Abstract:

【Objective】 To investigate the anti-bacterial mechanism of soybean isoflavone (SI) and provide a theoretical basis for the development of high-performance and low toxicity of antibacterial drugs. 【Method】 Respiratory metabolism test and 4'6-diamidino-2-phenylindole (DAPI) staining assay were used to investigate the antibacterial mechanism of SI. 【Result】 The results indicated that the malic dehydrogenase (MDH) activity of Staphylococcus aureus was significantly inhibited by 0.8 mg?ml-1 SI and the malic dehydrogenase (MDH) activity of Staphylococcus aureus was remarkably reduced by 74.97% compared to the control group. The fluorescence microscopy and fluorescence spectrophotometer studies manifested that 4'6-diamidino-2- phenylindole (DAPI) could integrate with Staphylococcus aureus, and the quantity of DNA and RNA were significantly reduced by 33.53% and 39.82% after incubation with SI for 28 hours. 【Conclusion】 The results showed that SI could inhibit the growth of curtain bacteria significantly, the mechanisms of the inhibition activity may include inhibiting both respiratory metabolism and synthesis of nucleic acid.

Key words: soybean isoflavone')">soybean isoflavone, anti-bacterial mechanism, MDH, DAPI