title: Anti-oxidative Activity of Hydrolysate from Rice Bran Protein in HepG2 Cells.
abstract: Glutathione (GSH) is an ubiquitous thiol-containing tripeptide, which plays important roles in cellular protection from oxidative stress. In our search for a dietary source that can increase GSH levels, we discovered that a 24 h treatment of HepG2 cells with rice bran protein hydrolysate (RBPH), prepared by Umamizyme G-catalyzed hydrolysis, increased the GSH content in a dose-dependent manner. RBPH elevated the expression levels of γ-glutamylcysteine synthetase (γ-GCS), which constitutes the rate-limiting enzyme of GSH synthesis, and of another two enzymes, hemeoxygenase-1 (HO-1) and reduced nicotinamide adenine dinucleotide (phosphate): quinone oxidoreductase 1 (NQO1). This induction was preceded by the accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) inside the nucleus, which is a key transcription factor for the expression of the γ-GCS, HO-1, and NQO1. Pre-treatment of cells with RBPH produced a significant protective effect against cytotoxicity caused by H2O2or ethanol. These results indicate that RBPH exerts a protective effect against oxidative stress by modulating GSH levels and anti-oxidative enzyme expression via the Nrf2 pathway.
authors.affiliation: Department of Biochemistry, School of Pharmacy, Shujitsu University.
authors.forename: Chie
authors.initials: C
authors.lastname: Moritani
authors.affiliation: Department of Biochemistry, School of Pharmacy, Shujitsu University.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Kawakami
authors.affiliation: Satake Corporation.
authors.forename: Akiko
authors.initials: A
authors.lastname: Fujita
authors.affiliation: Satake Corporation.
authors.forename: Koji
authors.initials: K
authors.lastname: Kawakami
authors.affiliation: Okayama Prefectural Technology Center for Agriculture, Forestry, and Fisheries, Research Institute for Biological Sciences (RIBS).
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hatanaka
authors.affiliation: Department of Biochemistry, School of Pharmacy, Shujitsu University.
authors.forename: Seiji
authors.initials: S
authors.lastname: Tsuboi
mesh_terms: D000975:Antioxidants / Q000302:isolation & purification / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000378:metabolism; D012275:Oryza / Q000737:chemistry*; D018384:Oxidative Stress / Q000187:drug effects*; D010940:Plant Proteins / Q000737:chemistry*; D011492:Protein Hydrolysates / Q000302:isolation & purification / Q000494:pharmacology*; D015398:Signal Transduction
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D010940:Plant Proteins; D011492:Protein Hydrolysates; D005978:Glutathione
keywords: anti-oxidative; glutathione; nuclear factor erythroid 2-related factor 2; rice bran