Roles of Catalase and Hydrogen Peroxide in Green Tea Polyphenol-Induced Chemopreventive Effects

Tetsuya Yamamoto, Jill Lewis, John Wataha, Douglas Dickinson, Baldev Singh, Wendy B. Bollag, Eisaku Ueta, Tokio Osaki, Mohammad Athar, George Schuster, Stephen Hsu

Research output: Contribution to journalArticle

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Abstract

The green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) possesses promising anticancer potential. Although in vivo studies unveiled the metabolic routes and pharmacokinetics of EGCG and showed no adverse effects, in vitro studies at high concentrations demonstrated oxidative stress. EGCG causes differential oxidative environments in tumor versus normal epithelial cells, but the roles that EGCG, hydrogen peroxide (H2O2), and intracellular catalase play in the epithelial system are largely unknown. The current study employed enzyme activity assays, reactive oxygen species quantification, and immunoblotting to investigate whether EGCG-induced differential effects correlate with levels of key antioxidant enzymes and H 2O2. It was found that normal human keratinocytes with high catalase activity are least susceptible to H2O2, whereas H2O2 caused significant cytotoxicity in oral carcinoma cell lines. However, the EGCG-induced differential effects could not be duplicated by H2O2 alone. The addition of exogenous catalase failed to completely prevent the EGCG-induced cytotoxicity and rescue the EGCG-induced growth arrest in the tumor cells. The antioxidant N-acetyl-L-cysteine rescued the tumor cells from H2O 2-induced damage only, but not from EGCG-induced mitochondrial damage. Finally, alterations in catalase or superoxide dismutase activities were not observed upon EGCG exposure. In conclusion, although endogenous catalase may play a role in response to H2O2-induced cytotoxicity, the EGCG-induced cytotoxic effects on tumor cells mainly result from sources other than H2O2.

Original languageEnglish (US)
Pages (from-to)317-323
Number of pages7
JournalJournal of Pharmacology and Experimental Therapeutics
Volume308
Issue number1
DOIs
StatePublished - Jan 1 2004

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Polyphenols
Tea
Catalase
Hydrogen Peroxide
Neoplasms
epigallocatechin gallate
Antioxidants
Acetylcysteine
Enzyme Assays
Keratinocytes
Immunoblotting
Superoxide Dismutase
Reactive Oxygen Species
Oxidative Stress
Pharmacokinetics
Epithelial Cells
Carcinoma
Cell Line

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

Cite this

Roles of Catalase and Hydrogen Peroxide in Green Tea Polyphenol-Induced Chemopreventive Effects. / Yamamoto, Tetsuya; Lewis, Jill; Wataha, John; Dickinson, Douglas; Singh, Baldev; Bollag, Wendy B.; Ueta, Eisaku; Osaki, Tokio; Athar, Mohammad; Schuster, George; Hsu, Stephen.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 308, No. 1, 01.01.2004, p. 317-323.

Research output: Contribution to journalArticle

Yamamoto, T, Lewis, J, Wataha, J, Dickinson, D, Singh, B, Bollag, WB, Ueta, E, Osaki, T, Athar, M, Schuster, G & Hsu, S 2004, 'Roles of Catalase and Hydrogen Peroxide in Green Tea Polyphenol-Induced Chemopreventive Effects', Journal of Pharmacology and Experimental Therapeutics, vol. 308, no. 1, pp. 317-323. https://doi.org/10.1124/jpet.103.058891
Yamamoto, Tetsuya ; Lewis, Jill ; Wataha, John ; Dickinson, Douglas ; Singh, Baldev ; Bollag, Wendy B. ; Ueta, Eisaku ; Osaki, Tokio ; Athar, Mohammad ; Schuster, George ; Hsu, Stephen. / Roles of Catalase and Hydrogen Peroxide in Green Tea Polyphenol-Induced Chemopreventive Effects. In: Journal of Pharmacology and Experimental Therapeutics. 2004 ; Vol. 308, No. 1. pp. 317-323.
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