ABSTRACT
The brown seaweed Padina tetrastromatica which can be collected from Gulf Of Mannar Sea shore Thoothukudi, India. In this present study was focused on the antimicrobial activity of the selected seaweed against six human pathogenic bacteria (Gram +ve: Staphylococcus aureus, Bacillus subtilis, Lactobacillus acidophilus and Gram -ve: Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis) by the agar well diffusion method. Here, different concentrations of the extract from Padina tetrastromatica were tested for probable antimicrobial activity and the extracts were prepared by five different solvents such as Acetone, Chloroform, Ethanol, Ethyl acetate and methanol. The experimental results shows that the highest antimicrobial activity 15mm was shown by Ethyl acetate extract against S. aureus and the lowest activity observed in methanol extract 1mm against E.coli. The experiment concludes that the extract of Ethyl acetate forms a good activity against all the six organisms.