Isolation And Identification Of Endophytic Fungi Producing Flavonoids From Davidia Involucrate Baill

Objective To isolate endophytic fungi producing active substances from Davidia involucrate Baill.Methods Endophytic fungi strains were isolated by issue - culture method from Davidia involucrate Baill.The result showed that,the endophytic fungi in Davidia involucrate Baill is isolated by the surface sterilization method with 70%of ethyl alcohol and 0.1%of HgCl₂.The best sterilization time of the stem is 4～5min to Davidia involucrate Baill.And The best sterilization time of the leaf should be controlled about 2min.Results To isolate endophytic fungi producing active substances from Davidia involucrate Baill.The inhibitory activity of endophytic fungi was detected taking Staphylococcus aureus,Bacillus subtilis and Escherichia coli as indicative bacteria.The active substances in the products of endophytic fungi was confirmed by High Performance Liquid Chromatography(HPLC).Conclusion One hundred and twenty six endophytic fungi strains were isolated from the leaves and branches of Davidia involucrate Baill,and their metabolic products had inhibitory activity,the inhibition rates to the three bacteria were 65%,71%,25% respectively.The endophytic fungi strain D37 was selected to screen its active substance as its activity of inhibitory effects on Staphylococcus aureus was the highest.The strain D37 produced quercetin and kaempferol about 31.9 mg per 100g of dry mycelium confirmed by HPLC.The endophytic fungi D37 was identificated as Aspergillus fumigatus according to the morphology of fungal and the similarity of nucleotide sequence of internal transcribed spacer(ITS) between rDNAs.Significance The endophytic fungi D37,isolated from Davidia involucrate Baill, could produce flavonoids.The endophytic fungi strain seperated from Davidia involucrate would be a candidator for flavonoids preparation.These endophytic fungi strains is resources for further research other bioactive compound,antibiosis experiment and so on.