泰山白首乌根际土壤真菌分离纯化及抗菌活性研究

Isolation, identification, and antibacterial activity evaluation of rhizosphere soil fungi in Cynanchum bungei Decne

目的从泰山白首乌根际土壤中分离筛选优良真菌菌株,并从中分离鉴定具有抗菌活性的活性化合物。方法采用梯度稀释平板划线法,从泰山白首乌根际泥样中分离真菌;以活性为导向,采用正/反相硅胶及半制备高效液相色谱方法对次级代谢产物进行单体化合物分离纯化,通过质谱和核磁共振等波谱方法确证活性化合物结构。结果从采集的3个样品中共分离得到83株真菌,其中筛选获得具有抑金黄色葡萄球菌和大肠埃希菌活性的菌株7株,并从黑曲霉SDFMU-45菌株的次级代谢产物中分离鉴定两个萘并吡喃酮类化合物rubrofusarin B(1)和fonsecin B(2)。结论对化合物1和2进行了抑菌活性测试,结果显示化合物1和2对金黄色葡萄球菌标准菌株的MIC值分别为250和187μg/mL,对大肠埃希菌标准菌株的MIC值分别为2.89和620μg/mL。

Objective Fungi were isolated from rhizosphere soil of Cynanchum bungei Decne., the excellent strains with antibacterial activities were screened, and the active compounds were isolated and identified. Methods The fungi were isolated from rhizosphere mud samples by the gradient dilution method. The compounds were separated and purified by using positive/reverse phase silica gel and semi-preparative high performance liquid chromatography, and the structures of the active compounds were confirmed by MS and NMR spectroscopic method.Results 83 strains of fungi were isolated from three samples, among which seven strains were screened to have the activity of inhibiting Staphylococcus aureus and Escherichia coli, and two naphthalene pyranones rubrofusarin B(1) and fonsecin B(2) were isolated and identified from the secondary metabolites of Aspergillus niger SDFMU-45.Conclusion The antimicrobial activity of compounds 1 and 2 was tested, and the results showed that the MIC values of compounds 1 and 2 against the standard strains of Staphylococcus aureus were 250μg/mL and 187μg/mL respectively, and 2.89μg/mL and 620μg/mL against the standard strains of E. coli.