title: Quercetin reduces oxidative damage induced by paraquat via modulating expression of antioxidant genes in A549 cells.
abstract: Oxidative injury can occur in the lung through the generation of reactive oxygen species (ROS) via redox cycling owing to intentional or accidental ingestion of paraquat (PQ), a common herbicide. A wide array of phytochemicals has been shown to reduce cellular oxidative damage by modulating cytoprotective genes. Quercetin, a well-known flavonoid, has been reported to display cytoprotective effects by up-regulating certain cytoprotective genes. In this context, we investigated the effect of quercetin on PQ-induced cytotoxicity in alveolar A549 cells, modulation of antioxidant genes, activation of transcription factor-Nrf2 and its target HO-1 expression. Quercetin reduced PQ-induced cytotoxicity in A549 cells that was evaluated by both 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl-tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. Modulation of antioxidant genes was compared when cells were treated with PQ, quercetin and both using qRT-PCR. Activation of transcription factor-Nrf2 and induction of its target gene, HO-1 was demonstrated by western blot analysis. A remarkable reduction in the ROS level as well as an increase in the total cellular glutathione (GSH) level occurred when PQ-exposed cells were treated with quercetin. Our findings suggest that quercetin may be used to mitigate or minimize oxidative stress via reducing the generation of ROS.
authors.affiliation: Department of Microbiology, School of Medicine, Soonchunhyang University, Cheonan, Chungnam, 330-090, South Korea.
authors.forename: Tamanna
authors.initials: T
authors.lastname: Zerin
authors.forename: Yong-Sik
authors.initials: YS
authors.lastname: Kim
authors.forename: Sae-Yong
authors.initials: SY
authors.lastname: Hong
authors.forename: Ho-Yeon
authors.initials: HY
authors.lastname: Song
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D018929:Cell Culture Techniques; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects*; D005978:Glutathione / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects* / Q000235:genetics*; D010269:Paraquat / Q000633:toxicity*; D011794:Quercetin / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D017382:Reactive Oxygen Species; D011794:Quercetin; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1; D005978:Glutathione; D010269:Paraquat