Bactericidal Potential of Seaweeds From Turicorin Coastal Waters, Gulf of Mannar, Southeastern India
Fresh samples of the seaweeds, Gracilaria edulis, Kappaphycus alvarezii, Stoechospermum marginatum and Sargassm muticum and Ulva lactuca, Caulerpa scalpelliformis were extracted with the different organic solvents. The Methanol, acetone, dichloromethane and hexane extracts (both natural concentration and crude) from seaweeds were screened against ten human pathogenic bacteria viz., Staphylococcus aureus, Micrococcus luteus, Streptococcus pyogenes, Bacillus subtilis, Enterobacter faecalis, Escherichia coli, Klebsiella pneumoniae, Shigella sonnei, Salmonella typhimurium and Vibrio cholera. Prominent activity was observed in Caulerpa scalpelliformis, followed by Stoechospermum marginatum, Gracilaria edulis, Sargassm tenerrimum, Ulva lactuca and Kappaphycus alvarezii. The active crude methanol extract of C. scalpelliformis was partitioned with ethyl acetate, butanol and water to localize the polarity of active bactericidal compounds. The ethyl acetate phase showed wide spectrum antibacterial activity against all human pathogenic bacteria. The zone of inhibition was varying between 8 and 18 mm. The maximum zone was observed against Klebsiella pneumoniae and minimum activity against Shigella sonnei, Escherichia coli, Salmonella typhimurium and Vibrio cholera.
Keywords: Seaweeds, antibacterial, human pathogens, Gulf of Mannar