青钱柳多糖抑菌活性及及作用机理

为研究青钱柳多糖的抑菌活性和作用机制，用不同质量浓度的青钱柳多糖处理细菌，通过最小抑菌浓度（minimum inhibitory concentration, MIC）、抑菌生长曲线分析青钱柳多糖对细菌的抑菌效果，并从抑制效果最佳的受试菌菌体电导率、细胞蛋白和核酸含量、还原糖的释放、呼吸链脱氢酶活性、脂质过氧化程度、细胞内ATP含量、细胞外碱性磷酸酶活力的角度来揭示其抑菌机理。结果表明，青钱柳多糖对金黄色葡萄球菌（Staphylococcus aureus）、大肠杆菌（Escherichia coil）、单增李斯特氏菌（Listeria monocytogenes）和鼠伤寒沙门氏菌（Salmonella typhimurium）有明显的抑制作用，MIC分别为2、4、6、6 mg/mL，对枯草芽孢杆菌（Bacillus subtilis）的抑菌性不明显；对指示菌的电导率、蛋白质和核酸渗漏、还原糖释放、呼吸链脱氢酶活性、细菌脂质过氧化程度、菌体胞内ATP和胞外碱性磷酸酶（AKP）含量均有影响。以上现象表明，青钱柳多糖的抑菌性主要是破坏菌体细胞壁和细胞膜完整性，改变其通透性，使得胞内大小分子物质外泄，抑制了细胞的呼吸代谢和引起氧化损失，进而影响细胞的生长代谢或造成细胞死亡，达到抑菌效果。

Bacteriostatic activity and mechanism of polysaccharides from Cyclocarya paliurus polysaccharides

The aim of this study is to investigate the antibacterial activity and mechanism of Cyclocarya paliurus polysaccharides against common bacteria. The antibacterial effects of Cyclocarya paliurus polysaccharides on five common bacteria were analyzed by minimum inhibitory concentration (MIC) and growth inhibition curve. The best inhibitory effect of the tested bacteria was from the aspects of conductivity, cellular protein and nucleic acid content, reducing sugar release, respiratory chain dehydrogenase activity, lipid peroxidation degree, intracellular ATP content, extracellular alkaline phosphatase activity to reveal the antibacterial mechanism. Cyclocarya paliurus polysaccharides showed significant inhibitory effects on Staphylococcus aureus, Escherichia coil, Listeria monocytogenes and Salmonella typhimurium, with MICs of 2, 4, 6 and 6 mg/mL, respectively. Cyclocarya paliurus polysaccharides showed no significant inhibitory effects on Bacillus subtilis. It also affected the conductivity, protein and nucleic acid leakage, reducing sugar release, respiratory chain dehydrogenase activity, bacterial lipid peroxidation, intracellular ATP and extracellular alkaline phosphatase (AKP) contents of the indicator bacteria. The antibacterial effect of Cyclocarya paliurus polysaccharides may mainly by destroying the integrity of the cell wall and cell membrane, changing its permeability, resulting in the release of intracellular large and small molecular substances, inhibiting the respiration and metabolism of cells and causing oxidative loss, thereby affecting the growth and metabolism of cells or causing cell death and achieving the antibacterial effect.