggested that the premise that the antioxidant efficiency of ascorbate is concentration-dependent is largely methodologically derived and does not reflect the antioxidant behavior of ascorbate per se. (C) Elsevier Science inc. 1999. All rights reserved.
|Item Type:||Journal article|
|Faculties and Schools:||Faculty of Life and Health Sciences|
Faculty of Life and Health Sciences > School of Biomedical Sciences
|Research Institutes and Groups:||Biomedical Sciences Research Institute|
Biomedical Sciences Research Institute > Northern Ireland Centre for Food and Health (NICHE)
|Deposited By:||Mrs Alison Deehan|
|Deposited On:||14 Jan 2010 14:56|
|Last Modified:||01 Nov 2011 09:53|
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