Study On The Second Metabolites Of Three Aspergillus Versicolor

Four chapters were included in the dissertation.The secondary metabolites of Aspergillus versicolor from different sources were systematic discussed in this study.In the first chapter,A.versicolor which was isolated from the mud of the South China Sea,was studied,and 15 rare linear type prenylated indole alkaloids were isolated and their biosynthetic pathway was proposed.In the second chapter,extraction,isolation,purification and biological activities of the secondary metabolites of endophytic fungi(A.versicolor)isolated from Lycoris radiata(L' Her.)Herb were discussed.In the third chapter,the terraneous fungus A.versicolor isolated from the mud of Yangtze River in the city of Wuhan was studied.The last chapter is a review about natural bicyclo[2.2.2]diazaoctane prenylated indole alkaloids reported until 2018.A.versicolor is belong to Aspergillus,Trichocomaceae,Eurotiales,Eurotiomycetes,Ascomycota,Fungi.It's a normal species and widely distributed in air,soil,corrupt plant,food and other products.A.versicolor has long,septate hyphae that appears glassy and transparent.Conidiphores,which are specialized hyphal stalks for asexual reproduction,typically measure 120–700 ?m in length.Conidiophores terminate in small vesicles(10–15 ?m in diameter)that are biseriate(i.e.,with two successive layers of cells interposing the vesicle and conidia).The studies of metabolites of A.versicolor have been carried out by many groups,and that showed the difference of metabolites was great in different environment,such as different hosts,different nutrient media and different conditions.On one hand,it showed the metabolites of A.versicolor were very abundant;on the other hand,A.versicolor was easily suffered by external environment.Three typical resources of A.versicolor(marine derived,endophytic and terrestrial)were cultivated on rice respectively.39 compounds,including 24 new ones,were isolated from marine derived A.versicolor.Their structures and absolute configurations were elucidated by extensive spectroscopic analyses,single-crystal X-ray diffraction,electronic circular dichroism(ECD)calculations and optical rotation calculation.The major isolated metabolites were alkaloids including linearly fused and angularly fused prenylated indole alkanoids(the concept of linearly fused and angularly fused were first proposed)and meroterpenoids.A series of linearly fused prenylated indole alkanoids(total 15 compounds divide into 6 types)were isolated and tested their activities of anti-inflammatory,and compounds 2 and 14 showed strong effects.In addition,7 new meroterpenoids were isolated.Aperversins A and B(16 and 17)possess a 5/6/6/6 ring system and the A ring is tetrahydrofuran ring.Asperversin C(18)was a 6/6/6 ring meroterpenoid with the A ring opened.The ACh E activities of compounds 16-23 were tested and only compound 22 showed moderate effect.27 compounds,including 3 new ones,were found in the endophytic fungi(A.versicolor)of L.radiata(L' Her.)Herb.Compound 1(21-epi-taichunamide D),an angularly fused prenylated indole alkanoid,was the second natural product containing a methylsulfonyl unit and was the C-21 epimer of the first one(taichunamide D).12 compounds were isolated from the terrestrial fungi(A.versicolor)from the mud of Yangtze River in the city of Wuhan.4 new sesquiterpene derivatives consist by drimane type sesquiterpenes and a N-acetyl-?-phenylalanine unit,and it's the first time to report the Nacetyl-?-phenylalanine unit in natural products.A new steroid,possessing a rare 6/6/6/5/5 ring,is the C-5 epimer of the co-isolated compound Mer-NF8054X(12).Six new linearly fused prenylated indole alkanoids were same with the ones isolated from the marine derived fungi.The phytochemical investigations of three sources A.versicolor lead to the isolation of linearly fused prenylated indole alkanoids,which promotes the research level of prenylated indole alkanoids and attactes the attention of scientists of biosynthesis and total synthesis,and the isolation of meroterpenoids greatly enriches the structural diversity of meroterpenoids.