2001/09/18 by Boxin Ou, Maureen Hampsch‐Woodill, Ronald L. Prior · 7 citations
Biochemistry, Genetics and Molecular Biology · Chemistry · Medicine · #Absorbance #Antioxidant #Antioxidant capacity #Biochemistry #Chemistry #Chromatography #Electron Spin Resonance Studies #Fluorescein #Fluorescence #Free Radicals and Antioxidants #Oxygen radical absorbance capacity #Photochemistry #Phytochemicals and Antioxidant Activities #Radical
paper · doi:10.1021/jf010586o
openalex publication_date 2001/09/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
An improved method of oxygen radical absorbance capacity (ORAC) assay has been developed and validated using fluorescein (3',6'-dihydroxyspiro[isobenzofuran-1[3H],9'[9H]-xanthen]-3-one) as the fluorescent probe. Our results demonstrate that fluorescein (FL) is superior to B-phycoerythrin. The oxidized FL products induced by peroxyl radical were identified by LC/MS, and the reaction mechanism was determined to follow a classic hydrogen atom transfer mechanism. In addition, methodological and mechanistic comparison of ORAC(FL) with other widely used methods was discussed. It is concluded that, unlike other popular methods, the improved ORAC(FL) assay provides a direct measure of hydrophilic chain-breaking antioxidant capacity against peroxyl radical.