Antimicrobial and anti-tumor activities of endophytes from Lycium barbarum of Ningxia

Abstract

The antimicrobial activity and cytotoxicity in vitro of the fermentation broth of 10 endophytic strains isolated from Lycium barbarum were determined to screen high activity endophytic strains. Sequences analysis of ITS and 16S rDNA was used for molecular identification of the strains. The results showed that 5 endophytic fungi had no inhibitory activity against the tested pathogens. Endophytic actinomycete strain AL6 had a certain inhibitory effect on 3 kinds of pathogenic fungi, and strain AL5 only had strong inhibitory activity against Staphylococcus aureus. However, the anti-tumor activity of endophytic fungi was significantly higher than that of actinomycetes. Four endophytic fungi strains exhibited the growth inhibition rate of above 50% against at least one of the tested tumor cells when the concentration of fermentation broth was 0.2 g•L⁻¹. Sequences analysis showed that 5 endophytic fungi strains belonged to genus Aspergillus, Penicillium and Emericella, and the 5 endophytic actinomycetes strains belonged to genus Aspergillus, Penicillium and Emericella. Aspergillus strain FL1 had stronger inhibitory activity against A549 and HeLa cells, and the IC₅₀ values were 0.022，0.028 g•L⁻¹, respectively, which was worthy of further study.