Isolation and identification of DPPH radical scavenging compounds in Kurosu (Japanese unpolished rice vinegar)

J Agric Food Chem. 2002 Oct 23;50(22):6501-3. doi: 10.1021/jf020458f.


Dihydroferulic acid (DFA) and dihydrosinapic acid (DSA) were isolated from Kurosu (unpolished rice vinegar) as the major constituents responsible for Kurosu's radical scavenging activity. The levels of antioxidative activity of DFA and DSA in DPPH radical scavenging were higher than those of their respective structurally related compounds, ferulic acid and sinapic acid. The concentrations of DFA and DSA were low in common rice vinegar (polished rice vinegar), suggesting that Kurosu is more advantageous than rice vinegars as an antioxidative food item. As the concentrations of DFA and DSA were low in unpolished rice, too, these acids are thought to be produced in Kurosu through the process of the fermentation from ferulic acid and sinapic acid, respectively.

MeSH terms

  • Acetic Acid / chemistry*
  • Antioxidants / analysis
  • Antioxidants / chemistry
  • Antioxidants / isolation & purification*
  • Biphenyl Compounds
  • Coumaric Acids / analysis
  • Coumaric Acids / chemistry
  • Coumaric Acids / isolation & purification
  • Fermentation
  • Free Radical Scavengers / analysis
  • Free Radical Scavengers / chemistry
  • Free Radical Scavengers / isolation & purification*
  • Free Radicals / metabolism
  • Japan
  • Oryza / chemistry*
  • Picrates / metabolism*


  • Antioxidants
  • Biphenyl Compounds
  • Coumaric Acids
  • Free Radical Scavengers
  • Free Radicals
  • Picrates
  • sinapinic acid
  • ferulic acid
  • 1,1-diphenyl-2-picrylhydrazyl
  • Acetic Acid