Antiplasmodial metabolites isolated from the marine octocoral Muricea austera.

Bioassay-guided fractionation of the MeOH extract from the octocoral Muricea austera collected in the Pacific coast of Panama led to the isolation of eight compounds, including three tyramine derivatives (1-3), two steroidal pregnane glycosides (4, 5), and three sesquiterpenoids (6-8). Compounds 2-5 are new natural products, and their structures were determined on the basis of their spectroscopic data (HRMS, 1D and 2D NMR, and CD studies). The antiprotozoal activities of the natural compounds 1-8 as well as those of a series of synthetic glycosides (11-22) and tyramine derivatives (23-35) were evaluated in vitro against a drug-resistant Plasmodium falciparum and intracellular form of Trypanosoma cruzi.