Gymnocin-B with the largest contiguous polyether rings from the red tide dinoflagellate, Karenia (formerly Gymnodinium) mikimotoi

A new cytotoxic polyether, gymnocin-B, was isolated from the red tide dinoflagellate, Karenia mikimotoi. Its structure was characterized by 15 contiguous ether rings and a 2-methyl-2-butenal side chain. Gymnocin-B showed cytotoxicity against P388 cells.