Studies On Isolation And Screening Of Marine Fungi In Dongshan Bay And Natural Products Of Active Strain

In view of the uniqueness of the marine environment compared to the terrestrial environment,natural products derived from marine microorganisms have attracted the attention of researchers.In order to adapt to the complex and special marine environment,marine fungi have formed a uniquc mechanism of survival and metabolism.Their natural products arc diverse in structure and have remarkable activity,and are important sources for the development of new drugs.In this thesis,we have systematically studied 81 marine fungi isolated from samples of sea mud from Dongshan Bay,Zhangzhou,Fujian,and completed the work of molecular identification,small-scale fermentation,screening of antimicrobial activity and cytotoxic activity.The strain WZW-F-30 was identified with the best activity.Having large-scale fermentation of the strain WZW-F-30,natural products derived from this strain were isolated using normal phase silica gel column chromatography,RP-18 reverse phase silica gel column chromatography,LH-20 gel column chromatography,thin layer chromatography and high performance liquid chromatography,and determined by nuclear magnetic resonance spectroscopy and mass spectrometry.81 marine fungi isolated and purified from 20 samples of sea mud by seawater PDA medium and seawater Rose Bengal medium were distributed in 21 genera by ITS molecular identification,mainly Penicillium,Talaromyces,Aspergillus,Phoma and so on.Antimicrobial activity and cytotoxic activity screening results of the crude extracts obtained from small-scale fermentation showed the strain with the best activity is WZW-F-30,which belongs to Phoma gardeniae.A total of 17 compounds,including 5 new compounds,were isolated and purified from the crude extracts obtained from large-scale fermentation of marine fungus WZW-F-30.Known compounds patulin and chlorogentisyl alcohol were isolated and identified to be main components for bioactivity.New compounds WZW-04-036-01 and WZW-04-103-01 have significant antibacterial activity against Bacillus pumilus,Bacillus subtilis,Staphylococcus aureus,Escherichia coli and Mycobacterium smegmatis.In addition,new compound WZW-04-103-01 have cytotoxic activity on cancer cell lines such as Jeko-1,MDA-MB-231 and A375.In summary,these results show that marine fungi are rich in natural products resources and are important sources for the development of new drugs.