Castalagin is an

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 ...

, a type of hydrolyzable tannin, found in oak and

chestnut 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 unrel ...

wood and in the stem barks of '' Anogeissus leiocarpus'' and ''

Terminalia avicennoides ''Terminalia avicennioides'' ( bm, Wolobugun) is a tree species in the genus '' Terminalia'' found in West Africa. Castalagin and flavogallonic acid dilactoneThe use of microfluorometric method for activity-guided isolation of antiplasmodial com ...

''. Castalagin is the

diastereomer In stereochemistry, diastereomers (sometimes called diastereoisomers) are a type of stereoisomer. Diastereomers are defined as non-mirror image, non-identical stereoisomers. Hence, they occur when two or more stereoisomers of a compound have di ...

of vescalagin in C-1 of the glycosidic chain. Castalagin/ vescalagin are the most abundant ellagitannins in white wine stored in

oak barrels Oak is used in winemaking to vary the color, flavor, tannin profile and texture of wine. It can be introduced in the form of a barrel during the fermentation or aging periods, or as free-floating chips or staves added to wine fermented in a vess ...

. During aging of wines, these two compounds were progressively extracted from the wood and were transformed into new derivatives by chemical reactions. Therefore, castalagin/ vescalagin and their derivatives contribute to the color and the taste of wines and spirits stored in oak barrels.

Sources

Castalagin was first isolated in

Fagaceae The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as ever ...

family woody species : ''Quercus'' (oak) and ''

Castanea 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 unrelate ...

'' (chestnut) by Walter Mayer and co-workers (1967). In some chestnut species, such as ''

Castanea sativa ''Castanea sativa'', the sweet chestnut, Spanish chestnut or just chestnut, is a species of tree in the family Fagaceae, native to Southern Europe and Asia Minor, and widely cultivated throughout the Temperate climate, temperate world. A substa ...

'', heartwood could contain 63 mg of castalagin/ vescalagin per gram of dry wood. In some wines, these two isomers represent about 40 to 70% of total ellagitannins.

Biosynthesis

In some plants including oak and chestnut, the ellagitannins are formed from

1,2,3,4,6-pentagalloyl-glucose 1,2,3,4,6-Pentagalloylglucose is the pentagallic acid ester of glucose. It is a gallotannin and the precursor of ellagitannins. Pentagalloyl glucose can precipitate proteins, including human salivary α-amylase. Natural occurrence 1,2,3,4,6-Pe ...

and further elaborated via oxidative dehydrogenation ( tellimagrandin II and casuarictin formations). After conversion of casuarictin to pedunculagin, the pyranose ring of the

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

opens and the family of compounds including casuariin, casuarinin, castalagin, and castlin, vescalagin and vescalin forms. Castalagin thus forms from a penta galloyl-glucose structure. Castalagin and vescalagin (1,2,3,5- nonahydroxytriphenoyl-4,6- hexahydroxydiphenoyl-glucoses) can be further polymerized in their corresponding

dimer Dimer may refer to: * Dimer (chemistry), a chemical structure formed from two similar sub-units ** Protein dimer, a protein quaternary structure ** d-dimer * Dimer model, an item in statistical mechanics, based on ''domino tiling'' * Julius Dimer ( ...

s roburin A and roburin D, and 33-carboxy-33-deoxyvescalagin.

Derivatives

Castalagin and other related ellagitanins polymerizes or forms complexes with anthyocyanins and

flavonoids Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

. The flavono-ellagitannin known as

acutissimin A Acutissimin A is a flavono-ellagitannin, a type of tannin formed from the linking of a flavonoid with an ellagitannin. In 2003, scientists at Institut Européen de Chimie et Biologie in Pessac, France found that when the oak tannin vescalagin in ...

is created when the oak tannin vescalagin interacts with

catechin Catechin is a flavan-3-ol, a type of secondary metabolite providing antioxidant roles in plants. It belongs to the subgroup of polyphenols called flavonoids. The name of the catechin chemical family derives from ''catechu'', which is the tanni ...

flavan-3-ol Flavan-3-ols (sometimes referred to as flavanols) are a subgroup of flavonoids. They are derivatives of flavans that possess a 2-phenyl-3,4-dihydro-2''H''-chromen-3-ol skeleton. Flavan-3-ols are structurally diverse and include a range of comp ...

found in wine. Grandinin is a castalagin glycoside which forms by binding to the pentose lyxose. Chemical hydrolysis of Castalagin/ Vescalagin produces vescalene and vescalin which are potent topoisomerase II inhibitors.

References

{{Ellagitannin Ellagitannins