The Secondary Metabolites And Activities Of Marine-derived Fungus Aspergillus Sp.SCS-KFD66

The oceans cover nearly three-quarters of the earth's surface and contain all types of microorganisms.Marine microorganisms have different biosynthetic pathways and enzymatic reaction systems of secondary metabolites from terrestrial microorganisms,because they are in a high pressure environment with high salinity and oligotrophic.It also causes marine microorganisms to produce many compounds with complex structure,significant activity and relatively high yield.Marine fungus are an important part of marine microorganisms.The new natural active products isolated and purified from marine fungus' fermentation products is of great significance to the development and utilization of marine microorganism.In this paper,72 strains of marine fungus were isolated from 11 marine samples which collected from Haikou Bay and South China Sea.An active strain Aspergillus sp.SCS-KFD66 from Sangumnolaria chincnsis collected in Haikou Bay were acquired through combinatory method of chemical screening(TLC and HPLC)and bioactive evaluation(antibacterial,?-glucosidase inhibions activities).The target strain was finally identified as the research object and its active secondary metabolites were studied.The main results are as follows.Basing on silica gel column chromatography,Sephadex LH-20 gel column chromatography,thin layer chromatography and high performance liquid chromatography,forty-one compounds were isolated from Aspergillus sp.SCS-KFD66.The planar structure and the absolute configurations of compounds were determined by nuclear magnetic resonance,mass spectrum,optical rotation,infrared absorption spectrum,ultrabiolet,X-ray crystallographic and electron circular dichroism methods.The chemical structures of compounds include seven terpenoids,two polyketones,four lactones,eleven benzene derivatives,five steroids,three anthraquinones,two alkaloids,one pyran ketones and six fatty acids.Among them,ten new compounds were found,they were identified and named as Aspergoid A,Aspergoid B,Aspergoid C,Aspergoid D,3-Epi-trans-4-hydroxylinalool 3,6-oxide,12,13-Dedihydroversiol,Methyl 6-oxo-3,6-dihydro-2H-pyran-4-carboxylate,Methyl 2-oxotetrahydro-2H-pyran-4-carboxylate,Aspergoid E and Aspergoid F.The pure compounds isolated were tested for antibacterial,?-glucosidase,acetylcholinesterase inhibitory activities and DPPH radical scavenging,in bitro biological activity screening model by 96-well microtiter plates method,PNPG method,Ellman colorimetric method and DPPH method,respectively.The results showed that Protocatechualdehyde has inhibitory activity against Escherichia coli with MIC value of 64 ug/mL;Helvolic acid,1,3,8-Trihydroxy-6-methylanthracene-9,10-dione and(E)-4-oxonon-2-enoic acid have high inhibitory activity against Staphylococcus aureus with MIC values of 2,16 and 16 ug/mL;Helvolic acid and Protocatechualdehyde have inhibitory activity against Listeria monocytogenes with MIC values of 128 ug/mL;(E)-4-oxonon-2-enoic acid has high inhibitory activity against Bacillus subtilis with MIC values of 4 ug/mL,respectively.Protocatechualdehyde and 2,5-Dihydroxybenzaldehyde showed ?-glucosidase inhibitions,IC50 value of 16 is 0.38 mM;Twelve compounds showed acetylcholinesterase inhibitions,of which the IC50 value of Protocatechualdehyde is 0.32 mM;Thirteen compounds showed DPPH radical scavenging activitiy,of which 2,5-Dihydroxybenzaldehyde,(E)-ferulic acid and 15?-Hydroxyl-(22E,24R)-ergosta-3,5,8,22-tetraen-one with IC50 values of being 0.05,0.05 and 0.04 mM,respectively.