The Induced Structural Characterization And Function Research Of Two Fungus’ Secondary Metabolites

Symbiotic fungi possess extensive biodiversity and its secondary metabolites possess enormous structural and chemical diversity,so it gradually became an important source of new active substances.This dissertation focused on the biotransformation of p-aminobenzoic acid by Daldinia eschscholzii TL01 and the structures identification and bioactivity evaluation of secondary metabolites generated by the Peniophora incarnate Z4,which was isolated from Bruguiera gymnorrhiza.A total of twenty-two compounds were isolated from the two fungal fermentation broth by a combination of chromatographies over silica gel,ODS reverse column,gel filtration over Sephadex LH-20 and semipreparative HPLC.The structures of fifteen new compounds were elucidated by series of analytical methods(HRESIMS,1H NMR,13C NMR,1H-1H COSY,HSQC,HMBC,NOESY,IR CD)and single-crystal X-ray diffractions.Furthermore,new compounds were assayed in vitro for antimicrobial and cytotoxic activities.Twelve compounds were isolated(1-12)from D.eschscholzii TL01 cocultured with p-aminobenzoic acid,eight of which were novel compounds.Among them,compounds 1-5 and 11-12 were polymerized by the derivative of p-aminobenzoic acid and DPBD.Some of the compounds were assayed in vitro for cytotoxic activity.However,no compounds showed significant cytotoxicity against the tested cell lines at a concentration of 10 μM.The endophytic fungus Peniophora incarnate Z4 was isolated from the stem of Bruguiera gymnorrhiza,which was collected from mangrove in SanYa,hainan province.Repeated column chromatographies of the extract from the cultures of the fungul strains led to the isolation of ten compounds(13-22),inclunding two new alkaloids,three new tetrahydroxanthenones and one new chromone.Compound 15 showed significant cytotoxic activity against A375,MCF-7 and HL-60 cell lines(IC50<10μM).Furthermore,natural products from the Symbiotic fungus was reviewed in the thesis.