Fucoxanthin, Tetraprenylated Toluquinone and Toluhydroquinone Metabolites from Sargassum heterophyllum Inhibit the in vitro Growth of the Malaria Parasite Plasmodium falciparum

In the course of our search for antimalarial leads from marine algae, four metabolites, sargaquinoic acid, sargahydroquinoic acid, sargaquinal and fucoxanthin, were isolated from the South African alga Sargassum heterophyllum. Fucoxanthin and sargaquinal showed good antiplasmodial activity toward a chloroquine-sensitive strain (D10) of Plasmodium falciparum (IC50 1.5 and 2.0 microM, respectively), while sargaquinoic acid and sargahydroquinoic acid were only moderately active (IC50 12.0 and 15.2 microM, respectively).