RESUMO
The antipsychotic drug, prochlorperazine (Pcp), was tested for its antimicrobial efficacy against 103 strains belonging to both gram positive and gram negative bacteria. The drug was found to possess maximum activity against Staphylococcus aureus, Vibrio cholerae and Shigella spp. Pcp was moderately active against E. coli but most of the strains belonging to Bacillus spp, Klebsiella spp, Salmonella spp and Lactobacillus spp were found to be resistant to this drug. The drug was tested for its mode of antibacterial activity against Shigella dysenteriae 1 and it was found to be bacteriostatic in action. In in vivo studies, Pcp offered significant protection to Swiss albino mice at concentrations of 0.75 micro g/g (P < 0.01) and 1.5 microg/g (P < 0.001) body weight when challenged with 50 median lethal dose of Salmonella typhimurium NCTC 74. Thus the result depicts that prochlorperazine may emerge as a strong antimicrobial drug to replace the conventional antibiotics and to overcome the problem of drug resistance.