The Study On The Chemical Constituents And Biological Activities Of Three Strains Of Plant Endophytic Fungi

Endophytic fungi are a kind of fungi that live in healthy plant tissues or organs.It exists in almost all living plants.Endophytic fungi mainly live in symbiosis and have a wide variety.Endophytic fungi in plants can produce a variety of secondary metabolites in the process of metabolism,which show a variety of biological activities.On the basis of checking literatures related to plant endophytic fungi,we selected three plant endophytic fungi Alternaria sp.,Trichoderma koningiopsis and Penicillium sp.to study their chemical constitutent and biological activity including strain activation,fermentation,extraction,purification,structure identification,and biological activity evaluation etc.The results are as follows:(1)The endophytic fungus Alternaria sp.GLZ-Y-5 isolated from Carum carvi was fermented in corn medium,extracted with ethyl acetate,and isolated by various column chromatography methods to yield five known compounds which were identified as alternariol-5-O-methyl ether(1),alternariol(2),2-(2 ’-hydroxypropyl)-5-methyl-7-hydroxychromone(3),dibutyl phthalate(4),alternariol(5).Compound 3was isolated from this genus for the first time.(2)The endophytic fungus Trichoderma koningiopsis YN-G-1 isolated from Taxus yunnanensis was fermented in rice medium,extracted with ethyl acetate,and isolated by various column chromatography methods to yield twelve known compounds which were identified as D-galactosyl(6),α-D-glucose(7),p-Tyrosol(p-hydroxyphenyl)-β-ethanol)(8),koninginin A(9),4,8-dihydroxy-2-(1-hydroxyhydroxy)-3,4,5,6,7,8-hexahydro-2H-1-benzopyran-5-one(10),terephthalic acid bis(2-ethyl-hexyl)ester(11),trichodermatides B(12),trichodermaketones C(13),koninginin B(14),(22E)-5a,8a-epidioxyergosta-6,22-dien-3b-ol(15),n-Triacont-11-enoic acid(16)and drechslerol-B(17).Compounds 8,11,12,13,16 and 17 were isolated from T.koningiopsis for the first time.(3)The endophytic fungus Penicillium sp.HT-G-8 isolated from Tripterygium hypoglaucum was fermented in corn medium,extracted with ethyl acetate,and isolated by various column chromatography methods to yield five known compounds which were identified as vertistin(18),alternariol-5-O-methyl ether(1),gramin B(19),4,8-dihydroxy-2-(1-hydroxyhydroxy)-3,4,5,6,7,8-hexahydro-2H-1-benzopyran-5-one(10),dibutyl phthalate(4).Compounds 10 and 19 were isolated from this genus for the first time.(4)The inhibitory activities of monoamine oxidase(MAO),acetylcholinesterase(ACh E),phosphatidylinositol 3-kinase(PI3K)and phosphodiesterase 1(PDE1)of 19 compounds were evaluated by UV-Vis spectrophotometry and in vitro kinase detection kit method.The results showed that compound 2 exhibited strong anti-PI3 K activity and moderate anti-PDE1 activity with IC50 value of 7.81 μg/m L and 98.16μg/m L respectively;Compound 19 had moderate anti-PDE1 activity with IC50 value of 95.12 μg/m L;Compound 13 had moderate anti-PI3 K activity with inhibition rate of 67.44% at 10.0 μg/m L.The other compounds showed no significant activity to the above four enzymes.(5)Molecular docking of the isolated 19 compounds α-glucosidase,xanthine oxidase and nitric oxide synthase were carried out.The results showed that compound11 has higher docking scores with the above enzyme than the positive controls kaempferol,coniferyl ferulate and 12-dien-28-oil acid.Compound 19 has higher docking scores with α-glucosidase than the positive control.These results indicated that compounds 11 and 19 may have potent activities.