Coumarin's Anti-Quorum Sensing Activity Can Be Enhanced When Combined with Other Plant-Derived Small Molecules

Molecules. 2021 Jan 3;26(1):208. doi: 10.3390/molecules26010208.

Abstract

Coumarins are class of natural aromatic compounds based on benzopyrones (2H-1-benzopyran-2-ones). They are identified as secondary metabolites in about 150 different plant species. The ability of coumarins to inhibit cell-to-cell communication in bacterial communities (quorum sensing; QS) has been previously described. Coumarin and its derivatives in plant extracts are often found together with other small molecules that show anti-QS properties too. The aim of this study was to find the most effective combinations of coumarins and small plant-derived molecules identified in various plants extracts that inhibit QS in Chromobacterium violaceum ATCC 31532 violacein production bioassay. The coumarin and its derivatives: 7-hydroxycoumarin, 7.8-dihydroxy-4-methylcoumarin, were included in the study. Combinations of coumarins with gamma-octalactone, 4-hexyl-1.3-benzenediol, 3.4.5-trimethoxyphenol and vanillin, previously identified in oak bark (Quercus cortex), and eucalyptus leaves (Eucalyptus viminalis) extracts, were analyzed in a bioassay. When testing two-component compositions, it was shown that 7.8-dihydroxy-4-methylcoumarin, 4-hexyl-1.3-benzendiol, and gamma-octalactone showed a supra-additive anti-QS effect. Combinations of all three molecules resulted in a three- to five-fold reduction in the concentration of each compound needed to achieve EC50 (half maximal effective concentration) against QS in C. violaceum ATCC 31532.

Keywords: Chromobacterium violaceum; QS inhibitors; coumarins; plant-derived molecules; quorum sensing.

MeSH terms

  • Chromobacterium / metabolism*
  • Coumarins* / chemistry
  • Coumarins* / isolation & purification
  • Coumarins* / pharmacology
  • Eucalyptus / chemistry*
  • Phytochemicals* / chemistry
  • Phytochemicals* / isolation & purification
  • Phytochemicals* / pharmacology
  • Plant Bark / chemistry*
  • Plant Leaves / chemistry*
  • Quercus / chemistry*
  • Quorum Sensing / drug effects*

Substances

  • Coumarins
  • Phytochemicals

Supplementary concepts

  • Chromobacterium violaceum