Cytotoxic Plakortides from the Brazilian Marine Sponge Plakortis angulospiculatus.

Three new plakortides, 7,8-dihydroplakortide E (1), 2, and 10, along with known natural products 3, 4, spongosoritin A (5), 6-8, and plakortide P (9), were isolated from Brazilian specimens of Plakortis angulospiculatus. Compounds 2, 3, 5, and 7-9 displayed cytotoxic activities with IC50 values ranging from 0.2 to 10 μM.

Identification of pyrroloformamide as a cytokinesis modulator.

Discovered in the late 1940s, the pyrrolinonodithioles represent a family of potent disulfide-containing natural products. Although they are understood in a synthetic and biosynthetic context, the biological role of these materials remains unresolved. To date, their activity has been suggested to arise through regulating RNA metabolism, and more recently they have been suggested to function as backup thiols for detoxification.

Kocurin, the true structure of PM181104, an anti-methicillin-resistant Staphylococcus aureus (MRSA) thiazolyl peptide from the marine-derived bacterium Kocuria palustris.

A new thiazolyl peptide, kocurin (1), was isolated from culture broths of a marine-derived Kocuria palustris. Its structural elucidation was accomplished using a combination of spectroscopic and chemical methods, including HRMS, extensive 1D and 2D NMR analysis, MS/MS fragmentation, and chemical degradation and Marfey's analysis of the resulting amino acid residues. The structure herein reported corrects that previously assigned to PM181104 (3).

Studies on the secondary metabolites of a Pseudoalteromonas sp. isolated from sediments collected at the northeastern coast of Brazil.

Continuing search for anticancer compounds from the marine environment, we have studied microorganisms that inhabit intertidal sediments of the northeastern Brazilian coast. Of the 32 strains isolated, 13 were selected for biological evaluation of their crude extracts. The acetate extract obtained from a Gram-negative bacterium was strongly active against cancer cell lines with IC(50) values that ranged from 0.