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 Hexahydroxydiphenic acid is an organic compound with the formula HO)3C6HCO2Hsub>2. It is the oxidatively coupled derivative of gallic acid It is a white solid, although samples are typically brown owing to oxidation. left, 142px, Ellagic 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'' (

gall Galls (from the Latin , 'oak-apple') or ''cecidia'' (from the Greek , anything gushing out) are a kind of swelling growth on the external Tissue (biology), tissues of plants, fungi, or animals. Plant galls are abnormal outgrowths of plant tissu ...

s), 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 ...

). 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, 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. Glyceride ...

s).

Metabolism

Biosynthesis

Plants produce ellagic acid from hydrolysis of

tannins Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner' ...

such as ellagitannin and

geraniin Geraniin is a dehydroellagitannin found in geraniums. It is found for instance in ''Geranium thunbergii'', which is one of the most popular folk medicines and also an official antidiarrheic drug in Japan. It can also be found in the rind of ''Neph ...

Biodegradation

Urolithins are

gut flora Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut ...

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 in 1831. Maximilian Nierenstein 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 ...

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

with

arsenic acid Arsenic acid or trihydrogen arsenate is the chemical compound with the formula . More descriptively written as , this colorless acid is the arsenic analogue of phosphoric acid. Arsenate and phosphate salts behave very similarly. Arsenic acid as ...

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 wid ...

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

Phellinus linteus ''Phellinus linteus'' (Japanese "meshimakobu", Chinese "song gen", Korean "sanghwang", English "mesima", American English "black hoof mushroom") is a mushroom. It is shaped like a hoof, has a bitter taste, and in the wild grows on mulberry tree ...

''.

In food

The highest levels of ellagic acid are found in raw chestnuts,

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 tru ...

pecan The pecan (''Carya illinoinensis'') is a species of hickory native to the southern United States and northern Mexico in the region of the Mississippi River. The tree is cultivated for its seed in the southern United States, primarily in Georgia, ...

s, cranberries, raspberries,

strawberries The garden strawberry (or simply strawberry; ''Fragaria × ananassa'') is a widely grown Hybrid (biology), hybrid species of the genus ''Fragaria'', collectively known as the strawberries, which are cultivated worldwide for their fruit. The f ...

, and grapes, as well as

distilled beverage Liquor (or a spirit) is an alcoholic drink produced by distillation of grains, fruits, vegetables, or sugar, that have already gone through alcoholic fermentation. Other terms for liquor include: spirit drink, distilled beverage or hard ...

s. 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- ...

es and

pomegranates 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 region. It was introduc ...

Research and health claims

Ellagic acid has been marketed as a

dietary supplement A dietary supplement is a manufactured product intended to supplement one's diet by taking a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients either extracted from food sources or that are synthetic in orde ...

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 Scientific evidence is evidence that serves to either support or counter a scientific theory or hypothesis, although scientists also use evidence in other ways, such as when applying theories to practical problems. "Discussions about empirical e ...

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