ABSTRACT
1,2-Benzenedicarboxylic acid, diisooctyl ester [diisooctyl phthalate] isolated from the roots of Plumbago zeylanica was screened for its antibacterial activity against eleven human pathogenic bacteria viz., Bacillus subtilis, B. cereus, B. megaterium. Escherichia coli, INABA ET [Vibrio], Shigella dysenteriae, S. sonnei, Salmonella typhi, S. paratyphi, Staphylococcus aureus and Pseudomonas mutabilis. The antibacterial activity of the compound was evaluated using the disc diffusion and macrodilution method. The compound showed moderate to good antibacterial activity against almost all the test bacterial pathogens. The largest zone of inhibition 22 mm, 14 mm, 11 mm, and 6 mm in diameter were recorded against Pseudomonas mutabilis at the concentration of 50 micro g, 20 micro g, 10 micro g and 5 micro g/disc respectively. The compound exhibited the lowest MIC [40 micro g/ml] against Bacillus subtilis, B. cereus, B. megaterium, Escherichia coli, Shigella sonnei, Salmonella paratyphi and Pseudomonas mutabilis and MBC [160 micro g/ml] against Bacillus cereus, B. megaterium, Escherichia coli and Pseudomonas mutabilis