Calcigeroside

Three monosulfated pentaoside glycosides isolated from the Far Eastern sea cucumber Pentamera calcigera, calcigerosides B (82), Cl (83) and C2 (84) were not active in vitro against standard mouse and human tumor cell lines (P-388, A-549, HT-29, and Mel-28) while their desulfated derivatives (85, 86 and 87 respectively) showed moderate cytotoxic activity (IC50 = 5 p,g/ml) [72]. 

Calcigeroside C2 and its desulfated derivative were individually tested in vitro against four standard human and mouse tumoral cell lines (P-388, A-549, HT-29 and Mel-98). Only the desulfated derivative showed moderate cytotoxicity (IC50 = 5 ig/ml). 

Calcigeroside E (54), Fig. (23) is a new disulfated pentaglycoside isolated from the sea cucumber Calcigera pentamera [70]. 

Saponin 60 has the aglycone of holothurin Ai [96] whereas holothurin B3 has the same aglycon side chain as the 3P-hydroxyholost-7-ene aglycones in cucumarioside G4 [63], eximisoside A [64] and calcigeroside E [69]. 

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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