Mass-directed fractionation based on a Trypanosoma brucei brucei active fraction from the Australian sponge Pseudoceratina sp. led to the isolation of a novel bromotyrosine alkaloid, pseudoceratinazole A (1). Compound 1 is the first dimeric bromotyrosine alkaloid containing an imidazole-bridging moiety. © 2010 Elsevier Ltd. All rights reserved.