title: Comparison of the total oxyradical scavenging capacity and oxygen radical absorbance capacity antioxidant assays.
abstract: Epidemiological studies have shown that phytochemicals in fruits and vegetables may decrease the incidence of cancer. The antioxidant activity of phytochemicals may be partially responsible for the reduced cancer risk. In this study, the antioxidant activity of several phytochemicals was compared using two different antioxidant assays: the oxygen radical absorbance capacity (ORAC) assay, which measures the decrease in fluorescence decay caused by antioxidants, and the total oxyradical scavenging capacity (TOSC) assay, which measures the decrease in ethylene production caused by antioxidants. TOSC and ORAC values were measured for 11 different phytochemicals, and values were expressed as micromol of Trolox equivalents/mg. As expected, a correlation was seen between the TOSC values and the ORAC values (R2 = 0.60). Quercitin, maritime pine bark extract (Pycnogenol, Horphag Research Ltd., Geneva, Switzerland), grape skin extract, and green tea polyphenols had the highest overall antioxidant activity of the 11 phytochemicals measured. Lemon fruit and citrus bioflavonoids had the lowest overall antioxidant activity. Rutin and alpha-lipoic acid had low ORAC values but high TOSC values when compared to the other phytochemicals. The correlation between the in vitro TOSC and ORAC antioxidant assays suggests that both assays may be useful in identifying phytochemicals with high antioxidant activity.
authors.affiliation: Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah 84602-5253, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Tomer
authors.forename: Lee D
authors.initials: LD
authors.lastname: McLeman
authors.forename: Seiga
authors.initials: S
authors.lastname: Ohmine
authors.forename: Philip M
authors.initials: PM
authors.lastname: Scherer
authors.forename: Byron K
authors.initials: BK
authors.lastname: Murray
authors.forename: Kim L
authors.initials: KL
authors.lastname: O'Neill
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology*; D002839:Chromans / Q000032:analysis; D002957:Citrus / Q000737:chemistry; D005030:Ethylenes / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005638:Fruit / Q000737:chemistry; D010636:Phenols / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D059808:Polyphenols; D017382:Reactive Oxygen Species / Q000737:chemistry*; D012431:Rutin / Q000494:pharmacology; D013662:Tea / Q000737:chemistry; D008063:Thioctic Acid / Q000494:pharmacology; D027843:Vitis / Q000737:chemistry
chemical_list: D000975:Antioxidants; D002839:Chromans; D005030:Ethylenes; D005419:Flavonoids; D016166:Free Radical Scavengers; D010636:Phenols; D010936:Plant Extracts; D059808:Polyphenols; D017382:Reactive Oxygen Species; D013662:Tea; D012431:Rutin; D008063:Thioctic Acid; C036216:ethylene; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid