大豆异黄酮对金黄色葡萄球菌的抑菌机制研究

Anti-Bacterial Mechanism of Soybean Isoflavone on Staphylococcus aureus

【目的】研究大豆异黄酮(Soybean isoflavone,SI)的抑菌机制。【方法】本试验利用呼吸代谢抑制实验和4',6-二脒基-2-苯基吲哚(4',6-diamidino-2-phenylindole,DAPI)荧光染色对大豆异黄酮的抑菌机制进行研究。【结果】呼吸代谢抑制实验结果表明,当SI的终浓度为0.8mg·ml-1时,可显著抑制金黄色葡萄球菌苹果酸脱氢酶的活性,SI组苹果酸脱氢酶的比活性与对照组相比降低了74.97%。DAPI染色结果显示,DAPI可以和金黄色葡萄球菌内的核酸结合,经过SI作用28h后,菌体内的核酸含量呈明显下降趋势,其中DNA的荧光强度减少了33.53%,RNA减少了39.82%。【结论】SI具有有较强的抑菌活性,其抑菌机制是通过抑制细菌的呼吸代谢和核酸的合成等方面实现的。

[ 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.