Preliminary Screening of Anti-Biofilm, Anti-Larval Settlement and Cytotoxic Potential of Seaweeds and Seagrasses Collected from Pondicherry and Rameshwaram Coastal Line, India

A total of ten seaweeds and four seagrasses were used in the present investigation to study the effect of crude methanol extracts on anti-biofilm activity using a microtiter-plate and anti-larval settlement assay using cyprids of barnacle Balanus amphitrite. Of these fourteen species tested, seagrass Halophila ovalis showed noticeable anti-biofilm activity against Listeria monocytogenes, Vibrio parahaemolyticus, Acinetobacter baumannii, Salmonella typhi and Staphylococcus aureus. Whereas, brown seaweed Sargassum wightii reduced the biofilm formation by L. monocytogenes, V. parahaemolyticus, A. baumannii, Pseudomonas aeruginosa and V. anguillarum. Red seaweeds Gelidiella acerosa and Hypnea musciformis reduced biofilm formation by V. fischeri and seagrasses, Syringodium isoetifloium and Halophila ovalis subsp. ramamurthiana reduced the biofilm formation by S. typhi, V. fischeri and V. anguillarum. Seagrass H. ovalis completely inhibited larval settlement of B. amphitrite at the concentration of 80 μg/ml. Methanol extract of seagrass; H. ovalis showed significant cytotoxicity on brine shrimp.