Studies On The Secondary Metabolites Of The Desert Plant Endophytic Fungus Chaetosphaeronema Hispidulum And Ganoderma Flexipes

Natural products are an important source for biological pesticides and lead compounds for new drugs,while fungi have the ability to produce secondary metabolites with novel structure and extensive activity.With the development of society,it is difficult to find novel compounds from coo-mmon microorganism.Due to the special environment of high temperature,drought and oligotrophic in desert areas,endophytic fungi living in desert areas can adapt to the influence of various biological and abiotic factors,and can produce secondary metabolites with complex and diverse structures and extensive biological activities.In addition,Ganoderma lucidum is a mushroom fungus,which contains a variety of pharmacologically active ingredients.It has an ancient history of medicinal use in China.In recent years,it has become a research hotspot at home and abroad.Therefore,a desert plant endophytic fungus Chaetosphaeronema hispidulum and Ganoderma flexipes Pat.were selected as research objects to find new biologically active secondary metabolites.Fifteen compounds were isolated from an endophytic fungi C.hispidulum(TS-8-1)and G.hainanense,by using various column chromatographies(Silica gel,Sephadex LH-20 and HPLC)and identified by multiple spectroscopic methods(NMR and HR-ESIMS).Compounds 1-6 were isolated from C.hispidulum,including Hispidulactone F(1),Hispidulactone B(2),2R,4R-sonnerlactone(3),2R,4S-sonnerlactone(4),Hispidulactone D(5)and Dihydroresorcylide(6),where compound 1 is a new compound.The sterechemistries of the hydroxyl groups at C-3 in 1 and 2,and at C-4 in 3 and 4 were determined by modified Mosher's reactions.Compound 7-14 was isolated from G.flexipes,including one alkaloid compound Lucidimine D(7)and six triterpenoids compounds,namely Ganoderic acid Z(8),Ganoderic acid TR(9),Ganoderic lactone(10),5?-lanosta-7,9(11),24-triene-15?-26-dihydroxy-3-one(11),Methyl Ganoderenate D(12),Methyl Ganoderate C1(13),Lucid-umol A(14),of which compound 10 is a new compound.Biological activity test showed that compounds 1 and 4 displayed significant antitumor activities against Hep G2 cancer cell lines with a dose-dependent relationship.Compounds 9 and 11 showed different selective cytotoxic activities against three tumor cell lines(B16,Hep G2,HCT116).In addition,the advance on secondary metabolites from fungi inhibited in unique ecological niches was reviewed,which can provide references for further research,and the studies on secondary metabolites and GTLs of endophytic fungi in desert plants were reviewed to provide technical reference for similar studies.