In vitro antibacterial mechanism of alcoholic extract of malt against Escherichia coli and Staphylococcus Aureus in intestinal microflora
Objective To determine the antibacteria activity of alcoholic extract of malt on intestinal microorganisms and elucidate its antibacteria mechanism in vitro.Methods The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of each microorganism were determined with the microbroth dilution method.The growth curves of Escherichia coli and Staphylococcus aureus were plotted before and after the treatment with alcoholic extract of malt at various time points.The mechanism of action was measured by fluorescence microscopy,crystal violet staining experiments,lactate dehydrogenase activity assays,and alkaline phosphatase content analyses.Results Maltol extract showed significant antibacterial effect against 8 intestinal microorganisms,with MIC and MBC against Escherichia coli and Staphylococcus aureusall all measured at 25 and 12.5 mg·mL-1,respectively.Biofilm formation ability of Escherichia coli and Staphylococcus aureus was dose-dependently weakened ad compared with that of the control group.At 2MIC,the cell membrane damage in the bacteria treated with alcoholic extract of malt,was very severe compared with that of the control group.Additionally,bacterial lactate dehydrogenase activity decreased gradually with increasing alcoholic extract of malt concentration,obviously different with that of the control group.Alkaline phosphatase content peaked at 3 hours for Escherichia coli and 6 hours for Staphylococcus aureus before the stabilizing.Conclusion Maltol extract demonstrates great antibacterial activity against intestinal microorganisms primarily by disrupting the cell membrane integrity,causing intracellular substance leakage and bacterial death.
alcoholic extract of maltgut microbeantibacteria mechanism
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