Secondary Metabolites From Three Endophytic Fungi Inhabiting In Salvia Miltiorrhiza And Their Bioactivities

Plant endophytic fungi are fungi that live in healthy plants and do not cause significant disease in the host.Such microorganisms can produce a lot of natural products with novel structure and biological activity in the special environment symbiotic with the host,which has high research value.Salvia miltiorrhiza is a traditional Chinese medicine,which has the effects of promoting blood circulation,scavenging free radicals,anti-tumor,and anti-inflammatory.It is one of the most widely used herbs.Based on this,Salvia miltiorrhiza was selected as the object,using modern microorganism separation technology to isolate and identify endophytic fungi,and the chemical composition and biological activity of the fermentation extracts of the three target strains were studied in order to discover structures with novel skeletons and significant biological activities.We hope this research can provide a basis for new drug research and development.The main research contents are as follows:(1)Isolation,purification and identification of endophytic fungi from Salvia miltiorrhiza: a total of 18 endophytic fungal were isolated from Salvia miltiorrhiza by modern microbial isolation technology,and they were identified by molecular biology techniques as Colletotrichum truncatum,Fusarium proliferatum,Sclerotinia sp.Albifimbria terrestris,Fusarium oxysporum,Edenia gomezpompae,Colletotrichum spaethianum,Alternaria alternata,Aspergillus flavus,Corynespora cassiicola,Talaromyces pinophilus,Didymella Americana,Aspergillus assiutensis,Penicillium crustosum,Chaetomium globosum,Colletotrichum gloeosporioides,Alternaria burnsii,Cladosporium cladosporioides.Through literature search,three of them were found to have further research value(Talaromyces pinophilus,Chaetomium globosum,Colletotrichum gloeosporioides).(2)Chemical constituents of 3 strains of endophytic fungi from Salvia miltiorrhiza: the OSMAC strategy was used to screen the fermentation conditions of the three target strains,and a medium with the most abundant metabolites was selected for large-scale fermentation.Using natural product research methods to study the chemical composition of the fermentation culture.Using modern spectrum analysis to identify the chemical structure of compounds.Thirty monomer compounds(including six new compounds)were isolated from the conjugates of three endogenous fungal fermentation cultures.The specific results are as follows:(1)a total of 9 monomer compounds were isolated from the fermentation culture of Talaromyces pinophilus,including 1 terpene(1),1 polyene(2),7 other small molecule compounds(3-9),among which compounds 1 and 2 are new compounds;(2)a total of 13 monomer compounds were isolated from Chaetomium globosum fermentation culture,including 4 ketones(10-13),3 alkaloids(14-16),and 3 steroids(20-22),3 other small molecule compounds(17-19),of which compounds 10 and 11 are new compounds;(3)8 monomer compounds were isolated from the fermentation culture of Colletotrichum gloeosporioides,including 2 terpenoids(23,24),3 indole alkaloids(25,26,29),and 1steroid(28),an organic acid compound(30)in which compounds 23 and 24 are new compounds.(3)Biological activity screening: The compounds isolated above were studied for resistance to crop pathogenic fungi and human pathogenic bacteria.Research indicates:(1)Compounds 1,2,4,14,15 and 16 have different degrees of activity against crop pathogenic fungi,among which Compound 14 has the most significant activity(MIC value reaches 3.13-25 μg/m L);(2)Compounds 1,2,4,5,8 and 9 have certain activity against sensitive bacteria,and Compound 14 has significant inhibitory activity against clinically resistant bacteria(MIC value 3.13-6.25 μg/m L);(3)Compounds 15 and 16 have significant inhibitory activity on human tumor cell lines.