title: Hyperoside Induces Endogenous Antioxidant System to Alleviate Oxidative Stress.
abstract: BACKGROUND
  Hyperoside, a flavonoid which is mainly found in Hypericum perforatum L., has many biological effects. One of the most important effects is to prevent the oxidative stress induced by reactive oxygen species. However, the molecular mechanisms underlying its effect are not fully understood. Oxidative stress is implicated in the occurrence of various physical diseases. A wide array of enzymatic antioxidant defense systems include NADH: quinone oxidoreductase 1, superoxide dismutase, and heme oxygenase-1 (HO-1). In the present study, the protective effects of hyperoside against hydrogen peroxide-induced oxidative stress in human lens epithelial cells, HLE-B3, were investigated in terms of HO-1 induction.
  
  
  METHODS
  The protein and mRNA expressions of HO-1 were examined by Western blotting and reverse transcriptase-PCR assays, respectively. To evaluate the ability of hyperoside to activate nuclear factor erythroid 2-related factor 2 (Nrf2), Western blotting and electrophoretic mobility shift assay were performed with nuclear extracts prepared from HLE-B3 cells treated with hyperoside. The activation of extracellular signal-regulated kinase (ERK), the upstream kinase of Nrf2 signaling, was monitored by Western blot analysis. The protective effect of hyperoside in HLE-B3 cells against hydrogen peroxide was performed by MTT assay.
  
  
  RESULTS
  Hyperoside increased both the mRNA and protein expression of HO-1 in a time- and dose-dependent manner. In addition, hyperoside elevated the level of of Nrf2 and its antioxidant response element-binding activity, which was modulated by upstream of ERK. Moreover, it activated ERK and restored cell viability which was decreased by hydrogen peroxide.
  
  
  CONCLUSIONS
  Hyperoside is an effective compound to protect cells against oxidative stress via HO-1 induction.
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Xia
authors.initials: X
authors.lastname: Han
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Mei Jing
authors.initials: MJ
authors.lastname: Piao
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Min Chang
authors.initials: MC
authors.lastname: Oh
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Pattage Madushan Dilhara Jayatissa
authors.initials: PM
authors.lastname: Fernando
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Kyoung Ah
authors.initials: KA
authors.lastname: Kang
authors.affiliation: Department of Biochemistry, Jeju National University School of Medicine, Jeju, Korea University of Science and Technology, Daejeon, Korea.
authors.forename: Yea Seong
authors.initials: YS
authors.lastname: Ryu
authors.affiliation: Radiation Biotechnology Research Division, Korea Atomic Energy Research Institute, Jeongeup, Korea University of Science and Technology, Daejeon, 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, Korea University of Science and Technology, 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 University of Science and Technology, Daejeon, Korea.
authors.forename: Jin Won
authors.initials: JW
authors.lastname: Hyun
keywords: Antioxidants; Heme oxygenase-1; Hyperoside; Oxidative stress