Isolation, Identification and Antagonism on Microorganisms and Cancer Cells by Active Endophytes from Rehmannia glutinosa Libosch
怀地黄活性内生菌的分离鉴定及抗菌抗肿瘤活性

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.