Study On Antimicrobial Effect And Preliminary Mechanism Of The Tablets Of Yinhuamiyanling Against Escherichia Coli

Yinhuamiyanling Tablets is a traditional Chinese medicine preparation whichcontains honeysuckle, Scutellaria barbata, knotgrass and other ingredients. The tablethas the function of clearing away heat and toxic material, as well as the function ofdiuresis promoting. It is commonly used in the clinical treatment of urinary tractinfections such as acute pyelonephritis, acute cystitis and damp-heat in lower-Jiao, is thecommonly used medicines for refractory urinary tract infection in clinical treatmentcurrently. At present, there is no research report about the antibacterial mechanism ofYinhuamiyanling Tablets, therefore, this research is about the preliminary discussion onthe inhibition mechanism on the basis of antimicrobial activity of YinhuamiyanlingTablets95%ethanol extract on E. coli which is the main pathogenic bacteria of urinarysystem infection. The purpose is in order to better guide clinical medication, and tomake rational clinical medication programs, and to provide a theoretical basis andexperimental data verification.In this thesis, we determined the antibacterial activity of Yinhuamiyanling Tablets95%ethanol extract on E. coli strains in vitro by using agar dilution method anddcylinder-plate method, MIC50-90and MBC50-90of Yinhuamiyanling Tablets95%ethanolextract on E. coli strains were50～100mg/ml and100～250mg/ml, respectively. Weanalyzed the antibacterial mechanism by plotting the time-killing curve (KCs), andobserving the ultrastructural changes in cell morphology using scanning andtransmission electron microscopy and SDS-PAGE. The KCs showed thatYinhuamiyanling Tablets95%ethanol extract delayed E. coli’s split time, extended thelogarithmic growth phase, accelerated the entry into recession, and destroyed the normalgrowth cycle of the bacteria, thus inhibited the growth and reproduction of bacteria. The E. coli bacteria surface subsidence, SAG at both ends and thorn-shaped bumps, andseverely deformed can be seen with a scanning electron microscope after the treatmentof Yinhuamiyanling Tablets95%ethanol extract. It can be seen that the thalli ofrefraction varied apparently, cell deformation and folds occurred, and some cell wallswere depression with a negative stained transmission electron microscope after the drugtreatment. Thalli with contraction and expansion, cell wall blurred or even missing,cytoplasm pyknotis disintegrated and formed to small vacuoles can be observed afterdrug treatment with ultrathin transmission electron microscope. Electron microscopeshowed that the bacteriostatic mechanism might be drug interference or destruction ofE.coli’s cell wall synthesis or destruction of molecular weight protein in bacteria, so thatthe call ultrastructure changed, then achieved the purpose of inhibition or sterilization.Bacterial protein electrophoresis band was displayed by SDS-PAGE, significantdifferences were presented between dosing group and control group, after the drugtreatment,5protein band of bacteria scumbled and the protein bands which molecularweight was170KD and60KD became lighter apparently, the protein bands with themolecular weight of130KD,100KD and70KD were changed. This phenomenonsuggested Yinhuamiyanling Tablets95%ethanol extract may affect the normalexpression of the bacterial protein or affect its function, thus inhibited the synthesis ofsome key structures and some functional proteins.In summary, Yinhuamiyanling Tablets95%ethanol extract has a certain inhibitoryactivity on E. coli strains, the preliminary antibacterial mechanisms of YinhuamiyanlingTablets95%ethanol extract may be related to extension of the bacterial division cycleand the inhibition of the growth and reproduction, while drugs may interfere with ordamage the cell wall synthesis in E.coli or destroy bacteria molecular weight protein,resulting in the changes of cell ultrastructure and the reduction of proteins.