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The ellagitannins are a diverse class of
hydrolyzable tannin A hydrolyzable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids. At the center of a hydrolyzable tannin molecule, there is a carbohydrate (usually D-glucos ...
s, a type of polyphenol formed primarily from the oxidative linkage of
galloyl 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. It ...
groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their
galloyl 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. It ...
groups are linked through C-C bonds, whereas the galloyl groups in gallotannins are linked by depside bonds. Ellagitannins contain various numbers of
hexahydroxydiphenoyl 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. ...
units, as well as
galloyl 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. It ...
units and/or sanguisorboyl units bounded to sugar moiety. In order to determine the quantity of every individual unit, the hydrolysis of the extracts with
trifluoroacetic acid Trifluoroacetic acid (TFA) is an organofluorine compound with the chemical formula CF3CO2H. It is a structural analogue of acetic acid with all three of the acetyl group's hydrogen atoms replaced by fluorine atoms and is a colorless liquid with ...
in methanol/water system is performed. Hexahydroxydiphenic acid, created after hydrolysis, spontaneously lactonized to ellagic acid, and
sanguisorbic acid Sanguisorbic acid is a constituent of some ellagitannins. It is constituted by a hexahydroxydiphenic acid unit linked by an O-C bond to a gallic acid. The differences with its isomers, valoneic acid and nonahydroxytriphenic acid, are that the hydro ...
to sanguisorbic acid dilactone, while gallic acid remains intact. Ellagitannins generally form macrocycles, whereas gallotannins do not.


Examples

*
Castalagin Castalagin is an ellagitannin, a type of hydrolyzable tannin, found in oak and chestnut wood and in the stem barks of '' Anogeissus leiocarpus'' and '' Terminalia avicennoides''. Castalagin is the diastereomer of vescalagin in C-1 of the glycosid ...
* Castalin *
Casuarictin Casuarictin is an ellagitannin, a type of hydrolysable tannin. It can be found in ''Casuarina'' and '' Stachyurus'' species.Tannins of Casuarina and Stachyurus species. I: Structures of pendunculagin, casuarictin, strictinin, casuarinin, casuariin, ...
*
Grandinin Grandinin is an ellagitannin. It can be found in ''Melaleuca quinquenervia'' leavesPolyphenols of Melaleuca quinquenervia leaves - pharmacological studies of grandinin. Moharram F. A., Marzouk M. S., El-Toumy S. A. A., Ahmed A. A. E. and Aboutabl ...
* Oenothein B from Willowherbs (Epilobium spp.) *
Roburin A Roburin A is a tannin found in oak wood ('' Quercus robur'' and '' Quercus petraea'' or '' Quercus alba'') or oak cork ('' Quercus suber''). It is a dimeric compound, composed of two vescalagin subunits probably linked through an ether bond betwe ...
*
Tellimagrandin II Tellimagrandin II is the first of the ellagitannins formed from 1,2,3,4,6-pentagalloyl-glucose. It can be found in '' Geum japonicum'' and '' Syzygium aromaticum'' (clove).Purification and Characterization of Eugeniin as an Anti-herpesvirus Compoun ...
*
Terflavin B Terflavin B is an ellagitannin, a type of hydrolysable tannin. It can be found in ''Myrobalanus chebula'' (''Terminalia chebula''), the black chebulic, and in ''Terminalia catappa'', the Indian almond. It is formed from a nonahydroxytriphenic acid ...
*
Vescalagin Castalagin is an ellagitannin, a type of hydrolyzable tannin, found in oak and chestnut wood and in the stem barks of '' Anogeissus leiocarpus'' and '' Terminalia avicennoides''. Castalagin is the diastereomer of vescalagin in C-1 of the glycosi ...
*
Pomegranate ellagitannin The pomegranate ellagitannins, which include punicalagin isomers, are ellagitannins found in the sarcotestas, rind (peel), bark or heartwood of pomegranates (''Punica granatum''). Chemistry As the chemistry of punicalagins became known it was ...
s, many compounds **
Punicalagin Punicalagin is an ellagitannin, a type of phenolic compound. It is found as alpha and beta isomers in pomegranates (''Punica granatum''), ''Terminalia catappa'', '' Terminalia myriocarpa'', and in '' Combretum molle'', the velvet bushwillow, a pla ...
**
Punicalin Punicalin is an ellagitannin. It can be found in ''Punica granatum'' (pomegranate) or in the leaves of ''Terminalia catappa'', a plant used to treat dermatitis and hepatitis. It is also reported in '' Combretum glutinosum'', all three species bein ...


Metabolism


Degradation

Urolithin Urolithins are microflora metabolites of dietary ellagic acid derivatives, such as ellagitannins. 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 ...
s, such as
urolithin A Urolithin A is a metabolite compound resulting from the transformation of ellagitannins by the gut bacteria. It belongs to the class of organic compounds known as benzo-coumarins or dibenzo-α-pyrones. Its precursors – ellagic acids and el ...
, are microflora human metabolites of dietary ellagic acid derivatives.


Natural occurrences

Ellagitannins are reported in
dicotyledon The dicotyledons, also known as dicots (or, more rarely, dicotyls), are one of the two groups into which all the flowering plants (angiosperms) were formerly divided. The name refers to one of the typical characteristics of the group: namely, t ...
eous angiospermes, and notably in species in the order
Myrtales The Myrtales are an order of flowering plants placed as a sister to the eurosids II clade as of the publishing of the ''Eucalyptus grandis'' genome in June 2014. The APG III system of classification for angiosperms still places it within the eu ...
, such as the pomegranate.


See also

*
Urolithin Urolithins are microflora metabolites of dietary ellagic acid derivatives, such as ellagitannins. 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 ...
-
Urolithin A Urolithin A is a metabolite compound resulting from the transformation of ellagitannins by the gut bacteria. It belongs to the class of organic compounds known as benzo-coumarins or dibenzo-α-pyrones. Its precursors – ellagic acids and el ...
* Polyphenols *
List of antioxidants in food This is a list of antioxidants naturally occurring in food. Vitamin C and vitamin E – which are ubiquitous among raw plant foods – are confirmed as dietary antioxidants, whereas vitamin A becomes an antioxidant following metabolism of ...


References


Further reading

* Quideau, Stéphane (editor). ''Chemistry and Biology of Ellagitannins: An Underestimated Class of Bioactive Plant Polyphenols'', 2009, World Scientific Publishing.
Table of Contents Preface

Chapter 1


External links


Tannin Chemistry
(Tannin Handbook, Copyright 1998, 2002, 2011, Ann E. Hagerman) {{Ellagitannin Aromatase inhibitors