title: ESR study on the structure and hydroxyl radical-scavenging activity relationships of ginsenosides isolated from Panax ginseng C A Meyer.
abstract: Ginsenosides have been regarded as the main active components of Panax ginseng C. A. Meyer, and the antioxidant activity of ginsenosides in vivo is well described. However, there has been virtually no report describing the direct free radical-scavenging activities of ginsenosides through the long history of ginseng research. The hydroxyl radical (*OH)-scavenging activity test using an electron spin resonance spectrometer (ESR) is suggested to be the most appropriate to measure the antioxidant activities of ginsenosides. Therefore, we investigated the *OH-scavenging and ferrous metal ion-chelating activities of several ginsenosides of Panax ginseng using ESR for the identification of active ginsenosides and its structure and activity relationships. As a result, 20(S)-Rg(3) showed the strongest activity, and the next were in the decreasing order of Rb(1), Rg(1), Rc, Rb(2), and Rd when dissolved with water. The *OH-scavenging activities of ginsenosides were related to the ferrous metal ion-chelating activities of their aglycone, 20(S)-protopanaxadiol. In addition, the ferrous metal ion-chelating activities of ginsenosides were thought to be influenced by their types of hydrophilic sugar moieties.
authors.affiliation: Institute of Natural Medicine, University of Toyama, Toyama, Japan.
authors.forename: Ki Sung
authors.initials: KS
authors.lastname: Kang
authors.forename: Takako
authors.initials: T
authors.lastname: Yokozawa
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamabe
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Jeong Hill
authors.initials: JH
authors.lastname: Park
mesh_terms: D004578:Electron Spin Resonance Spectroscopy; D016166:Free Radical Scavengers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D036145:Ginsenosides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000737:chemistry*; D015394:Molecular Structure; D005894:Panax / Q000737:chemistry*; D012502:Sapogenins / Q000737:chemistry / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: D016166:Free Radical Scavengers; D036145:Ginsenosides; D012502:Sapogenins; D017665:Hydroxyl Radical