African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5233

Full Length Research Paper

In vitro anti-bacterial activity of a novel isoquinoline derivative and its post antibacterial effects on Pseudomonas aeruginosa

Piyush Bihari Lal1, Naresh Kumar3, Tasleem Arif3, T. K. Mandal3, K. Akhilesh Verma1, G. L.Sharma2 and Rajesh Dabur3*
1BR Ambedkar Centrefor Biomedical Research, Delhi University, Delhi- 110 0072 2Institute of Genomics and Integrative Biology, DU Campus, Delhi-110007. 3Regional Research Institute (Ay), Nehru Garden, Kothrud, Pune – 411 038.
Email: [email protected]

  •  Accepted: 15 March 2008
  •  Published: 31 May 2008


The isoquinolines are of great importance to humanity because of their medicinal value and different structure. There have been many researches on the isoquinolines, but relatively few pure compounds have been investigated for their antibacterial activity. The in vitro activity of a novel synthetic antimicrobial compound1-(4-choloro-phenyl)-6,7-dimethoxy-2-methyl-1,2,3,4, tetrahydroisoquinoline was evaluated against Pseudomonas aeruginosa(ATCC27853) using standard methods approved by Clinical and Laboratory Standards Institute. The minimum inhibitory concentration of the compound which inhibited more than 90% growth (MIC90) of P. aeruginosa was found to be ranged from 24.0 to 6.0 mg ml-1 in different media. The ET50 (concentration which lyses 50% erythrocytes) of the compound was observed to be 450 mg ml-1. It was found that the compound down-regulated the expression of PQS, elastase and pyocyanin, the important virulence factors of P. aeruginosa. Proteomics studies revealed that the compound inhibited/down regulated the expression of PhnA and oprL proteins of P. aeruginosa which are crucial for PQS synthesis and membrane integrity. This type of compounds may provide avenue for the discovery of clinically useful antibacterial drugs.


Key words: Isoquinoline, P. aeruginosa, virulent factors, antimicrobial activity, proteomics.