130px, Castalagin is a representative ellagitannin, characterized by coupled gallic acid substituents
The ellagitannins are a diverse class of
hydrolyzable tannin
A hydrolysable 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 hydrolysable tannin molecule, there is a carbohydrate (usually D-gluc ...
s, a type of
polyphenol
Polyphenols () are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as ...
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 groups are linked through C-C bonds, whereas the galloyl groups in gallotannins are linked by
depside bonds.
Ellagitannins contain various numbers of
hexahydroxydiphenoyl units, as well as
galloyl 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 a synthetic organofluorine compound with the chemical formula CF3CO2H. It belongs to the subclass of per- and polyfluoroalkyl substances (PFASs) known as ultrashort-chain perfluoroalkyl acids (PFAAs). TFA is not ...
in
methanol
Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical compound and the simplest aliphatic Alcohol (chemistry), alcohol, with the chemical formula (a methyl group linked to a hydroxyl group, often ab ...
/water system is performed. Hexahydroxydiphenic acid, created after hydrolysis, spontaneously lactonized to
ellagic acid, and
sanguisorbic acid to sanguisorbic acid dilactone, while
gallic acid remains intact.
Ellagitannins generally form
macrocycles, whereas gallotannins do not.
Examples
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Castalagin
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Castalin
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Casuarictin
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Grandinin
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Oenothein B from Willowherbs (Epilobium spp.)
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Roburin A
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Tellimagrandin II
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Terflavin B
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Vescalagin
Castalagin is an ellagitannin, a type of hydrolyzable tannin, found in oak and chestnut wood and in the stem barks of ''Terminalia leiocarpa'' and ''Terminalia avicennoides''.
Castalagin is the diastereomer of vescalagin in C-1 of the glycosidic c ...
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Pomegranate ellagitannin
The pomegranate ellagitannins, which include punicalagin isomers, are ellagitannins found in the sarcotestas, rind (peel), bark or heartwood of the pomegranate fruit (''Punica granatum'').
Chemistry
As the chemistry of punicalagins became kno ...
s, many compounds
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Punicalagin
Punicalagin (''Pyuni-cala-jen'') 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 ...
**
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 ...
Metabolism
Degradation
Urolithins, such as
urolithin A, 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, ...
eous angiospermes, and notably in species in the order
Myrtales, such as the
pomegranate
The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punica, Punicoideae, that grows between tall. Rich in symbolic and mythological associations in many cultures, it is thought to have o ...
.
See also
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Urolithin -
Urolithin A
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Polyphenol
Polyphenols () are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as ...
s
*
List of antioxidants in food
Other links
MALDI-TOF Mass Spectrometric Analysis of Hydrolysable Tannins
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
Wood extracts