Secondary Metabolites Of Four Marine Actinomycetes And Their Biological Activities

Since the discovery of antibiotics,it has helped people to solve many problems.The use of antibiotics,coupled with the improvement of housing and living conditions at that time,caused the death rate of some diseases to be greatly reduced.In the 1950 s,with the discovery of penicillin and streptomycin,antibiotics entered a golden period.Major pharmaceutical companies have joined the ranks of antibiotic production.Antibiotics did help people solve a lot of problems in the beginning.However,as the number of antibiotics used has increased,a series of problems have followed.In order to survive,pathogens have mutated to adapt to this antagonistic effect of antibiotics,which have made the pathogens resistant.Secondly,the development of new antibiotics is not as fast as people think,but the demand for antibiotics has not decreased.Therefore,there is an urgent need to develop new antibiotics to deal with these problems.Actinobacteria are Gram-positive bacteria with high G+C DNA content that constitute one of the largest bacterial phyla,and they are ubiquitously distributed in both aquatic and terrestrial ecosystems and some actinomycetes can also produce enzyme inhibitors and vitamins and other substances.In recent years,it has become more and more difficult to isolate monomer compounds with novel structure and biological activity from soil actinomycetes.And as bacterial resistance and various diseases have not been completely overcome,the development of new drug sources and the discovery of more effective drugs have become the focus and hotspot of current research.Since Marine actinomycetes live in a special environment,their secondary metabolites are rich in structure and have a wide range of biological activities,such as the antibacterial,antiviral tumor and immunosuppression.They are an important source of microbial drugs.This laid the foundation for the development of drugs from Marine sources.In this study,35 strains of actinomycetes were screened and four strains of Streptomyces sp.S1610-1 Streptomyces sp.XY1812-4 Streptomyces sp.NH1836 Nocardiaceae oc1611-1 were screened.Four strains of actinomycetes were fermented,the fermentation products were extracted with ethyl acetate,the crude extract was obtained,the crude extract was separated,the monomer compound was obtained,and the monomer compound was studied.The strain Streptomyces sp.s1610-1 was obtained from the laboratory.the strain was isolated from the sponge body,choose YMS medium,by solid fermentation,resulting from the ethyl acetate extract of crude extractings from 6.05 g,the crude extract by silica gel column chromatography and HPLC purification technology,using nuclear magnetic resonance spectra of compounds identified,get compounds 1-7,a total of seven compounds.The strain Streptomyces sp.XY1812-4 was isolated from the sediment sample collected from Xiaoshidao,Weihai.Choose Gauze's Medium,by solid fermentation,resulting from the ethyl acetate extract of crude extractings from 16.5 g,and the crude extract by normal phase silica gel column chromatography,reversed-phase silica gel column chromatography and HPLC purification,separation technologies such as compounds are obtained by nuclear magnetic resonance(NMR)spectra identification of 8 to 12,a total of five compounds.The strain Nocardiaceae OC1611-1 was obtained from the laboratory,It isolated from the sediment sample collected from Xiaoshidao,Weihai.Choose Gauze's Medium,by solid fermentation,resulting from the ethyl acetate extract of crude extractings from 10.8 g,and the crude extract by normal phase silica gel column chromatography,reversed-phase silica gel column chromatography and HPLC purification,separation technologies such as compounds are obtained by nuclear magnetic resonance(NMR)spectra identification of 13 to 15,a total of six compounds.The strain Streptomyces sp.NH1836 was obtained from the laboratory,It isolated from the sediment sample collected from Hainan.Choose Gauze's Medium,by solid fermentation,resulting from the ethyl acetate extract of crude extractings from 24.6 g,and the crude extract by normal phase silica gel column chromatography,Sephadex LH20 gel column chromatography and reverse silica gel column chromatography were used for separation and purification to identify its molecular structure,and two compounds 19,20 were obtained.The antibacterial activities of some compounds were studied,among which compound 9,16 and 19 had inhibitory effect on most of the indicator strains,and compound 19 had the best inhibitory effect on most of the indicator strains,compound 11 and 12 only had inhibitory effect on some of the indicator strains,and compound 3 and 6 had no inhibitory effect on all the indicator strains.