[摘要]:The anticancer target isoprenylcysteine carboxyl methyltransferase (Icmt) was the focus of a natural product high-throughput screening campaign. The Australian marine sponge Pseudoceratina sp. yielded aplysamine 6, a new bromotyrosine derivative with an a,p-unsaturated amide linkage, as the bioactive constituent. Its structure was determined by ID and 2D NMR spectroscopy.