Bioactive Natural Products Of Aspergillus Sp. OUCMDZ-1914, An Aciduric Fungus From The Mangrove

The microorganism which live in the ocean special habitat can produce a variety of bioactive compound. Aciduric microorganism are the representative of the special ocean microorganism, it has different inheritance backgrounds and metabolic mechanism compared with ordinary microorganisms. The mangrove ecosystem is a junction of land and sea typical environment, its toot segment suffer long erosion from sea water, soil around it demonstrate acidic which contain ample microbial resources. Recent studies show that fungi isolated from the soil of mangrove root can generate numerous novel and bioactive compounds and has great potential for exploitation. So far it is rarely reported about the microorganisms from mangrove acidic soil, this work is worth intensive study and has bright future.In order to obtain aciduric talented fungi and separate novel and antiviral compounds from secondary metabolites, a screen study is carried out by integrated diversity of chemical screening and bioactive evaluation. The studies included purification of fungi from mangrove soil, screening talented strains from aciduric fungus, exploring the fermentation conditions of the target fungi, the fermentation and compound separation from aciduric fungi, the structural elucidation and biological evaluation of the compounds.We have separate and purified strains from sponge and coral in South China Sea, finaly obtained 68 fungal strains,20 actinomycete strains. Also we have separate and purified strains from mangrove soil in Wenchang, and got 43 aciduric fungal strains. After diversity of chemical screening and bioactive evaluation, we selected two aciduric fungal OUCMDZ-1914 and OUCMDZ-1525 as target strains and further research was carried against OUCMDZ-1914.Then we investigating effects of different fermentation conditions, including optimal pH, optimal medium and optimal fermentation methods, at last confirmed the optimum fermentation conditions of this strain. After scale fermentation, we use thin layer chromatography, pressure and vacuum silica gel column chromatography, gel Sephadex LH-20 column chromatography and semi-preparative HPLC chromatography,12 compounds were isolated from fermentation products of this strain(see Fig.1) wherein there was a new compound. The structures were respectively determined by means of NMR, MS, UV, IR, OR, CD, X-ray.The activity of the compounds against influenza A vims (H1N1), human cancer cells and Glycosidase inhibitory activity were evaluated. The results show that compound 2 exhibited moderate activity against H1N1 virus, the activity was equal to positive drug ribavirin, compounds 1 exhibited weak activity against H1N1 virus. Compound 5 showed cytotoxicities against MCF-7 cells, A549 cells and K562 cells with the IC50 values 4.45 μM,0.23 μM,3.68 μM respectively. Compound 7 showed anti-diabetic activity with IC50 0.84 mM.