| The study of microbial fermentation products(microbial secondary metabolites)occupies a pivotal position in the study of natural products.The microorganism has the characteristics of small form,diverse species,fast propagation,short growth period and suitable for survival in different environments.Based on these characteristics,microorganisms have great advantages in industrialization and become the main source of discovering new bioactive compounds.By studying the secondary metabolites of microorganisms,this experiment conducted structure identification,activity testing,application exploration and source analysis of secondary metabolites.The reverse research of significance of microbial fermentation strains function in the process of human obtaining natural products was conducted.Two strains of Streptomyces were selected from two different soil samples by active tracing and literature investigation.Streptomyces maoxianensis and Streptomyces sp.HS-NF-1178,and the secondary metabolites of the two strains of Streptomyces were extracted and studied.Two strains of streptomyces were fermented,and the fermentation liquid was identified by resin adsorption,silica gel column chromatography,HPLC,and so on,and the methods of identification,such as NMR,IR and high resolution mass spectrometry.A total of 9 compounds were obtained,of which six were new compounds.(1)Streptomyces maoxianensis: The total separation of 3 compounds,of which two were new compounds,Maoxianamides a(1)and Maoxianamides B(2).The two were isomers and belonged to unsaturated fatty acid amide compounds.The known compounds were consistent with 1(10)E,5E-Germacradiene-2,11-Diol structures.(2)Streptomyces sp.HS-NF-1178: A total of 6 compounds were isolated,of which 4 were new compounds and 2 were reported compounds.Two known compounds were consistent with the structure of Lankacinol(4)and Lankacyclinol(6)respectively.The other 4 new compounds were named after the chemical nomenclature:1)N-((3R,4E,6E,8S,10 E,12E,14 S,16S)-8,14-dihydroxy-5,11,19,20-tetramethyl-18-oxo-2,17-dioxa-bicyclo[14.3.1]icosa-1(19),4,6,10,12-pentaen-3-yl)-2-hydroxypropanamide(5);2)(6S)-4-hydroxy-3,5-dimethyl-6-((2S,3E,5E,8S,9E,11E)-2,8,13-trihydroxy-5,11-dimethyltr ideca-3,5,9,11-tetraenyl)-5,6-dihydropyran-2-one(7);3)(4E,7S,8E,10 E,13S,14 E,16E)-7,13,18-trihydroxy-4,10,16-trimethyloctadeca-4,8,10,14,16-pentaen-3-one(8);4)2-((1E,3E,5S,7E,9E,11 S,13E)-5,11-dihydroxy-2,8,14-trimethyl-15-oxoheptadeca-1,3,7,9,1 3-pentaenyl)-5-methyloxazolidin-4-one(9)?The activity of the remaining 8 compounds was tested in addition to 3(too little amount),and the results showed that: Maoxianamides A and B showed a certain cytotoxicity to human lung cancer cell A549,human hepatocellular carcinoma Hep G2 and leukemia K562 cells.At the same time,compound 5,compound 6,compound 8 and compound 9 showed certain cytotoxicity to human prostate cancer cell PC-3 and human lung cancer cell A549.The activity of compound 9 was relatively better,and the IC50 value for two cancer cells was 30.3 and 27.3 ?g/mL,respectively.Maoxianamides A and B had inhibitory effects on the soybean germ nuclei,both MIC value were between 0.08-0.4 mg/m L;The MIC range of compound 4 to Micrococcus luteus and resistant Staphylococcus aureus was respectively between 0.08-0.4 mg/mL and 0.4-2mg/m L.The MIC range of compound 5 to Micrococcus luteus is between 0.4-2 mg/mL,and the MIC range of compound 7 against Bacillus subtilis and resistant Staphylococcus aureus was between 2-10mg/mL. |
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