老蒜提取物石油醚部位对大肠杆菌的抑制作用研究

Inhibitory effect of Petroleum Ether Fractions of Aged Garlic Extract on Escherichia coli

本文自制了两种老蒜提取物(aged garlic extract,AGE)AGE-1和AGE-2,用石油醚进行萃取后挥干溶剂得到AGE-1和AGE-2的石油醚部位。采用微量肉汤稀释法测定了AGE-1和AGE-2的石油醚部位对大肠杆菌的最低抑菌浓度,发现AGE-1和AGE-2的石油醚部位对大肠杆菌的最低抑菌浓度分别为31μg/m L和62μg/m L。通过大肠杆菌生长曲线、细胞内容物泄漏、培养液电导率的测定以及激光共聚焦显微镜和扫描电子显微镜观察等方法研究了AGE-1和AGE-2石油醚部位对大肠杆菌的抑菌机理,发现AGE-1和AGE-2的石油醚部位在其最低抑菌浓度下能够抑制大肠杆菌的生长发育,导致细胞内电解质和大分子物质的泄漏,并能对大肠杆菌细胞壁和细胞膜造成损伤,改变细胞膜的通透性,促使细胞凋亡或坏死,从而使大肠杆菌细胞表面粗糙,菌体之间互相黏连,细胞形态发生变形和凹陷。

In this study, two kinds of Aged garlic extract（AGE-1 and AGE-2） were prepared and the two samples were extracted by petroleum ether to obtain the petroleum ether fractions of AGE-1 and AGE-2. The minimum inhibitory concentration（MIC） of AGE-1 and AGE-2 against Escherichia coli was determined by broth microdilution method. The MIC of AGE-1 and AGE-2 against Escherichia coli was 31 μg/m L and 62 μg/m L, respectively. The antibacterial mechanism of AGE-1 and AGE-2 against Escherichia coli was studied by growth curves, leakage of cell contents, conductivity of culture medium, confocal and scanning electron microscope. Further research found that AGE-1 and AGE-2 inhibited the growth of Escherichia coli, damaged the cell wall and cell membrane, changed the permeability of cell membrane, which led to the leakage of electrolyte and macromolecules as well as cell apoptosis. The cell surface was rough and the cell was sticky and depressed.