Measuring Antioxidant Capacity Using the ORAC and TOSC Assays
Recent epidemiological studies have shown that there may be a link between oxidative stress and the development of several types of chronic diseases. Studies have also shown that diets rich in fruits and vegetables may decrease the incidence of cancer and other chronic diseases. The antioxidant activity of the phytochemicals these foods contain may be partially responsible for the decreased incidence of these diseases in people who regularly consume them. While there are several assays currently used to assess the antioxidant activity of phytochemicals and other antioxidant compounds, two are reviewed here in detail. The first is the oxygen radical absorbance capacity (ORAC) assay, which measures the decrease in fluorescence decay caused by antioxidants, and the second is the total oxyradical scavenging capacity (TOSC) assay, which measures the decrease in ethylene gas production caused by the inhibition of the thermal hydrolysis of ABAP (2,2′-Azobis(2-methyl-(propionamidine) dihydrochloride) by KMBA (α-keto-γ-(methylthio)butyric acid sodium salt) in the presence of antioxidant compounds. These two assays are discussed here, with an in depth review of their methodology and correlation.
Key wordsORAC Oxygen radical absorbance capacity assay TOSC Total oxyradical scavenging capacity assay Antioxidant Phytochemical Oxidative stress Fluorescein Trolox equivalents
- 1.Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods (2007); Nutrient Data Laboratory, Agricultural Research Service, US Department of Agriculture, United States Department of Agriculture.Google Scholar
- 6.Lang AE, Lozano AM (1998) Parkinson’s disease. First of two parts. N Eng J Med 339:111–114Google Scholar
- 7.Packer L, Colman C (1999) The anti-oxidant miracle. Wiley, New YorkGoogle Scholar
- 9.Halliwell B, Gutteridge JMC, Cross CE (1992) Free Radicals, antioxidants, and human disease: where are we now? J Clin Lab Med 119:598–620Google Scholar
- 10.Tomer DP (2003) Measuring parameters that are important in cancer prevention and treatment: assessing antioxidant activity and angiogenesis. Brigham Young University, Master’s ThesisGoogle Scholar
- 11.McLeman LD (2004) Evidence of synergistic intracellular antioxidant networking and antioxidant regulation of cellular lipid peroxidation in HL-60 acute promyelogenous leukemia. Master’s Thesis. Brigham Young University. 1-37.Google Scholar
- 12.O’Neill K, Murray B (2002) Power plants. Woodland Publishing, UtahGoogle Scholar
- 22.Pellegrini N, Del Rio D, Colombi B, Bianchi M, Brighenti F (2003) Application of the 2, 2’-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation assay to a flow injection system for the evaluation of antioxidant activity of some pure compounds and beverages. J Agric Food Chem 51:260–264PubMedCrossRefGoogle Scholar
- 25.Gorinstein S, Martin-Belloso O, Katrich E, Lojek A, Ciz M, Gligelmo-Miguel N, Haruenkit R, Park YS, Jung ST, Trakhtenberg S (2003) Comparison of the contents of the main biochemical compounds and the antioxidant activity of some Spanish olive oils as determined by four different radical scavenging tests. J Nutr Biochem 14:154–159PubMedCrossRefGoogle Scholar
- 27.Prior RL, Hoang H, Gu L, Wu X, Bacchiocca M, Howard L, Hampsch-Woodill M, Huang D, Ou B, Jacob R (2003) Assays for hydrophilic and lipophilic antioxidant capacity (oxygen radical absorbance capacity (ORAC(FL))) of plasma and other biological and food samples. J Agric Food Chem 51:3273–3279PubMedCrossRefGoogle Scholar
- 30.Adapted from http://www.bmglabtech.com/application-notes/fluorescence-intensity/orac-148.cfm. Consulted 7/9/08.
- 34.Lichtenthaler R, Rodrigues RB, Maia JGS, Papagiannopoulos M, Fabricius H, Marx F (2005) Total oxidant scavenging capacities of Euterpe oleracea Mart. (Acai) fruits. Int J Food Sci Nutr 56(1):53–64Google Scholar