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Free Radical Scavenging Properties of Wheat Extracts

2002; American Chemical Society; Volume: 50; Issue: 6 Linguagem: Inglês

10.1021/jf010964p

1520-5118

Liangli Yu, Scott D. Haley, Jonathan Perret, Mary Harris, John J. Wilson, Ming Qian,

Food Quality and Safety Studies

Three hard winter wheat varieties (Akron, Trego, and Platte) were examined and compared for their free radical scavenging properties and total phenolic contents (TPC). Free radical scavenging properties of wheat grain extracts were evaluated by spectrophotometric and electron spin resonance (ESR) spectrometry methods against stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH•) and radical cation ABTS•+ (2,2'-azino-di[3-ethylbenzthiazoline sulfonate]). The results showed that the three wheat extracts differed in their capacities to quench or inhibit DPPH• and ABTS•+. Akron showed the greatest activity to quench DPPH radicals, while Platte had the highest capacity against ABTS•+. The ED50 values of wheat extracts against DPPH radicals were 0.60 mg/mL for Akron, 7.1 mg/mL for Trego, and 0.95 mg/mL for Platte under the experimental conditions. The trolox equivalents against ABTS•+ were 1.31 ± 0.44, 1.08 ± 0.05, and 1.91 ± 0.06 μmol/g of grain for Akron, Trego, and Platte wheat, respectively. ESR results confirmed that wheat extracts directly reacted with and quenched free radicals. The TPC were 487.9−927.8 μg gallic acid equivalents/g of grain. No correlation was observed between TPC and radical scavenging capacities for DPPH• and ABTS•+ (p = 0.15 and p > 0.5, respectively). Keywords: Wheat; radical scavenging; antioxidant; phenolic; ESR; ABTS•+; DPPH