Antibacterial Activity of Four Plant Extracts Extracted from Traditional Chinese Medicinal Plants against <i>Listeria monocytogenes, Escherichia coli, </i>and <i>Salmonella enterica </i>subsp. <i>enterica</i> serovar Enteritidis

• Main Authors: R.L. McMurray, M.E.E. Ball, M.M. Tunney, N. Corcionivoschi, C. Situ
• Format: Article
• Language: English
• Published: MDPI AG 2020-06-01
• Series: Microorganisms
• Subjects: antibiotic resistance; pathogens; plant extracts; in vitro model; time–kill assay; broth microdilution
• Online Access: https://www.mdpi.com/2076-2607/8/6/962

The worldwide ethnobotanical use of four investigated plants indicates antibacterial properties. The aim of this study was to screen and determine significant antibacterial activity of four plant extracts in vitro and in a poultry digest model. Using broth microdilution, the concentrations at which four plant extracts inhibited <i>Listeria monocytogenes, Salmonella enteritidis,</i> and <i>Escherichia coli</i> over 24 hours was determined. <i>Agrimonia pilosa </i>Ledeb<i>, Iris domestica </i>(L.) Goldblatt and Mabb<i>, Anemone chinensis </i>Bunge<i>, </i>and<i> Smilax glabra </i>Roxb all exhibited a minimum inhibitory concentration (MIC) of 62.5mg/L and a minimum bactericidal concentration (MBC) of 500mg/L against one pathogen. <i>A. pilosa </i>Ledeb was the most effective against <i>L. monocytogenes </i>and <i>E. coli</i> with the exception of <i>S. enteritidis</i>, for which <i>A. chinensis </i>Bunge was the most effective. Time–kills of <i>A. pilosa </i>Ledeb and<i> A. chinensis </i>Bunge against <i>L. monocytogenes, E. coli</i> and <i>S. enteritidis</i> incubated in poultry cecum were used to determine bactericidal activity of these plant extracts. <i>A. chinensis </i>Bunge<i>, </i>significantly reduced <i>S. enteritidis </i>by ≥ 99.99% within 6 hours. <i>A. pilosa Ledeb</i> exhibited effective significant bactericidal activity within 4 hours against <i>L. monocytogenes</i> and <i>E. coli</i>. This paper highlights the potential of these plant extracts to control pathogens commonly found in the poultry gastrointestinal tract.