Isolation And Identification Of Bioactive Compounds From Sediments Of Qingdao

Due to their special habitats,marine microorganisms can produce secondary metabolites with bioactivities.20 strains of marine fungi were isolated from 8 sea mud samples collected from the coastal sediments of Qingdao.Three different solid mediums,brown rice,corn and wheat were used for small-scale fermentation to obtain the crude extracts.The crude extracts were evaluated against Staphylococcus aureus,Escherichia coli and Candida albicans by filter paper diffusion and microdilution methods.At the same time,HPLC analysis were carried out to analyze the chemical diversity of the crude extracts.Strains QD1-1,QD1-2,QD3-2,QD4-1,QD7-1,QD7-2,QD7-3,QD7-5,QD7-7 and QD8-1 showed antibacterial activity against Staphylococcus aureus.Strain QD3-2 displayed antifungal activity against Candida albicans.According to HPLC analysis,the chemical diversity of metabolites of QD4-2,QD4-1,QD1-1were abundant.Combined with the results of antibacterial activity and HPLC fingerprint analysis,3 potential strains,including QD4-1,QD4-2 and QD1-1 were investigated on chemical constituents.According to phylogenetic combined analysis of the ITS sequences,QD4-2,QD4-1,QD1-1 were identified as Penicillium polonicum,Talaromyces adpressus and Talaromyces rugulosus.Strains QD4-2,QD4-1,and QD1-1 were separately cultured in brown rice solid media,chromatography and HPLC were used to sparate and purify the crude extracts.The structures of the compounds were characterized by means of extensive analysis of spectroscopic techniques such as mass spectrometry(MS),nuclear magnetic resonance(NMR).3 compounds were isolated from the fermentation extracts of marine fungi QD4-2,which were identified as 3-O-methyl-14-hydroxyviridicatin(1),aflaquinolone F(2),aflaquinolone I(3).1 was new compound.5 compounds were isolated from the fermentation extracts of marine fungi QD4-1,which were identified as 5,7-dihydroxy-4,6-dimethylisobenzofuran-1(3H)-one(4),penicillide(5),bacillisporin B(6),trans-p-hydroxy cinnamic methyl ester(7)and4,6-dihydroxy-5-methylisobenzofuran-1(3H)-one(8).The antibacterial activities of the compounds were evaluated.Compound 5 showed antibacterial activity against Staphylococcus aureus,activities with minimum inhibitory concentration(MIC)value of 100 ?g/m L.