Antibacterial activity of extracts of six macroalgae from the northeastern Brazilian coast

Hexane, chloroform and ethanol extracts of six marine macroalgae (Rhodophyta and Chlorophyta) from North Ceará coast (Northeast Brazil) were evaluated for antibacterial activity by the single disk method. Best results were shown by the hexane extracts of Amansia multifida against enteric Gram-negative strains such as Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, S. Choleraesuis, Serratia marcescens, Vibrio cholerae and the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus.