title: Direct radical scavenging by the bisbenzylisoquinoline alkaloid cepharanthine.
abstract: Cepharanthine (Ceph) is known as a potent antiperoxidative agent. Recently, we characterized the antiperoxidative effects of Ceph [Biochim. Biophys. Acta 1426 (1999) 133]. However, it was not clear whether the antiperoxidative effect is really due to its direct radical scavenging activity. Therefore, we studied the interaction of Ceph with the hydroxyl radical (*OH) by the electron paramagnetic resonance (EPR) technique. Results showed that Ceph actually scavenged *OH derived by the Fenton reaction. We also found that Ceph radicals were generated on interaction of Ceph with *OH in neutral aqueous solution, but not in acidic solution, consistent with the pH-dependent anti-lipid peroxidation activity of Ceph. Hence, we concluded that anti-lipid peroxidation by Ceph is due to its direct radical scavenging activity.
authors.affiliation: Faculty of Pharmaceutical Sciences, The University of Tokushima, Shomachi-1, Tokushima 770-8505, Japan. kogure@ph.tokushima-u.ac.jp
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kogure
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Kazutoyo
authors.initials: K
authors.lastname: Abe
authors.forename: Michinori
authors.initials: M
authors.lastname: Akasu
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tamaki
authors.forename: Kenji
authors.initials: K
authors.lastname: Fukuzawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Terada
mesh_terms: D000470:Alkaloids / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology*; D044182:Benzylisoquinolines; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D015227:Lipid Peroxidation / Q000187:drug effects; D052117:Benzodioxoles
chemical_list: D000470:Alkaloids; D000975:Antioxidants; D044182:Benzylisoquinolines; D016166:Free Radical Scavengers; D017665:Hydroxyl Radical; C006947:cepharanthine; D052117:Benzodioxoles