Mangroves have enormous ecological value. They protect and stabilize coastlines, enrich coastal waters, yield commercial forest products and support coastal fisheries. Mangroves are among the world’s most productive ecosystems, producing organic carbon well in excess of the ecosystem requirements and contributing significantly to the global carbon cycle. Extracts from mangroves and mangrove dependent species have proven activity against human, animal and plant pathogens. The extracts were found to contain alkaloids, carboxylic acids, flavonoids, xanthoproteins, tannins, phenols, saponins,
coumarin, sugars, resins, steroids and proteins.
Antibiotic resistance is currently the greatest challenge to the effective treatment of infections globally. The occurrence of resistance and the considerable resources spent on antibiotics globally are convincing reasons for concern about ensuring adequate and proper use of these powerful agents.
With the difficulty in treating recalcitrant infections and the growing resistance to antibiotics, new therapeutic modalities are becoming increasingly necessary. The interruption of bacterial quorum sensing (QS) or cell to cell communication is known to attenuate virulence, while limiting selective pressure toward resistance. In the study described here we had made an attempt to screen 10 commonly available mangrove and mangrove associated plants for their anti-QS activity using biosensor strain Chromobacterium violaceum (MTCC 2656). Of the screened plants, 5 showed QS inhibition: Terminalia catappa, Avicennia nitida, Morinda citrifolia, Derris trifoliata, Hibiscus tiliaceus. These plants were further examined for their effects on QS system and biofilm formation in Pseudomonas aeruginosa and Staphylococcus aureus which are the well-known pathogens of humans. Any of the plant extract that shows quorum sensing inhibition does not have an effect of biofilm of P.aeruginosa, while these extract has a quorum quenching mechanism unrelated to static or cidal effects.