Cytotoxic and antifungal triterpene glycosides from the Patagonian sea cucumber Hemoiedema spectabilis

Structure and Cytotoxicity of a New Lanostane-Type Triterpene Glycoside from the Sea CucumberHolothuria hilla

A new triterpene glycoside, hillaside C (1), was isolated from the sea cucumber Holothuria hilla Lesson, which is found in the South China Sea, and its structure has been elucidated by spectral analysis (ESI-MS and NMR) and chemical transformations. Four known compounds, holothuria A, thymine, uracil, and cholesterol, were also obtained. Compound 1 exhibited significant cytotoxicity against eight human tumor cell lines (A-549, MCF-7, IA9, CAKI-1, PC-3, KB, KB-VIN, and HCT-8) with IC50 values in the range of 0.15-3.20 microg/ml.

Cytotoxic Sulfated Triterpene Glycosides from the Sea CucumberPseudocolochirus violaceus

Bioassay-guided fractionation of the active BuOH extract of the sea cucumber Pseudocolochirus violaceus resulted in the isolation of three new sulfated triterpene glycosides, i.e., violaceusides I, II, and III (1-3, resp.), as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. Their structures were elucidated by spectroscopic methods including 2D-NMR and MS experiments, as well as chemical evidence. Compounds 1-3 exhibit the same structural features, i.e., the presence of a 16-oxo group in the holostane-type triterpene aglycone with the C(7)=C(8) bond, but differ in the side chains and the tetrasaccharide moieties. Compound 1 possesses one sulfate group, while 2 and 3 are disulfated glycosides. All the glycosides showed significant in vitro cytotoxicities against human gastric cancer MKN-45 and human colon cancer HCT-116 cells.

Two new bioactive triterpene glycosides from the sea cucumber Pseudocolochirus violaceus

By activity-guided fractionation, two new triterpene glycosides, violaceusides A (1) and B (2), were isolated from the sea cucumber Pseudocolochirus violaceus as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. By extensive 2D NMR techniques and chemical evidence, the structures of the two new glycosides were established as 16beta-acetoxy-3-O-[3-O-methyl-beta-D-glucopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-beta-D-quinovopyranosyl-(1 --> 2)-4-O-sodiumsulphate-beta-D-xylopyranosyl]-holosta-7,24-diene-3beta-ol (1) and 16beta-acetoxy-3-O-[3-O-methyl-beta-D-glucopyranosyl-(1 --> 3)-beta-D-xylopyranosyl-(1 --> 4)-beta-D-glucopyranosyl-(1 --> 2)-4-O-sodiumsulphate-beta-D-xylopyranosyl]-holosta-7,24-diene-3beta-ol (2), respectively. The two glycosides also exhibited significant cytotoxicity against HL-60 and BEL-7402 cancer cell lines.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, lanostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleannes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins. The literature from January to December 2002 is reviewed and 221 references are used.

Bioresources from echinoderms

More than 6,500 species have been recorded in the phylum Echinodermata. A variety of biologically active substances have been isolated from the echinoderm species: saponins, glycolipids, carotenoids, porphyrins, naphthoquinones, venoms and others. Several substances unique to the echinoderm have also been reported and some of them showed high potentiality as a new medicament. This chapter gives an overview of the history of the exploitation of echinoderm species in the Orient, presents studies on the biologically active substance obtained from them, and discusses questions related to the exploitation of the echinoderm and prospects of development of new medications.