New oleanane-type saponins from Astragalus flavescens
Makaleler > Tam Makale · 2007
Yazarlar: S Avunduk, AC Mitaine-Offer, T Miyamoto, Özgen ALANKUŞ, MA Lacaille-Dubois
Planta Medica, Uluslararası, Wos, 2007, cilt 73
Özet
Six new oleanane-type saponins were isolated by solid/liquid preparative chromatography, from a methanolic extract of the roots of a Turkish plant of the Fabaceae family, Astragalus flavescens Boiss. While mainly cycloartane-type saponins were found in the genus Astragalu s [1], their aglycone was identified as (21α,22β,24β,29α)-21,22,24,29-tetrahydroxyolean-12-ene mainly by 600MHz 2D NMR techniques and mass spectrometry. Two heterosidic linkages were established at the C3 and C22 positions of this aglycone. At The C3 position, either of two oligosaccharidic chains were found, α-L-rhamnopyranosyl-(1(→2)-β-D-xylopyranosyl-(1(→2)-β-D-glucuronopyranosyl and α-L-rhamnopyranosyl-(1(→2)-β-D-glucopyranosyl-(1(→2)-β-D-glucuronopyranosyl, and at the C22 position, the hydroxyl group can be either free or substituted with a β-D-glucopyranosyl unit or an α-L-arabinopyranosyl unit. References: [1] Verrota, L., El-Sebakhy, N.A. (2001) Studies in Natural Products Chemistry, Vol. 25. Atta-ur-Rahman (Ed.). Elsevier. Amsterdam.