Studies On The Bioactive Constituents From A Marine-derived Fungus Aspergillus Flavus OUCMDZ-2205

Marine derived microorganism including marine fungus, marine actinomycetes are the main source of marine drug development in terms of the novel structure and unique bioactivity of their secondary metabolites. Alkaloid compounds are one important class compounds of natural products, which commonly been founded in many medicine and prodrug. In this dissertation, TLC was utilized to identify the fungus which has the alkaloid compounds in secondary metabolites, according to the "talented strain" screen model. The strain Aspergillus flavus shows the alkaloid compounds in secondary metabolites and bioactivity in anti-tumor test was identified and was chosen as the final talented stain. The strain Aspergillus flavus was fermented in big scale. Furthermore, the anti-humor activities on MCF-7cell line and anti-activity tests of these compounds were evaluated initially.12compounds were obtained from the fermentation extracts in the broths and mycelia of the stain, the isolation of these compounds were conducted by the column chromatography on silica gel and Sephadex LH-20, as well as high performance liquid chromatography. Based on the method of spectroscopy (IR, UV, MS,1D-NMR and2D-NMR) and X-ray diffraction, CD spectra experiment, the structures of these compounds were elucidated. Among these12compounds, compounds1,2,3and4are indole-diterpenes, compound5and6are a-cyclopiazonic acid and iso-a-cyclopiazonic acid,7is Aflatoxin B1,8is ditryptophenaline and9is leporine,10is6,8-dimethoxy-citreoisocoumarin, compound11and12are7-O-acetyl-kojic acid and kojic acid respectively。 And compound1,2and10are new compound.The anti-tumor activities of these compounds on the cancer cell line MCF-7(human breast cancer cell) in vitro by MTT methods were assayed. The result of the assay showed compound6indicated the cytotoxicity against the cell line MCF-7. The antibacterial bioactivities of these compounds against various bacteria are tested. The bioassays of compound1,7and9exhibited the growth inhibitory activity against Staphylococcus aureus.In sum, among these isolated compounds, compound1,2and10are new compounds achieved from the talented strain Aspergillus flavus. Eight of the compounds belong to alkaloids. Studies mentioned above provided us novel structures for leading anti-tumor compounds search and offered the source of the microorganism for new drug development.