Preventive Effect of Epigallocatechin Gallate, the Main Component of Green Tea, on Acute Lung Injury Caused by Air Pollutants
Ken-Ichiro Tanaka,
Shunsuke Nakaguchi,
Sachie Shiota,
Yuka Nakada,
Kaho Oyama,
Okina Sakakibara,
Mikako Shimoda,
Akio Sugimoto,
Masaki Ichitani,
Takanobu Takihara,
Hitoshi Kinugasa,
Masahiro Kawahara
Affiliations
Ken-Ichiro Tanaka
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Shunsuke Nakaguchi
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Sachie Shiota
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Yuka Nakada
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Kaho Oyama
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Okina Sakakibara
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Mikako Shimoda
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Akio Sugimoto
Central Research Institute, ITO EN, Ltd., 21 Mekami, Makinohara 421-0516, Japan
Masaki Ichitani
Central Research Institute, ITO EN, Ltd., 21 Mekami, Makinohara 421-0516, Japan
Takanobu Takihara
Central Research Institute, ITO EN, Ltd., 21 Mekami, Makinohara 421-0516, Japan
Hitoshi Kinugasa
Central Research Institute, ITO EN, Ltd., 21 Mekami, Makinohara 421-0516, Japan
Masahiro Kawahara
Laboratory of Bio-Analytical Chemistry, Research Institute of Pharmaceutical Sciences, Musashino University, 1-1-20 Shinmachi, Nishitokyo 202-8585, Japan
Reducing the health hazards caused by air pollution is a global challenge and is included in the Sustainable Development Goals. Air pollutants, such as PM2.5, induce respiratory and cardiovascular disorders by causing various inflammatory responses via oxidative stress. Catechins and polyphenols, which are components of green tea, have various protective effects, owing to their antioxidant ability. The main catechin in green tea, epigallocatechin gallate (EGCG), is potentially effective against respiratory diseases, such as idiopathic pulmonary fibrosis and asthma, but its effectiveness against air-pollution-dependent lung injury has not yet been investigated. In this study, we examined the effect of EGCG on urban aerosol-induced acute lung injury in mice. Urban aerosol treatment caused increases in inflammatory cell counts, protein levels, and inflammatory cytokine expression in the lungs of ICR mice, but pretreatment with EGCG markedly suppressed these responses. Analyses of oxidative stress revealed that urban aerosol exposure enhanced reactive oxygen species (ROS) production and the formation of ROS-activated neutrophil extracellular traps (NETs) in the lungs of mice. However, ROS production and NETs formation were markedly suppressed by pretreating the mice with EGCG. Gallocatechin gallate (GCG), a heat-epimerized form of EGCG, also markedly suppressed urban aerosol-dependent inflammatory responses and ROS production in vivo and in vitro. These findings suggest that EGCG and GCG prevent acute lung injury caused by urban aerosols through their inhibitory effects on ROS production. Thus, we believe that foods and medications containing EGCG or GCG may be candidates to prevent the onset and progression of acute lung injury caused by air pollutants.
