Isolation,Identification And Bioactvity Of Secondary Metabolites From Two Streptomyces Strains

In view of the secondary metabolites of streptomyces contains abundant resources of bioactive substances,an actinomycetes strain named ZZ035 with significant biological activity such as antibacterial activity was obtained after the tests of chemical screening and biological activity screening being carried out in this paper,which was inspired by the practice of anti-infection-resistant soil.The classification and identification of strain ZZ035 were conducted by means of observing the strain morphological characteristics?testing its antibacterial activity and using the molecular biology method in this paper,and the research of isolation?structural identification and activity about its metabolic secondary products were proceeded in the next.Meanwhile,Azalomycin Fsa,one composition isolated from the secondary metabolites of Streptomyces 211726 by our research group,were further researched on its activity against methicillin-resistant staphylococcus aureus?MRSA?due to the urgency of the MRSA resistant drug development.The main contents and results are as follows:1.The actinomycete ZZ035 was identified by culture characteristics and molecular biology methods and it turned out to be Streptomyces cinnamonensis ZZ035.The GenBank number of its 16S rRNA gene sequence is KJ995739.The activity studies have shown that:The fermentation broth of this strain has significant antibacterial activity against methicillin-resistant staphylococcus aurcus,and so on.2.The fermentation products of Streptomyces sp.ZZ035 were isolated by means of modern separation techniques such as column chromatography and thin layer chromatography,then two crystals named 1 and 2 and two extracts named 3 and 4 were obtained,respectively.The structures of the two crystals were identified by IR,NMR and MS spectroscopy?GC-MS and HRESI-MS?,and the results show that they were identified as a y-aminobutyric acid derivatives named 5-Amonimethyl-2-iminoimidazolidine-4-carboxylic acid 1 and a number of triglyceride compounds 2 respectively;The study of the activity of the latter showed that compound 2 is a novel compound of a newly substituted aminobutyric acid derivative.3.The hydrocarbon signals of glycerol and acyl moieties about the glyceride esters were researched with detailed analysis,literature comparision and full attribution,using 1D,2D NMR and GC-MS techniques,combined with computer simulation.Compared to the reported literature,our research have more detailed NMR spectral data and accurate hydrocarbon signal attribution,Especially the signal of coupling relationship and fracture attribution of hydrogen atoms attached to glycerol can be used to accurately distinguish triglycerides from monoesters and diesters,which providing a new important basis for qualitative and quantitative analysis about triglycerides,diesters and monoesters;Meanwhile the exact attribution of the acyl part provides a simple and novel method for determining the acyl terminal type of the glyceride mixture by 13C NMR analysis.4.The study of the activity of the compound 1 and the extracts 3 and 4 showed that:compound 1 had a significant inhibitory activity to y-aminobutyric acid transaminase,and the IC₅₀ is about 60 ?mol/L,which is comparable to the positive control drug Vigabatrin and is worthy of further study as a new y-aminobutyric acid transaminase inhibitor and a novel aminobutyric acid derivative;the extracts 3 and 4 both have obvious antibacterial activity,which are worth of a further study.5.Azalomycin F5a,one composition of secondary metabolites of Streptomyces 211726,was further researched on its activity against methicillin-resistant staphylococcus aureus?MRSA?.The results show that:Azalomycin F5a exhibits great activity agaist MRSA and a narrow mutant selection window,and the mutant selection window can be narrowed or even closed with the combination of vitamin K3.Thus it can delay or prevent the resistance for testing MRSA strains to Azalomycin Fsa,which showing the good prospects for application and development of Azalomycin F5a.And it also provides a reference for methods and ideas for delaying or preventing clinical pathogen resistance.