二氢槲皮素对大肠杆菌的抑菌作用机理  

Antimicrobial Mechanism of Dihydroquercetin against Escherichia coli

作　　者：蔡瑾[1] 闫然 王梦亮[1] 王琪[4] CAI Jin;YAN Ran;WANG Mengliang;WANG Qi(Institute of Applied Chemistry,Shanxi University,Taiyuan 030006,China;Modern Research Center for Traditional Chinese Medicine,Shanxi University,Taiyuan 030006,China;The Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education,Shanxi University,Taiyuan 030006,China;School of Life Science,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学应用化学研究所,山西太原030006 [2]山西大学中医药现代研究中心,山西太原030006 [3]山西大学化学生物学与分子工程教育部重点实验室,山西太原030006 [4]山西大学生命科学学院,山西太原030006

出　　处：《食品科学》2023年第19期18-26,共9页Food Science

基　　金：山西省基础研究计划自然科学研究面上项目(20210302123451)。

摘　　要：食源性病菌给食品安全带来重大的挑战。二氢槲皮素(dihydroquercetin,DHQ)可作为食品防腐剂,但目前鲜见其抑菌机理的相关报道。本实验发现DHQ对6种食源性致病菌,即金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、普通变形杆菌、产气肠杆菌和热带假丝酵母菌均有显著抑制作用(P<0.05),且对大肠杆菌的抑制活性最佳,故以大肠杆菌为指示菌,研究DHQ的抑菌机理。利用扫描电子显微镜和透射电子显微镜观察,发现在DHQ作用下的大肠杆菌严重变形,表现出黏连、折叠、质壁分离、出现空泡结构等现象。荧光探针被用来测定膜内活性氧(reactive oxygen species,ROS)水平,结果显示DHQ能显著增加细胞内的ROS水平(P<0.05)。利用Annexin V-FITC/PI试剂盒检测细胞膜的通透性和完整性,发现随着DHQ质量浓度增加,细胞膜通透性显著增加(P<0.05),细胞膜的完整性遭到破坏。使用罗丹明123检测细胞膜电位,结果表明DHQ会引起大肠杆菌细胞膜去极化,造成膜电位显著降低(P<0.05)。细胞膜内Ca^(2+)检测结果表明,DHQ会导致胞内Ca^(2+)外漏,影响菌体的正常生长代谢和功能活动。采用碘化丙啶/核糖核酸酶(propidium iodide/ribonuclease,PI/RNase)染色缓冲液检测细胞周期,结果表明DHQ干扰了大肠杆菌正常的细胞周期。研究结果揭示了DHQ主要作用于细胞膜,影响正常传代,从而达到抑制大肠杆菌的效果。Foodborne pathogens pose a major challenge to food safety.Dihydroquercetin(DHQ)can be used as a food preservative;however,its antimicrobial mechanism is still unclear.This study found that DHQ had significant antimicrobial activity against Staphylococcus aureus,Bacillus subtilis,Escherichia coli,Proteus vulgaris,Enterobacter aerogenes and Candida tropicalis(P<0.05),the effect being most pronounced against E.coli.The antimicrobial mechanism against E.coli was investigated.Observation by scanning electron microscopy(SEM)and transmission electron microscopy(TEM)revealed that the DHQ-treated cells became distorted and exhibited phenomena such as adhesion,folding,plasmolysis,and the occurrence of vacuoles.DHQ resulted in a significant increase in the level of reactive oxygen species(ROS)inside the cell membrane as determined using a fluorescence probe.The determination of Annexin V-FITC/P kit showed that cell membrane permeability significantly increased with increasing DHQ concentration(P<0.05)and cell membrane integrity was damaged.Cell membrane potential measurement by Rhodamine 123 staining revealed that DHQ caused cell membrane depolarization,leading to a significant reduction in membrane potential(P<0.05).Moreover,DHQ caused intracellular Ca^(2+)leakage,which perturbed the growth,metabolism and functional activity of E.coli.DHQ interfered with the cell cycle of E.coli as determined using propidium iodide/ribonuclease(PI/RNase)staining buffer.These findings revealed that DHQ can inhibit E.coli growth mainly by acting on the cell membrane and consequently affecting the normal passage of cells.

关 键 词：二氢槲皮素 抑菌活性 大肠杆菌 抑菌机理 

分 类 号：TS201.3[轻工技术与工程—食品科学]