Studies On The Secondary Metabolites Of Three Marine-derived Fungi

The marine environment with high salinity, high pressure, low light or no light, unusual high temperature or low temperature and other unique characteristics make it very likely that marine microorganisms and the chemicals they produce will be quite different from those associated with terrestrial biology. The marine fungi are an important composition of Marine microorganisms. In recent years, secondary metabolites obtained from marine-derived fungi have gained considerable attention, as many of them are structurally unique and possess interesting biological and pharmacological properties.In this study,230 fungal strains were isolated from 13 samples, including 9 sponge samples that collected from Xisha Island,3 mangrove roots collected from Hainan province and one holothurian that from Qingdao province. Using cytotoxicity assay and P388 cell line as bioactive screen model,19 fungal strains were obtained with cytotoxic activity. Together with applying the TLC and HPLC chemical screen assays, one Xisha sponge derived fungus Aspergillus versicolor HDN14-156 was selected for further study. Two South China Sea marine sediment derived fungi Aspergillus sydowii HDN13-107 and Penicillium brocae HDN12-143 isolated by previous work were also studied.In all,36 compounds were isolated and purified, from theEtOAC extracts of the 3 aimed strains, by using solvent extraction, silica gel column, ODS, Sephadex LH-20, MPLC、HPLC etc.18 compounds (1-18) were isolated from fungus Aspergillus versicolor HDN14-156,4 compounds (19-22) were isolated from Aspergillus sydowii HDN13-107 and 14 compounds (23-36) were isolated from Penicillium brocae HDN12-143, Basing on spectral data (IR、UV、MS、NMR) and their physicochemical properties, structures of the 36 compounds were determined. Among them there are 1 cvclohexenone (1).3 alkvlated phenol (2-4),5 diketopiperazines (5-9),2 Cyclic dipeptides (10-11),5 sesquiterpenoids (5、19-22),5 alkaloids (23-27),3 butyrolactones (28-30),2 alkenones (31-32),2 steroids (17-18),2 ethers (6,9),1 curvularin (33) and 5 benzene derivatives (7-8、34-36).With the purpose of exploring the potential therapeutical effect of the compounds. The new compounds (1-3) were tested for antitumor activities against A-549, P-388 by use of the MTT or SRB method and anti-microbial activities against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Candida albicans, smegmatis Mycobacterium phlei by paper strip method. Unfortunately none of them showed antitumor activity or anti-microbial activity.In sumary,230 fungi were isolated from 9 sponge samples,3 mangrove roots and one holothurian.19 fungal strains were obtained with cytotoxic activity that make a contribution to rich laboratory strains.36 compounds including 3 new compounds were obtained, making efforts to the researching of natural products.