Abstract: Objective To study the antibacterial effect of dandelion aqueous extract on Enterobacteriaceae in vitro. Methods The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of dandelion aqueous extract against Enterobacteriaceae were determined using the minimum double dilution method. The MALDI-TOF mass spectrometer was used to detect the effect of dandelion aqueous extract on the types and contents of Enterobacteriaceae bacteria protein. Results The MIC and MBC of dandelion for Escherichia coli were 0.125 g·mL^-1 and 0.5 g·mL^-1 respectively, 0.125 g·mL^-1 and 0.5 g·mL^-1 for Enterobacter kobei, 0.06 g·mL^-1 and 0.25 g·mL^-1 for Enterobacter cloacae, 0.06 g·mL^-1 and 0.5 g·mL^-1 for Citrobacter freundii, and 0.125 g·mL^-1 and 0.5 g·mL^-1 for Salmonella typhi. Dandelion could inhibit the types and contents of proteins of five strains of bacteria. Conclusion The aqueous extract of dandelion has different degrees of inhibition on the growth and protein synthesis of Enterobacteriaceae.

Key words: dandelion, Enterobacteriaceae, MIC, MBC, protein