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 unrelate ...

wood and in the stem barks of ''

Anogeissus leiocarpus ''Anogeissus leiocarpa'' (African birch; bm, ngálǎma) is a tall deciduous tree native to the savannas of tropical Africa. It is the sole West African species of the genus ''Anogeissus'', a genus otherwise distributed from tropical central a ...

'' and '' Terminalia avicennoides''. 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 dif ...

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 ve ...

. During

aging of wines The aging of wine is potentially able to improve the quality of wine. This distinguishes wine from most other consumable goods. While wine is perishable and capable of deteriorating, complex chemical reactions involving a wine's sugars, acids ...

, 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 eve ...

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 nut (fruit), nuts they produce. Th ...

'' (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 world. A substantial, long-lived ...

'', 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 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 ...

formations). After conversion of

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, usi ...

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 Nonahydroxytriphenic acid is a moiety found in some ellagitannins such as roburin A, B,C and D, castalagin or grandinin Grandinin is an ellagitannin. It can be found in ''Melaleuca quinquenervia'' leavesPolyphenols of Melaleuca quinquenervia leav ...

-4,6- hexahydroxydiphenoyl-glucoses) can be further polymerized in their corresponding dimers roburin A and roburin D, and 33-carboxy-33-deoxyvescalagin.

Derivatives

Castalagin and other related ellagitanins polymerizes or forms complexes with anthyocyanins and flavonoids. The flavono-ellagitannin known as acutissimin A 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 ta ...

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 Type II topoisomerases are topoisomerases that cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils. They use the hydrolysis of ATP, unlike Type I topoisomerase. In this process, these enzymes change th ...

inhibitors.

References

{{Ellagitannin Ellagitannins