Iantherans A and B, unique dimeric polybrominated benzofurans as Na,K-ATPase inhibitors from a marine sponge, Ianthella sp. Original Research Article

Two novel tetrabrominated benzofuran derivatives, named iantherans A and B, were isolated from an Australian marine sponge of the genus Ianthella. The unique structures comprised of 2,3-bis(sulfooxy)-1,3-butadiene and two brominated benzofuran moieties were determined by spectroscopic and chemical methods. Iantheran A has a (Z,Z)-1,3-butadiene moiety, whereas iantheran B is the geometric isomer possessing a (Z,E)-1,3-butadiene moiety. The inhibitory activities of the iantherans and their derivatives against Na,K-ATPase as well as the efficacy of iantheran A against other several enzymes were evaluated.