香茅醛对金黄色葡萄球菌的抑制作用

该研究探讨香茅醛（Citronellal,CIT）对金黄色葡萄球菌（Staphylococcus aureus,S. aureus）的抑菌作用。采用微量肉汤稀释法及时间-杀菌曲线确定了CIT对S.aureus的抑菌活性。CIT对S.aureus最小抑菌浓度（MIC）及最小杀菌浓度（MBC）均为0.80 mg/mL，且具有快速杀菌作用，1.60 mg/mL的CIT处理0.5 h后，S. aureus活菌数从5.65 log CFU/mL下降到0.00。经CIT处理后，S. aureus胞外K+浓度显著升高至2.63 mg/L，碘化丙啶（PI）荧光强度与对照相比升高5 326.83 A.U.，表明CIT会影响细胞膜通透性，导致胞内小分子及大分子物质泄出。扫描电镜观察下发现，高浓度CIT能严重破坏S.aureus细胞形态及结构。此外，通过紫外可见光光谱发现，CIT在加入S. aureus的DNA后，吸收峰发生明显的增色效应，与对照组相比最大差值为0.45 A.U.，表明CIT可能通过沟槽结合与DNA相互作用，干扰DNA的正常生物功能，抑制细胞生长。综上所述，CIT可作为S. aureus生长...

Antibacterial Effect of Citronellal against Staphylococcus aureus

The minimal inhibitory concentration of Citronellal against Staphylococcus aureus was determined using broth dilution, and the results were analyzed using a time-kill curve. Citronellal showed a rapid bactericidal effect at a minimum concentration of 0.80 mg/mL. After treating Staphylococcus aureus with 1.60 mg/mL of Citronellal for 0.5 h, the live bacteria count decreased from 5.65 log CFU/mL to 0.00 CFU/mL. After Citronellal treatment, the extracellular potassium ion concentration of Staphylococcus aureus increased significantly to 2.63 mg/L, and the fluorescence intensity of propidium iodide was 5 326.83 A.U. greater than that of the control group. This demonstrated that Citronellal can affect the permeability of Staphylococcus aureus cell membranes, causing leakage of intracellular micro- and macromolecules. Scanning electron microscopy results showed that high concentrations of Citronellal could seriously damage the morphology and structure of Staphylococcus aureus cells. UV-visible spectrum analysis showed that after adding Staphylococcus aureus DNA to Citronellal, the absorption peak exhibited a clear enhancement effect, with a maximum difference of 0.45 A.U. compared with the control group. This suggested that Citronellal interacts with DNA via groove binding, interfering with the normal biological function of DNA, and inhibiting cell growth. In conclusion, Citronellal could be used as a natural and efficient bacteriostatic agent preventing the growth of Staphylococcus aureus by destroying cell membrane integrity, altering DNA structure, and interfering with normal physiological activities of the bacterial cells. This study provides a theoretical basis for the application of Citronellal in the food industry.