Study Of Secondary Metabolites Of Marine Fungus BY1

To adapt to the special marine environment(such as high salt, high pressure, oligotrophic),marine fungi can produce a series of products with special structure and biological activity.These products are important sources of new drugs. This paper identified one endophytic fungus BY1 which isolated from mangrove plant Sesuvium portulacastrum in Jimei district, Xiamen,Fujian province, and optimized the fermentation media and culture conditions, then purified its secondary metabolites, analyzed the structure and biological activities(antibacterial and antioxidant) of the pure compounds. The main results were shown as the following:(1) The colony and microscopic morphology of the strain BY1 belonged to typical morphology characteristics of Aspergillus sp., and the 28 S r DNA sequence of the strain BY1 was 100%similar to the strain Aspergillus clavatonanicus(AF459727.1). So the strain BY1 was identified as Aspergillus clavatonanicus.(2) This paper optimized the fermentation media and culture conditions(days, seawater concentration, loading volume) of strain BY1. According to the results of biomass, the weight of metabolites, antibacterial and antioxidant, the fermentation conditions of strain BY1 were determined: 40% seawater of MA liquid medium, loading volume 100 m L/250 m L, culturing in the shaker of 28 o C, 190 rpm for 9 days.(3) 7 compounds were isolated and purified from the secondary metabolites of strain BY1 by using silica gel column, ODS, PTLC and Sephadex LH-20. Using NMR and MS spectral analysis methods, structures of the compounds C1, B-11-2 and D5-1 were determined, they were clavatol, 1-O-methylemodin and 3-(hydroxymethy) phenol, respectively. Compound B-11-2 was the first isolated from mangrove fungus. Through the method of HPLC the yield of compound C1 was determined, it was 82.8 mg/L. The antibacterial and antioxidant activities of the 7 pure compounds were assayed. Compound C1 had antibacterial activity to Staphylococcus aureus and Bacillus subtilis at the concentration 100 μg/m L with Iz(9.7±0.8) mm and(13.6±6.4) mm,respectively. Compounds D7-1, B-11-2 and E10 showed stronger scavenging activities to ABTS+with EC50(21.25±5.26) μg/m L,(23.62±4.15) μg/m L and(26.03±3.83) μg/m L, respectively.Compounds D7-1 and E10 showed stronger scavenging activities to DPPH with EC50(2.73±0.44)μg/m L and(8.72±0.94) μg/m L, respectively.In all, the research results of the paper provide theoretical foundation and technical support for further development and research of the marine fungus BY1.