Isolation And Structure Analysis Of Secondary Metabolites From Marine Fungi Exophiala And Three Marine Actinomycete

The secondary metabolites and its biological activity of Marine fungi Exophiala sp and three strains of Marine actinomycetes were explored in this thesis.These strains were cultured by liquid submerged fermentation.Their fermented broth which have removed the microbes by centrifugation were concentrated in vacuo and extracted with ethyl acetate.The organic layer was dried over Na2SO4(anhydrous)and concentrated in vacuo to afford the organic crude.The crude was subjected to repeated column chromatography over RP-18,Sephadex LH-20,and silica gel to purify their chemical constituents.Their structures were elucidated through NMR,MS,and other physicochemical data.Finally,the bioactivities of these compounds were exploredThe strain Exophiala sp was selected on a Martin medium containing 3,4,5,6-Tetrachlorofluorescein from sea mud and identified by ITS rDNA sequence.This strain was cultured in the potato dextrose medium with a total volume of 5 L by liquid submerge fermentation.The fermented broth was extracted with ethyl acetate.The ethyl acetate layer was concentrated in vacuo and afforded 2.8 g organic crude.Two compounds XF01 and ZXW04 were obtained from this crude by several column chromatography.XF01 was a new compound and identified as 2-nonyl-4-(3,4,5-trihydroxy-6’-(hydroxymethyl)-tetrahydro-2H-pyran-2-yloxy)benzoicacid.ZXW04 was a mixture of 4-(β-D-galactopyranosyloxy)-2-hydroxy-6-nonyl-benzoic acid and 2,4-dihydroxy-6-nonylbenzoic acid.Compounds ZXW08 and ZXW09 were obtained from the acid hydrolysis of ZXW04 and was identified as 2,4-dihydroxy-6-nonyl-benzoic acid-methyl ester)and 5-nonyl-1,3-Benzenediol.ZXW08 and ZXW09 were new natural compounds.It was indicated that ZXW08 and ZXW09 possessed the inhibitory activity on Bacillus subtilis and yeast at the concentration of 0.2μg/μL.Based upon their biological activities and chemical constituents,3 marine actinomycetes(NO.12-432,10-209 and 02-104)were selected from 52 strains for further exploration.Then these strains were fermented with the liquid modified Gauze’ medium.Their fermented broth was extracted with ethyl acetate and afforded the organic crude.The strains 12-432 was fermented in a total volume of 10 L and afforded 1.6222 g organic crude.9 compounds(ZXW13,ZXW14,ZXW15,ZXW16,ZXW17,ZXW18,ZXW19,ZXW20 and ZXW21)were obtained by repeated column chromatography.The structures of compounds ZXW13,ZXW14,ZXW15,ZXW16,ZXW17 and ZXW18 were identified as 4-(2-hydroxypropan-2-yl)-1,5-dimethyldecahydronaphthalene-1,5-diol,4-hydroxyphenethyl acetate,2-(3-hydroxy-2-(hydroxymethyl)-1-iminopropyl)phenol,7-(2-hydroxypropan-2-yl)-1,4a-dimethyl-decahydronaphthalene-1,5-diol,(4-oxo-3,4-dihy dro-2H-chromen-3-yl)methyl acetate and 5-(6-hydroxy-6-methylheptyl)-dihydrofuran-2(3H)-one.Compounds ZXW13,ZXW15,ZXW17 and ZXW18 were new natural products.The strains 10-209 was fermented in a total volume of 17 L and afforded 0.7023 g organic crude.5 compounds(ZXW11,ZXW25,ZXW27,ZXW29 and ZXW28)were obtained by repeated column chromatography.Their structures of compounds ZXW11,ZXW25,ZXW27 and ZXW29 were identified as 8,10-dihydroxy-2(2-hydroxypropan-2-yl)-4,9-dimethyl-1,2,3,4,4a,11b-hexahydronaphtho[2,3-b]benzofura n-6,11-dione,2,7-dichloro-1-naphthaldehyde,4-hydroxyl-benzaldehydeand(E)-2-hydroxy-2,6-dimethyl-8-(3a,5,6-trihydroxy-6-methyl-3a,5,6,7-tetrahydro-4H-inden-1-yl)oct-6-en-3-one.Compounds ZXW11,ZXW27 and ZXW29 were new natural products.The experimental results indicated that compound ZXW25 possessed the activity against Escherichia coli and Bacillus subtilis at the concentration of 0.2 μg/μL and compound ZXW11 had the activity against Bacillus subtilis at the same concentration.The strains 02-104 was fermented in a total volume of 0.5 L and afforded 0.129 g organic crude.Three compounds ZXW02,ZXW03 and ZXW06 were obtained from the crude.The structures of ZXW03 and ZXW06 and identified as 1H-indole-5-propanoic acid-methyl ester and 1H-indole-5-ethanol respectively.The results of this study show that the secondary metabolites of marine microorganisms are diverse in chemical structure and biological activity.