Studies On The Secondary Metabolites Produced By Two Marine-derived Fungi

Marine-derived microorganism has become one of the abundant sources of active compounds due to the special and intricate living environment. In recent years, kinds of compounds with new chemical structures and distinct activities have been isolated from marine-derived microorganism, among which many possess antitumor constituents. With the purpose of discovering new-style active compounds, this thesis probes into the screening of cytotoxic marine-derived microorganism and the secondary metabolites produced by two marine-derived fungi. Studies include isolation of microorganism from mangrove mud and deep sea sediments samples, screening of cytotoxic strains, preliminary evaluation of active strains, isolation and structural elucidation of the secondary metabolites.From twelve samples collected from Guangdong and Pacific sediments, 237 microorganisms were isolated (fungi: 99; actinomycetes: 138) These strains were evaluated for their cytotoxicities against mouse leukemia tumor cells (P-388) and connecting with chemical screenings (such as TLC and HPLC). Finally, 5 fungi and 8 actinomycetes derived from Mangrove mud; together with 7 fungi and 5 actinomycetes isolated from deep-sea samples were detected antitumor activities and furnished considerable chemical constituents. Some exploration was made on the fermentation conditions of the 12 active fungi, and one of them, HDN10421, isolated from Mangrove mud was selected as target strain. Additionally, in the continue on the work of our laboratory, the fungus ZLN-29 was further researched including the identification (as Penicillium sp.) by ITS and scale up fermentation.By means of silica gel column, solvent extraction, Sephadex LH20, ODS-C18, PHPLC, etc, 17 compounds were separated and purified from the extracts of the two aimed strains. By dint of modern spectral analysis (UV, MS, NMR, and IR) and physico-chemical properties, the structures (see Fig.1) of 11 compounds were elucidated. Furthermore, the chemical structures of these compounds were relate to butyrolactone (1), polyketones (2-3), macropolyesters (4-6), macropolyesters analogues (7), meroterpenoids (8-9), and steroides (10-11).Summarily, this work obtained twenty-five active marine-derived microorganism, and 17 compounds (11 of them were elucidated) from two marine-derived active fungi.