| Numerous unique and novel compounds were isolated from marine-derived fungi, and the studies of secondary metabolites from marine-derived fungi became popular in the world in recent years.The background and significance of the studies on mangrove endophytic fungi, and the study process of the bioactivity metabolites from mangrove endophytic fungi in the past decade were described in this dissertation. The studies on the secondary metabolites of five mangrove fungi (GX1-5E, GX4-1B, ZH4-E2, SBE-14, ZH209) collected from the South China Sea were carried out. Fourty-nine compounds including ten new compounds, (2-1)2-4, (3-1), (3-3), (4-1), (4-2), (4-3) and (4-4), were isolated from the culture of these fungi through chromatographic separation. Their structures were identified by UV, IR, NMR and MS spectrum. In addition, four new single crystals (2-1), (2-2), (2-7) and (4-1) were obtained, the absolute configuration of (4-1) was elucidated by X-ray diffraction of single crystal using CuKαradiation. The absolute configuration of (4-2) and (4-3) were presumed by NOESY spectrum and the biosynthetical relationship with (4-1). The complete 1H and 13C NMR assignments for coumarin (3-2) were reported for the first time, and two errors on 13C NMR assignments for compound (3-2) previously reported in the literatures were corrected. The presumed biosynthetic relationships in compounds (2-1)2-8, and in compounds (4-1)4-3 were proposed. In the bioactivity assays against tyrosinase andα-glucosidase, (2-6) exhibited moderate tyrosinase inhibitory activity with IC50 value of 65.6μM, (2-3) showed mild inhibitory activity onα-glucosidase. Compounds (2-1) and (2-5) displayed cytotoxicity on tumor cell lines MCF-7, MDA-MB-435, Hep3B, Huh7, SNB19 and U87MG with IC50 values between 30.16 75.52μM, compound (2-3) showed inhibitory activity on U87MG cell with IC50 value 61.91μM.In chapter 1, the background and significance of the studies on mangrove endophytic fungi were described. The resource distribution of mangrove and mangrove endophytic fungi in China were summarized. The study process of the bioactivity metabolites from mangrove endophytic fungi in the past decade were reviewed, mainly focused on the new compounds and their relevant biological activities.Chapter 2 focused on the metabolites of marine-derived mangrove fungus Aspergillus tubingensis (GX1-5E) from the South China Sea. Four new compounds, rubasperone A(2-1),rubasperone B(2-2),rubasperone C(2-3),rubasperone D(2-4), together with four known compounds TMC 256 A1(2-5),rubrofusarin B(2-6),fonsecin(2-7),flavasperone(2-8) were isolated from the fungus. In addition, three new single crystals (2-1), (2-2), (2-7) were obtained, the structural elucidation for compounds (2-1), (2-2), (2-7) were confirmed by single-crystal X-ray diffraction. The possible biosynthetic relationships in these compounds were discussed. In the bioactivity assays against tyrosinase andα-glucosidase, (2-6) exhibited moderate tyrosinase inhibitory activity with IC50 value of 65.6μM, (2-3) showed mild inhibitory activity onα-glucosidase. Compounds (2-1) and (2-5) displayed cytotoxicity on tumor cell lines MCF-7, MDA-MB-435, Hep3B, Huh7, SNB19 and U87MG with IC50 values between 30.16 75.52μM, compound (2-3) showed inhibitory activity on U87MG cell with IC50 value 61.91μM.The metabolites from the strain of mangrove endophytic fungus GX1-4B were studied in chapter 3, nine compounds were obtained, their structures were identified as 8-hydroxy-4-hydroxymethyl-6-methoxy-3-methylisocoumarin(3-1),3-hydroxy methyl-6,8-dimethoxycoumarin (3-2),1,10-bihydroxy-8-methyl-dibenz[b,e]oxepin -6,11-dione (3-3), 1,10-bihydroxy-dibenz[b,e]oxepin-6,11-dione (3-4), vermistatin (3-5), 6-demethylvermistatin (3-6), 5,7-dihydroxy-2-methyl-4H-chromen-4-one (3-7),succinic acid (3-8) and ergosterol (3-9) based on the analysis of its spectral data and physi-chemical properties, of which, (3-1) and (3-3) were new compound. The complete 1H and 13C NMR assignments for coumarin (3-2) were reported for the first time, two probable errors on 13C NMR assignments for compound (3-2) previously reported in the literatures were corrected by 1D and 2D NMR.In chapter 4, eight natural compounds, (7R,8S)-7-hydroxy-3,7-dimethyl-8-((S)- 3-methyl-2-oxopentyl)-7,8-dihydro-6H-isochromen-6-one (4-1), monochaetin(4-2), 1-hydroxymonochaetin(4-3),3-hydroxy-6'-desmethylterphenyllin(4-4), 3,3''-dihydroxy -6'-desmethylterphenyllin (4-5), 3-hydroxy-4-(2,6,6-trimethyl-tetrahydro-2H- pyran-2-yl)benzoic acid (4-6), 3-hydroxy-2-methylbenzoic acid (4-7), 3,8-dihydroxy -3-methyl-3,4-dihydroisochromen-1-one (4-8) were isolated from the culture of mangrove endophytic fungus ZH4-E2, three of which are new compounds (4-1, 4-3, 4-4). A single crystal of (4-1) were obtained, the absolute configuration of (4-1) was elucidated by X-ray diffraction of the single crystal using CuKαradiation. The presumed biosynthetic relationships for compounds (4-1)4-3 were discussed.The results of studies on two strains of mangrove fungi SBE-14 and ZH209 were reported in chapter 5, twenty-four compounds were isolated from their cultures, their structures were elucidated as alternariol monomethyl ether(5-1), alternariol(5-2), dehydroaltenusin(5-3), altertoxin I(5-4), altenusin(5-5), citreorosein (5-6), emodin (5-7), physcion (5-8) , chrysophanol (5-9), skyrin (5-10) , oxyskyrin (5-11), cyclo-(Pro-Ile)(5-12),cyclo-(Pro-Val)(5-13),cyclo-(Phe-Pro)(5-14),3,6-di-sec-butyl- 1,4-dihydroxypiperazine-2,5-dione (5-15),cyclo-(Pro-Leu)(5-16),1-(2,4-dihydroxy phenyl)ethanone (5-17), p-hydroxybenzaldehyde (5-18), 4-(2-hydroxyethyl)phenol (5-19), 4-hydroxy-3,6-dimethyl-2H-pyran-2-one (5-20), 3-methyl-6,8-dihydroxyiso- coumarin (5-21), 8-hydroxy-3,5-dimethylisochroman-1-one (5-22), peroxy-ergosterol (5-23), mannitol (5-24) by the analysis of their spectral data and physi-chemical properties.
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