Secondary Metabolites Of Two Endophytic Fungi From Medicinal Plants And Their Bioactivities

There are many kinds of endophytic fungi in medicinal plants.Due to their special living environment and long-term mutually beneficial symbiotic relationship with host plants,endophytic fungi of medicinal plants can produce secondary metabolites with novel structures and unique activities.Some endophytic fungi of medicinal plants can even produce active substances that are identical or similar to the host plants.Based on these characteristics,two hosts of medicinal plants,Panax notoginseng and Campsis grandiflora were selected,and one endophytic fungus of Panax notoginseng and one endophytic fungus of Campsis grandiflora were used as research objects.The experiments of fermentation,extraction,separation,structure identification and biological activity evaluation were used to study their secondary metabolites,hoping to find natural products with novel structures and significant activities.First of all,this paper combined the existed research contents of Emericella sp.XL029 and used the OSMAC?One Strain,Many Compounds?strategy to study its secondary metabolites.The rice+MEB was selected as the fermentation medium,and16 monomer compounds were finally obtained after static fermentation,organic solvent extraction,monomer compound separation and structure identification.The 16compounds included five polyketones?EC 1-5?,two sesquiterpenoids?EC 6-7?,six xanthone compounds?EC 8-13?,one steroidal compound?EC 14?and two other types of compounds?EC 15-16?.Compounds EC 1-4 were identified as new compounds by modern spectroscopy techniques,and compounds EC 5-7 were new compounds that have obtained by our research group.Secondly,through the screening of antibacterial activity of crude extracts and literature research,a strain,Colletotrichum acutatum XL499 with good antibacterial activity but few researches for secondary metabolites was selected.The rice+glucose was selected as the fermentation medium.After the fermentation and separation,12monomer compounds were obtained,including one fatty acid compound?EC 17?,two glycoside compounds?EC 20-21?,three amide compounds?EC 22-24?,one steroidal compound?EC 28?and five other types of compounds?EC 18-19,EC 25-27?.Compound EC 17 was identified as a new compound by modern spectroscopy techniques.The above isolated compounds were subjected to research on anti-agricultural pathogenic fungi,anti-human pathogenic bacteria and cytotoxic activities.The results of anti-pathogenic fungi activity showed that the compounds EC 1,EC 2,EC 3,EC 5,EC 7,EC 8,EC 14,EC 18,EC 19,EC 24 and EC 26 had good resistance to pathogenic fungi.Among them,the pathogenic fungi inhibitory activities of the compounds EC 18 and EC 19 were the most significant.The MIC values of compound EC 18 against Sclerotinia sclerotiorum,Colletotrichum acutatum Simmonds and Alternaria alternata were 12.5?g/mL.The MIC values of compound EC 19 against Sclerotinia sclerotiorum and Colletotrichum acutatum Simmonds were 12.5?g/mL.The MIC values of compound EC 19 against Phytophthora parasitica and Alternaria alternata were 6.25?g/mL.The results of anti-human pathogenic bacteria activity showed that the compound EC 2 had good inhibitory activities against Salmonella typhi,the compounds EC 3 and EC 5 had good inhibitory activities against Micrococcus lysodeikticus,and the compound EC 7 had good inhibitory activity against Bacillus cereus,and the MIC values were 25?g/mL.The results of cytotoxic activity assay showed that compound EC 14 had significant inhibitory effects on five kinds of tumor cells?Huh7,MGC,A549,Hct116,MDA231?.Among them,compound EC 14 had the strongest inhibitory activities against Hct116 and MDA231 cells with IC₅₀ values of 43.50?M and 47.13?M,respectively.In summary,28 monomeric compounds were isolated from the secondary metabolites of two medicinal endophytic fungi,containing five new compounds,some of which have good antifungal,antibacterial and antitumor activities.