Phytochemical examination of the bulbs of Ornithogalum saundersiae yielded six cholestane rhamnosides, two of which had previously been isolated from the same plant material. However, detailed spectroscopic analysis of the aglycone led us to revise the configuration of the C-11 hydroxyl group of the latter two and reassign their structures as (22S)cholest-5-ene-3β,11α,16β,22-tetrol 16-O-α-L-rhamnopyranoside and (22S)-cholesta-5,24-diene-3β,11α,16β,22-tetrol 16-O-α-L-rhamnopyranoside, respectively. The other four are new naturally occurring constituents and their structures were determined to be (22S)-cholest-5-ene-3β,11α,16β,22-tetrol 16-O-(2,3-di-O-acetyl-α-L-rhamnopyranoside), (22S)-cholest-5-ene-3β,11α,16β,22-tetrol 16-O-{2-O-acetyl-3-O-(3,4,5-trimethoxybenzoyl)-α-L-rhamnopyranoside}, (22S)-cholest-5-ene-3β,11α,16β,22-tetrol 16-O-{2-O-acetyl-3-O-(p-methoxybenzoyl)-α-L-rhamnopyranoside} and (22S)-cholesta-5,24-diene-3β,11α,16β,22-tetrol 16-O-(2,3-di-O-acetyl-α-L-rhamnopyranoside), respectively. The isolated compounds were evaluated for their cytostatic activity against leukemia HL-60 cells.
Liliaceae, cytostatic activity, bulbs, HL-60 cells, Ornithogalum saundersiae, cholestane rhamnosides
NCBI PubMed ID: 10501027Publication DOI: 10.1016/S0031-9422(99)00240-XJournal NLM ID: 0151434Publisher: Elsevier
Correspondence: Mimaki Y
Institutions: School of Pharmacy, Tokyo University of Pharmacy and Life Science, Horinouchi 1432-1, Hachioji, Tokyo 192-0392, Japan
Methods: 13C NMR, 1H NMR, EI-MS, IR, FAB-MS, HPLC, molecular modeling, optical rotation measurement, molecular mechanics, cytotoxicity assay, HMBC, HMQC, COSY, NOESY, HR-FAB-MS, molecular dynamics, HCl hydrolysis, absolute configuration determination, alkaline methanolysis, cytostatic activity assay
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