Abstract
Four new trisulfated triterpene glycosides, fallaxosides D4 (1), D5 (2), D6 (3) and D7 (4) have been isolated from the sea cucumber Cucumaria fallax (Cucumariidae, Dendrochirotida). The structures of the glycosides have been elucidated by 2D NMR spectroscopy and HRESIMS. All the glycosides have the lanostane aglycones of a rare non-holostane type with 7(8)-, 8(9)- or 9(11)-double bonds, one or two hydroxyl groups occupying unusual positions in the polycyclic nucleus and shortened or normal side chains. The pentasaccharide carbohydrate moieties of 1–4 have three sulfate groups. The cytotoxic activity of glycosides 1–4 against the ascite form of mouse Ehrlich carcinoma cells and mouse spleen lymphocytes and hemolytic activity against mouse erythrocytes have been studied.
Highlights
Triterpene glycosides are characteristic metabolites of sea cucumbers
The sea cucumbers were extracted with 70% ethanol under reflux during 5 h
CHCl3/EtOH/H2O (100:125:25 and 100:150:50) as mobile phases to obtain the fraction containing polar trisulfated pentaosides
Summary
Triterpene glycosides are characteristic metabolites of sea cucumbers (class Holothurioidea, phylum Echinodermata). We have started studies on the Far-Eastern sea cucumber Cucumaria fallax [6] which contains exclusively non-holostane oligoglycosides having unusual double bond positions and uncommon sites of oxidation in their aglycone moieties. We report the isolation of four new trisulfated glycosides, fallaxosides D4 –D7 (compounds 1–4) with earlier unknown aglycones and their structures, established by analysis of 1 H-, 13 C-NMR and 2D NMR (1 H1 H COSY, 1D TOCSY, HMBC, HSQC, ROESY) spectra and confirmed by HRESI mass spectrometry. The biogenesis of these unusual metabolites is discussed
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