Pentamera calcigera

Several triterpene glycosides isolated from the sea cucumbers Cucumaria echinata and Pentamera calcigera contain a carbonyl group at C-23 in the side chain, Fig. (15). This structural feature is absent in 3(i-hydroxyholost-9(l l)-ene aglycones. 

Fig. (15). Structures of glycosides isolated from the sea cucumbers Cucumaria echinata and Pentamera calcigera...

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]. 

Avilov, S.A., Antonov, A.S., Drozdova, OA., Kalinin, V.I., Kalinovsky, A.I., Stonik, V.A., Riguera, R., and Jimenez, C. (2000a) Triterpene glycosides from the far-eastern sea cucumber Pentamera calcigera. 1. Monosulfrted glycosides and cytotoxicity of their imsidfated derivatives. J. Nat. Prod., 63, 65-71. 

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

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