Ellagic acid
Ellagic acid is a polyphenol found in numerous fruits and vegetables. It is the dilactone of hexahydroxydiphenic acid.
Name
The name comes from the French term acide ellagique, from the word galle spelled backward because it can be obtained from noix de galle, and to distinguish it from acide gallique. The molecular structure resembles to that of two gallic acid molecules being assembled "head to tail" and bound together by a C–C bond and two lactone links.Metabolism
Biosynthesis
Plants produce ellagic acid from hydrolysis of tannins such as ellagitannin and geraniin.Biodegradation
Urolithins are gut flora human metabolites of dietary ellagic acid derivatives. Ellagic acid has low bioavailability, with 90% remaining unabsorbed from the intestines until metabolized by microflora to the more bioavailable urolithins.History
Ellagic acid was first discovered by chemist Henri Braconnot in 1831. Maximilian Nierenstein prepared this substance from algarobilla, dividivi, oak bark, pomegranate, myrabolams, and valonea in 1905. He also suggested its formation from galloyl-glycine by Penicillium in 1915. Julius Löwe was the first person to synthesize ellagic acid by heating gallic acid with arsenic acid or silver oxide.Natural occurrences
Ellagic acid is found in edible nuts. It is also found in oak species such as the North American white oak and European red oak.The macrophyte Myriophyllum spicatum produces ellagic acid.
Ellagic acid can be found in the medicinal mushroom Phellinus linteus.