Eudesmacarbonate, a Eudesmane-Type Sesquiterpene from a Marine Filamentous Cyanobacterial Mat (Oscillatoriales) in the Florida Keys.

A new, cyclic carbonate eudesmane-type sesquiterpene, eudesmacarbonate (), was isolated from marine filamentous cyanobacterial mats associated with apparent ingestion-related intoxications of captive bottlenose dolphins in the Florida Keys. Sequencing of 16S rDNA revealed that mats were composed of closely related Oscillatoriacean species including a previously undocumented species of . The structure of was elucidated by (+)-HRESIMS, 1D and 2D NMR, single-crystal X-ray diffraction, and vibrational circular dichroism data. Toxicity of was assessed in the zebrafish embryo/larval model, and was found to exhibit effects qualitatively similar to those observed for the known neurotoxin brevetoxin-2 and consistent with neurobehavioral impairment.