title: Stereospecificity in hydroxyl radical scavenging activities of four ginsenosides produced by heat processing.
abstract: The activity-guided fractionation of sun ginseng (SG, heat processed Panax ginseng C. A. Meyer at 120 degrees C) was carried out to identify its main active hydroxyl radical (*OH) scavenging components. As a result, the n-BuOH fraction mainly consisting of ginsenosides showed the strongest activity. Of several ginsenosides of SG, the *OH scavenging activities of relatively high contents of 20(S)-Rg(3), 20(R)-Rg(3), Rk(1), and Rg(5) were compared. Rg(5) and 20(S)-Rg(3) showed strong *OH scavenging IC(50) values of 0.15 and 0.44 mM, respectively, and these activities were prominently higher than each of their respective isomers. Therefore, stereospecificity exists in the *OH scavenging activities of ginsenosides produced by heat processing. Especially, the double bond at carbon-20(22) or the OH group at carbon-20 geometrically close to OH at carbon-12 is thought to increase the *OH scavenging activity of ginsenosides.
authors.affiliation: Institute of Natural Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Ki Sung
authors.initials: KS
authors.lastname: Kang
authors.forename: Hyun Young
authors.initials: HY
authors.lastname: Kim
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamabe
authors.forename: Takako
authors.initials: T
authors.lastname: Yokozawa
mesh_terms: D016166:Free Radical Scavengers / Q000737:chemistry* / Q000494:pharmacology; D036145:Ginsenosides / Q000737:chemistry* / Q000494:pharmacology; D006358:Hot Temperature; D017665:Hydroxyl Radical / Q000737:chemistry* / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D016166:Free Radical Scavengers; D036145:Ginsenosides; D017665:Hydroxyl Radical