Other Thousands of Previously Unknown Bile Acids Discovered. Researchers have uncovered thousands of bile acids that the gut microbiome uses to communicate with the rest of the body. (Mar 2024) The underappreciated diversity of bile acid modifications

Michael Harrop

Active member
Jul 6, 2023


  • Mining of public, untargeted LC-MS/MS data reveals a large diversity of bile acids
  • This work created an MS/MS spectral library resource of modified bile acids
  • Polyamine biosynthetic pathway-derived metabolites amidated to bile acids discovered
  • American-to-Mediterranean diet transition altered levels of polyamine bile amidates


The repertoire of modifications to bile acids and related steroidal lipids by host and microbial metabolism remains incompletely characterized. To address this knowledge gap, we created a reusable resource of tandem mass spectrometry (MS/MS) spectra by filtering 1.2 billion publicly available MS/MS spectra for bile-acid-selective ion patterns. Thousands of modifications are distributed throughout animal and human bodies as well as microbial cultures. We employed this MS/MS library to identify polyamine bile amidates, prevalent in carnivores. They are present in humans, and their levels alter with a diet change from a Mediterranean to a typical American diet. This work highlights the existence of many more bile acid modifications than previously recognized and the value of leveraging public large-scale untargeted metabolomics data to discover metabolites. The availability of a modification-centric bile acid MS/MS library will inform future studies investigating bile acid roles in health and disease.

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