Huang Wei, Wang Jian-Qing, Song Hai-Yan, Zhang Qian, Liu Guang-Fa
Tianjin University of Science & Technology, Tianjin 300222, People's Republic of China; China Packaging Research & Test Center, Tianjin 300457, People's Republic of China.
Tianjin University of Science & Technology, Tianjin 300222, People's Republic of China.
Asian Pac J Trop Med. 2017 Jul;10(7):663-669. doi: 10.1016/j.apjtm.2017.07.006. Epub 2017 Jul 28.
To find a natural plant essential oil (EO) with excellent antimicrobial effects on food-borne bacteria and to explore the mechanism of its antimicrobial function against Escherichia coli (E. coli).
The antimicrobial activity of seven EOs against Gram-negative E. coli ATCC 8739 and Gram-positive Staphylococcus aureus ATCC 6538 was investigated using agar disk diffusion method, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of each EO was determined using the broth dilution method. The chemical composition of the Trachyspermum copticum (T. copticum) EO was analyzed using gas chromatography-mass spectrometry (GC/MS). In order to explore the mechanism of the antimicrobial action, 1 MIC and 2 MIC of T. copticum EO was added to a suspension of E. coli, the growth curve and the scanning electron microscopy (SEM) analysis of E. coli, and the release of cell constituents and protein and potassium ions from the bacterial cell were measured.
The T. copticum EO had the best antimicrobial activity against the test bacteria, and 10 compounds accounting for 94.57% of the total oil were identified, with the major components being thymol (46.22%), p-cymene (19.03%), and γ-terpinene (22.41%). The addition of 1 MIC that T. copticum EO significantly inhibited the growth of E. coli and increased the release of cell constituents and protein and potassium ions from the bacterial cells. Scanning electron micrographs showed that T. copticum EO caused most of the E. coli cell membranes to collapse and rupture, leading to cell death.
These results indicate that T. copticum EO is a good natural antimicrobial agent for food-borne pathogens.
寻找一种对食源细菌具有优异抗菌效果的天然植物精油（EO），并探究其对大肠杆菌（E. coli）抗菌作用的机制。
采用琼脂平板扩散法研究7种EO对革兰氏阴性大肠杆菌ATCC 8739和革兰氏阳性金黄色葡萄球菌ATCC 6538的抗菌活性，并用肉汤稀释法测定每种EO的最低抑菌浓度（MIC）和最低杀菌浓度（MBC）。采用气相色谱 - 质谱联用（GC/MS）分析藏茴香（T. copticum）EO的化学成分。为探究抗菌作用机制，将1 MIC和2 MIC的藏茴香EO添加到大肠杆菌悬液中，测定大肠杆菌的生长曲线、扫描电子显微镜（SEM）分析，以及细菌细胞中细胞成分、蛋白质和钾离子的释放情况。
藏茴香EO对受试细菌具有最佳抗菌活性，鉴定出占总油94.57%的10种化合物，主要成分是百里香酚（46.22%）、对伞花烃（19.03%）和γ - 萜品烯（22.41%）。添加1 MIC的藏茴香EO显著抑制大肠杆菌生长，并增加细菌细胞中细胞成分、蛋白质和钾离子的释放。扫描电子显微镜照片显示，藏茴香EO导致大多数大肠杆菌细胞膜塌陷和破裂，导致细胞死亡。
这些结果表明，藏茴香EO是一种用于食源性病原体的良好天然抗菌剂。
