The antimicrobial activity of Allium ursinum aqueous extract prepared using high pressure extraction was evaluated. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of A. ursinum extract for six bacterial pathogens were determined using the broth macrodilution method. Although the A. ursinum extract was shown to be effective toward all investigated foodborne bacteria, its antimicrobial activity depended on its concentration and bacterial strain. Listeria monocytogenes was the most sensitive to antimicrobial activity of A. ursinum extract among all tested pathogens. Accordingly, the lowest MIC and MBC of A. ursinum extract were determined for L. monocytogenes (28 and 29 mg/mL). The tested extract showed a similar antimicrobial potential to other examined bacterial strains (Salmonella Enteritidis, Proteus hauseri, Enterococcus faecalis and two strains of Escherichia coli) with MIC and MBC values at concentrations of 29 and 30 mg/mL, respectively. The dependence of the antimicrobial activity of the A. ursinum extract on the level of contamination of tested pathogens was also observed. The increase in the contamination level caused an intense reduction in antibacterial potential of the A. ursinum extract. The composition of the A. ursinum extract was analyzed and found to be a good source of polyphenols and sulfur compounds. However, considering the applied extraction method and the HPLC analysis of bioactive compounds, the antimicrobial potential may be attributed more to polyphenol content. The obtained results that the extracts have shown toward food pathogens open the possibility of using the tested extracts as natural additives in a variety of food products.
Keywords: Allium ursinum; antimicrobial activity; polyphenolics; subcritical water extraction; sulfur compounds.