Abstract

Pomegranate, Punica granatum L. is frequently used for the treatment of gastero-intestinal resistant organisms, oral bacteria, highly pathogenic and antibiotic-resistant organisms (Salmonellae and Pseudomonas aeruginosa) and a few skin infecting pathogens, including fungus and methicillin-resistant Staphylococcus aureus (MRSA). In this study, an in vitroantimicrobial activity and phytochemical analysis of ethanolic pericarp extract of P. granatum was carried out. A total of 21 microorganisms (19 bacteria and 2 fungi) were used for antimicrobial activity by disc diffusion, broth dilution methods and a standard procedure was employed to identify the phytoconstituents. Ethanolic extract of pericarp showed significant bactericidal activity against Yersinia enterocolitica (25.8 mm),Staphylococcus epidermidis (24.6 mm), Salmonella enterica (21.2 mm), Burkholderia cepacia (19.4 mm), S. aureus (19.2 mm), Salmonella paratyphi A (18.8 mm), Salmonella typhimurium (18.6 mm), Escherichia coli (18.4 mm) and P. aeruginosa (18.2 mm) were documented. Based on broth dilution technique, the lowest concentration of ethanolic pericarp extract (512 µg/ml) showed significant inhibitory activity against S. epidermidis andY. enterocolitica and 1,024 µg/ml was observed as a minimum inhibitory concentration (MIC) value against S. aureus, Streptococcus mutans, S. paratyphi A, S. typhimurium,Salmonella brunei, P. aeruginosa and B. cepacia. The results of ethanolic extract of P. granatum pericarp showed significant inhibitory activity when compared with other organisms. The highest minimum inhibitory activity was observed against bacteria when compared with fungi. The inhibitory effect could be due to the presence of some of the secondary metabolites like phenolic compounds, flavonoids, terpenoids, phytosterols, glycosides and tannins detected in the ethanolic pericarp extract of P. granatum.

Key words: Punica granatum, phytoconstituents, antimicrobial activity, disc diffusion and broth dilution methods, minimum inhibitory concentration (MIC).