RESUMEN
Antibacterial activity of methanol and ethanol extracts of the ascidian, Phallusia arabica was evaluated by disc diffusion method against various human pathogen isolates. Two different concentrations (0.5and 1mg/ml) were analyzed. The crude methanol extract was more active exhibiting a broad-spectrum antibacterial activity than the ethanol extract against the pathogenic microbes tested. Maximum inhibition zone (12 mm) was observed against Pseudomonas aeruginosa in 1 mg ml-1 concentration crude methanol extract. The inhibition zone was 3 mm in Escherichia coli for ethanol extract of 0.5 mg ml-1 concentration. The ranges of inhibition zone in the tested extracts were lesser than the standard antibiotics used in all the strains. The MIC and MBC for methanolic extract tested in study inferred that the values range between 0.70-0.95 mg/ml and 0.85-1.1 mg/ml respectively.