Antibacterial activity of artocarpanone isolated from Artocarpus heterophyllus heartwoods against diarrheal pathogens and its mechanism of action on membrane permeability

Artocarpus heterophyllus has been used as ingredient of folk medicine. Artocarpanone isolated from the heartwood of A. heterophyllus exhibited an antibacterial activity. The present study was undertaken to investigate its activity against diarrheal pathogenic bacteria including Escherichia coli, Vibrio cholera, Shigella sonnei, Salmonella typhimurium, and S. typhi. The effect of this compound on membrane permeability was also evaluated. Broth microdilution was used to determine antibacterial activity. Time-kill assay was selected to confirm any bactericidal activity. Bacteriolysis assay and loss of 260 nm absorbing material were used to assess the alteration on membrane cell. Artocarpanone displayed strong antibacterial activity against E. coli with MIC and MBC value of 3.9 and 7.8 µg/mL, respectively. Time-kill curve also confirmed the bactericidal activity of this compound. Artocarpanone only showed moderate antibacterial activity against V. cholera and did not perform any activity against S. typhimurium, and S. typhi. Supra-MIC (4 × MIC) of artocarpanone was able to decrease membrane permeability of E. coli after 24 h incubation and lead cell lysis. These results indicated that artocarpanone has potency as antibacterial against E. coli by altering membrane cell.