Table of Contents
ISRN Pharmaceutics
Volume 2012, Article ID 584073, 4 pages
Research Article

Antibacterial Activity of Fistulin: A Protease Inhibitor Purified from the Leaves of Cassia fistula

1Research Department of Microbiology, Asan Memorial College, Chennai 600 100, India
2Department of Biochemistry, School of Life Sciences, Vels University, Chennai 600 117, India

Received 17 March 2012; Accepted 1 May 2012

Academic Editors: F. de la Calle, H. R. Pezza, and G. Ragno

Copyright © 2012 I. Arulpandi and R. Sangeetha. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Plant protease inhibitors (PPIs) are one of the important components of a plant’s defense machinery. PPIs are active against the insects and microbes which invade the plant. Cassia species possess anti-insecticidal and antimicrobial properties and this study was aimed at investigating the antibacterial efficacy of a PPI present in the leaves of Cassia fistula. A PPI, fistulin, was isolated from the leaves of C. fistula and purified by gel filtration chromatography. The antibacterial activity of the purified fistulin was studied against five bacterial strains, namely, Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Escherichia coli. The PPI was found to be very active against S. aureus, E. coli, B. subtilis, and K. pneumonia, and its efficacy was comparable to the standard drug, streptomycin sulphate.