title: The uremic solute indoxyl sulfate acts as an antioxidant against superoxide anion radicals under normal-physiological conditions.
abstract: The effect of the uremic solute indoxyl sulfate (IS) on scavenging superoxide anion radicals (O(2)(*-)) generated from both the xanthine/xanthine oxidase (X/XO) system and activated neutrophils was investigated by electron paramagnetic resonance spectroscopy, combined with 2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide (EMPO). The findings show that the presence of normal-physiological serum concentrations of IS (0.1-10 microM) resulted in decreased formation of EMPO-superoxide adduct without affecting XO activity. Furthermore, IS showed scavenging activity against cell-derived O(2)(*-) generated from activated neutrophils. In addition, IS also eliminated hydroxyl radicals. These findings suggest that IS acts as a novel endogenous antioxidant under normal-physiological conditions.
authors.affiliation: Department of Biopharmaceutics, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Iwao
authors.forename: Yuka
authors.initials: Y
authors.lastname: Tasaki
authors.forename: Keizo
authors.initials: K
authors.lastname: Sato
authors.forename: Yu
authors.initials: Y
authors.lastname: Ishima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kadowaki
authors.forename: Toru
authors.initials: T
authors.lastname: Maruyama
authors.forename: Masaki
authors.initials: M
authors.lastname: Otagiri
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D007200:Indican / Q000097:blood / Q000737:chemistry*; D009504:Neutrophils / Q000378:metabolism; D011758:Pyrroles / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry*
chemical_list: C406273:2-ethoxycarbonyl-2-methyl-3,4-dihydro-2H-pyrrole-1-oxide; D000975:Antioxidants; D011758:Pyrroles; D013481:Superoxides; D007200:Indican