Secondary Metabolites Of Endophytic Fungi Chaetomium Sp.Eef-S10 And Their Biological Activities

Chaetomium sp.Eef-S10,an endophytic fungus from the fruit of Eucalyptus exserta,was used as the research object to isolate and identify the secondary metabolites in the endophytic fungi Chaetomium sp.Eef-S10 and evaluate their biological activities.The main results are as follows:（1）14 compounds were obtained from the ethyl acetate layer of the endophytic fungus Chaetomium sp.Eef-S10,by means of silica gel column chromatography,dextran gel column chromatography,semi-preparative HPLC and recrystallization purification method.The structures of the compounds were analyzed and elucidated by UV,HR-ESI-MS,1D and 2D NMR,and comparative references.Finally 8 compounds were successfully identified,including 3 Depsidones.In the 8 compounds,compound Oy-15 suspected is a new compound,named Mollicellins O（Oy-15）,and the other 7 known compounds were identified as Mollicellins H（Oy-2）,Mollicellins G（Oy-9）and Dibutyl phthalate（Oy-7）,4-Methyl-5,6-dihydro-2H-pyran-2-one（Oy-8）,2,6-Dihydroxy-3,4-dimethylbenzoicacid methylester（Oy-11）and2,4-Dihydroxy-3,6-dimethylbenzoate（Oy-12）.The2,6-Dihydroxy-3,4-dimethylbenzoicacidmethylester（Oy-11）,2,4-Dihydroxy-3,6-dimethylbenzoate（Oy-12）and Mollicellins O（Oy-15）were the first time isolated from Chaetomium.sp..（2）The inhibitory activities of the secondary metabolites of Chaetomium sp.Eef-S10on the growth of 7 test bacteria were determined by Multi-well plate-MTT-chromogenic assay screening.Only Mollicellin G（Oy-9）showed certain antibacterial activity.In the concentration of 200μg/mL,the growth inhibition rate against Bacillus subtilis,Staphylococcus aureus,Agrobacterium tumefaciens and Ralstonia solanacearum were100%.This is the first report on the antibacterial activities of Mollicellin H（Oy-2）、Mollicellin G（Oy-9）、2,6-Dihydroxy-3,4-dimethylbenzoic acid methyl ester（Oy-11）、2,4-Dihydroxy-3,6-dimethylbenzoate（Oy-12）and Mollicellins O（Oy-15）.（3）The inhibitory activities of the secondary metabolites of Chaetomium sp.Eef-S10on the growth of two tested fungI of Colletotrichum gloeosporioides of Dalbergia odorifera and Camellia anthracnose were determined by mycelial growth rate method.At the concentration of 200μg/mL,the inhibitory activities of all monomeric compounds isolated from the endophytic fungus Chaetomium sp.Eef-S10 didn’t reach 50%,indicating indirectly that the tested compounds do not have resistance to Colletotrichum gloeosporioides of Dalbergia odorifera and Camellia anthracnose potential.（4）The antioxidative activities of secondary metabolites of endophytic fungi Chaetomium sp.Eef-S10 were determined by the porous plate-DPPH removal method.Among them,only Mollicellins O（Oy-15）showed antioxidant activity,the scavenging capacity of DPPH IC₅₀0 was 71.92μg/mL.The DPPH-scavenging capacity of other compounds did not yet reached 50%at the concentration of 200μg/mL.This thesis is the first time foe the antioxidant activities reports on the Depsidone compounds.