Sea cucumber glycosides

Table 3 shows the 13C-NMR data for the sugar units of sea cucumber glycosides containing different pentasaccharide chains. 

Recently several new structural types of aglycons have been discovered in our laboratory [3-7]. Monosaccharide compositions of sea cucumber glycosides usually include D-xylose, D-quinovose, 3-0-methyl-D-glycose, D-3-O-methylxylose and D-glucose and rarely 6-O-acethyl-D-glucose [8,6]. 

The inhibition of biosyntheses of nucleic acids and proteins in rat spinal cord cell cultures were also studied to ascertain the mechanism of action of sea cucumber glycosides [137]. Addition of holotoxin Ai (33) to incubation media (2.5-5 p,g/ml) inhibited " C-alanine incorporation into the acid-insoluble cell fraction more... 

Thus sea cucumber glycosides are strong but not absolute defenses against various predators. 

The defensive action of sea-cucumber glycosides against feeding competitors connects with the same functional components as... 

The biological activities of sea cucumber glycosides and physical properties of these substances indicate an important external defensive function. Their functions must correlate with membranotropic action of glycosides against model biological test-systems. 

Immunomodulatory action of sea cucumber glycosides at very low concentrations has the greatest interest from the pharmacological point of view. It reasonable, that this action is also related to the modifying effect on membranes of target cells. 

Recently, we have reviewed for the first time the chemical structures of sea cucumber glycosides and the principal spectral features of the aglycones and oligosaccharide chains in their H- and C-NMR spectra [55]. Most of these triterpenoid oligoglycosides contain an aglycone... 

Calcigeroside B (62b) has a quinovose terminal residue attached to another quinovose unit. This structural feature is unique for sea cucumber glycosides [69]. Psolusoside B (62a) showed inhibition of rat brain Na", K -ATPase with an To value of 3 x lO " M [99]. Calcigerosides B (62b), Cl (62c) and C2 (62e) were individually tested in vitro against four standard human and mouse tumoral cell lines (P-388, A-549, HT-29 and Mel-98). Only their desulfated derivatives showed moderate cytotoxicity (IC50 = 5 pg/ml) [70]. 

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