中药单体组合物的筛选优化及对大肠杆菌的抑菌作用

Screening and optimization of monomer composition of traditional Chinese medicine and its antibacterial activity on Escherichia coli

旨在研究由不同单体组成的中药单体组合物对多重耐药大肠杆菌的抑菌作用。通过最小抑菌浓度(MIC)、分级抑菌指数(FICI)、中药单体组合物的筛选、中药单体组合物的剂量配比优化等试验,获得一种由绿原酸、黄芩苷、厚朴酚按照质量比为2∶4∶1的中药单体组合物。通过测定中药单体组合物对多重耐药大肠杆菌的生长曲线、相对电导率、核酸和蛋白渗漏、胞外碱性磷酸酶(AKP)含量、胞内DNA含量变化的影响,初步探究中药单体组合物对多重耐药大肠杆菌的体外抑菌作用。结果显示:绿原酸、黄芩苷、厚朴酚、硫酸小檗碱对多重耐药大肠杆菌的MIC分别为6.25、6.25、6.25和1.25 mg/mL,不同组分之间存在协同或相加作用,其中绿原酸和厚朴酚联用的FICI为0.5。中药单体组合物可以抑制细菌的生长,破坏大肠杆菌细胞的完整性,引起细胞内容物渗漏使菌液的电导率显著升高(P<0.05),菌液OD_(260 nm)、OD_(280 nm)值显著升高(P<0.05),AKP含量显著升高(P<0.05),DNA含量变化明显。本研究表明中药单体组合物主要通过破坏多重耐药大肠杆菌的细胞膜、细胞壁的结构完整性从而实现抑菌作用,为中药复方治疗或预防细菌性疾病的药物筛选和研发奠定基础。

The aim of this experiment was to study the bacteriostatic effect of Chinese medicine monomer composition composed of different monomers on multi-drug resistant Escherichia coli(E.coli).Through the minimum inhibitory concentration(MIC),fractional inhibitory in⁃dex(FICI),the screening of traditional Chinese medicine monomer composition and the dose ratio optimization test of traditional Chinese medicine monomer composition,a traditional Chinese medicine monomer composition composed of chlorogenic acid,baicalin and magnolol at the mass ratio of 2∶4∶1 was obtained.By measuring the effects of the traditional Chinese medicine monomer composition on the growth curve,relative conductivity,nucleic acid and protein leakage,extracellular alkaline phosphatase(AKP)content,and intracellular DNA content of multidrug-resistant E.coli,the in vitro antibacterial effect of the traditional Chinese medicine monomer composition on multidrugresistant E.coli was preliminarily explored.The results showed that the MIC of chlorogenic acid,baicalin,magnolol and berberine sulfate against multidrug-resistant E.coli were 6.25,6.25,6.25 and 1.25 mg/mL,respectively.There was a synergistic or additive effect between different components,and the FICI of chlorogenic acid and magnolol was 0.5.The monomer composition of the traditional Chinese medicine inhibited the growth of bacteria,destroyed the integrity of the E.coli cells,caused leakage of cell contents,significantly increased the con⁃ductivity of the bacterial solution(P<0.05),and significantly raised the OD_(260)nm and OD_(280)nm values of the bacterial solution(P<0.05).The AKP content increased significantly(P<0.05),and the DNA content also changed significantly.This study indicated that the monomer composition of traditional Chinese medicine mainly destroyed the structural integrity of the cell membrane and cell wall of multidrug-resistant E.coli to achieve bacteriostatic action,which laid a foundation for the screening and development of traditional Chinese medicine compounds for the treatment or prevention of bacterial diseases in pgs.