怀地黄活性内生菌的分离鉴定及抗菌抗肿瘤活性

利用平板分离法从怀地黄(Rehmannia glutinosa Libosch)中分离出内生菌共130株,包括67株细菌、50株真菌和13株放线菌。利用大肠杆菌、金黄色葡萄球菌和黑曲霉作为供试菌株,通过对峙试验和平板点接法筛选出8株对3种供试菌株均具有较强拮抗作用的内生菌。经菌种形态观察、生理生化实验以及16S rRNA序列测定,这8株活性内生菌均为假单胞菌属的细菌,并分别与Pseudomonas fluorescens、Pseudomonas thivervalensis、Pseudomonas chlororaphis、Pseudomonas koreensis和一个未定种具有最高相似性。对这8株活性内生菌进行液体发酵、不同有机溶剂抽提和抗菌抗肿瘤研究,结果表明它们的乙醇抽提物和乙酸乙酯抽提物均不同程度地对3种供试菌株和食管癌细胞系Ec9706具有抑制作用。其中2-2号菌株(Pseudomonas chlororaphis)抗菌抗肿瘤作用最强,具有重要的开发价值。

Isolation, Identification and Antagonism on Microorganisms and Cancer Cells by Active Endophytes from Rehmannia glutinosa Libosch

Using the methods of plate cultivation, 130 strains of endophytes were isolated from Rehmannia glutinosa Libosch, including 67 bacteria, 50 fungi and 13 actinomycetes. From them, 8 isolates of bacteria were selected due to their high and wide antagonistic activities to the tested microbial strains, Escherichia coli, Staphalocolcus aureus and Aspergillus niger on the plate confrontation. The 8 active strains of bacteria were classified to genus of Pseudomonas and shared the highest identities respectively with 5 species including Pseudomonas fluorescens, Pseudomonas thivervalensi, Pseudomonas chlororaphis, Pseudomonas koreensis and one unidentified according to their morphological, physiological and chemical characteristics and 16S rRNA sequences. Active products were obtained from the 8 strains through liquid fermentation and further extraction by different organic solvents. Activity studies indicated that the extraction products from all the 8 strains using ethyl acetate or ethanol exhibited significant inhibition on the 3 tested types of microorganisms and esophageal cancer cells Ec9706. Among them, strain 2-2 had the highest activities of both anti-microorganisms and anticancer showing important value of development.