Antibacterial activity of some medicinal plant extracts

Abstract

Antibacterial activity of hot aqueous and methanolic extracts prepared from six plants (Terminallia chebula, Terminallia bellerica, Phyllanthus emblica, Punica granatum, Lawsonia alba and Mikania micrantha) used in traditional folk medicines of India were screened against five pathogenic bacteria (Staphylococcus aureus MTCC 2940, Bacillus subtilis MTCC 441, Escherichia coli MTCC 739, Proteus vulgaris MTCC 426 and Enterobacter aerogenes MTCC 111). The highest antibacterial potentiality was exhibited by the methanolic leaf extract of T. chebula, followed by the aqueous fruit extract of T. bellerica. The leaf extract of T. chebula can be considered to be as equally potent as the most effective antibiotics, such as ciprofloxacin, gentamycin, kanamycin, ofloxacin and cephalexin. A sensitivity test performed with commonly used sensitivity test disks resulted in the appearance of multiple drug resistance phenotypes of the bacteria tested. A comparision of data in the inhibition zones of pathogenic bacteria showed that gentamycin, ofloxacin, kanamycin and tobramycin were effective against all of the bacterial strains tested. © 2007 The Japanese Society of Pharmacognosy and Springer.