Study on antibacterial activities of compound volatile oil extracted from Jianwei Yinqiao powder

[Objective] To study the antibacterial activities for Escherichia coli and Staphylococcus aureus of the compound volatile oil extracted from the compound recipe Jianwei Yinqiao powder and its β-cyclodextrin inclusion compound with turbid dtermination in test tube. [Methods] The concentration of Escherichia coli or Staphylococcous aureus was fixed and different concentrations of the volatile oil were added into the above bacteria solution, then the inhibition rates of the compound volatile oil with different concentrations were determined, and the minimum inhibitory concentration(MIC) and the minimum bactericidal concentration(MBC) of the compound volatile oil were calculated. [Results] The absorbance of the volatile oil ethanol solution preserved at 4℃ and protected from light had no significant differences(P0.05)from the initial absorbance at the maximum absorption wavelength 257 nm within 20 h, which showed that the compound volatile oil was relatively stable within 20 h. The compound volatile oil was included by β-cyclodextrin to increase the stability of the compound volatile oil solution. The compound volatile oil had good antibacterial activities against Escherichia coli and Staphylococcus aureus before or after included, and the MIC and the MBC of volatile oil against Escherichia coli were about 1.25 μL/m L and 5 μL/m L. The MIC and the MBC against Staphylococcus aureus were about 0.63 μL/m L and 10 μL/m L. After the β-cyclodextrin inclusion of the compound volatile oil was dissolved in the liquid medium at 37 ℃, the inhibition rate for Escherichia coli and Staphylococcus aureus were 39.1% and 23.4% respectively. [Conclusion] The compound volatile oil extracted from Jianwei Yinqiao powder has good inhibitory activities against Escherichia coli and Staphylococcus aureus in vitro. The compound volatile oil was included by β-cyclodextrin to increase the stability of the volatile oil collusion and the β-cyclodextrininclusion of the compound volatile oil still has a strong antibacterial activity against the above gram-bacteria. The study should provide a reference for the further development and use of the compound essential oil from Yinqiaosan decoction.