Protective effects of green tea polyphenol extracts against ethanol-induced gastric mucosal damages in rats: stress-responsive transcription factors and MAP kinases as potential targets

Mutat Res. 2005 Nov 11;579(1-2):214-24. doi: 10.1016/j.mrfmmm.2005.03.027. Epub 2005 Aug 10.

Abstract

There are multiple lines of compelling evidence from epidemiologic and laboratory studies supporting that frequent consumption of green tea is inversely associated with the risk of chronic human diseases including cancer. The chemopreventive and chemoprotective effects of green tea have been largely attributed to antioxidative and anti-inflammatory activities of its polyphenolic constituents, such as epigallocatechin gallate. The present study was designed to evaluate the efficacy of green tea polyphenols in protecting against alcohol-induced gastric damage and to elucidate the underlying mechanisms. Intragastric administration of ethanol to male Sprague-Dawley rats caused significant gastric mucosal damage, which was accompanied by elevated expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) as well as transient activation of redox-sensitive transcription factors, such as NF-kappaB and AP-1, and mitogen-activated protein kinases (MAPKs). Oral administration of the green tea polyphenolic extract (GTE) significantly ameliorated mucosal damages induced by ethanol and also attenuated the ethanol-induced expression of COX-2 and iNOS. Inactivation of MAPKs, especially p38 and ERKl/2, by GTE might be responsible for inhibition of ethanol-induced expression of COX-2 and iNOS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cyclooxygenase 1 / drug effects
  • Cyclooxygenase 1 / metabolism
  • Cyclooxygenase 2 / drug effects
  • Cyclooxygenase 2 / metabolism
  • Ethanol / adverse effects*
  • Flavonoids / pharmacology*
  • Gastric Mucosa / drug effects*
  • Gastric Mucosa / metabolism
  • Gastric Mucosa / pathology
  • Gastritis / chemically induced
  • Gastritis / pathology
  • Gastritis / prevention & control
  • HSP70 Heat-Shock Proteins / drug effects
  • HSP70 Heat-Shock Proteins / metabolism
  • Male
  • Membrane Proteins / drug effects
  • Membrane Proteins / metabolism
  • Mitogen-Activated Protein Kinases / drug effects*
  • NF-kappa B / drug effects
  • NF-kappa B / metabolism
  • Nitric Oxide Synthase Type II / drug effects
  • Nitric Oxide Synthase Type II / metabolism
  • Phenols / pharmacology*
  • Plant Extracts / pharmacology*
  • Polyphenols
  • Rats
  • Rats, Sprague-Dawley
  • Stress, Physiological
  • Tea
  • Transcription Factor AP-1 / drug effects
  • Transcription Factor AP-1 / metabolism
  • Transcription Factors / drug effects*

Substances

  • Flavonoids
  • HSP70 Heat-Shock Proteins
  • Membrane Proteins
  • NF-kappa B
  • Phenols
  • Plant Extracts
  • Polyphenols
  • Tea
  • Transcription Factor AP-1
  • Transcription Factors
  • Ethanol
  • Nitric Oxide Synthase Type II
  • Cyclooxygenase 1
  • Cyclooxygenase 2
  • Ptgs1 protein, rat
  • Mitogen-Activated Protein Kinases