Cardenolide aus Ornithogalum boucheanum ¹

Abstract

From leaves and bulbs of Ornithogalum boucheanum (Kunth) Aschers. et Graebn. (Liliaceae), cardenolides were isolated by a combination of column and droplet counter-current chromatography. Their structure elucidation was performed mainly by means of ¹H-NMR, ¹³C-NMR, EI-MS, and LD-MS studies as well as by acid and/or enzymatic hydrolysis of the glycosides followed by identification of genins and sugar moieties (TLC, GC). Eight cardenolides were identified as sarmentogenin-3-O-6′-deoxy-β-D-allosido-β-D-xylosido-α-L-rhamnoside, sarmentogenin-3-O-6′-deoxy-β-D-allosido-β-D-xylosido-β-D-apioside, 15β, 16α-dihydroxyuzarigenin-3-O-β-D-digitoxosido-β-D-xylosido-α-L-rhamnoside, sarmentogenin-3-O-β-D-digitoxosido-β-D-xylosido-β-D-apioside, syriogenin-3-O-β-D-digitoxosido-β-D-xylosido-α-L-rhamnoside, sarmentogenin-3-O-α-L-rhamnosido-β-D-apioside, uzarigenin-3-O-β-D-digitoxosido-β-D-xylosido-α-L-rhamnoside, and digitoxigenin-3-O-6′-deoxy-β-D-allosido-β-D-xyloside. This is the first report of the occurrence of 15β, 16α-dihydroxyuzarigenin. The presence of three genins - syriogenin, uzarigenin, and digitoxigenin - in the genus Ornithogalum is described for the first time. For cardenolides, not only the combination of three different monosaccharides in one glycoside is unusual, but, especially, the occurrence of apiose, which was not known for cardiac glycosides until now.