Studies On Secondary Metabolites From Three Marine Fungi

Marine fungi are a kind of important source for Marine natural products. In order to discover new bioactive secondary metabolites, biological and chemical methods are integrated to study secondary metabolites of marine fungi. The studies contained isolation of microorganisms, fungal fermentation, isolation of compounds, the structural elucidation and bioactive evaluation of pure compounds.46 fungal strains were isolated from the Atlantic deep-sea sediments and the Indian Ocean water samples. All strains were identified and cultured to detect fungal antibacterial and anticancer activity by disc diffusion and MTT assay method. Then three strains that had rich secondary metabolites were picked out according to HPLC and TLC screening.Large-scale fermentations of three fungi were carried out to obtain the active extracts respectively. By means of chromatography over silica gel column, Sephadex LH-20, preparative TLC and semi-preparative HPLC, sixteen compounds(CH1-CH16) were isolated from the fungi in the Atlantic deep-sea sediments and sixteen compounds(CH17-CH32) were isolated from two fungal strains in the Indian Ocean water samples. Based on their physico-chemical properties and spectral data(IR, UV, MS, NMR, etc.), structures of 32 pure compounds are respectively determined. The anticancer activities of the compounds against human cancer cells were determined by the MTT assay method, and 8 compounds showed moderate cytotoxicity. Antimicrobial activity was tested by disk diffusion and microdilution method, 7 compounds showed weak inhibitory activities.In conclusion, 32 compounds were obtained from the three marine fungi, including 4 new compounds, 8 anticancer compounds, 7 antimicrobial compounds, 6 compounds that promote zebrafish angiogenesis and 2 compounds that protect the zebrafish heart. This study suggests that Marine fungi have great potential for research and is one of the important sources of new active compounds. This study also provides certain scientific basis for the effective use of Marine resources.