贵州光枝勾儿茶内生真菌Diaporthe sp.代谢产物分离鉴定及其抑菌活性研究

Isolation,Identification and Antibacterial Activity Research of Metabolites of Endophytic Fungus Diaporthe sp.from Berchemia polyphylla var.leioclada in Guizhou

为探究黔产苗药光枝勾儿茶中1株具有抗菌活性的内生真菌Diaporthe sp.QX4G6代谢产物的化学成分,并从中筛选抑菌活性化合物,经对菌株Diaporthe sp.QX4G6扩大培养后,利用多种分离方法对代谢产物进行分离纯化,结合光谱技术与文献报道鉴定其结构;以微量肉汤二倍稀释法和平板涂布法分别测定单体化合物对大肠杆菌和沙门氏菌的抑菌活性。结果表明,从Diaporthe sp.QX4G6菌株代谢产物中分离纯化得到4个单体化合物,经核磁共振和质谱分析,分别鉴定为邻苯二甲酸二丁酯(化合物1)、1-[(12E,16E)-12,16-二十碳二烯酰基]-2-[(E,E)-7,10-十八碳二烯酰基]-3-硬脂酰基甘油化合物(2)、3-(4-甲苯氧基)-丙酸(化合物3)、酪醇(化合物4)。抑菌试验结果显示,化合物1—3对大肠杆菌和沙门氏菌均表现出一定的抑制活性,相同条件下对沙门氏菌的抑制作用较强;其中化合物3的抑菌活性最强,对2株细菌的最小抑菌浓度(MIC)分别为7.81μg/mL和3.91μg/mL,最小杀菌浓度(MBC)分别为15.63μg/mL和7.81μg/mL。综上,4个化合物均为首次从茎点霉属(Diaporthe sp.)内生真菌代谢产物中分离得到,其中3个化合物在体外对大肠杆菌和沙门氏菌具有一定的抑菌作用,为进一步开发利用光枝勾儿茶内生真菌代谢产物提供科学依据。

The aim is to investigate the chemical constituents of the metabolites of endophytic fungus Diaporthe sp.QX4G6 from Berchemia polyphylla var.leioclada in Guizhou,which has antibacterial activity,and to screen the antibacterial active compounds.After expanding culture of the strain Diaporthe sp.QX4G6,the metabolites were isolated and purified by various separation methods,and their structures were identified by spectrography combined with literature reports.The bacteriostatic activity of the monomers against E.coli and Salmonella was determined by microbroth dilution method and plate coating method,respectively.The results showed that four monomer compounds were isolated and purified from the metabolites of Diaporthe sp.QX4G6.The compounds were analyzed by NMR and MS.They were identified as dibutyl phthalate(compound 1),1⁃[(12E,16E)⁃12,16⁃eicosadienoyl]⁃2⁃[(E,E)⁃7,10⁃octadecadienoyl]⁃3⁃stearacylglycerol(compound 2),3⁃(4⁃toluoxy)⁃propionic acid(compound 3),tyrosol(compound 4).The results of bacteriostatic test showed that compounds 1—3 displayed certain inhibitory activity against E.coli and Salmonella,and the inhibitory effect on Salmonella was stronger under the same conditions.Compound 3 showed the strongest antibacterial activity with MIC(minimum inhibitory concentration)of 7.81μg/mL and 3.91μg/mL,and MBC(minimum bactericidal concentration)of 15.63μg/mL and 7.81μg/mL,respectively.In summary,all the four compounds were isolated from the metabolites of endophytic fungus Diaporthe sp.for the first time,and three compounds showed certain antibacterial activity on E.coli and Salmonella in vitro,which provided a theoretical basis for further development and utilization of endophytic fungal metabolites from Berchemia polyphylla var.leioclada.