Search

Five sphingoid bases, penasin A (1), penasin B (2), and a mixture of penasins C-E (3-5), were identified from a marine sponge Penares sp. as cytotoxic constituents. The structure of the common polar head part was assigned by analysis of the NMR data, whereas the structures of the long aliphatic chains including the locations of double bond(s) and a branched methyl group were determined by analysis of tandem FABMS and (13)C NMR data together with the GC-MS analysis of ozonolysis products. The absolute configuration of the headgroup was defined for the mixture of 3-5 by the modified Mosher method. Penasins exhibit moderate cytotoxicity against HeLa and P388 cells.

The new phytosphingosine-type ceramide asteriaceramide A (1) and glucocerebroside asteriacerebroside G (2), together with two known cerebrosides, asteriacerebrosides A and B, were isolated from lipophilic fractions of the whole bodies of the Northern Pacific starfish Asterias amurensis Lütken. The water-soluble fraction afforded two known asterosaponins, glycoside B(2) and asterosaponin-1. The structures of 1 and 2 were determined on the basis of chemical and spectroscopic evidence as (2S,3S,4R,13Z)-2-[(2'R)-2-hydroxyhexadecanoylamino]-13-docosene-1,3,4-triol (1) and 1-O-(beta-d-glucopyranosyl)-(2S,3R,4E,13Z)-2-[(2'R)-2-hydroxytetradecanoylamino]-4,13-docosadiene-1,3-diol (2). Compounds 1, 2, and asteriacerebrosides A and B promoted plant growth in sprouts of Brassica campestris.

Two new sphingosines, (2S,3R)-2-(docosanoyl amino)nonadecane-1,3-diol (1) and (2S,3S,4R)-2-[(2'R)-2'-hydroxynonadecanoylamino]nonadecane-1,3,4-triol (3), along with the known (2S,3R,4E)-2-(heptadecanoylamino)octadec-4-ene-1,3-diol, have been isolated from Pseudopterogorgia australiensis, of the Indian Ocean. The structures were deduced from spectral and chemical methods. Compounds 1-3 showed moderate antibacterial activity.

The marine sponge Grayella cyatophora furnished several new homologous sphingosines having the same acyl substituent. Structure elucidations were achieved by spectroscopic methods and chemical transformations.

An anhydrophytosphingosine named pachastrissamine (3) has been isolated as a cytotoxic principle of a sponge, Pachastrissa sp., and the structure including the absolute configuration determined by spectroscopic and chemical analysis.

Two new sphingosine 4-sulfates (1 and 2) have been isolated from the sponge Spirastrella abata as cytotoxic constituents. The gross structures of 1 and 2 were determined by spectroscopic analysis, and their stereochemistry was established by chemical conversion. The compounds exhibited significant cytotoxicity against a small panel of five human tumor cell lines.

The Caribbean marine sponge Haliclona vansoesti was found to contain a high amount (5% dry wt) of a new analogue of 4-sphingenine, (2R,3R, 7Z)-2-aminotetradec-7-ene-1,3-diol (1). Its structure was determined by detailed spectroscopic analysis. The relative configuration was deduced from the NMR data of the corresponding acetonide 5, while the absolute configuration was secured via protection of the primary alcohol and amino groups, and esterification of the secondary alcohol with Mosher's reagent.