ChemInform Abstract: Isolation and Structural Elucidation of Steroid Oligoglycosides from the Starfish Asterias rubens by Means of Direct Online LC‐NMR‐MS Hyphenation and One‐ and Two‐Dimensional NMR Investigations.

Abstract

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Two New Asterosaponins from the Far Eastern Starfish Lethasterias fusca

“…Elucidation of the pentasaccharide moiety of 2 was carried out in the same manner as for compound 1 ( xy-5-cholest-9(11)-en-3-yl sulfate. Compound 2 has an aglycon with the rare 23-hydroxy-cholestane side chain previously reported only from the starfish Distolasterias nipon [11] and Asterias rubens [13].…”

“…The water-soluble materials from the EtOH extract of L. fusca were sequentially subjected to chromatographic separation on columns of Polychrom 1, Sephadex LH-20, Si gel and Florisil, followed by HPLC on semi-preparative and analytical Diasfer-110-C18 columns to yield two new asterosaponins, lethasteriosides A (1) and B (2), along with previously known glycosides 3-5 ( Figure 1). Compounds 3-5 were identified by comparison of their 1 H and 13 C NMR, and MS spectra with those of thornasteroside A (3), which was first reported from the starfish Acanthaster planci [3,5], anasteroside A (4) from Anasterias minuta [6], and luidiaquinoside (5) from Luidia quinaria [7]. Structures of the new compounds were mainly elucidated by 1 H-1 H COSY, HSQC, HMBC, NOESY, and TOCSY experiments.…”

“…1 H and13 C NMR data and HMBC and NOESY correlations of the oligosaccharide moieties of lethasteriosides A (1) and B (2) (35ºC,  in ppm, J in Hz).…”

Introduction to hyphenated techniques and their applications in pharmacy

“…A combination of matrix solid-phase dispersion extraction and LC-NMR-MS was applied in the rapid on-line identification of asterosaponins of the starfish Asterias rubens . [2324] The LC-NMR-MS provided structural information in one single chromatographic run and was suitable for saponins in the molecular mass range 1200–1400 amu. This technique also allowed semiquantitative LC-NMR measurements through methyl signals (Me-18 and Me-19) of the steroidal skeleton.…”

Phytochemical analysis of the Southern Australian marine alga, Plocamium mertensii using HPLC‐NMR

“…Most of these studies have described the identification of known members of these structure classes by HPLC-NMR, but the technique has also been used to determine the structures of new analogues of known compounds. HPLC-NMR applications have dealt mainly with the characterisation of plant-derived mixtures (Clarkson et al, 2006), while applications to secondary metabolites of microorganisms (Abel et al, 1999;Kleinwachter et al, 2000) or marine natural products (Hostettmann et al, 1998;Bobzin et al, 2000;Sandvoss et al, 2000Sandvoss et al, , 2001 are still relatively uncommon. Publications to date have focused mainly on the characterisation and identification of small molecules up to a molecular weight of about 700, but HPLC-NMR has also been successfully applied to identify saponins of a molecular weight up to 1400 and to characterise larger biomolecules such as glycosphingolipids (Backer et al, 1999;Sandvoss et al, 2000Sandvoss et al, , 2001.…”