L-Theanine healed NSAID-induced gastric ulcer by modulating pro/antioxidant balance in gastric ulcer margin

J Nat Med. 2014 Oct;68(4):699-708. doi: 10.1007/s11418-014-0852-x. Epub 2014 Jul 1.

Abstract

L-Theanine is a unique non-protein-forming amino acid present in tea [Camellia sinensis (L.) O. Kuntze]. In the present work, we evaluated the healing effect of L-theanine on NSAID (indomethacin)-induced gastric ulcer. Histology of the stomach tissues revealed maximum ulceration on the third day after indomethacin administration (18 mg/kg, single dose p.o.) which was accompanied by increased lipid peroxidation; protein carbonylation; Th1 cytokine synthesis, and depletion of thiol, mucin, prostaglandin (PG) E, Th2 cytokine synthesis; and total antioxidant status in mice. L-Theanine healed gastric ulcer at a dose of 10 mg/kg b.w. but aggravated the ulcerated condition at a higher dose of 40 mg/kg b.w. At 10 mg/kg b.w., L-theanine significantly alleviated the adverse oxidative effect of indomethacin through enhanced synthesis of PGE2 by modulation of cyclo-oxygenase-1 and 2 [COX-1 and COX-2] expression, Th1/Th2 cytokine balance, and restoration of cellular antioxidant status at the gastric ulcer margin. The present study revealed for the first time the dose-dependent biphasic effect of a natural neuroprotective agent, L-theanine, on gastric ulcer disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / toxicity*
  • Antioxidants / metabolism
  • Glutamates / chemistry
  • Glutamates / therapeutic use*
  • Indomethacin / toxicity
  • Lipid Peroxidation
  • Male
  • Mice
  • Oxidative Stress / drug effects
  • Prostaglandin-Endoperoxide Synthases / metabolism
  • Stomach Ulcer / chemically induced
  • Stomach Ulcer / drug therapy*
  • Stomach Ulcer / genetics
  • Stomach Ulcer / metabolism

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Antioxidants
  • Glutamates
  • theanine
  • Prostaglandin-Endoperoxide Synthases
  • Indomethacin