A polycyclic polyether, isolated from marine dinoflagellate Karenia breve (Ptychodiscus brevis, or Gymnodinium breve in earlier literatures) is one of the toxins responsible for the 'red tide' massive fish kills. This compound forms a ladder-like-arranged multiple ring structure with an unusual acrolein side-chain on one of the terminal rings. Together with other congeners, they are known to disrupt neurotransmission by opening sodium channels. MW: 897.1. Purity >95% by HPLC