title: Geographic variation of natural products of tropical nudibranch Asteronotus cespitosus.
abstract: Extracts of the dorid nudibranch Asteronotus cespitosus from two geographically separate regions of Australia and from the Philippines were compared using thin-layer, high-performance liquid and gas chromatography and 1H NMR analysis. Halogenated metabolites were detected in all mollusk specimens. The major component detected in digestive tissue of specimens from the Great Barrier Reef in northeastern Australia was 4,6-dibromo-2-(2'.4'-dibromophenoxy)phenol (1), with minor amounts of 3,5-dibromo-2-(3',5'-dibromo-2'-methoxyphenoxy)phenol (2). In a specimen collected from northwestern Australia, only 3,5-dibromo-2-(3',5'-dibromo-2'-methoxyphenoxy)phenol was found. The specimen from the Philippines contained 2,3,4,5-tetrabromo-6-(2'-bromophenoxy)phenol (3) together with a novel chlorinated pyrrolidone (4). In addition, the sesquiterpenes dehydroherbadysidolide (5) and spirodysin (6) were detected in the digestive organs and mantle tissue of the nudibranchs from the Great Barrier Reef and from the Philippines, whereas these chemicals were not found in the specimen from northwestern Australia. All of the chemicals (1-3,5, and 6) have previously been isolated from the sponge Dysidea herbacea, as have chlorinated metabolites related to 4. This is the first time the characteristic halogenated metabolites that typify Dysidea herbacea have been reported from a carnivorous mollusk, which implies a dietary origin as opposed to de novo synthesis.
authors.affiliation: Department of Chemistry, The University of Queensland Brisbane, Australia. sfahey@mailbox.uq.edu.au
authors.forename: Shireen J
authors.initials: SJ
authors.lastname: Fahey
authors.forename: Mary J
authors.initials: MJ
authors.lastname: Garson
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D014644:Genetic Variation; D005843:Geography; D006842:Hydrocarbons, Brominated / Q000378:metabolism* / Q000494:pharmacology; D020128:Inhibitory Concentration 50; D007941:Leukemia P388 / Q000378:metabolism; D051379:Mice; D008974:Mollusca / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010636:Phenols / Q000378:metabolism* / Q000494:pharmacology; D011760:Pyrrolidinones / Q000737:chemistry; D012717:Sesquiterpenes / Q000378:metabolism* / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D006842:Hydrocarbons, Brominated; D010636:Phenols; D011760:Pyrrolidinones; D012717:Sesquiterpenes