title: Hydroxyl radical scavenging activities of isoquinoline alkaloids isolated from Coptis chinensis.
abstract: The hydroxyl radical (*OH) scavenging and ferrous ion chelating activities of four isoquinoline alkaloids isolated from Coptis chinensis Franch were studied for the identification of their structural characteristics to scavenge *OH. The *OH was generated via Fe(II)-catalazed Fenton reaction in this study and the reliable measurement of *OH scavenging activities of isoquinoline alkaloids were achieved using electron spin resonance (ESR) spectrometry method. At the 1 mM concentration, berberrubine (85%) showed the strongest *OH scavenging activity and the next were in the decreasing order of coptisine (79%), berberine (23%), and palmatine (22%). The ferrous ion chelating effects of the alkaloids showed similar pattern with their *OH scavenging effects. These results suggest that *OH scavenging effects of the alkaloids were closely related to their ferrous ion chelating activities. In addition, metal chelating functional groups such as hydroxy group at C-9 and methylenedioxy group at C-9 and C-10 were thought to contribute to the *OH scavenging activities of the isoquinoline alkaloids.
authors.affiliation: Research Institute of Pharmaceutical Sciences, College of Pharmacy, Seoul National University, Seoul, 151-742, Korea.
authors.forename: Moon Hee
authors.initials: MH
authors.lastname: Jang
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Ki Sung
authors.initials: KS
authors.lastname: Kang
authors.forename: Takako
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Jeong Hill
authors.initials: JH
authors.lastname: Park
mesh_terms: D039323:Coptis / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification; D017665:Hydroxyl Radical / Q000737:chemistry*; D007502:Iron Chelating Agents / Q000737:chemistry* / Q000302:isolation & purification; D007546:Isoquinolines / Q000737:chemistry* / Q000302:isolation & purification; D015394:Molecular Structure; D027343:Rhizome; D013329:Structure-Activity Relationship
chemical_list: D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D007546:Isoquinolines; D017665:Hydroxyl Radical