The Screening For Bioactive Fungus From Deep-sea Sediment And The Primary Study On Secondary Metabolites From Strain WP-K-3

In this study, marine fungus isolated from marine sediment samples originated from west of the Pacific Ocean beside the equator, were screened for antimicrobial, antitumor, Acetylcholinesterase(AChE) inhibitory activities and Cysteine protease inhibitory activities. One of the strains with high activity was chosen for further research on its secondary metabolites. This study aims at finding potential bioactive strains and their metabolites, thus lays a foundation on exploring and utilizing marine sediment fungus and new microbial pharmaceutical.83 strains of fungus were isolated from 18 marine sediment samples. After cultured on PDB and GPY medium, their ethyl acetate extracts were tested for antibacterial, antifungal, AChE inhibitory activities and Cysteine protease inhibitory activities by using paper disk diffusion method, MTT method, improved Ellman method and Houseman method respectively. The results show that 36 strains(43.4% of the total strains) could inhibit one or more sensitive microbes named Escherichia coli, Staphlococcus auerus, Bacillus subtilis, Candida albicans and Aspergillus niger, the number of such activity strains are 16, 28, 5, 4, and 3 respectively, the ratio to the total tested strains are 19.3%,33.7%,6.0%,4.8% and 3.6% respectively;70strains could inhibit the growth of KB and/or Raji tumor cell lines, including 57 strains on KB cell and 58 strains on Raji cell, the ratio to the total tested strains are 68.7%, 69.9% respectively. Strains of WP-M-5,DY-G-4,DY-C-2,WP-J-3,and WP-O-3 were chosen for further study of their IC50 against Raji cell, their IC50 values are 5.0,1.1,2.8,1.9 and 0.5μg/mL respectively. At the same time, 7 strains were found that have AChE inhibitory activities. No strains have cysteine protease inhibitory activity.When identified by traditionally morphological characteristics with the use of ribosomal DNA (rDNA), WP-K-3 was classified as Aspergillius niger. It was selected to study on its secondary metabolites. Using Silica Column Chromatography, RP-18 Silica...