Ichthyotoxic brominated diphenyl ethers from a mixed assemblage of a red alga and cyanobacterium

Structure clarification and biological properties

Takashi L. Suyama, Zhengyu Cao, Thomas F. Murray, William H. Gerwick

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Primary fractions from the extract of a tropical red alga mixed with filamentous cyanobacteria, collected from Papua New Guinea, were active in a neurotoxicity assay. Bioassay-guided isolation led to two natural products (1,2) with relatively potent calcium ion influx properties. The more prevalent of the neurotoxic compounds (1) was characterized by extensive NMR, mass spectrometry, and X-ray crystallography, and shown to be identical to a polybrominated diphenyl ether metabolite present in the literature, but reported with different NMR properties. To clarify this anomalous result, we synthesized a candidate isomeric polybrominated diphenyl ether (3), but this clearly had different NMR shifts than the reported compound. We conclude that the original isolate of 3,4,5-tribromo-2-(2,4-dibromophenoxy)phenol was contaminated with a minor compound, giving rise to the observed anomalous NMR shifts. The second and less abundant natural product (2) isolated in this study was a more highly brominated species. All three compounds showed a low micromolar ability to increase intracellular calcium ion concentrations in mouse neocortical neurons as well as toxicity to zebrafish. Because polybrominated diphenyl ethers have both natural as well as anthropomorphic origins, and accumulate in marine organisms at higher trophic level (mammals, fish, birds), these neurotoxic properties are of environmental significance and concern.

Original languageEnglish
Pages (from-to)204-210
Number of pages7
JournalToxicon
Volume55
Issue number2-3
DOIs
StatePublished - Feb 2010

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Halogenated Diphenyl Ethers
Rhodophyta
Cyanobacteria
Algae
Nuclear magnetic resonance
Biological Products
Ions
Calcium
Papua New Guinea
Aquatic Organisms
X Ray Crystallography
Zebrafish
Phenol
Biological Assay
Mammals
Birds
Bioassay
X ray crystallography
Mass Spectrometry
Fishes

All Science Journal Classification (ASJC) codes

  • Toxicology

Cite this

Ichthyotoxic brominated diphenyl ethers from a mixed assemblage of a red alga and cyanobacterium : Structure clarification and biological properties. / Suyama, Takashi L.; Cao, Zhengyu; Murray, Thomas F.; Gerwick, William H.

In: Toxicon, Vol. 55, No. 2-3, 02.2010, p. 204-210.

Research output: Contribution to journalArticle

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