Preliminary Study On Metabolites Of Two Aschersonia Isolates

Entomogenous fungi are classified as fungi that grow either inside or on the surface of insect bodies,which eventually cause the death of the host insect.Entomogenous fungus is a rich source of natural bioactive compounds.In recent years,some lead compounds found in the metabolites of entomogenous fungus Aschersonia and its teleomorph that have anti-tumor,anti-bacterial,anti-inflammatory,and insecticidal activity.In order to search for novel bioactive natural products,we have investigated chemical constituents and bioactivities of the metabolites from Aschersonia WYTY-21 and WYTY-23.On the basis of a series of chromatographic techniques including TLC,ODS,Sephadex LH-20 and R-HPLC,twelve compounds involved in two new and seven firstly isolated compounds were obtained from the broth(filtrate)and mycelia of Aschersonia.Compounds including 5a,8a-epidioxy-24(R)-methylcholesta-6,22-diene-3?-ol(1*),dustanin(2*),3?-acetoxy-15a,22-dihydroxyhopane(3*),ergosterol(4*),and 7?,15a,22-trihydroxyhopane(5*)were isolated from WYTY-23.The other metabolites containing(7R,8R,8aS)-5-chlor-3-((3R,4R,5S,E)-3,4-dihydroxy-3,5-dimet hylhept-1-enyl)-7,8-dihydroxy-7-methyl-8,8a-dihydro-1H-isochromen-6(7H)-one(6*),(7R,8R,8aR)-5-chloro-3-((3R,4R,5S,E)-3,4-dihydroxy-3,5-dimethylhept-l-enyl)-7-hy droxy-7-methyl-6-oxo-6,7,8,8a-tetrahydro-lH-isochromen-8-ylacetate(7*),(7R,8R,8a R)-5-chloro-3-((3R,4R,5S,E)-3,4-dihydroxy-3,5-dimethylhept-l-enyl)-7,8-dihydroxy-7-methyl-8,8a-dihydro-1H-isochromen-6(7H)-one(8*),5-chloro-3-((3R,4R,5S,E)-3,4-dihydroxy-3,5-dimethylhept-l-enyl)-7,8-dihydroxy-7-methyl-7,8-dihydro-6H-isochro men-6-one(9*),isochromophilon ?(10*),sclerotioramine(11*)and flufuran(12*)were originated from WYTY-21.In this study,the structure of the isolated compounds was elucidated by extensive spectroscopic methods containing NMR,EIMS,HREIMS,CD,Mosher,and so forth.MTT assay method was used to conduct in vitro anti-tumor activity screening of monomeric compounds.The results showed that the compounds(1*?12*)displayed different inhibitory activity on the growth of human hepatoma cell BEL-7404,but expressed no cytotoxicity to two strains of normal cells(human liver cells HL-7702 and human kidney epithelial cell HEK-293T).Among them,compouds 7*,8*,10*,11*,indicated a significant inhibition effect on BEL-7404 with an IC50 value of 17.4?mol/L,16.1?mnol/L,6.2?mol/L,11.6 ?mol/L,respectively.Moreover,compounds 1*,10*,11*showed a significant inhibitory activity to human gastric cancer cells SGC-7901,with IC50 values of 56.1 ?mol/L,14.3 ?mol/L,18.5?mol/L,respectively.