Antibacterial activity in marine algae from the coast of Yucatan, Mexico

Ethanolic and lipidsoluble extracts from 21 marine algal species (10 Chlorophyta, 2 Phaeophyta and 9 Rhodophyta) from the coast of Yucatan, Mexico, were evaluated for antibacterial activity against pathogenic microbes (4 Grampositive, 5 Gramnegative and one fungus). All species with antibacterial activity (18) were active against the Grampositive bacteria (Bacillus subtilis, Streptococcus faecalis and Micrococcus luteus), and most of the algal species exhibited activity against B. subtilis (89% in ethanolic soluble extracts and 94% in lipidsoluble extracts). The lipidsoluble extract of Ceramium nitens exhibited the highest activity among the species tested. The results are significant because no antibacterial activity has been found in previous research on this, or any other, species from this genus. The antimicrobial activities associated with extracts from different thallus regions (apical, basal and stolon) of selected Caulerpa species (C. ashmeadii, C. paspaloides and C. prolifera) were also evaluated. Results generally indicate that the stolon of Caulerpa has the highest antibacterial activity.