Secondary Metabolites And Their Biological Activities Of Three Plant Endophytic Fungi

This thesis is divided into four chapters.In chapters 1 and 2,the secondary metabolites of Robillarda sessilis from Hemerocallis fulva L and Aspergillus flavus from Salvia miltiorrhiza Bge were studied by using the OSMAC(one strain many compounds)strategy.Meanwhile,the biological activities of anti-clinical drug-resistant bacteria and anti-crop pathogenic fungi were tested for some pure compounds which were extracted and isolated from a fermentation product.The third chapter is about the secondary metabolites and biological activities of the endophytic fungi from Cirsium setosum;the fourth chapter is the structural types,and biological activities of indole alkaloids in fungi are reviewed.The secondary metabolites of the above fungi were separated and purified by various chromatographic techniques(silica gel column chromatography,dextran gel chromatography,ODS reversed-phase column chromatography,HPLC).MS,IR,UV,ECD,and other methods were exploited to help to identify their structures,57 compounds were isolated and identified from the above fungal materials,including two new bisindole compounds,one new monoindole compound,and 5 new natural products,and the biological activities of some compounds were tested.Several active molecules were found.1.Study on chemical constituents and biological activities of endophytic fungi of Hemerocallis fulva L(Robillada sessilis)An endophytic fungus of R.sessilis was isolated and purified from H.fulva L in Huanggang,Hubei province.Based on the OSMAC strategy of changing different media,the most suitable liquid medium for the growth of the fungus was screened was DPY;at the same time,the epigenetic modification strategy was used to excavate its biosynthetic potential.Through large-scale fermentation,27 compounds were isolated and identified from their fermentation products,including 2 new bisindole compounds,1 new monoindole compound,and 5 bisindole natural products.pure compounds were tested for their anti-clinical drugresistant and anti-crop pathogenic fungi activities.The results showed that some of the compounds had biological activity.2.Chemical constituents and biological activities of Aspergillus flavu from Salvia miltiorrhiza BgeAn endophytic fungus of A.flavus was isolated and purified from the root of S.miltiorrhiza Bge,which grew in Wuhan,Hubei province.The optimal medium screened by the OSMAC strategy was used for large-scale through solid fermentation.A total of 21 compounds were isolated and identified in their fermentation products.Some pure compounds were tested for anti-clinical drug-resistant bacteria and anti-crop pathogenic fungi activities.The results showed no significant biological activity.3.Secondary metabolites and their biological activities of Chaetomium bostrychodes from Cirsium setosumAn endophytic fungus of C.bostrychodes was isolated and purified from the root of C.setosum,which grew in Yinchuan Ningxia province.It was cultured and fermented on a large scale with MEB and rice solid medium.Nine pure compounds were isolated and identified from their fermentation products.The compounds were tested for anti-clinical drug-resistant bacteria and anti-crop pathogenic fungi activities.The results showed no significant biological activity.4.Review—Structural types and biological activities of indole alkaloids from fungal secondary metabolitesThe secondary metabolites of fungi are a significant part of new compounds.Indole alkaloids play an essential role.They have unique skeleton structures and diverse biological activities.They are considered precursors for developing new drugs,so they have always been studied in the scientific community as a hot spot.This chapter reviews fungal indole alkaloids’ structures and biological activities to provide some references for future research.