Treechada Sirirak, Thanomjit Supavita, Kanda Panthong, and Supayang Voravuthikunchai

pp. 535 - 544

Abstract

The objective of this study was to investigate the effect of crude extracts of Punica granatum Linn.
pericarp with 3 different solvents against pathogenic Gram-negative bacilli. Ethanolic extracts showed the
antibacterial activity against all strains tested including enterohaemorrhagic Escherichia coli 4 strains (E. coli
O157: H7, E. coli O26: H11, E. coli O111: NM, E. coli O22), Pseudomonas aeruginosa, Shigella boydii and
Salmonella london. Inhibition zones ranged from 10.02 to 19.15 mm. Minimum inhibitory concentration (MIC)
and minimum bactericidal concentration (MBC) ranged from 0.09 to 3.13 mg/ml and 3.13 to 25 mg/ml,
respectively. Aqueous extract had low antibacterial activity while crude chloroform extracts had no effect on
the growth of these strains. Ethyl acetate and n-butanol fractions of P. granatum pericarp demonstrated high
activity with the best MIC and MBC values of 0.02 to 0.78 mg/ml and 0.19 to 6.25 mg/ml, respectively. As
ethanolic extract of P. granatum was very effective against these pathogenic bacteria, further investigation on
this plant species may provide alternative, but bioactive, medicines for the treatment of Gram-negative
bacterial infection.