Urolithin

Urolithins are microflora metabolites of dietary ellagic acid derivatives, such as ellagitannins.^[1] They are produced in the gut, and found in the urine in the form of urolithin B glucuronide after absorption of ellagitannins-containing foods, such as pomegranate.^[2] During intestinal metabolism by bacteria, ellagitannins and punicalagins are converted to urolithins, which have unknown biological activity in vivo.^{[medical citation needed]}

Chemical structure of urolithin A.

Ellagitannins exhibit low bioavailability and are transformed in the gut to ellagic acid and its microbiota metabolites.^{[medical citation needed]} Urolithins are found in plasma mostly as glucuronides at low concentrations.^[3] Urolithins production is dependent on the gut microbiome enterotype. Individuals producing urolithins show a much higher abundance of the Clostridium leptum group of Firmicutes phylum than Bacteroides or Prevotella.^{[medical citation needed][4]}

Known molecules

• Urolithin A (3,8-Dihydroxyurolithin)
• Urolithin A glucuronide
• Urolithin B (3-Hydroxyurolithin)
• urolithin B glucuronide
• Urolithin D (3,4,8,9-Tetrahydroxyurolithin)

catabolic intermediates:

• Urolithin M-5
• Urolithin M-6
• Urolithin M-7
• Urolithin C (3,8,9-Trihydroxy urolithin)
• Urolithin E (2,3,8,10-Tetrahydroxy urolithin)

See also

• Pomegranate ellagitannins