title: 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.affiliation: Department of Pharmaceutical Engineering, International University of Korea, Jinju, Republic of Korea.
authors.forename: Yong Pil
authors.initials: YP
authors.lastname: Hwang
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Sun Woo
authors.initials: SW
authors.lastname: Jin
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Jae Ho
authors.initials: JH
authors.lastname: Choi
authors.affiliation: Jeollanamdo Institute of Natural Resources Research, Jeollanamdo, Republic of Korea.
authors.forename: Chul Yung
authors.initials: CY
authors.lastname: Choi
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Hyung Gyun
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Se Jong
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea.
authors.forename: Yongan
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Convergence Medicine, Asan Institute for Life Sciences, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Republic of Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Lee
authors.affiliation: Department of Food and Medicine, College of Public Health and Natural Science, International University of Korea, Jinju, Republic of Korea.
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Chung
authors.affiliation: Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea. Electronic address: hgjeong@cnu.ac.kr.
authors.forename: Hye Gwang
authors.initials: HG
authors.lastname: Jeong
mesh_terms: D000818:Animals; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D018927:Anti-Asthmatic Agents / Q000494:pharmacology*; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001249:Asthma / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology; D015153:Blotting, Western; D016207:Cytokines / Q000378:metabolism; D005260:Female; D005971:Glutamates / Q000494:pharmacology*; D007249:Inflammation / Q000139:chemically induced / Q000188:drug therapy* / Q000276:immunology; D051379:Mice; D008813:Mice, Inbred ICR; D010047:Ovalbumin / Q000633:toxicity*; D012137:Respiratory System / Q000187:drug effects*
chemical_list: D018926:Anti-Allergic Agents; D018927:Anti-Asthmatic Agents; D000893:Anti-Inflammatory Agents; D016207:Cytokines; D005971:Glutamates; C026166:theanine; D010047:Ovalbumin
keywords: Airway inflammation; Cytokine; L-theanine; NF-κB; Ovalbumin