title: A saponin conjugated with 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one from Dolichos lablab.
abstract: A new 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated saponin, lablab saponin I, was isolated from the hypocotyl of hyacinth bean (Dolichos lablab). The structure was elucidated by 1H NMR and 13C NMR spectroscopy and chemical techniques as 3-O-[alpha-L-rhamnopyranosyl- (1-->2)-beta-D-galactopyranosyl(1-->2)-beta-D-glucuronopyranosyl(1 -->)]-22-O- [2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one(2'-->)]-3 beta, 22 beta, 24-trihy-droxyolean-12-en-28-al. SOD (superoxide dismutase)-like activity depended upon the DDMP group and the aldehyde group (C-28) of the aglycone was observed in the order of lablab saponin I > glutathione > soyasaponin beta g > maltol. The soybean saponin Bb, lacking the DDMP moiety was found not to exhibit the SOD-like activity.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Tohoku University, Miyagi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshiki
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: K
authors.initials: K
authors.lastname: Okubo
authors.forename: I
authors.initials: I
authors.lastname: Nagoya
authors.forename: T
authors.initials: T
authors.lastname: Sakabe
authors.forename: N
authors.initials: N
authors.lastname: Tamura
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009828:Oleanolic Acid / Q000031:analogs & derivatives*; D010944:Plants / Q000737:chemistry*; D012503:Saponins / Q000737:chemistry* / Q000302:isolation & purification; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: C093057:3-O--(rhamnopyranosyl-1-2-galactopyranosyl-1-2-glucuronopyranosyl-1-)-22-O-(2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyrano-4-one-2'-)-3,22,24-trihydroxy-olean-12-en-28-al; D012503:Saponins; D009828:Oleanolic Acid; D013482:Superoxide Dismutase