| Ulapualide B (1) is a macrolide that was first isolated from the eggmasses of the nudibranch Hexabranchus sanguineus but which presumably is sequestered by the mollusk from a dietary source as a defensive chemical. The compound is then passed on to its eggmasses which have a known predator, the aeolid nudibranch Favorinus japonicus. This hypothesis was tested by using isotope ratio mass spectrometry to "fingerprint" ulapualide and follow the compound from the nudibranch to its eggmasses.;Preliminary results indicate that ulapualide is not simply passed from the nudibranch to the eggmasses. It was also shown that ulapualide is present in Favorinus japonicus.;A sponge of the genus Strongylophora, collected at Puako, Hawaii, has yielded three C-19 oxidized pregnanes (2, 3 and 4) from the lipophilic extract. One of the compounds showed marginal cytotoxicity against two tumor cell lines. Some pregnanes are human sex hormones which suggests their potential therapeutic use. The structure of 2 was confirmed by x-ray diffraction crystallography.;The volatile halogenated constituents of the acorn worm, Balanoglossus aurantiacus were determined by gas chromotography-mass spectrometry. These compounds were under investigation for their possible role as mediators of the microbiology in the animals' habitat. Twenty compounds containing halogens were identified in the extracts of the animal. The compounds consisted of one chlorinated aromatic, twelve brominated aromatics, five aromatic compounds containing both chlorine and bromine, and two nitrogenous compounds containing chlorine. None of the chlorinated compounds had previously been reported from acorn worms.;A sponge of the genus Rhabdastrella, collected in Manado, Sulawesi, Indonesia, yielded stelliferinoside (5), a new isomalabaricane triterpenoid containing a ribopyranose glycoside, and the previously described stelliferin A (6). Both compounds show marginal cytotoxicity against two tumor cell lines.;A phenolic compound 7 isolated from a sponge collected in Manado, Indonesia, contains three stereocenters but has zero optical rotation at the sodium D line. This compound is structurally related to compounds shown to inhibit H, K-ATPase activity. (Abstract shortened by UMI.). |
