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

A new,
cyclic carbonate eudesmane-type sesquiterpene, eudesmacarbonate (1), 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 Neolyngbya. The structure of 1 was elucidated by (+)-HRESIMS,
1D and 2D NMR, single-crystal X-ray diffraction, and vibrational circular
dichroism data. Toxicity of 1 was assessed in the zebrafish
embryo/larval model, and 1 was found to exhibit effects
qualitatively similar to those observed for the known neurotoxin brevetoxin-2
and consistent with neurobehavioral impairment.