Identification Of Three Chaetomium Sp. Strains And Study On Their Active Secondary Metabolites

Three fungi strains No.06、No.12and No.16from Ginkgo biloba L.that can producevarious secondary metabolites were selected by chemical screening methods, andwere identified as Chaetomium globosum based on the ITS gene sequences.Strain No.06showed antagonism against Valsa mali. Strain No.12showed activityagainst Valsa mali and Fusarium oxysporum. Strain No.16had inbibitional effect onValsa mali, Sclerotinia sclerotiorum and Colletotrichum gloeosporioides.Bioguided isolation of active compounds from their secondary metabolites wasused. The main isolation methods include silica gel, Sephadex LH-20, andreversed-phase Rp-C18column chromatography. The structures of compounds wereelucidated by means of spectroscopic techniques including1D and2D-NMR(1H-NMR,13C-NMR,1H-1H COSY, HMQC, HMBC and NOESY) as well as massspectrometry (EI-MS, ESI-MS and HR-ESI-MS). At last, cytotoxicity and antifungalactivity of compunds were also tested. The results are as follows:（1）Chaetomugilin D and Chaetoglobosin A were isolated from the fermentationextract of strain No.06.（2）Chaetomugilin D,5’-epichaetovirdin A, Chaetomugilin A, Chaetoglobosin Cwere obtained from the strain No.12.（3）Three novel compunds Chaetomugilide A-C were harvested from the secondarymetabolites of strain No.16. The extract with low polarity was analyzed by GC-MSand27compounds were determined.（4）Cheatomuglin D,5’-epichaetovirdin A, Chaetoglobosins A, Chaetomugilide A,Chaetomugilide B, Chaetomugilide C showed remarkable cytotoxicity on the Artemiasalina with the mortality of58.4%,54.3%,85.3%,79.5%,75.4%,52.1%respectively,at the concentration of10g/mL. （5）Paper disk diffusion method was used to test the antifungal activity of compunds.Chaetomugilin A exhibited marked inhibitory effects on Valsa mali with inhibitoryrate of76.3%, at the concentration of10μg·disk-1. The present study established thebasis for the discovery of bioactive lead compounds and provided theoreticalfoundation for further utilization of the microbial resources.