COMPARATIVE STUDY OF THE ANTIBACTERIAL ACTIVITY OF SEAWEED (Sargassum muticm) AND FRESHWATER WEED (Spirodela polyrrhiza): Antibacterial activity of seaweed and freshwater weed

Development of new drugs is needed to resist the situation of diseases caused by drug resistant bacteria for public health safety. Natural resource is a big source to find candidates having antibacterial activity and aquatic weed is such a natural resource possessing such activity. The current study was aimed to determine the effectiveness of sea weed (Sargassum muticum) and fresh water weed/duckweed (Spirodela polyrrhiza) against six bacterial isolates Klebsiella pneumonia, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Pseudomonas luteola and Bacillus subtilis. The potency of methanol and ethanol extracts of these weeds was compared to determine the best candidate of weeds in inhibiting bacteria. Both agar well diffusion method and micro dilution was done to observe the antibacterial activity. Ethanol extract of Sargassum muticum worked best against Pseudomans aeruginosa (30mm zone of inhibition) and no activity against Bacillus subtilis. Methanol extract of the same Sargassum muticum showed less activity compared to ethanol extract except for Bacillus subtilis where it showed 21mm zone of inhibition. Ethanol and methanol extracts of Spirodela polyrrhiza showed less antibacterial activity against the bacteria compared to Sargassum muticum. They showed no antibacterial activity against Klebsiella pneumonia and Staphylococcus aureus. On average, the extracts impart a significant antibacterial activity against these six bacteria which are resistant to several antibiotics. Even one of them (Escherichia coli) is resistant to 4th generation cephalosporin but still fairly susceptible for extracts. The antibacterial properties of these marine and freshwater weeds can be subjected to develop new therapeutics to inhibit the resistant bacteria.