Echinosulfonic acids A-C and echinosulfone A: Novel bromoindole sulfonic acids and a sulfone from a southern Australian marine sponge, Echinodictyum

The crude EtOH extract of an Echinodictyum sp. collected during trawling op erations in the Great Australian Eight, Australia, displayed antibacterial and antiparasitic properties. Bioassay-directed fractionation yielded three novel sulfonic acids, the echinosulfonic acids A to C (1-3), and a new sul fone, echinosulfone A (4). Structures were assigned to these compounds on t he basis of detailed spectroscopic analysis. It was determined that echinos ulfonic acids A-C (1-3) and echinosulfone A(4) contributed to the antibacte rial but not antiparasitic activity of the crude extract.