Identification of didecyldimethylammonium salts and salicylic acid as antimicrobial compounds in commercial fermented radish kimchi

J Agric Food Chem. 2015 Mar 25;63(11):3053-8. doi: 10.1021/jf5063588. Epub 2015 Mar 17.

Abstract

Daikon radish (Raphanus sativus) fermented with lactic acid bacteria, especially Leuconostoc or Lactobacillus spp., can be used to make kimchi, a traditional Korean fermented vegetable. Commercial Leuconostoc/radish root ferment filtrates are claimed to have broad spectrum antimicrobial activity. Leuconostoc kimchii fermentation products are patented as preservatives for cosmetics, and certain strains of this organism are reported to produce antimicrobial peptides (bacteriocins). We examined the antimicrobial agents in commercial Leuconostoc/radish root ferment filtrates. Both activity-guided fractionation with Amberlite XAD-16 and direct extraction with ethyl acetate gave salicylic acid as the primary agent with activity against Gram-negative bacteria. Further analysis of the ethyl acetate extract revealed that a didecyldimethylammonium salt was responsible for the Gram-positive activity. The structures of these compounds were confirmed by a combination of (1)H- and (13)C NMR, high-performance liquid chromatography, high-resolution mass spectrometry, and tandem mass spectrometry analyses. Radiocarbon dating indicates that neither compound is a fermentation product. No antimicrobial peptides were detected.

Keywords: Leuconostoc/radish root ferment filtrate; Raphanus sativus; antimicrobial peptides; bacteriocins; didecyldimethylammonium salts; salicylic acid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology
  • Fermentation
  • Food Microbiology
  • Gram-Negative Bacteria / drug effects
  • Leuconostoc / metabolism*
  • Quaternary Ammonium Compounds / chemistry*
  • Quaternary Ammonium Compounds / isolation & purification
  • Quaternary Ammonium Compounds / pharmacology
  • Raphanus / chemistry
  • Raphanus / metabolism
  • Raphanus / microbiology*
  • Salicylic Acid / chemistry*
  • Salicylic Acid / isolation & purification
  • Salicylic Acid / pharmacology

Substances

  • Anti-Bacterial Agents
  • Quaternary Ammonium Compounds
  • Salicylic Acid
  • didecyldimethylammonium