Highly -Methylated Peptides from the Antarctic Sponge Are Active against .

Malaria, caused by the parasite , continues to threaten much of the world's population, and there is a pressing need for expanding treatment options. Natural products have been a vital source of such drugs, and here we report seven new highly -methylated linear peptides, friomaramide B () and shagamides A-F (-) from the marine sponge , collected in Antarctic waters, which demonstrate activity against three strains of blood-stage The planar structures of these metabolites were solved by interpreting NMR data, as well as HRESIMS/MS fragmentation patterns, while Marfey's analysis was used to establish the configurations of the amino acids. Reisolation of the previously reported compound friomaramide A () allowed us to revise its structure. The panel of isolated compounds allowed establishing structure/activity relationships and provided information for future structure optimization for this class of inhibitory metabolites.