title: Validation of Analytical Methods for Plasma Total Antioxidant Capacity by Comparing with Urinary 8-Isoprostane Level.
abstract: Although several analytical methods for measuring total antioxidant capacity (TAC) have been applied to biological samples, there were often dissimilar results due to the different principles of methods applied. Thus, this study aimed to validate four conventional analytical methods for measuring plasma TAC, including the ABTS assay, DPPH assay, FRAP assay, and ORAC assay, by comparing with urinary 8-isoprostane concentration. In addition, TAC results were compared with antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase in erythrocyte, and catalase in plasma. Plasma TAC measure by ABTS assay was strongly correlated with the result by FRAP assay. Plasma TAC by FRAP and ORAC assays were negatively correlated with erythrocyte SOD activity. The agreement among the four TAC assay methods and 8-isoprostane was determined using 95% prediction limits of linear regression, expressed as the mean of 8-isoprostane ± 95% prediction limits. The ABTS method better agreed with 8-isoprostane than the other methods, demonstrating narrow prediction of limits. Furthermore, only plasma TAC determined by the ABTS assay was inversely correlated with urinary 8-isoprostane (r= -0.35,p< 0.05). In summary, the ABTS assay would be an appropriate method to measure overall plasma antioxidant capacity and predict the body's antioxidant status.
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Sang Gil
authors: SG
authors: Lee
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Taoran
authors: T
authors: Wang
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Terrence M
authors: TM
authors: Vance
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Patrice
authors: P
authors: Hubert
authors: Department of Food Science and Biotechnology, Kyung Hee University, Yongin 17104, Republic of Korea.
authors: Dae-Ok
authors: DO
authors: Kim
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Sung I
authors: SI
authors: Koo
authors: Department of Nutritional Sciences, University of Connecticut, Storrs, CT 06269-4017, USA.
authors: Ock K
authors: OK
authors: Chun
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D002374:Catalase / Q000097:blood; D015237:Dinoprost / Q000031:analogs & derivatives* / Q000652:urine; D004912:Erythrocytes / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000097:blood / Q000378:metabolism; D006801:Humans; D010084:Oxidation-Reduction; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D000975:Antioxidants; C075750:8-epi-prostaglandin F2alpha; D015237:Dinoprost; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: 8-isoprostane; ABTS assay; FRAP assay; Total antioxidant capacity; superoxide dismutase