A ganglioside molecular species, LMG-2 (1), has been structure of 1 has been elucidated. 1 is a ganglioside molecular species of starfish resembling the mammalian obtained from the water-soluble lipid fraction of the chloroform/methanol extract of the starfish Luidia maculata.
ganglioside GM 3 . In addition, 1 shows neuritogenic activity toward the rat pheochromocytoma cell line PC-12 cell. On the basis of chemical and spectroscopic findings, the In our previous studies, the ganglioside molecular species (C-2Ј)]. The 13 C-NMR spectrum of 1 also reveals signals due to three anomeric carbon atoms at δ C ϭ 105.0, 105.3, LG-2, which has been obtained from the starfish Astropecten latespinosus, has been found to show antitumor ac-101.0, one of which (δ C ϭ 101.0) is a quaternary carbon signal suggesting the existence of sialic acid. Furthermore, tivity against murine lymphoma L1210 cells, [1] and another ganglioside molecular species GAA-7, obtained from the 1 is presumed to have normal type (major) and ante-iso types (minor) of terminal methyl groups, because the car-starfish Asterias amurensis versicolor showed neuritogenic and growth-inhibitory activities towards the mouse neuro-bon signals are observed at δ C ϭ 14.5 (normal form), δ C ϭ 11.7 and 19.5 (ante-iso form) in the 13 C-NMR spectrum of blastoma cell line (Neuro 2a). Continuing the previous studies, we have conducted the isolation and structure eluci-1. The negative-ion fast atom bombardment mass spectrum (FAB MS) exhibits a series of quasi-molecular ion peaks dation of the biologically active glycosphingolipids from the starfish Luidia maculata (Yatsudesunahitode in Japanese) which are different by 14 mass units ([M Ϫ H] Ϫ at m/z 1241, 1255, 1269, 1283, 1297, 1311). Therefore, 1 is suggested to with the object of searching for lead compounds for new medicines. In the preceding paper, we reported isolation and be a molecular species of phytosphingosine-type ganglioside possessing 2-hydroxy fatty acid and three monosac-characterization of the new sulfatide molecular species LMG-1, obtained from the starfish L. maculata. In this charides. The fatty acid and long-chain base (phytosphingosine) constituents and the structure of sialosyl oligosaccha-paper the isolation, structure determination and biological activity of a new ganglioside molecular species from the ride moiety of 1 are determined as follows. starfish are described.
The structure of the ceramide moiety was examined first. A water-soluble lipid fraction, obtained from the chloro-When 1 was methanolyzed with 5% HCl/MeOH, a mixture form/methanol extract of the whole bodies of L. maculata, of fatty acid methyl ester (FAM) was obtained together was subjected to reversed-phase, followed by normal-phase with a mixture of methyl glycosides and long-chain base column chromatography to give a ganglioside molecular (LCB). A gas chromatographyϪmass spectrometry (GCspecies LMG-2 (1) showing a single spot in normal-phase MS) analysis of the FAM mixture shows the existence of thin-layer chromatography (TLC).
three components (FAM 1Ϫ3) which are characterized Compound 1 shows strong hydroxy (3389 cm Ϫ1 ) and amas methyl 2-hydroxydocosanoate, methyl 2-hydroxytriide (1637 cm Ϫ1 ) absorptions in the IR spectrum. The 13 Ccosanoate, methyl 2-hydroxytetracosanoate. The major NMR spectrum of 1 shows the characteristic signals of a FAM is methyl 2-hydroxydocosanoate. On the other hand, phytosphingosine-type ceramide possessing a 2-hydroxy by means of the GCϪMS analysis of the TMS derivative fatty acid and a sugar moiety at C-1 (Table ) [δ C ϭ 70.0 of the LCB mixture, the LCB components are suggested to (C-1), 51.4 (C-2), 75.6 (C-3), 72.5 (C-4), 175.8 (C-1Ј), 72.3 be 2-amino-1,3,4-pentadecantriol (LCB-1), 2-amino-1,3,4hexadecantriol (LCB-2), 2-amino-1,3,4-heptadecanetriol (LCB-3), 2-amino-1,3,4-octadecanetriol (LCB-4) and 2-[ ] Parts 37 and 1: Ref.