Enzymic oxidation of catechin to a polymer structurally related to some phlobatannins

Hathway, D. E.; Seakins, J. W. T.

doi:10.1042/bj0670239

Cited by 77 publications

(21 citation statements)

References 10 publications

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“…Studies on the effect of pH on the utilization of catechin by A. flavus (dicat) were carried out at acid pH levels, because at pH values above 6.0 catechin was found to undergo oxidative polymerization. The same phenomenon has been observed by Hathway and Seakins (1957), while studying the action of mushroom, potato, and tobacco polyphenol oxidases on catechin.…”

Section: Identification Of Degradation Products Of Cateclzin By a Jlsupporting

confidence: 71%

Astringency in fruits. I. Microbial degradation of catechin

Chandra¹,

Al.²,

Nayudamma³

1969

Can. J. Microbiol.

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Four molds (Aspergillus fumigatus, A. terreus, A. niger, Penicillium species) and a Streptomyces species capable of degrading catechin were isolated from soil by enrichment techniques. These organisms and Aspergillus flavus (dicat), isolated from a dicatechin medium, were compared for their ability to degrade catechin. The studies indicated that A. flavus (dicat) was the most active of the organisms tested. The degradation of catechin by A. flavus (dicat) was optimal at pH 5.0 and 0.3% catechin. Phloroglucinol carboxylic acid and protocatechuic acid were identified as products of the degradation.

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Section: Identification Of Degradation Products Of Cateclzin By a Jlsupporting

confidence: 71%

Astringency in fruits. I. Microbial degradation of catechin

Chandra¹,

Al.²,

Nayudamma³

1969

Can. J. Microbiol.

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“…There are more positions available on the resorcinol ring to couple with 4-methyl-o-quinone, and thus more isomers might be expected. Based on data from the reaction between resorcinol and p-benzoquinone (18), the similar condensation reactions of pyrogallol and methyl gallate (5), the enzymatic oxidation of catechin (6), and the autoxidation of resorcinol (7) Figures 2 and 3. Its primary function is in the formation of 4-methyl-o-quinone, since nonenzymatically synthesized 4-methyl-o-quinone added to these compounds gave the same colored products with the same absorption spectra.…”

Section: Resultsmentioning

confidence: 99%

Effect of Phloroglucinol and Resorcinol on the Clingstone Peach Polyphenol Oxidase-catalyzed Oxidation of 4-Methylcatechol

1971

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Phloroglucinol and resorcinol are not substrates for clingstone peach (Prunus persica) polyphenol oxidase, but they react with 4-methyl-o-quinone, produced either enzymatically or nonenzymatically, to give an intense red or red-brown color with a maximal absorption at about 470 nanometers. Several colored products were isolated from an ethyl acetate extract of the reaction by two-dimensional thin layer chromatography. Based on thin layer chromatographic and spectral studies of the enzymatic and nonenzymatic reactions, polyphenol oxidase does not play a role in the reaction between 4-methyl-o-quinone and phloroglucinol, resorcinol, d-catechin, or orcinol. In such reactions, the function of polyphenol oxidase is the formation of 4-methyl-o-quinone which then reacts nonenzymatically with the above phenols. Activation energies of both enzymatic and nonenzymatic reactions were determined. o-Benzoquinone, as well as other o-quinones produced from the oxidation of catechol, is highly reactive. Not only can it react with other molecules of catechol (3), but it also reacts with amino acids, peptides, and proteins (10,12,13). Loomis and Battaile (9) pointed out that phenols can combine with proteins reversibly by hydrogen bonding, but after oxidation they combine with proteins irreversibly via covalent condensation.Phenolic compounds such as phloroglucinol and resorcinol are inhibitors of some polyphenol oxidases. For example, both phloroglucinol and resorcinol are competitive inhibitors of potato PPO3 (16), and phloroglucinol is a competitive inhibitor of peach PPO (14). On the other hand, Shannon and Pratt (17) reported that addition of phloroglucinol or resorcinol increased the rate of browning in the apple PPO-catalyzed oxidation of chlorogenic acid.Although free phloroglucinol and resorcinol are not abundant in plants, their derivatives such as the flavonoid compounds are distributed widely in plants. Using In the absence of other phenolics, the effect of 4-methylcatechol concentration on enzyme activity was studied at 420 nm. 4-Methylcatechol concentrations were varied from 9.3 X 10' to 55.8 X 10-M. The Michaelis constant was determined by the method of Lineweaver and Burk (8).Absorption Spectral Studies. The following reaction mixtures were prepared and incubated at 30 C: (I) for the enzymatic reaction: (a) 4.6 ml of 1 x I0-' M 4-methylcatechol plus 0. phloroglucinol. Spectra of each reaction were taken after 10 min, 2 hr, and 2 days. All reagents were prepared in 0.1 M citrate-0.2 M phosphate buffer, pH 6.8.Chemically synthesized 4-methyl-o-quinone was prepared according to Cason (1) and recrystallized twice from benzene. The product was kept in a brown bottle and stored in a freezer for better stability.Thin Layer Chromatography. For the enzymatic reaction, phloroglucinol at a final concentration of 8.2 X 10-' M was prepared in 5 ml of 0.1 M citrate-0.2 M phosphate buffer at pH 6.8. The compound was allowed to react with an equimolar amount of 4-methylcatechol (contained in 2 ml of the same buffer solut...

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“…Evidence for the presence of esters (and possibly glycosides) of ferulic, protocatechuic and gallic acids in some chill hazes comes from the liberation of these acids when appropriate hazes undergo mild acid hydrolysis. [38][39][40][41][42][43][44][45][46][47][48][49] Catechins have also been emphasized as potential haze precursors by McFarlane.48>49 Just as anthocyanogens are immediate haze precursors only when in a polymeric form, so flavonol, catechin and phenolic and hydroxycinnamic ester residues are effective in the production of beer hazes only when incor porated into polymers or co-polymers. How ever, a small part of the polyphenolic moiety of hazes may be present in the form of simple polyphenols such as anthocyanogens, cate chins and flavonols.…”

Section: Resultsmentioning

confidence: 99%

Phenolic Constituents of Beer and Brewing Materials. Ii. The Role of Polyphenols in the Formation of Non-Biological Haze

Gramshaw

1967

Journal of the Institute of Brewing

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Simple and polymeric polyphenols differ in the way in which they influence the development of chill and permanent hazes in bottled beer. The addition of simple anthocyanogens to beer causes a marked increase in the rate of haze formation whereas added polymeric materials induce immediate and intense turbidities.Beer anthocyanogens constitute a class of materials ranging in complexity from simple compounds to heterogeneous polymers which sometimes include polyphenolic units that are incapable of yielding anthocyanidins with acid. The extent to which the various anthocyanogens present in beer are involved in haze formation is not reflected by their contributions to the overall anthocyanogen value of the beer.

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Enzymic oxidation of catechin to a polymer structurally related to some phlobatannins

Cited by 77 publications

References 10 publications

Astringency in fruits. I. Microbial degradation of catechin

Astringency in fruits. I. Microbial degradation of catechin

Effect of Phloroglucinol and Resorcinol on the Clingstone Peach Polyphenol Oxidase-catalyzed Oxidation of 4-Methylcatechol

Phenolic Constituents of Beer and Brewing Materials. Ii. The Role of Polyphenols in the Formation of Non-Biological Haze

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