Stadies On The Secondary Metabolites And Their Bioactivities Of A Marine-derived Fungi Aspergillus Violaceus WZXY-m64-17

Natural products are the basic units of survival and evolution of marine organisms,with vitality,and each molecule we have discovered is an interpretation of life.Marine derived microbes form self defense system due to long-term survive in ecological stress and ecological competition.Microbes produce secondary metabolites to maintain their own survival and reproduction.The secondary metabolites of marine fungi contained a variety of skeleton in novel and significant biological activity,are valuable resources of natural active pharmaceutical compounds,marine fungi not only variety,but also the change of marine environment diversity in different habitats in the same fungus will appear different subspecies,the secondary metabolites are different.Therefore,actively studying the secondary metabolites of marine fungi can not only enrich the content of marine natural medicine,but also consider as the key to elucidate the ecological significance of the relevant secondary metabolites and become important sources of new lead compoundsIn this thesis,Aspergillus violaceus WZXY-m64-17 were selected based on the chemical screening.This strain was fermented in rice culture medium with artificial seawater.The fermentation products were extracted with 95%methanol water and petroleum ether to obtain 95%methanol water fraction.Then the95%methanol water fraction was isolated with silica gel,ODS colum chromatograph,sephadex LH-20 colum chromatograph and HPLC,resulting in the isolation of 30 compounds,including 10 new compounds,which are compounds 1-2,16-17,22-28,29,respectively.Compound 22-26 are a novel sulphur containing compound.The compounds were identified by spectroscopic methods(NMR,HRESIMS),X-ray single-crystal diffraction analysis,CD analysis,ECD calculation,modified Mosher's method,Marfey's method and Snatzke's method.Becides,the biosynthetic pathway of alkaloids were proposed.Some compounds of this strain were tested for their biological activity including anti-Staphylococcus aureus(ATCC 29213),cytotoxic activity(cell lines including tumor cell lines U937,HCT-8,MCF-7,and normal cell line Vero)and anti-AchE activity.And the structure-activity relationship was discussed.In this research,compounds 3-6,18 showed activity against Staphylococcus aureus and compounds 22-24,27 showed selective cytotoxic activity against tumor cell lines U937,HCT-8,MCF-7 and normal cell line Vero.There no compounds showed anti-AchE activity.