Anti-H1N1Secondary Metabolites From The Mangrove-derived Aciduric Fungus Penicillium Camemberti OUCMDZ-1492

Aciduric microorganism is an extremely important class of special habitatmicroorganisms. It is possible to produce a variety of unique bioactive substances andhas potential value because it has different genetic backgrounds and metabolicpathways compared with ordinary microorganisms. The mangrove is a junction ofland and sea typical ecosystem, its soil is acidic with rich microbial resources. Themicroorganisms of aciduric fungus from the mangrove soil have very different geneticand physiological characteristics compared with microorganisms in the otherenvironment, they can produce unique secondary metabolites and has great potentialfor medicine. It is rarely reported about Studies on the microorganisms frommangrove acidic soil, the research is enticing.In order to discover bioactive new compounds derived from aciduric fungus, astudy is carried out by integrated chemical screening and bioactive screening. Thestudies contained isolation of microorganisms from mangrove soil, screening talentedstrains from aciduric fungus, the fermentation conditions fumble of the target strains,the fermentation and compound separation, the structural elucidation and biosyntheticpathway speculation, bioactive evaluation and structure activity relationshipevaluation of pure compounds.205strains of aciduric fungi have been isolated from acid soil of mangrove rootscollected in Wenchang of Hainan Island. The EtOAc extracts of these fungi wereevaluated with the combinatory method of chemical screening (TLC and HPLC) andbioactive evaluation (cytotoxicities and antiviral activity), one aciduric fungi weredetermined as aciduric talented strains and its secondary metabolites were in-depthresearch.After investigating effects of different fermentation conditions, includingmedium, pH, fermentation methods, on secondary metabolites of this strains, the optimum fermentation conditions were determined. Because the secondarymetabolites of Penicillium camemberti OUCMDZ-1492were different in these twoconditions that were two medium strains metabolism with same acidity (pH5), thestrains Penicillium camemberti OUCMDZ-1492was fermented twice with differentscale. After that, the whole broths were extracted with ethyl acetate to give fermentextracts. Basing on extensive silica gel column chromatography, Sephadex LH-20andHPLC, seventeen compounds were isolated from Penicillium camembertiOUCMDZ-1492, respectively. By means of modern spectral analysis (NMR, MS, UV,IR, CD), quantum chemical calculations and chemical methods, the structures (see Fig.1) of seventeen pure compounds were respectively determined, including eight newcompounds. Among them there are eleven indole diterpenoid compounds (1-11), sixα-pyrones compounds (12-16) and an amide compound (17).The use of in vitro and in vivo biological activity screening model, the activity ofthe compounds against human cancer cells was determined by the SRB and MTTassay method, against influenza A virus (H1N1) was evaluated by the CPE inhibitionassay and against pathogenic bacteria was assessed by Agar dilution method. Finally,compounds1–3and5–10exhibited significant activity against H1N1virus with IC50values of28.3,38.9,32.2,73.3,34.1,26.2,6.6,77.9and17.7μM, respectively.In conclusion, seventeen pure compounds were obtained from the aciduricfungus, including six new indole diterpenoid compounds, one new polyketidecompound and one amide compound, compounds1–3and5–10exhibited strongeanti-H1N1activity. These studies found that low pH conditions are more conducive toOUCMDZ-1492produced a wealth of secondary metabolites and increased itschemical diversity. Furthermore, secondary metabolites of microorganisms can beregulated by external pH and some silent genes could be activated at low external pH.