肉桂精油气相熏蒸对白色葡萄球菌的抗菌机制

Antibacterial Mechanism of Gas Phase Fumigation of Cinnamon Essential Oil Against Staphylococcus Albus

采用肉桂精油水浴加热的气相熏蒸方式对白色葡萄球菌进行抗菌实验,通过测定最低抑菌浓度(Minimum inhibitory concentration,MIC)与最低杀菌浓度(Minimum bactericidal concentration,MBC)测定肉桂精油抗菌活性,通过分析细胞外液的电导率、DNA、蛋白质和丙二醛(Malondialdehyde,MDA)含量,探究肉桂精油的抗菌机制。研究表明,肉桂精油水浴加热的气相熏蒸对白色葡萄球菌MIC和MBC均为10μL/L;5μL/L和10μL/L的低精油浓度下,肉桂精油造成细菌细胞膜载体蛋白变性,离子运输受阻造成胞外溶液电导率下降;造成小部分蛋白质、DNA外流,导致细菌蛋白质代谢异常;同时引起细菌产生自由基生理防御使MDA含量升高。50μL/L和100μL/L的高精油浓度下,细胞外液电导率、DNA和蛋白质含量骤升说明细菌细胞膜已受到严重破坏,而MDA值维持在较低水平说明高浓度下精油杀菌速率较快,细菌未及时进行生理防御。

In this work,the antibacterial mechanism of Staphylococcus albus was investigated by the gas phase fumigation heated by cinnamon essential oil in water bath of Antibacterial activity of cinnamon essential oil was determined by minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)and antimicrobial mechanism of cinnamon essential oil was analyzed by extracellular fluid conductivity,DNA,protein and MDA tests.The results showed that the MIC and MBC of cinnamon essential oil against Staphylococcus albus are both 10μL/L.At the low concentration of 5μL/L and 10μL/L essential oil,solution conductivity in extracellular was decreased by the obstruction of ion transport for which cinnamon essential oil causes denaturation of bacterial cell membrane carrier proteins and lead to abnormal protein metabolism and partial protein and DNA efflux in bacteria.According to the increase in MDA content,essential oils cause bacteria to produce free radical physiological defense as well.At the high concentration of 50μL/L and 100μL/L essential oil,bacterial cell membrane damaged seriously has been indicated by the sudden rise of extracellular fluid conductivity,DNA and protein content.Meanwhile,MDA maintaining a low level indicates that bacteria are killed by high concentrations of essential oils without timely physiological defense.