Inhibitory effects of l-theanine on airway inflammation in ovalbumin-induced allergic asthma.

Abstract

l-theanine, a water-soluble amino acid isolated from green tea (Camellia sinensis), has anti-inflammatory activity, antioxidative properties, and hepatoprotective effects. However, the anti-allergic effect of l-theanine and its underlying molecular mechanisms have not been elucidated. In this study, we investigated the protective effects of l-theanine on asthmatic responses, particularly airway inflammation and oxidative stress modulation in an ovalbumin (OVA)-induced murine model of asthma. Treatment with l-theanine dramatically attenuated the extensive trafficking of inflammatory cells into bronchoalveolar lavage fluid (BALF). Histological studies revealed that l-theanine significantly inhibited OVA-induced mucus production and inflammatory cell infiltration in the respiratory tract and blood vessels. l-theanine administration also significantly decreased the production of IgE, monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-4, IL-5, IL-13, tumor necrosis factor-alpha (TNF-α), and interferon-gamma in BALF. The lung weight decreased with l-theanine administration. l-theanine also markedly attenuated the OVA-induced generation of reactive oxygen species and the activation of nuclear factor kappa B (NF-κB) and matrix metalloprotease-9 in BALF. Moreover, l-theanine reduced the TNF-α-induced NF-κB activation in A549 cells. Together, these results suggest that l-theanine alleviates airway inflammation in asthma, which likely occurs via the oxidative stress-responsive NF-κB pathway, highlighting its potential as a useful therapeutic agent for asthma management.

• Authors: Yong Pil Hwang, Sun Woo Jin, Jae Ho Choi, Chul Yung Choi, Hyung Gyun Kim, Se Jong Kim, Yongan Kim, Kyung Jin Lee, Young Chul Chung, Hye Gwang Jeong
• Journal: Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association (Food Chem Toxicol) Vol. 99 Pg. 162-169 (Jan 2017) ISSN: 1873-6351 [Electronic] England
• PMID: 27908701 (Publication Type: Journal Article)
• Copyright: Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical References

• Anti-Allergic Agents
• Anti-Asthmatic Agents
• Anti-Inflammatory Agents
• Cytokines
• Glutamates
• theanine
• Ovalbumin

Topics

• Animals
• Anti-Allergic Agents (pharmacology)
• Anti-Asthmatic Agents (pharmacology)
• Anti-Inflammatory Agents (pharmacology)
• Asthma (chemically induced, drug therapy, immunology)
• Blotting, Western
• Cytokines (metabolism)
• Female
• Glutamates (pharmacology)
• Inflammation (chemically induced, drug therapy, immunology)
• Mice
• Mice, Inbred ICR
• Ovalbumin (toxicity)
• Respiratory System (drug effects)