Antibacterial Potential and UV-HPLC Analysis of Laboratory- Grown Culture of Anabaena variabilis

Abstract: The study was undertaken to investigate the antibacterial activity of different organic extracts prepared from biomass and spent medium of laboratory-grown Anabaena variabilis against Staphylococcus aureus MTCC-740, Escherichia coli MTCC-739, Pseudomonas aeruginosa MTCC-741, Salmonella typhi MTCC-733 and Klebsiella pneumoniae MTCC-139. Antibacterial activity was evaluated by disc diffusion assay and Minimum Inhibitory Concentration of all the active crude extracts was determined by broth micro dilution assay. The methanol extract showed more potent activity than hexane and ethyl acetate extracts. However, dichloromethane extract and spent medium were found to be inactive against all the test organisms. No inhibitory effect was found against Klebsiella pneumoniae. Minimum Inhibitory Concentration of all the active crude extracts was determined by broth microdilution assay. The MIC of methanol extract against Staphylococcus aureus and Escherichia coli are 256 and 512 μg/ml, respectively. While it was more than 512 μg/ml against Pseudomonas aeruginosa and Salmonella typhi. Methanol extracts was further analysed by UV-Vis spectroscopy and HPLC. The antibacterial activity was compared with standard antibiotic Ciprofloxacin.