Stereochemistry of a Cyclic Epicatechin Trimer with <i>C</i><sub>3</sub> Symmetry Produced by Oxidative Coupling

Kawazoe, Rina; Matsuo, Yosuke; Saito, Yoshinori; Tanaka, Takashi

doi:10.1002/ejoc.202001579

Cited by 4 publications

(4 citation statements)

References 65 publications

(18 reference statements)

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“…The (+)-catechin/(−)-epicatechin model produced, as expected, additional chromatographic peaks (peaks [25][26][27][28][29][30][31][32][33][34][35] and spots in the heat map (Figures 6 and 7) likely derived from both (+)-catechin and (−)-epicatechin. S2.…”

Section: Oxidation Dimers Of a Mixture Of (+)-Catechin And (−)-Epicat...supporting

confidence: 70%

“…However, it was possible to find masses corresponding to trimers in the zone where the dimers were more present. Kawazoe and co-workers [33] described a cyclic epicatechin trimer produced by oxidative coupling. This type of compound may show a lower mobility than the non-cyclic trimers in the TIMS.…”

Section: Oxidation Dimers Of a Mixture Of (+)-Catechin And (−)-Epicat...mentioning

confidence: 99%

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Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

et al. 2022

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Dehydrodicatechins resulting from (epi)catechin oxidation have been investigated in different foods and natural products, but they still offer some analytical challenges. The purpose of this research is to develop a method using ultra-high performance liquid chromatography coupled with trapped ion mobility spectrometry and tandem mass spectrometry (UHPLC−ESI−TIMS−QTOF−MS/MS) to improve the characterization of dehydrodicatechins from model solutions (oxidation dimers of (+)-catechin and/or (−)-epicatechin). Approximately 30 dehydrodicatechins were detected in the model solutions, including dehydrodicatechins B with β and ε-interflavanic configurations and dehydrodicatechins A with γ-configuration. A total of 11 dehydrodicatechins B, based on (−)-epicatechin, (+)-catechin, or both, were tentatively identified in a grape seed extract. All of them were of β-configuration, except for one compound that was of ε-configuration. TIMS allowed the mobility separation of chromatographically coeluted isomers including dehydrodicatechins and procyanidins with similar MS/MS fragmentation patterns that would hardly be distinguished by LC-MS/MS alone, which demonstrates the superiority of TIMS added to LC-MS/MS for these kinds of compounds. To the best of our knowledge, this is the first time that ion mobility spectrometry (IMS) was applied to the analysis of dehydrodicatechins. This method can be adapted for other natural products.

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Section: Oxidation Dimers Of a Mixture Of (+)-Catechin And (−)-Epicat...supporting

confidence: 70%

Section: Oxidation Dimers Of a Mixture Of (+)-Catechin And (−)-Epicat...mentioning

confidence: 99%

Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

et al. 2022

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“…They have the structure corresponding to dehydrodicatechin A, dehydrodicatechin B, and quinone–methide type. Dimers and trimers were detected from the coupling oxidation of epicatechin (Kawazoe et al., 2021). A ring of epicatechin formed the C–C bond with the B ring of its corresponding o ‐quinone to form a dimer, followed by intramolecular oxidative coupling to generate dehydrodiepicatechin A.…”

Section: O‐quinone Reaction Mechanismmentioning

confidence: 99%

From polyphenol to o‐quinone: Occurrence, significance, and intervention strategies in foods and health implications

Geng

Liu

et al. 2023

Comp Rev Food Sci Food Safe

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Polyphenol oxidation is a chemical process impairing food freshness and other desirable qualities, which has become a serious problem in fruit and vegetable processing industry. It is crucial to understand the mechanisms involved in these detrimental alterations. o-Quinones are primarily generated by polyphenols with di/tri-phenolic groups through enzymatic oxidation and/or auto-oxidation. They are highly reactive species, which not only readily suffer the attack by nucleophiles but also powerfully oxidize other molecules presenting lower redox potentials via electron transfer reactions. These reactions and subsequent complicated reactions are capable of initiating quality losses in foods, such as browning, aroma loss, and nutritional decline. To attenuate these adverse influences, a variety of technologies have emerged to restrain polyphenol oxidation via governing different factors, especially polyphenol oxidases and oxygen. Despite tremendous efforts devoted, to date, the loss of food quality caused by quinones has remained a great challenge in the food processing industry. Furthermore, o-quinones are responsible for the chemopreventive effects and/or toxicity of the parent catechols on human health, the mechanisms by which are quite complex. Herein, this review focuses on the generation and reactivity of oquinones, attempting to clarify mechanisms involved in the quality deterioration of foods and health implications for humans. Potential innovative inhibitors and technologies are also presented to intervene in o-quinone formation and subsequent reactions. In future, the feasibility of these inhibitory strategies should be evaluated, and further exploration on biological targets of o-quinones is of great necessity.

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“…Thus, mechanisms that directly produce oligomeric products from monomeric catechins possibly exist in TR production. The oxidation of 3 alone with polyphenol oxidase affords B–A ring coupling products (Figure A). ,, In the reaction, dimeric products are detected in only trace amounts and oligomeric products are dominantly accumulated (Figure S1). This is because the B–A ring coupling products retain unreacted A- and B-rings, which undergo further couplings.…”

Section: Introductionmentioning

confidence: 99%

Oligomerization Mechanisms of Tea Catechins Involved in the Production of Black Tea Thearubigins

Hashiguchi,

Teramoto,

Katayama

et al. 2023

J. Agric. Food Chem.

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Thearubigins (TRs) are chemically ill-defined black tea pigments composed of numerous catechin oxidation products. TRs contain oligomeric components; however, the oligomerization mechanisms are poorly understood. The comparison of the 13C nuclear magnetic resonance (NMR) spectra of TRs with different molecular sizes suggested the participation of A-ring methine carbons in the oligomerization. Crushing fresh tea leaves with phloroglucinol, a mimic of the catechin A-rings, yielded the phloroglucinol adducts of the B-ring quinones of pyrogallol-type catechins and dehydrotheasinensins, indicating that intermolecular oxidative couplings between pyrogallol-type B-rings and A-rings are involved in the oligomerization. This is supported by the comparison of the 13C NMR spectra of the oligomers generated from the dehydrotheasinensins and epicatechin. Furthermore, the presence of the quinones or related structures in the catechin oligomers is shown by condensation with 1,2-phenylenediamine. The pyrogallol-type catechins account for approximately 70% of tea catechins; therefore, the B–A ring couplings of the pyrogallol-type catechins are important in the catechin oligomerization involved in TR production.

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Stereochemistry of a Cyclic Epicatechin Trimer with C₃ Symmetry Produced by Oxidative Coupling

Cited by 4 publications

References 65 publications

Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

From polyphenol to o‐quinone: Occurrence, significance, and intervention strategies in foods and health implications

Oligomerization Mechanisms of Tea Catechins Involved in the Production of Black Tea Thearubigins

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Stereochemistry of a Cyclic Epicatechin Trimer with C3 Symmetry Produced by Oxidative Coupling

Cited by 4 publications

References 65 publications

Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

Improved Analysis of Isomeric Polyphenol Dimers Using the 4th Dimension of Trapped Ion Mobility Spectrometry—Mass Spectrometry

From polyphenol to o‐quinone: Occurrence, significance, and intervention strategies in foods and health implications

Oligomerization Mechanisms of Tea Catechins Involved in the Production of Black Tea Thearubigins

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Stereochemistry of a Cyclic Epicatechin Trimer with C₃ Symmetry Produced by Oxidative Coupling