Tunneling effect in vitamin E recycling by green tea

Nagaoka, Shin‐ichi; Nitta, A.; Suemitsu, Ai; Mukai, Kazuo

doi:10.1039/c6ra05986d

Cited by 8 publications

(10 citation statements)

References 44 publications

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“…

k_{r}^{AOH}

values were reported in a previous study (see Ref. ). Measurement was performed in ethanol at 25.0°C.…”

Section: Methodsmentioning

confidence: 87%

“…Absorption of α‐Toc • at 428 nm was negligible at the concentrations of α‐TocH ([α‐TocH] = (0.727‐3.64) × 10 −4 M) used for reaction. The result suggests that α‐Toc • radical produced by the reaction with ArO • is regenerated quickly to α‐TocH by reaction with EGC (reaction ) . By analyzing the decay curves of ArO • at 376 nm, k obsd values were determined.…”

Section: Resultsmentioning

confidence: 99%

“…It has been reported that CatHs function as an AOH by (i) scavenging LOO • (reaction ) and (ii) regenerating α‐Toc • to α‐TocH (reaction )

LO {normalO}^{•} + CatH \overset{k_{inh}}{\to} LOOH + Ca {normalt}^{•},

α - To {normalc}^{•} + CatH \overset{k_{r}}{\to} α - TocH + Ca {normalt}^{•},

where Cat • denotes a catechin radical.…”

Section: Introductionmentioning

confidence: 99%

“…

LO {normalO}^{•} + CatH \overset{k_{inh}}{\to} LOOH + Ca {normalt}^{•},

α - To {normalc}^{•} + CatH \overset{k_{r}}{\to} α - TocH + Ca {normalt}^{•},

where Cat • denotes a catechin radical. Several kinetic studies have been performed for the reactions of CatHs with (i) LOO • (reaction ) and (ii) α‐Toc • (reaction ) . The results indicated that both the reactions are important for the antioxidant actions of CatHs.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Finding of remarkable synergistic effect on the aroxyl‐radical‐scavenging rates under the coexistence of α‐tocopherol and catechins

Mukai

Nagai

Ouchi

et al. 2019

Int J of Chemical Kinetics

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Measurements of aroxyl radical (ArO•)‐scavenging rate constants (ks AOH ) of antioxidants (AOHs) (α‐tocopherol (α‐TocH) and three catechins (CatHs) (ie, epicatechin (EC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG)) were performed in ethanol solution, using stopped‐flow spectrophotometry. ks AOH values were measured not only for each AOH, but also for the mixtures of two AOHs (α‐TocH and CatH). A notable synergistic effect that the ksαnormal- TocH value of α‐TocH increases 1.29, 1.84, and 1.65 times under the coexistence of constant concentrations of EC, EGC, and EGCG, respectively, was observed for the solutions including α‐TocH and CatH. Similarly, ks CatH values of CatHs (EC, EGC, and EGCG) increased 1.72, 2.25, and 2.34 times under the coexistence of constant concentrations of α‐TocH, respectively. UV‐Vis absorption of α‐tocopheroxyl radical (α‐Toc•) (λmax = 428 nm), which had been produced by reaction of α‐TocH with ArO•, decreased remarkably under the coexistence of α‐TocH and CatHs due to the fast α‐TocH‐regeneration reaction by CatHs. The result suggests that the prooxidant reaction due to α‐Toc• is suppressed by the coexistence of CatHs. By analyzing the formation and decay curves of α‐Toc•, it has been ascertained that one molecule of EGCG having three OH groups at B‐ring may rapidly regenerate three molecules of α‐Toc• to α‐TocH.

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“…

k_{r}^{AOH}

values were reported in a previous study (see Ref. ). Measurement was performed in ethanol at 25.0°C.…”

Section: Methodsmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 99%

“…It has been reported that CatHs function as an AOH by (i) scavenging LOO • (reaction ) and (ii) regenerating α‐Toc • to α‐TocH (reaction )

LO {normalO}^{•} + CatH \overset{k_{inh}}{\to} LOOH + Ca {normalt}^{•},

α - To {normalc}^{•} + CatH \overset{k_{r}}{\to} α - TocH + Ca {normalt}^{•},

where Cat • denotes a catechin radical.…”

Section: Introductionmentioning

confidence: 99%

“…

LO {normalO}^{•} + CatH \overset{k_{inh}}{\to} LOOH + Ca {normalt}^{•},

α - To {normalc}^{•} + CatH \overset{k_{r}}{\to} α - TocH + Ca {normalt}^{•},

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Finding of remarkable synergistic effect on the aroxyl‐radical‐scavenging rates under the coexistence of α‐tocopherol and catechins

Mukai

Nagai

Ouchi

et al. 2019

Int J of Chemical Kinetics

Self Cite

View full text Add to dashboard Cite

show abstract

“…Antioxidant synergism has been strengthened with different compounds such as folic acid and vitamin B-12 (Bhattacharjee et al, 2016), vitamin E and β-carotene (Palozza and Krinsky 1992), catechin and malvidin 3-glucoside (Rossetto et al, 2002) and tea polyphenols and vitamin E (Nagaoka et al, 2016). Therefore antioxidant synergistic effects of different amino acids might have a greater effect than that ofthe single antioxidant amino acid and there were only limited reports available on this topic.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the in vitro Antioxidant Capacities via the interaction of amino acids

Liu¹,

Wang

2018

Emir J Food Agric

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In this article, antioxidant capacities of 20 amino acids were quantitatively determined via methodology of mixing one amino acid with the others and using four antioxidant assays to understand the synergistic effects of the individual amino acid contributing to the total antioxidant capacity. Some of the individual amino acids and their mixtures showed their characteristics of antioxidant capacities, and antioxidant peptides showed different results in different experiments. From the ABTS assay study, it was found that nine of 20 amino acids had antioxidant capacities, and most of their mixtures had synergetic effects, Moreover, an oxygen radical absorbance capacity assay study was conducted, and the results aligned well with the ABTS study. However, the DPPH and FRAP assay studies, indicated that cysteine was the only amino acid having antioxidant effect in 20 amino acids. The result showed that the combinations of high antioxidant amino acids and weak antioxidant amino acids or non-antioxidant amino acids led to an obvious increase in antioxidant capacity compared with the theoretical antioxidant capacity.

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Chebulic acid derivatives from Balakata baccata and their antineuroinflammatory and antioxidant activities

Zhao

Lan

et al. 2021

Bioorganic Chemistry

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Tunneling effect in vitamin E recycling by green tea

Cited by 8 publications

References 44 publications

Finding of remarkable synergistic effect on the aroxyl‐radical‐scavenging rates under the coexistence of α‐tocopherol and catechins

Finding of remarkable synergistic effect on the aroxyl‐radical‐scavenging rates under the coexistence of α‐tocopherol and catechins

Enhancing the in vitro Antioxidant Capacities via the interaction of amino acids

Chebulic acid derivatives from Balakata baccata and their antineuroinflammatory and antioxidant activities

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