铁皮石斛内生真菌的分离及其体外抑菌和抗肿瘤活性初步研究

目的分离铁皮石斛Dendrobium officinale内生真菌,研究内生真菌的分布并初步探讨和筛选具有抑菌和抗肿瘤活性的特异菌株。方法利用组织分离法和分子生物学方法分离、鉴定内生真菌;以大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌作为受试对象,采用对峙法和管碟法分别对内生真菌及其发酵代谢产物的醋酸乙酯萃取相进行抑菌实验;采用MTT法对内生真菌代谢产物醋酸乙酯萃取相进行体外抗肿瘤活性检测。结果从铁皮石斛中分离得到28株内生真菌,分子鉴定结果显示,分离的内生真菌归属于10个属,其中镰刀菌属为优势属。抑菌实验结果显示28株内生真菌中,有7株至少能对1种指示菌有抑菌作用,其代谢产物的醋酸乙酯萃取相对3种指示菌和Hep G2细胞具有不同程度的抑制作用。结论铁皮石斛内生真菌种群丰富,从中分离得到的内生真菌具有潜在的抑菌和抗肿瘤活性,为进一步开发抑菌、抗肿瘤候选药物奠定基础。

Isolation of endophytic fungi from Dendrobium officinale and preliminary evaluation of in vitro biological activity

Objective To study the distribution of endophytic fungi from Dendrobium officinale and screen the distinctive fungi with antimicrobial and antitumor activities. Methods Endophytic fungi were isolated by the conventional method and cylinder-plate method with Staphylococcus aureus, Escherichia coli, and Bacillus subtilis as subjects. The metabolites of ethyl acetate extracts with antitumor activity were identified based on MTT assay. Results A total of 28 strains of the endophytic fungi were isolated from D. officinale. By analyzing the data of molecular identity, there were 10 species in D. officinale, in which Fusarium Link is a dominant. The ethyl acetate extracts of the fermentation broth had different antibiotic activities on the indicator microorganisms, and had antitumor effect on HepG2 cells. Conclusion Endophytic fungi isolated from D. officinale have rich diversity and have antimicrobial and antitumor activities, which could be potential for developing antimicrobial and antitumor reagents.