Polybrominated Diphenyl Ethers from the Indonesian Sponge Lamellodysidea herbacea

Four new (1−4) and 10 known polybrominated diphenyl ethers (5−14) have been isolated from the title sponge. The structures of the new entities were elucidated by interpretation of spectroscopic data and chemical transformations. These metabolites showed potent antimicrobial activity against Bacillus subtilis and moderate/weak cytotoxicity against NBT-T2 rat bladder epithelial cells. The major constituent 14 was treated under debromination conditions to give eight derivatives, which were subjected to a structure−activity relationship study. The results indicated that the presence of two phenolic hydroxyl groups and bromines at C-2 and/or C-5, as in 2, is important for the exhibition of antibacterial activity.