为了探讨姜厚朴水提物（GMB）对大肠杆菌和金黄色葡萄球菌的抑菌机理，试验对GMB作用下菌体形态结构、膜系统上离子通道的酶活力和能量代谢等方面进行了研究。结果表明，GMB对大肠杆菌和金黄色葡萄球菌的MIC分别为6.25、12.5 mg/mL。大肠杆菌胞外AKP酶和β-半乳糖苷酶吸光度值分别增加1.78和4.24倍，GMB作用4 h后电导率显著上升，膜上Na+K+-ATP酶活性从0.42增加到1.74 mg prot/mL，且为阴性对照的1.7倍；金黄色葡萄球菌体表出现囊泡状、不规则的突起结构，SDH酶活性、总ATP酶活性和胞内蛋白质含量分别降低40%、23.4%和17.9%，且AKP酶活和电导率均有所增加。由此推测出GMB主要是通过破坏大肠杆菌细胞壁、膜结构，增加其渗透性和通透性，造成胞内物质外流和蛋白质合成量下降等现象，进而抑制菌体生长。而GMB抑制金黄色葡萄球菌的作用机制是增加细胞壁的通透性、降低能量代谢相关酶的活性，干扰其正常的代谢活动。

To determine the antibacterial mechanism of ginger mix-fried magnolia bark (GMB) against Escherichia coli and Staphylococcus aureus, the morphological structure of the bacterial cells, enzyme activity in the ion channels of cell membrane, and energy mechanism after treatment with GMB were studied. The results showed that the minimum inhibitory concentrations (MICs) of GMB against E. coli and S. aureus were 6.25 and 12.5 mg/mL, respectively. The absorbance values for extracellular alkaline phosphatase (AKP) and β-galactosidase in E. coli increased 1.78-fold and 4.24-fold, respectively. Four hours after GMB treatment, the conductivity of the culture medium changed significantly, and membrane Na+K+-ATPase activity increased from 0.42 to 1.74 mg prot/mL, which was 1.7 times higher than that of the negative control. There were vesicular or irregular projections on the cell surface of S. aureus, and the sorbitol dehydrogenase (SDH) activity, total adenosine triphosphate (ATP) activity, and soluble protein content decreased by 40%, 23.4%, and 17.9%, respectively, whereas AKP enzymatic activity and conductivity increased. These results suggested that GMB increased E. coli cell permeability by disrupting the cell wall and damaging membrane structure, which resulted in an outflow of intracellular material and a decreased amount of synthesized proteins, thereby inhibiting bacterial growth. GMB appeared to inhibit S. aureus by enhancing the cell wall permeability, reducing the activity of enzymes related to energy metabolism, and interfering with the normal metabolic activities.

北京市优秀人才培养资助D项目（2012D005003000006）