Hydroxyl radical scavenging activities of isoquinoline alkaloids isolated from Coptis chinensis

• DOI: 10.1007/s12272-009-1305-z
• Publication Date: 2009-04-22T05:48:14Z
• Authors: Moon Hee Jang; Hyun Young Kim; Ki Sung Kang; Takako Yokozawa; Jeong Hill Park
• Keywords: 0301 basic medicine; Structure-Activity Relationship; 03 medical and health sciences; Molecular Structure; Hydroxyl Radical; Electron Spin Resonance Spectroscopy; Free Radical Scavengers; Iron Chelating Agents; Isoquinolines; Rhizome; Coptis

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.