title: Protective Effect of an Isoflavone, Tectorigenin, Against Oxidative Stress-induced Cell Death via Catalase Activation.
abstract: BACKGROUND
  Isoflavones are biologically active compounds that occur naturally in a variety of plants, with relatively high levels in soybean. Tectorigenin, an isoflavone, protects against hydrogen peroxide (H2O2)-induced cell damage. However, the underlying mechanism is unknown.
  
  
  METHODS
  The MTT assay was performed to determine cell viability. Catalase activity was assessed by determining the amount of enzyme required to degrade 1 μM H2O2. Protein expression of catalase, phospho-extracellular signal-regulated kinase (ERK), IκB-α, and NF-κB were evaluated by Western blot analysis. A mobility shift assay was performed to assess the DNA-binding ability of NF-κB. Transient transfection and a NF-κB luciferase assay were performed to assess transcriptional activity.
  
  
  RESULTS
  Tectorigenin reduced H2O2-induced death of Chinese hamster lung fibroblasts (V79-4). In addition, tectorigenin increased the activity and protein expression of catalase. Blockade of catalase activity attenuated the protective effect of tectorigenin against oxidative stress. Furthermore, tectorigenin enhanced phosphorylation of ERK and nuclear expression of NF-κB, while inhibition of ERK and NF-κB attenuated the protective effect of tectorigenin against oxidative stress.
  
  
  CONCLUSIONS
  Tectorigenin protects cells against oxidative damage by activating catalase and modulating the ERK and NF-κB signaling pathway.
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea; School of Medical Science and Laboratory Medicine, Jiangsu University, Jiangsu, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Mei Jing
authors.initials: MJ
authors.lastname: Piao
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Min Chang
authors.initials: MC
authors.lastname: Oh
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Jeong Eon
authors.initials: JE
authors.lastname: Park
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Kristina
authors.initials: K
authors.lastname: Shilnikova
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Moon
authors.affiliation: Department of Microbial Chemistry, College of Pharmacy, Kyung Hee University, Seoul, Korea.
authors.forename: Dong Hyun
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Radiation Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, Korea.
authors.forename: Uhee
authors.initials: U
authors.lastname: Jung
authors.affiliation: Department of Radiation Biology, Environmental Radiation Research Group, Korea Atomic Energy Research Institute, Daejeon, Korea; Department of Radiation Biotechnology and Applied Radioisotope, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: In Gyu
authors.initials: IG
authors.lastname: Kim
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea.
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Hyun
keywords: Catalase; Extracellular signal regulated kinases; Isoflavones; NF-kappa B; Tectorigenin