Study On Isolation Of Antibacterial Active Component From Aspergillus Niger And Mechanism

In this paper,Aspergillus niger xj and Aspergillus niger spore powder were taken as the materials of study.In savary-gilliard liquid medium,its fermented product can produce dry mycelium and dry fermented liquid respectively 2860.3 g,5986.5 g and the total dry weight of 8846.8 g.And then extracted with acetone solvent Aspergillus niger xj mycelia,fermentation broth,Aspergillus niger spore preparation of the corresponding extract,respectively,214.4 g,37.2 g,353.9 g.Analysis of Aspergillus niger xj mycelia and the fermentation broth,s were not significantly different by HPLC,can be merged into for the next step separation.Seven components(S3-S9)from Aspergillus niger xj fermented total extracts and 12 components(B1-B12)from Aspergillus niger spore extract were separated using conventional silica gel column chromatography.Then all the components were tested by the corresponding antibacterial activity to determine the best antibacterial activity of components.The S4 and B10 bacteriostatic rate is the highest component,were respectively 97.72 % and 98.22 %.However,due to the S4 component of the total dry weight is too little,the S3,S5,S6,S7,B10 and other components for the next step separation according to the actual situation.The chemical composition of the corresponding components was systematically separated by a variety of modern chromatographic separation techniques such as RP-18 gel column chromatography,Sephadex LH-20 column chromatography,small silica gel chromatography and TLC chromatography.A total of seven monomer compounds were obtained by separation and purification.The structures were identified by UV,EI-MS and 1D-NMR spectroscopy combined with physical constants determination and thin layer chromatography(TLC).The seven components was Ergosterol,R1,5,5 '-Oxydimethylene-bis(2-furaldehyde),R3,Palmitic acid,R5,Acetamide,2-chloro-N-(2,6-dimethylphenyl)-N-(1H-pyrazol-1-ylmethyl),R7,Nonacosane,R10,Cholesta-3,5-dien-7-one,R12,Dimethyl 5-nitroisophthalate,R15.R3?R7?R12?R15 are isolated from Aspergillus niger for the first time.Studies on the electrical conductivity,nucleic acid and protein leakage of Agrobacterium tumefaciens T-37 showed that the B10 composition had a significant effect on the conductivity,nucleic acid and protein leakage of T-37 culture medium.The results showed that the conductivity of B10 and benzylpenicillin potassium to T-37 reach peak during 0-3h stage and the conductivity value of B10 group was higher than that of benzylpenicillin potassium treatment group at the same time in 0-5 h(P<0.05).It can indicating that the B10 component has a great effect on the Agrobacterium tumefaciens T-37 cell membrane permeability than penicillin potassium.B10 components and penicillin potassium for T-37 nucleic acid and protein leakage have certain correlation.Nucleic acid and protein leakage of B10 component is mainly manifested in the late stage at 15-18 h,penicillin potassium on nucleic acid and protein leakage is mainly manifested in the early stage at 3-6 h.