The structures of two new monodesmosidic spirostanosides and a new bisdesmosidic furostanol glycoside isolated from the roots of Asparagus africanus Lam. (Liliaceae) have been elucidated as (25R)-3β-hydroxy-5β-spirostan-12-one 3-O-{β-D-glucopyranosyl-(1→2)-[α-L-arabinopyranosyl-(1→6)]-[β-D-glucopyranoside} (1), (25R)-5β-spirostan-3β-ol 3-O-{β- D-glucopyranosyl-(1→2)-[α-L-arabinopyranosyl-(1→6)]-[β-D-glucopyranoside} (2) and 26-O-β-D-glucopyranosyl]-22α-methoxy(25R)-furostan-3β,26-diol 3-O-{β-D-glucopyranosyl-(1→2)-[β-D-glucopyranoside} (3), respectively, by the combined use of one and two dimensional NMR experiments. The complete 13C and 1H assignments of the peracetyl spirostanosides and the furostanol oligoside were derived. The interconversions between the methoxyl and hydroxyl group at C-22 of the furostanol glycoside was investigated and the genuine furostanol oligoside of A. africanus appears to be the hydroxyl type based on the comparative study of the methanol, pyridine and dioxane extracts.
Liliaceae, Asparagus africanus, spirostanol glycoside furostanol glycoside, gloriogenin, smilagenin
NCBI PubMed ID: 10444861Publication DOI: 10.1016/S0031-9422(99)00051-5Journal NLM ID: 0151434Publisher: Elsevier
Institutions: Institut für Pharmazeutische Chemie, Universität Graz, Universitätsplatz 1, 8010 Graz, Austria, Schering A.G., Berlin Müllerstr. 170-178, 13342 Berlin, Germany, Ethiopian Health and Nutrition Research Institute, P.O. Box 1242, Addis Abeba, Ethiopia
Methods: 13C NMR, 1H NMR, IR, FAB-MS, GC-MS, TLC, UV, optical rotation measurement, acetylation, TOCSY, PC, DQF-COSY, HMBC, DEPT, COSY, HSQC, HCl hydrolysis, HSQC-TOCSY, HSQC-DEPT, trimethylsilylation
Found