Study On Secondary Motabolites From Endophytic Fungus Talaromyces Purpureogenus And Penicillium Rapier

The development of natural drugs has become the focus in recent years due to the negative effects of synthetic drugs,which may lead to severe issues of tissue residues and drug resistance.The mutualistic associations between endophytic fungus and host plants,have shown the characteristics of complex structures and diverse biological activities of the secondary metabolites,which has laid the material foundation for the exploration of the leading compounds and drug discovery,and which also has broaded the application prospects in the fields of industry,agriculture and biological pharmacy.In this paper,structures and biological activities of secondary metabolites of the endophytic fungus are researched.The research content mainly includes isolation and screening of bioactive endophytic fungus,separation and purification of secondary metabolites and structural elucidation,screening of biological activities of monomer compounds.37 Fungal strains were isolated from 10 plant samples,which were collected from Shijiahzuang,Hebei Province.Then we screened two endophytic fungus strain Talaromyces purpureogenus and Penicillium rapier as the research object of this thesis through small scale fermentation.By using solvent extraction,silica gel column,Sephadex LH-20,ODS,semi-preparative HPLC and other separation means,NMR,IR,UV,MS,CD spectroscopic techniques,18(1-18)and 12(19-30)compounds were isolated from endophytic fungus Talaromyces purpureogenus and Penicillium rapier,2 of them are new compounds(1-2).The absolute configurations(AC)were determined by comparing experimental electronic circular dichroism(ECD)and optical rotation(OR)of compounds 1 and 2 with the calculated ECD and OR data using quantum chemical calculations methods for the first time.In this study,part of the isolated compounds were evaluated for the antibacterial activity against 14 gram positive and negative pathogenic bacteria by micro-dilution methods,compounds 4 exhibited good inhibitory activities against Bacillus subtilis with MIC value of1.56 μM,compounds 5 exhibited notable inhibitory activities against Micrococcus lysodeikticus and Vibrio parahaemolyticus with MIC value of 0.73 and 0.18 μM,respectively.Part of the isolated compounds were tested for antioxidant activities with the DPPH methods,the results showed that the compounds had no obvious antioxidant activity.In conclusion,this study presents that natural products with good activities were isolated from Talaromyces purpureogenus and Penicillium rapier,and the absolute configuration of some compounds were determined by using ECD,OR and quantum chemical calculations methods for the first time.Activity screening indicated that some compounds have good antimicrobial activities,which provides the basis for the development and application of pharmaceutical lead compounds.