Human Metabolome Database (HMDB): Urolithin A belongs to the class of organic compounds known as coumarins and derivatives. These are polycyclic aromatic compounds containing a 1-benzopyran moiety with a ketone group at the C2 carbon atom (1-benzopyran-2-one). Ellagitannins are hydrolyzed in the gut to release ellagic acid, which is further processed by the gut microflora into urolithins through the loss of one of its two lactones and by successive removal of hydroxyl groups. Urolithin A is not known to be found in any food source. Urolithin A is an extremely weak basic (essentially neutral) compound (based on its pKa). The conversion of the ellagic acids into urolithin A depends on individual microflora composition and can vary significantly. Ellagic acid itself results from the hydrolysis of ellagitannins in the gut in the presence of water. Since the 2000s, urolithin A has been subject of preliminary studies regarding its possible biological effects. This effect has been observed in different animal species (mammalian cells, rodents and C. elegans).