title: Spirostanols obtained by cyclization of pseudosaponin derivatives and comparison of anti-platelet agglutination activities of spirostanol glycosides.
abstract: Naturally occurring saponins 3 and 4 have a normal type F ring and alpha-arranged CH(3)-21 group. Treatments of pseudosaponin peracetates 18 and 19 derived from 3 and 4, respectively, with alcoholic KOH, followed by acidification with acetic acid, gave spirostanols 20 and 22 having iso type F rings as major products. Structural analyses of sapogenins and saponins derived from pseudo derivatives 11, 12, 18 and 19 were performed by comparisons of their 1H-NMR spectral data and the X-ray analytical data of 3-O-p-bromobenzoyl sarsasapogenin 7, 3-O-acetyl diosgenin 13 and saponin 20. The mechanisms of ring-closure reaction of the side chain at C-22 of pseudosapogenins and pseudosaponins were deduced using stereomodels of the spirostanols derived from 11 under various reaction conditions. Inhibitory activities of saponin diglycosides 3, 4, 20, 21 and 25 on human platelet agglutinations induced by ADP and ristocetin were compared.
authors.affiliation: Faculty of Pharmaceutical Sciences, Josai University, Keyakidai 1-1, Sakado, 350-0295, Saitama, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Tobari
authors.forename: M
authors.initials: M
authors.lastname: Teshima
authors.forename: J
authors.initials: J
authors.lastname: Koyanagi
authors.forename: M
authors.initials: M
authors.lastname: Kawase
authors.forename: H
authors.initials: H
authors.lastname: Miyamae
authors.forename: K
authors.initials: K
authors.lastname: Yoza
authors.forename: A
authors.initials: A
authors.lastname: Takasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Nagamura
authors.forename: S
authors.initials: S
authors.lastname: Saito
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D018360:Crystallography, X-Ray; D006027:Glycosides / Q000138:chemical synthesis* / Q000494:pharmacology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D010975:Platelet Aggregation Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology; D012310:Ristocetin / Q000494:pharmacology; D012503:Saponins / Q000737:chemistry*; D013150:Spirostans / Q000138:chemical synthesis* / Q000494:pharmacology; D013261:Sterols / Q000138:chemical synthesis / Q000494:pharmacology
chemical_list: D006027:Glycosides; D010975:Platelet Aggregation Inhibitors; D012503:Saponins; D013150:Spirostans; D013261:Sterols; D012310:Ristocetin; D000244:Adenosine Diphosphate