Spectrophotometric assay of superoxide anion formed in Maillard reaction based on highly water-soluble tetrazolium salt

Anal Sci. 2002 Oct;18(10):1151-4. doi: 10.2116/analsci.18.1151.


A novel highly water-soluble tetrazolium salt, WST-1 (4-[3-(4-iodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate sodium salt), can be reduced to water-soluble formazan with a superoxide anion. Here, the WST-1 assay was applied to detect the superoxide anion generated during the Maillard reaction. A sample solution containing carbonyl compounds such as glyceraldehyde and glycolaldehyde (5 mM) and Na-acetyl-L-lysine (10 mM) was incubated for 2 days at 37 degrees C. The detection of a superoxide anion generated in the sample was performed by the WST-1 assay, and the result was compared with the cytochrome c assay. The reduction of WST-1 was almost perfectly (86-96%) inhibited by the addition of the superoxide dismutase (SOD). On the contrary, the reduction of cytochrome c was slightly (20-25%) inhibited by the addition of SOD. A similar result was observed for the addition of 4,5-dihydroxy-1,3-benzene disulfonic acid (Tiron). These results mean that the specificity of WST-1 to the superoxide anion was superior to that of cytochrome c. It was also possible to continuously monitor superoxide anion generation during the Maillard reaction by the coexistence of WST-1 in the reaction solution.

MeSH terms

  • Acetaldehyde / analogs & derivatives*
  • Acetaldehyde / chemistry
  • Cytochrome c Group / metabolism
  • Glyceraldehyde / chemistry
  • Lysine / analogs & derivatives*
  • Lysine / chemistry
  • Maillard Reaction*
  • Sensitivity and Specificity
  • Solubility
  • Solutions / chemistry
  • Spectrophotometry / methods*
  • Superoxide Dismutase / metabolism
  • Superoxides / analysis*
  • Superoxides / chemistry*
  • Superoxides / metabolism
  • Tetrazolium Salts / chemistry*
  • Water / chemistry*


  • 2-(4-iodophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium
  • Cytochrome c Group
  • Solutions
  • Tetrazolium Salts
  • Water
  • Superoxides
  • N(alpha)-acetyllysine
  • Glyceraldehyde
  • Superoxide Dismutase
  • Acetaldehyde
  • Lysine
  • glycolaldehyde