Claudia Muniain

Patagonicoside A: a novel antifungal disulfated triterpene glycoside from the sea cucumber Psolus patagonicus

Abstract A new triterpene glycoside, patagonicoside A (1), has been isolated from the sea cucumber Psolus patagonicus and its structure has been elucidated by 1D and 2D NMR (1H-, 13C-, 1H–1H COSY, HETCOR, COLOC and NOESY spectra), FAB-MS and chemical evidence. Compound 1 is a disulfated tetrasaccharide with a new aglycon moiety. Patagonicoside A (1) exhibits considerable antifungal activity against the pathogenic fungus Cladosporium cucumerinum.

Antiproliferative, cytotoxic and hemolytic activities of a triterpene glycoside from Psolus patagonicus and its desulfated analog.

Background: The major triterpene glycoside of the sea cucumber Psolus patagonicus and its desulfated analog were tested for their antiproliferative, cytotoxic and hemolytic activities, and their effect on NF-κB activation. Methods: The antiproliferative action of glycosides 1 and 2 were determined on 3 tumor cell lines. Their effect on the activation of NF-κB was evaluated by indirect immunofluorescence assay staining and the concomitant IκBα degradation was studied by Western blot. Results: Both compounds were able to suppress the growth of 3 tumor cell lines (Hep3B, MDA-MB231 and A549) and induced the activation of NF-κB, a key player linking chronic inflammation and cancer, concomitant with IκBα degradation in the A549 tumor cell line. Compounds 1 and 2 showed hemolytic activity with half maximal inhibitory concentration (IC50) values around 80 μM. Conclusions: Both glycosides showed low cytotoxic activity in A549 tumor cells in comparison with sea cucumber triterpene glycosides containing a linear tetrasaccharide chain. This could be a result of the uncommon presence of two 12α- and 17α-hydroxyl groups and a Δ7 double bond in the aglycone moiety. This aglycone functionalization may be related to their low membranolytic activity. Although glycosides 1 and 2 exert an antiproliferative effect, their mechanisms of action do not involve inhibition of NF-κB. Recently, it has been shown that diverse and new mechanisms of action are responsible for the antitumor and cytotoxic activities of marine compounds. Therefore, more extensive studies are needed to establish a mechanism of action and to deduce a clear structure-activity relationship of sea cucumber triterpene glycosides.

Fatty acid composition of the edible sea cucumber Athyonidium chilensis.

The edible sea cucumber Athyonidium chilensis is a fishery resource of high commercial value in Chile, but no information on its lipid and fatty acid composition has been previously reported. Phospholipids were the major lipid contents of the ethanolic extracts of tubules, internal organs and body wall of A. chilensis. Saturated fatty acids predominated in tubule phospholipids (40.69%), while in internal organs and body wall phospholipids, the monounsaturated fatty acids were in higher amounts (41.99% and 37.94%, respectively). The main polyunsaturated fatty acids in phospholipids were C20 : 2ω-6, arachidonic (C20 : 4ω-6) and eicosapentaenoic (C20 : 5ω-3) acids. These results demonstrate for the first time that A. chilensis is a valuable food for human consumption in terms of fatty acids.

Patagonicosides B and C, two Antifungal Sulfated Triterpene Glycosides from the Sea Cucumber Psolus patagonicus

Two new triterpene glycosides, patagonicosides B and C (2 and 3, resp.), together with the known patagonicoside A (1), have been isolated from the EtOH extract of the sea cucumber Psolus patagonicus. The structures of the new compounds were established on the basis of extensive NMR spectroscopic analysis (1H‐ and 13C‐NMR, 1H,1H‐COSY, HMBC, HSQC, TOCSY, and NOESY), HR‐ESI‐MS data, and chemical transformations. Compounds 1–3 and their desulfated analogs showed antifungal activities against the phytopathogenic fungus Cladosporium cladosporoides in a dose‐dependent fashion.

Pseudocnoside A, a new cytotoxic and antiproliferative triterpene glycoside from the sea cucumber Pseudocnus dubiosus leoninus

A new triterpene glycoside, pseudocnoside A (1), was isolated from the sea cucumber Pseudocnus dubiosus leoninus. The structure of the new compound was established on the basis of extensive NMR spectroscopic analysis (1H and 13C NMR, 1H,1H-COSY, HMBC, HSQC, TOCSY and NOESY), HR-ESI-MS data and chemical transformations. In addition, the cytotoxicity and antiproliferative activities of 1 and structurally related triterpene glycosides isolated from the sea cucumbers Psolus patagonicus and Hemioedema spectabilis were evaluated against cancer cell lines A-549 and HeLa.

Bromopyrrole alkaloids isolated from the Patagonian bryozoan Aspidostoma giganteum.

Nine new bromopyrrole alkaloids, aspidostomides A-H and aspidazide A (1-9), were isolated from the Patagonian bryozoan Aspidostoma giganteum. Aspidostomides A-H have dibromotyrosine- or bromotryptophan-derived moieties forming either linear amides or pyrroloketopiperazine-type lactams with a bromopyrrole carboxylic acid as a common structural motif. On the other hand, aspidazide A is a rare asymmetric acyl azide formed by an N-N link of two different pyrroloketopiperazine lactams and is the first isolated compound of this class from marine invertebrates. This work is the first report of secondary metabolites isolated from a bryozoan from the Patagonian region. The structures of compounds 1-9 were elucidated by spectroscopic methods and chemical transformations. One of these compounds, aspidostomide E (5), was moderately active against the 786-O renal carcinoma cell line.

Chemistry of Two Distinct Aeolid Spurilla Species:Ecological Implications

The lipophilic extracts of two marine aeolid nudibranch molluscs of the genus Spurilla collected in distinct geographical areas have been chemically analyzed. The Et2O extracts of the nudibranchs were dominated by the presence of usual fatty acids and sterols and contained terpenoid compounds 1 – 3 as minor metabolites. Spurillin A (1) and spurillin B (3) were new molecules whereas cis‐γ‐monocyclofarnesol (2) was already reported in the literature as a synthesis product. Interestingly, bursatellin (4), previously isolated from anaspidean molluscs of the genus Bursatella, was found in the butanol extract of both Spurilla species. Compounds 1 – 4 were not detected in the extracts of the sea‐anemone preys collected together with the molluscs.