The Chemistry of Wine Polyphenolic C-Glycosidic Ellagitannins Targeting Human Topoisomerase II
Polyphenolic nonahydroxyterphenoyl‐containing C‐glycosidic oak ellagitannins are found in wine as a result of the aging of this beverage in oak‐made barrels. Once in the slightly acidic wine (pH∼3–4), some of these complex natural products such as (−)‐vescalagin (1), but not its C‐1 epimer (−)‐casta...
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Published in | Chemistry : a European journal Vol. 11; no. 22; pp. 6503 - 6513 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Weinheim
WILEY-VCH Verlag
04.11.2005
WILEY‐VCH Verlag Wiley |
Subjects | |
Online Access | Get full text |
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Summary: | Polyphenolic nonahydroxyterphenoyl‐containing C‐glycosidic oak ellagitannins are found in wine as a result of the aging of this beverage in oak‐made barrels. Once in the slightly acidic wine (pH∼3–4), some of these complex natural products such as (−)‐vescalagin (1), but not its C‐1 epimer (−)‐castalagin (2), can capture grape‐derived nucleophilic entities such as ethanol, the flavanols catechin (10 a) and epicatechin (10 b), the anthocyanin oenin (13 b), and the thiolic glutathione (16) to furnish condensation products with retention of configuration at the C‐1 locus. A computer‐aided rationale of this high diastereoselectivity is given. These condensation products can contribute to the modulation of organoleptic properties of the wine, as evidenced by the 23 nm bathochromic shift color absorbance observed with the novel oenin‐based anthocyano‐ellagitannin (15 b). Hydrolysis of 1 under solvolytic conditions furnished another novel compound that we refer to as vescalene (21), in addition to the known (−)‐vescalin (18). Of pharmacological importance is the fact that most of these found‐in‐wine water‐soluble ellagitannin derivatives are much more potent than etoposide (VP‐16) at inhibiting top2‐mediated DNA decatenation in vitro (top2=topoisomerase II)). The known (−)‐vescalin (18) and the novel vescalene (21) fully inhibited top2 at 10 μM concentration!
The secrets of Bacchus! When wine is aged in oak‐made barrels, the oak‐derived polyphenolic C‐glycosidic ellagitannin (−)‐vescalagin can react with grape‐derived nucleophilic entities such as ethanol, the flavanols catechin and epicatechin, the anthocyanin oenin pigment and the thiolic glutathione to furnish condensation products in a diastereoselective manner (see scheme). |
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Bibliography: | istex:3996617563224B0B455D7566A6BDE9BDCA2E2A22 ark:/67375/WNG-ZGQ8707S-H ArticleID:CHEM200500428 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0947-6539 1521-3765 |
DOI: | 10.1002/chem.200500428 |