title: Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria.
abstract: OBJECTIVE
  To determine structure-function relationships of antibacterial phenolic acids and their metabolites produced by lactic acid bacteria (LAB).
  
  
  RESULTS
  Minimum inhibitory concentrations (MICs) of 6 hydroxybenzoic and 6 hydroxycinnamic acids were determined with Lactobacillus plantarum, Lactobacillus hammesii, Escherichia coli and Bacillus subtilis as indicator strains. The antibacterial activity of phenolic acids increased at lower pH. A decreasing number of hydroxyl groups enhanced the activity of hydroxybenzoic acids, but had minor effects on hydroxycinnamic acids. Substitution of hydroxyl groups with methoxy groups increased the activity of hydroxybenzoic, but not of hydroxycinnamic, acid. Metabolism of chlorogenic, caffeic, p-coumaric, ferulic, protocatechuic or p-hydroxybenzoic acids by L. plantarum, L. hammesii, Lactobacillus fermentum and Lactobacillus reuteri was analysed by LC-DAD-MS. Furthermore, MICs of substrates and metabolites were compared. Decarboxylated and/or reduced metabolites of phenolic acids had a lower activity than the substrates. Strain-specific metabolism of phenolic acids generally corresponded to resistance.
  
  
  CONCLUSIONS
  The influence of lipophilicity on the antibacterial activity of hydroxybenzoic acids is stronger than that of hydroxycinnamic acids. Metabolism of phenolic acids by LAB detoxifies phenolic acids.
  
  
  CONCLUSIONS
  Results allow the targeted selection of plant extracts for food preservation, and selection of starter cultures for fermented products.
authors: Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
authors: A F
authors: AF
authors: Sánchez-Maldonado
authors: A
authors: A
authors: Schieber
authors: M G
authors: MG
authors: Gänzle
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D001412:Bacillus subtilis / Q000187:drug effects; D003373:Coumaric Acids / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D007778:Lactobacillus / Q000187:drug effects / Q000378:metabolism*; D008826:Microbial Sensitivity Tests; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D003373:Coumaric Acids; D062385:Hydroxybenzoates; C017616:phenolic acid