title: [Isolation, purification and characterization of antifungal substances from Streptomyces hygroscopicus BS-112].
abstract: OBJECTIVE
  In order to provide the basis for application of Streptomyces hygroscopicus BS-112 and its antifungal active substances, we isolated and purified the active substances produced by strain BS-112, and then we examined their chemical structures and determined their inhibitory effects on Aspergillus flavus.
  
  
  METHODS
  We extracted and purified the antifungal active substances from strain BS-112 using column chromatography with X-5 macroporous resin and 200 - 300 mesh silica gel respectively, and then purified them by preparative HPLC with Venusil XBP C18 column. The chemical structures of active components were identified by means of spectroscopic analysis, including mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR). Their minimum inhibitory concentration and minimum fungicidal concentration against Aspergillus flavus were determined by the standard broth microdilution method.
  
  
  RESULTS
  We obtained four active components from the fermentation broth of strain BS-112 and their chemical structures were the same as Tetrins A and B, Tetramycins A and B. Assay using 96-well plate illustrated that the MIC of Tetrin A, Tetrin B, Tetramycin A and Tetramycin B against Aspergillus flavus were 3.13 microg/mL,12.56 microg/mL,1.56 microg/mL and 6.25 microg/mL respectively, and their MFC were 6.25 microg/mL, 25.0 microg/mL, 3.13 microg/mL and 12.56 microg/mL respectively.
  
  
  CONCLUSIONS
  The antifungal active substances of strain BS-112 were composed of four compounds, Tetrins A and B, Tetramycins A and B. The four active compounds showed strong inhibitory against Aspergillus flavus.
authors.affiliation: College of Life Science, Shandong Agricultural University, Taian 271018, China. nan25000@163.com
authors.forename: Nan
authors.initials: N
authors.lastname: Zhang
authors.forename: Changpo
authors.initials: C
authors.lastname: Sun
authors.forename: Zhen
authors.initials: Z
authors.lastname: Song
authors.forename: Hui
authors.initials: H
authors.lastname: Guo
authors.forename: Benfeng
authors.initials: B
authors.lastname: Zhang
authors.forename: Nianquan
authors.initials: N
authors.lastname: Qiu
authors.forename: Xunli
authors.initials: X
authors.lastname: Liu
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D001231:Aspergillus flavus / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D018942:Macrolides / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D013058:Mass Spectrometry; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D013302:Streptomyces / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000935:Antifungal Agents; D018942:Macrolides