| In medical clinic, due to the long-term use of antibiotics, drug-resistant strains of bacteria increased, and selecting the appropriate, sensitive antibiotics can shorten the course of disease, and improve the efficacy. The specific united application of antibiotics can effectively reduce the drug resistance of resistant bacterial strains. Clinical tests show that the united application of fluoroquinolones with berberine in treatment of bacterial disease is this particular.compatibility. The berberine is the main active component in Rhizoma Coptidis, the berberine derivatives synthesized through accessing lipophilic group, and showed the higher antibacterial activity compared with berberine. This study selected the norfloxacin, ofloxacin, enrofloxacin and8-hexyl berberine, conducted the antibacterial experiment in vitro, and to explore the mechanism of enhancing antibacterial effect, hoping to provide a theoretical basis for clinical application.Using the double dilution method, the anti-Staphylococcus aureus experiment of norfloxacin, ofloxacin, enrofloxacin, and8-exyl berberine in vitro was conducted. The results showed that the minimum inhibitory concentration (MIC) of enrofloxacin3.125ppm, levofloxacin25ppm, norfloxacin12.5ppm,8-hexyl berberine4ppm. Using the checkerboard dilution method, the fractional inhibitory concentration (FIC) was determined, Selecting8-exyl berberine combined with enrofloxacin and norfloxacin. The results showed that8-hexyl berberine combined with enrofloxacin FIC was0.125, and8-hexyl berberine combined with norfloxacin FIC was0.3125. The FIC were less than0.5, showed that8-hexyl berberine combined with norfloxacin, enrofloxacin had the good antibacterial synergy. The antibacterial synergy proportion of8-hexyl berberine combined with enrofloxacin was2:1, and8-hexyl berberine combined with norfloxacin2:1. To detect the Staphylococcus aureus growth in the condition of8-hexyl berberine combined with norfloxacinand enrofloxacin, the concentration was determined through measuring the optical density of bacteria suspension, and the bacteria growth curve was drawed. The results showed that the logarithmic growth of Staphylococcus aureus was inhibited significantly.Using ultraviolet spectrophotometry, the oil-water partition coefficients (LogP) of berberine and8-hexyl berberine in acid, alkali, neutral environment were measured. The results showed that the modified compound8-hexyl berberine increased the LogP value, improved the lipophilicity, enhanced the membrane absorption, and with better bioavailability.In the application of cell breaking technology, the8-hexyl berberine in the Staphylococcus aureus bacteria was identified by thin layer chromatography, and the content of8-hexyl berberine in the Staphylococcus aureus bacteria was measured by UV spectrophotometry. Experiment showed that the content of8-hexyl berberine in the Staphylococcus aureus bacteria was67%when8-hexyl berberine combined with enrofloxacin in the proportion of1:2, the content was17%when8-hexyl berberine combined with norfloxacin in the proportion of1:2, and7.5%when8-hexyl berberine only. The results demonstrated that the8-hexyl berberine absorption in Staphylococcus aureus bacteria when8-hexyl berberine combined with enrofloxacin and norfloxacin was significantly higher than that of single8-hexyl berberine. |
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