| Fungi exist widely in nature,and their diverse living environment enables them to produce secondary metabolites with complex structural types and diverse biological activities,such as penicillin with antibacterial activity and taxol with anticancer effect,which have been important sources of lead compounds for new drug research and development.In this thesis,three forest plant fungi,one endophytic fungus collected from desert plant and two pathogenic fungi isolated from ginseng were selected as research materials in order to find out new and active secondary metabolites.The crude extracts were separated and purified by silica gel column chromatography,gel column chromatography（Sephadex LH-20）,thin layer chromatography,semi-preparative liquid phase and other technologies.The structure of the compounds was analyzed and identified by nuclear magnetic resonance,high resolution mass spectrometry,infrared spectrum,ultraviolet spectrum,circular dichroism and other analytical techniques.A total of 31 compounds were isolated,including 2 new compounds,from three fungi.Cytotoxic,phytotoxic and antioxidant activities of some compounds were tested.（1）11 compounds Betaeniol（1）,Betaenone E（2）,Betaenone A（3）,Betaenone F（4）,Betalactone（5）,Xylariolide D（6）,Xylariolide F（7）,Spiciferol A（8）,Dehydrospicifernin（9）,Tyrosol acetate（10）,and 4-Hydroxybenzaldehyde（11）were obtained from the solid fermentation of endophytic fungus Neocamarosporium betae collected from desert plant,including two new compounds（1,5）.Biological activity test showed that compounds 1-3 and 5-9 were phytotoxic to foxtail leaves,among which compound 5 showed the strongest phytotoxicity while compounds 1-9 had no phytotoxicity on corn leaves,suggesting that compounds 1-3,5-9 were expected to develop into herbicides.Compounds 1 and9 exhibited moderate cytotoxicity against MCF-7 cells,with IC50 values of 35.16±1.28 and 26.60±3.32μM,respectively,and the IC50 value of cisplatin was 6.57±0.22μM.Compounds 1-2 showed strong cytotoxicity against B16 cells with IC50 values of 4.42±0.62 and 4.73±1.17μM,respectively,which were lower than that of cisplatin（17.95±3.16μM）.Compound 3 showed strong cytotoxicity against mouse liver cancer cells(IC50 value of 1.42±0.15μM)and moderate cytotoxicity against B16cells(IC50 value of 24.05±0.69μM).Compounds 1,4 and 9 showed moderate cytotoxicity against Hep G2 cells with IC50 values of 7.06±0.15,5.66±0.43 and 4.88±0.19μM,respectively.Compound 1had good cytotoxicity against three kinds of tumor cells and is expected to be developed as an antitumor drug.（2）9 known compounds（12-20）,including sterols and polyketides,were isolated from ferments of Rhexocercosporidium panacis for the first time.The results of bioactivity tests showed that compounds12-20 had no antioxidant activity and could not cause lessions on the surface of isolated ginseng roots,indicating that they were not causative agents of ginseng red coating root disease.（3）14 compounds（11,12-13,21-31）,including sterols and aromatic compounds,were isolated from ferments of Cylindrocarpon destructans for the first time.The results of the phytotoxic activity assay showed that compounds 11,21-31 failed to cause lessions on the surface of isolated ginseng roots and were not causative agents of ginseng root rust rot. |
