Chemical Investigations Into Secondary Metabolites Of Three Strains Of Plant Endophytic Fungi

Endophytic fungi spend their parts of or whole life stage in healthy tissues of the host asymptomatically.Endophytic fungi were discovered in most plants,which are closely interdependent with their hosts to certain degree.Moreover,endophytic fungi are biodiverse,easy to cultivate and resource-conservation,as well as have short growth cycle and diverse products,leading them to becoming one of ideal candidates of bioactive natural products research.In this study,chemical investigation of two strains of fungi from lichen and one from moss were conducted.After preceding preliminary screening of activities,three fungi Paecilomyces sp.(0207d),Cladosporium sp.(4153a)and Aspergillus sp.(7-2-1)were selected for fermentation and study.First,fungus strain was inoculated into PDB to obtain seed culture.And solid sterile rice medium was selected for large-scale fermentation,after which ethyl acetate crude extract could be gotten.Then,the crude extract was isolated and purified by silica gel,ODS,Sephadex LH-20,Medium Pressure Liquid Chromatography,as well as HPLC and so on.As a result,45 compounds were obtained,2 of which were new ones and 3 of which was first isolated as natural compound.The structures including planar and stereochemical structures were confirmed using nuclear magnetic resonance(NMR),mass spectra(MS),circular dichroism spectra(CD)and other methods.Moreover,parts of these compounds were tested about antifungal activity and cytotoxic activity.The result could be helpful to further study about the relationship between endophytic fungi and their hosts.