Antimalarial Bromotyrosine Derivatives from the Australian Marine Sponge Hyattella sp.

A drug discovery program aimed at identifying new antimalarial leads from a prefractionated natural product library has resulted in the identification of a new bromotyrosine alkaloid, psammaplysin G (1), along with the previously isolated compound, psammaplysin F (2). When tested against two different strains of the parasite Plasmodium falciparum (Dd2 and 3D7), 2 displayed IC(50) values of 1.4 and 0.87 mu M, respectively, while 1 showed 98% inhibition at 40 mu M against the chloroquine-resistant (Dd2) strain of P. falciparum.