title: Quercetin protects against pulmonary oxidant stress via heme oxygenase-1 induction in lung epithelial cells.
abstract: The lung is a primary target for oxygen toxicity because of its constant exposure to high oxygen levels and environmental oxidants. Quercetin is one of the most commonly found dietary flavonoids, and it provides cytoprotective actions via activation of specific transcriptional factors and upregulation of endogenous defensive pathways. In the present study, we showed that quercetin increased the levels of heme oxygenase (HO)-1 expression and protected against hydrogen peroxide (H(2)O(2))-induced cytotoxicity in lung epithelial cell lines. Quercetin suppressed H(2)O(2)-induced apoptotic events, including hypodiploid cells, activation of caspase 3 enzyme activity and lactate dehydrogenase release. This cytoprotective effect was attenuated by the addition of the HO inhibitor, tin protoporphyrin IX. In addition, the end products of heme metabolites catalyzed by HO-1, carbon monoxide and bilirubin, protect against H(2)O(2)-induced cytotoxicity in LA-4 cells. Quercetin may well be one of the promising substances to attenuate oxidative epithelial cell injury in lung inflammation.
authors.affiliation: Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
authors.forename: Yuta
authors.initials: Y
authors.lastname: Hayashi
authors.forename: Miyoko
authors.initials: M
authors.lastname: Matsushima
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Nakamura
authors.forename: Masataka
authors.initials: M
authors.lastname: Shibasaki
authors.forename: Naozumi
authors.initials: N
authors.lastname: Hashimoto
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Imaizumi
authors.forename: Kaoru
authors.initials: K
authors.lastname: Shimokata
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kawabe
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002460:Cell Line; D019610:Cytoprotection; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000187:drug effects / Q000201:enzymology; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D008168:Lung / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D051379:Mice; D009336:Necrosis / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control; D018384:Oxidative Stress / Q000187:drug effects*; D011794:Quercetin / Q000494:pharmacology*; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D014867:Water / Q000494:pharmacology
chemical_list: D000975:Antioxidants; D014867:Water; D011794:Quercetin; D051547:Heme Oxygenase-1