Studies On The Secondary Metabolites Of Pestalotiopsis Sp. LZU823977 And Aspergillus Flavus

The fungi of Pestalotiopsis?Amphisphaeriaceae?genus are distributed widely in tropical and temperate ecosystems as saprobes,pathogens,and endophytes of living plants.Increasingly,they are a major focus of secondary metabolite research because they are a rich source of bioactive secondary metabolites with diverse structural features.Pestalotiopsis is an asexual genus with many species.Molecular evidence indicates that,unlike those of the coelomycetous genera Colletotrichum and Phyllosticta,most of these species lack sexual morphogenesis.Some members of the genus are able to grow on the synthetic polymer polyurethane as its sole carbon source under both aerobic and anaerobic conditions,hence show promise as a form of bioremediation for waste reduction.Species within the fungal genus Pestalotiopsis have become a topic of research in many microbial-chemical and pharmacological laboratories because they contain structurally complex,biologically active metabolites.Aspergillus flavus is a saprotrophic and pathogenic fungus with a cosmopolitan distribution.It is best known for its colonization of cereal grains,legumes,and tree nuts.Postharvest rot typically develops during harvest,storage,and/or transit.A.flavus infections can occur while hosts are still in the field?preharvest?,but often show no symptoms?dormancy?until postharvest storage and/or transport.In addition to causing preharvest and postharvest infections,many strains produce significant quantities of toxic compounds known as mycotoxins,which,when consumed,are toxic to mammals.A.flavus is also an opportunistic human and animal pathogen,causing aspergillosis in immunocompromised individuals.,The secondary metabolites of Aspergillus flavus have caused widespread concern.In order to further study the fungus of Pestalotiopsis and Aspergillus flavus,to find the structure diverse,novel,and good biological activities of secondary metabolites.In this thesis,the ethyl acetate extracts of solid rice fermentation of fungi Pestalotiopsis LZU82397 and Aspergillus flavus were systematically isolated,using conventional silica gel column chromatography?CC?,Sephadex LH-20 gel column chromatography,preparative thin layer chromatography?PTLC?,reversed-phase MCI column chromatography,reversed-phase C-18 column chromatography,and recrystallization;use of HREIMS,1D NMR(¹H NMR,¹³C NMR,DEPT,NOE),2D NMR?¹H-¹H COSY,HSQC,HMBC?and other modern spectroscopy technology,and combined with relevant literature data.22 compounds were isolated from the fungi of Pestalotiopsis sp.LZU82397 and Aspergillus flavus.At the end of this thesis,the research progress of the chemical constituents and biological activities of Aspergillus fungi reported in recent years is reviewed.The results of chemical composition and activity studies carried out in this paper are expected to enrich the database of natural products,support the development and utilization of new drugs,and contribute to the development and utilization of natural products.