Radical chemistry of epigallocatechin gallate and its relevance to protein damage

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Radical chemistry of epigallocatechin gallate and its relevance to protein damage. / Hagerman, Ann E; Dean, Roger T; Davies, Michael Jonathan.

In: Nitric Oxide: Biology and Chemistry, Vol. 414, No. 1, 01.06.2003, p. 115-20.

Research output: Contribution to journalJournal articleResearchpeer-review

Harvard

Hagerman, AE, Dean, RT & Davies, MJ 2003, 'Radical chemistry of epigallocatechin gallate and its relevance to protein damage', Nitric Oxide: Biology and Chemistry, vol. 414, no. 1, pp. 115-20.

APA

Hagerman, A. E., Dean, R. T., & Davies, M. J. (2003). Radical chemistry of epigallocatechin gallate and its relevance to protein damage. Nitric Oxide: Biology and Chemistry, 414(1), 115-20.

Vancouver

Hagerman AE, Dean RT, Davies MJ. Radical chemistry of epigallocatechin gallate and its relevance to protein damage. Nitric Oxide: Biology and Chemistry. 2003 Jun 1;414(1):115-20.

Author

Hagerman, Ann E ; Dean, Roger T ; Davies, Michael Jonathan. / Radical chemistry of epigallocatechin gallate and its relevance to protein damage. In: Nitric Oxide: Biology and Chemistry. 2003 ; Vol. 414, No. 1. pp. 115-20.

Bibtex

@article{08e4cd4fcae84ab3af1206a3583ba51b,
title = "Radical chemistry of epigallocatechin gallate and its relevance to protein damage",
abstract = "The radical chemistry of the plant polyphenolics epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were investigated using electron paramagnetic resonance spectroscopy. Radical species formed spontaneously in aqueous solutions at low pH without external oxidant and were spin stabilized with Zn(II). The spectra were assigned to the gallyl radical and the anion gallyl radical, with only 10{\%} of the signal assigned to a radical from the galloyl ester. Spectral simulations were used to establish a pK(a) of 4.8 for the EGCG radical and a pK(a) of 4.4 for the EGC radical. The electrochemical redox potentials of EGCG and EGC varied from 1000 mV at pH 3 to 400 mV at pH 8. The polyphenolics did not produce hydroxyl radicals unless reduced metal ions such as iron(II) were added to the system. Zinc(II)-stabilized EGCG radicals were more effective protein-precipitating agents than unoxidized EGCG and produced irreversibly complexed protein. EGCG and other naturally occurring polyphenolics are effective radical scavengers but their radical products have the potential to damage biological molecules such as proteins.",
keywords = "Antioxidants, Catechin, Electron Spin Resonance Spectroscopy, Free Radicals, Hydrogen-Ion Concentration, Oxidation-Reduction, Serum Albumin, Bovine, Zinc Acetate",
author = "Hagerman, {Ann E} and Dean, {Roger T} and Davies, {Michael Jonathan}",
year = "2003",
month = "6",
day = "1",
language = "English",
volume = "414",
pages = "115--20",
journal = "Nitric Oxide: Biology and Chemistry",
issn = "1089-8603",
publisher = "Academic Press",
number = "1",

}

RIS

TY - JOUR

T1 - Radical chemistry of epigallocatechin gallate and its relevance to protein damage

AU - Hagerman, Ann E

AU - Dean, Roger T

AU - Davies, Michael Jonathan

PY - 2003/6/1

Y1 - 2003/6/1

N2 - The radical chemistry of the plant polyphenolics epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were investigated using electron paramagnetic resonance spectroscopy. Radical species formed spontaneously in aqueous solutions at low pH without external oxidant and were spin stabilized with Zn(II). The spectra were assigned to the gallyl radical and the anion gallyl radical, with only 10% of the signal assigned to a radical from the galloyl ester. Spectral simulations were used to establish a pK(a) of 4.8 for the EGCG radical and a pK(a) of 4.4 for the EGC radical. The electrochemical redox potentials of EGCG and EGC varied from 1000 mV at pH 3 to 400 mV at pH 8. The polyphenolics did not produce hydroxyl radicals unless reduced metal ions such as iron(II) were added to the system. Zinc(II)-stabilized EGCG radicals were more effective protein-precipitating agents than unoxidized EGCG and produced irreversibly complexed protein. EGCG and other naturally occurring polyphenolics are effective radical scavengers but their radical products have the potential to damage biological molecules such as proteins.

AB - The radical chemistry of the plant polyphenolics epigallocatechin gallate (EGCG) and epigallocatechin (EGC) were investigated using electron paramagnetic resonance spectroscopy. Radical species formed spontaneously in aqueous solutions at low pH without external oxidant and were spin stabilized with Zn(II). The spectra were assigned to the gallyl radical and the anion gallyl radical, with only 10% of the signal assigned to a radical from the galloyl ester. Spectral simulations were used to establish a pK(a) of 4.8 for the EGCG radical and a pK(a) of 4.4 for the EGC radical. The electrochemical redox potentials of EGCG and EGC varied from 1000 mV at pH 3 to 400 mV at pH 8. The polyphenolics did not produce hydroxyl radicals unless reduced metal ions such as iron(II) were added to the system. Zinc(II)-stabilized EGCG radicals were more effective protein-precipitating agents than unoxidized EGCG and produced irreversibly complexed protein. EGCG and other naturally occurring polyphenolics are effective radical scavengers but their radical products have the potential to damage biological molecules such as proteins.

KW - Antioxidants

KW - Catechin

KW - Electron Spin Resonance Spectroscopy

KW - Free Radicals

KW - Hydrogen-Ion Concentration

KW - Oxidation-Reduction

KW - Serum Albumin, Bovine

KW - Zinc Acetate

M3 - Journal article

C2 - 12745262

VL - 414

SP - 115

EP - 120

JO - Nitric Oxide: Biology and Chemistry

JF - Nitric Oxide: Biology and Chemistry

SN - 1089-8603

IS - 1

ER -

ID: 138275960