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Epicatechin-phloroglucinol

The chemical characteristics of the proanthocyanidins were elucidated by total oxidation and partial degradation in the presence of phloroglucinol followed by HPLC analysis. The native extract of proanthocyanidins contained (+) gallocatechin, (-) epigallocatechin, (h-) catechin, and (-) epicatechin units. ... [Pg.525]

In addition to the effect pH has on the overall reaction rate, it is also important to note the effect of pH on rearrangement reactions of (+)-catechin. At alkaline pH, these secondary rearrangement reactions dominate. Epimerization of (+)-catechin to (-b)-epicatechin is a prominent reaction at pH 9.0. This is not serious in terms of adhesive formulation because it does not alter the reactivity of the aromatic nucleus toward condensation with benzyl alcohols. However, in reactions at pH 10.0 or 11.0, the intramolecular rearrangement to catechinic acid dominates and results in loss of the phloroglucinol functionality. [Pg.201]

Epicatechin-(4a-6)-(-)-epicatechin (B5) Seeds Ricardo da Sdva et al. (1991c) HPLC, TLC, — H NMR, FAB-MS after enzymatic hydrolysis, acid hydrolysis, partial acid-catalysed degradation with phloroglucinol or phenylmethanethiol... [Pg.467]

Source From Thin-layer chromatography of galhc acid, methyl gaUate, pyrogaUol, phloroglucinol, catechol, resorcinol, hydroquinone, catechin, epicatechin, cinnamic acid, p-coumaric acid, ferulic acid and tannic acid, in J. Chromatogr. [Pg.1655]

Nearly all of the procyanidins isolated to date have either catechin or epicate-chin as terminal units. It is common to find 2/ ,3i -(2,3-c/5 )-stereochemistry for the procyanidin extender units and a 2/ ,3S-(2,3-/AiflrA25 )-configuration for the terminal unit. The catechin-(4a- 8)-epiafzelchin dimer isolated from Wisteria sinensis by Weinges (380) and the catechin-(4a- 2)-phloroglucinol isolated from Nelia meyeri by Kolodzeij (208) are the only natural procyanidins reported to date that are not terminated with either catechin or epicatechin. Nelia meyeri also contains epicatechin-(4)ff- 8)-epicatechin and epicatechin-(4)ff- 6)-epicatechin (209). [Pg.622]

See other pages where Epicatechin-phloroglucinol is mentioned: [Pg.310]    [Pg.310]    [Pg.201]    [Pg.261]    [Pg.269]    [Pg.289]    [Pg.37]    [Pg.1270]    [Pg.185]    [Pg.223]    [Pg.269]    [Pg.447]    [Pg.468]    [Pg.481]    [Pg.1090]    [Pg.72]    [Pg.95]    [Pg.179]    [Pg.64]    [Pg.522]    [Pg.287]    [Pg.201]    [Pg.133]    [Pg.49]    [Pg.1657]    [Pg.168]    [Pg.73]    [Pg.74]    [Pg.1018]    [Pg.598]    [Pg.600]    [Pg.610]    [Pg.625]    [Pg.632]    [Pg.632]    [Pg.635]    [Pg.656]    [Pg.303]   
See also in sourсe #XX -- [ Pg.8 ]



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