title: Superoxide- and 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activities of soyasaponin beta g related to gallic acid.
abstract: Soyasaponin beta p g at 1 mm had 8% scavenging activity for O2-, and 25 microM beta g scavenged 20.9% for the DPPH radical (IC50: 63.8 microM). In the soyasaponin beta g-gallic acid system, synerigistic effects were observed at a low level of gallic acid concentration. The spin density distribution calculated by the MNDO/AM1 method showed unpaired electron localization on the carbons at C-4 and C-6, and on the ketone group at C-4 of the DDMP moiety. Furthermore, for soyasaponin beta g, the MNDO/AM1 method gave an ionization potential of 8.38 eV, electron affinity of 1.16 eV and Mulliken electronegativity of 4.77 eV. Based on this evidence, the synergistic antiradical effects of the soyasaponin beta g-gallic acid system are assumed to involve two-electron reduction from gallic acid.
authors.affiliation: Department of Environmental Bioremediation, Graduate School of Agriculture, Tohoku University, Sendai, Miyagi, Japan. yoshiki@bios.tohoku.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshiki
authors.forename: T
authors.initials: T
authors.lastname: Kahara
authors.forename: K
authors.initials: K
authors.lastname: Okubo
authors.forename: T
authors.initials: T
authors.lastname: Sakabe
authors.forename: T
authors.initials: T
authors.lastname: Yamasaki
mesh_terms: D015764:Bepridil / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D001713:Biphenyl Compounds; D002240:Carbohydrate Sequence; D016166:Free Radical Scavengers / Q000378:metabolism / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D005707:Gallic Acid / Q000378:metabolism*; D008969:Molecular Sequence Data; D009828:Oleanolic Acid / Q000031:analogs & derivatives*; D010851:Picrates; D012503:Saponins / Q000378:metabolism / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism*
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D005609:Free Radicals; D010851:Picrates; D012503:Saponins; C089346:soyasaponin beta g; D013481:Superoxides; D005707:Gallic Acid; D009828:Oleanolic Acid; D015764:Bepridil; C004931:1,1-diphenyl-2-picrylhydrazyl