Journal ArticleDOI
Polymeric proanthocyanidins. Stereochemistry, structural units, and molecular weight
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TLDR
In this article, a C(4)-C(8)-or C(6)-linked polyflavan-3-ol structure was used to isolate polymeric proanthocyanidins from 22 plant sources.Abstract:
Homogeneous polymeric proanthocyanidins have been isolated from 22 plant sources and all are based on a C(4)–C(8)[or C(6)] linked polyflavan-3-ol structure. 13C N.m.r, spectroscopy in 2[H6]acetone–water is used to calculate the ratio of procyanidin to prodelphinidin monomer units, the average heterocyclic ring stereochemistry of the monomers, and the ratio of monomers to chain-terminating units. The majority of polymers isolated in this study possess monomers with predominantly a 2,3-cis stereochemistry [the same configuration as (–)-epicatechin]. The number-average molecular weight, calculated from monomer to terminal unit ratios, of the polymers is 1 500–5 000. The structure of the chain-terminating group is established by thiolysis degradation and g.l.c. analysis of the products.read more
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Proanthocyanidins and tannin-like compounds – nature, occurrence, dietary intake and effects on nutrition and health
TL;DR: Proanthocyanidins (syn condensed tannins) are complex flavonoid polymers naturally present in cereals, legume seeds and particularly abundant in some fruits and fruit juices as mentioned in this paper.
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Unravelling the conundrum of tannins in animal nutrition and health
TL;DR: The elucidation of tannin structure–activity relationships presents exciting opportunities for future feeding strategies that will benefit ruminants and the environment within the contexts of extensive, semi-intensive and some intensive agricultural systems.
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Analysis of Proanthocyanidin Cleavage Products Following Acid-Catalysis in the Presence of Excess Phloroglucinol
James A. Kennedy,Graham P. Jones +1 more
TL;DR: The results compared favorably to results obtained when benzyl mercaptan was used as the trapping nucleophile, indicating that phloroglucinol is an effective reagent for this analysis.
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Polyphenols in foods are more complex than often thought.
TL;DR: Current knowledge regarding the reaction mechanisms involved in some of these processes and the structures of the resulting products is reviewed, and their effects on organoleptic and nutritional quality are also discussed.
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Tannins: does structure determine function? An ecological perspective
TL;DR: It is argued that their structures suggest strong specificities for a variety of target molecules including proteins, digestive enzymes, and polysaccharides, but are nevertheless subject to the coevolutionary "arms race" (Feeny 1976).