Ellagic acid is a

polyphenol Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some o ...

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 backwards because it can be obtained from ''noix de galle'' ( galls), and to distinguish it from ''acide gallique'' (

gallic acid Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C6 H2( OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. I ...

). The molecule structure resembles to that of two gallic acid molecules being assembled "head to tail" and bound together by a C–C bond (as in

biphenyl Biphenyl (also known as diphenyl, phenylbenzene, 1,1′-biphenyl, lemonene or BP) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one ...

, or in diphenic acid) and two

lactone Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the co ...

links (cyclic

carboxylic ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides a ...

s).

Metabolism

Biosynthesis

Plants produce ellagic acid from hydrolysis of tannins such as

ellagitannin The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl ...

and geraniin.

Biodegradation

Urolithin Urolithins are Microbiota, microflora metabolites of dietary ellagic acid derivatives, such as ellagitannins. They are produced in the Gastrointestinal tract, gut, and found in the urine in the form of urolithin B glucuronide after absorption of e ...

s 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 urolintins.

History

Ellagic acid was first discovered by chemist

Henri Braconnot Henri Braconnot (29 May 1780 – 13 January 1855) was a French chemist and pharmacist. He was born in Commercy, his father being a counsel at the local parliament. At the death of his father, in 1787, Henri began his instruction in an elementar ...

in 1831.

Maximilian Nierenstein Maximilian Nierenstein (also known as Moses Max Nierenstein or Max Nierenstein; 1877–1946) was a professor of biochemistry at the University of Bristol. He is known for the Nierenstein reaction, an organic reaction describing the conversion of ...

prepared this substance from algarobilla, dividivi, oak bark,

pomegranate The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punicoideae, that grows between tall. The pomegranate was originally described throughout the Mediterranean Basin, Mediterranean re ...

, myrabolams, and valonea in 1905. He also suggested its formation from galloyl-glycine by ''

Penicillium ''Penicillium'' () is a genus of ascomycetous fungi that is part of the mycobiome of many species and is of major importance in the natural environment, in food spoilage, and in food and drug production. Some members of the genus produce pe ...

'' in 1915. Julius Löwe was the first person to synthesize ellagic acid by heating

with arsenic acid or silver oxide.

Natural occurrences

Ellagic acid is found in oak species such as the North American white oak (''

Quercus alba An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ...

'') and European red oak (''

Quercus robur ''Quercus robur'', commonly known as common oak, pedunculate oak, European oak or English oak, is a species of flowering plant in the beech and oak family, Fagaceae. It is a large tree, native to most of Europe west of the Caucasus. It is widel ...

''). The macrophyte '' Myriophyllum spicatum'' produces ellagic acid. Ellagic acid can be found in the medicinal mushroom '' Phellinus linteus''.

In food

The highest levels of ellagic acid are found in raw

chestnuts The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelated ...

walnut A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, '' Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true ...

s, pecans,

cranberries Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus ''Oxycoccus'' of the genus ''Vaccinium''. In Britain, cranberry may refer to the native species ''Vaccinium oxycoccos'', while in North America, cranberry ...

raspberries The raspberry is the edible fruit of a multitude of plant species in the genus ''Rubus'' of the rose family, most of which are in the subgenus '' Idaeobatus''. The name also applies to these plants themselves. Raspberries are perennial with ...

, strawberries, and grapes, as well as distilled beverages. It is also found in

peach The peach (''Prunus persica'') is a deciduous tree first domesticated and cultivated in Zhejiang province of Eastern China. It bears edible juicy fruits with various characteristics, most called peaches and others (the glossy-skinned, non-f ...

es and pomegranates.

Research and health claims

Ellagic acid has been marketed as a dietary supplement with various claimed benefits against cancer, heart disease, and other diseases. In the 21st century, numerous U.S.-based supplement companies received FDA warning letters for promoting ellagic acid with false anti-disease claims that violate the Federal Food, Drug, and Cosmetic Act. Ellagic acid has been identified by the FDA as a "fake cancer 'cure'". There is no scientific evidence to support the claims that ellagic acid can treat or prevent cancer.

References

{{Xenobiotic-sensing receptor modulators Antioxidants Biphenyls Coumarins Ellagitannins Health fraud Isocoumarins Lactones Pomegranate ellagitannins Pyrogallols