Free radical scavenging, DNA protection, and inhibition of lipid peroxidation mediated by uric acid

Beth Stinefelt, Stephen S. Leonard, Kenneth P. Blemings, Xianglin Shi, Hillar Klandorf

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


Uric acid (UA) has been proposed to be the dominant antioxidant in birds. The objective of this study was to investigate the quenching effect of varying concentrations of UA, including those found in avian plasma, on specific reactive oxygen species (ROS) and to determine the ability of UA to protect DNA and cellular membranes from ROS-mediated damage. Hydroxyl (asterisk inside a circle signOH) and superoxide (O2asterisk inside a circle sign -) radicals were detected by electron spin resonance (ESR) and their presence was reduced following addition of UA (p <0.05) in a concentration-dependent manner. UA inhibited hydroxyl-mediated DNA damage, indicated by the presence of more precise, dense bands of λ Hind III DNA after agarose gel electrophoresis and ethidium bromide staining (p <0.05). Lipid peroxidation of silica-exposed RAW 264.7 cell membranes was diminished (p <0.02) after addition of UA to the cell incubation mixture. These studies demonstrate that UA scavenges hydroxyl and superoxide radicals and protects against DNA damage and lipid peroxidation. These results indicate specific antioxidant protection that UA may afford birds against ROS-mediated damage.

Original languageEnglish
Pages (from-to)37-45
Number of pages9
JournalAnnals of Clinical and Laboratory Science
Issue number1
StatePublished - Dec 2005


  • DNA oxidation
  • Electron spin resonance
  • Lipid peroxidation
  • Oxidative stress
  • Uric acid

ASJC Scopus subject areas

  • Microbiology
  • Immunology and Allergy
  • Pathology and Forensic Medicine
  • Immunology
  • Molecular Biology
  • Hematology
  • Clinical Biochemistry
  • Medical Laboratory Technology


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