Glycosides of marine invertebrates. XV. A new triterpene glycoside — Holothurin A1 — From Caribbean holothurians of the family Holothuriidae

Holothurins B2, B3, and B4, New Triterpene Glycosides from Mediterranean Sea Cucumbers of the Genus Holothuria

“…The 13 C NMR spectrum of the aglycon moiety of 1 was identical to that of the tetraoside holothurin A 1 from H. floridana. 7 In confirmation of the carbohydrate chain structure, the MALDI TOF MS of the glycoside 1 exhibited a pseudomolecular ion peak at m/z 907 [M + Na] + in the positive ion mode and pseudomolecular ion peaks at m/z 861 [M -Na]and 715 [M -Na -Qui + H] -(due to the loss of a terminal monosaccharide residue) in the negative ion mode. All these data including results of 2D NMR experiments (presented in Figure 1 2) were very close to those of the known holothurin B (5), 5 but the signals of C-16 and C-17 were shifted upfield to 23.5 and 47.5 ppm, correspondingly, due to the absence of a hydroxy group at C-17.…”

Saponin and Fatty Acid Profiling of the Sea Cucumber Holothuria atra, α-Glucosidase Inhibitory Activity and the Identification of a Novel Triterpene Glycoside

“…Leucospilotaside A was also identified in the viscera of H. lessoni [ 58 ]. Holothurin A1 and holothurin A4 were isolated from H. floridana and H. grisea [ 67 ]. Scabraside D was detected from H. scabra and H. lessoni [ 10 , 68 , 94 ].…”

The Assignment of the Absolute Configuration of C-22 Chiral Center in the Aglycones of Triterpene Glycosides from the Sea Cucumber Cladolabes schmeltzii and Chemical Transformations of Cladoloside C

“…The importance of determination of the absolute configuration of the C-22 chiral center is defined by the frequent occurrence of holostane aglycones with either hydroxy-or acetoxy groups at this position in glycosides from different systematic groups of sea cucumbers [5][6][7][8][9][10], whose configurations were not assigned.…”

“…As already mentioned above, the aglycones having hydroxy-or acetoxy-groups at C-22, having a C-22 chiral center are not so rare in the sea cucumber glycosides. Four representatives of the family Holothuriidae, order Aspidochirotida are known to have glycosides with a 22-hydroxy-group: Holothuria floridana [5], H. grisea [6,7], Actinopyga flammea [8] and H. polii [10]. Three species of sea cucumber belonging to the order Dendrochirotida contain glycosides with 22-hydroxy-and/or 22-acetoxy-groups in the aglycones: Cucumaria frondosa [14][15] and Actinocucumis typica [17] (family Cucumariidae); Cladolabes schmeltzii (family Sclerodactylidae) [1,2,3].…”

“…Such a process of cyclization of the side chain could be considered as a biomimetic reaction, which models the biosynthetic process of the formation of widespread sea cucumber aglycones with a 22,25epoxy-group from the aglycones with an open side chain. The simultaneous presence in one species of sea cucumber of the glycosides having aglycones with an open side chain and oxygen functionality (hydroxy-or acetoxy-groups) at C-22 and the aglycones with an oxygenated cycle in the side chain[6][7][8][9][10] could be considered as indirect evidence for such a biosynthetic process.  SR sign distribution in 22-MTPA esters of 2 and absolute configuration of C-22 chiral center in the progenin 2.Since progenin 2 was isolated in sufficient amount in comparison with 3 it was selected for the assignment of the absolute configuration of the C-22 chiral center by application of a modified Mosher ' s method[4a-c].…”