Hillasides A and B, two new cytotoxic triterpene glycosides from the sea cucumber Holothuria hilla Lesson

Abstract

Two new triterpene glycosides, hillasides A (1) and B (2), were isolated from the sea cucumber H. hilla Lesson, together with one known glycoside holothuria B (3). Their structures were deduced by extensive spectral analysis and chemical evidences. The presence of conjugated double bonds [22E,24-diene] in the aglycone of 1 is a rare structural feature among sea cucumber glycosides. The two glycosides showed significant cytotoxicity against eight human tumour cell lines (A-549, MCF-7, IA9, CAKI-1, PC-3, KB, KB-VIN and HCT-8) with IC ₅₀ in the range of 0.1–3.8 μg/ml.

Keywords:

• Holothuria hilla
• Triterpene glycosides
• Cytotoxicity
• Hillaside A
• Hillaside B

Acknowledgements

This investigation was supported by a grant from Shanghai Foundation for New Drug Research awarded to Yang-HuaYi (02DZ19101) and a grant from the National Cancer Institution, awarded to K.H.L.(NIH, CA17625). We wish to thank Professor Yu-Lin Liao of Qingdao Oceanic University for taxonomic identification of the sea cucumber.