title: Lactobacilli prevent hydroxy radical production and inhibit Escherichia coli and Enterococcus growth in system mimicking colon fermentation.
abstract: OBJECTIVE
  To explore the effect of Lactobacillus on redox state of colon chyme.
  
  
  RESULTS
  Nine Lactobacillus strains were studied for the inhibition of lipid peroxide formation in Fe(2+)/ascorbate system and for their ability to chelate 'free' ferrous ion. The result shows both properties were strain specific and no relationship between them was found. Both properties of Lactobacillus paracasei Fn032, Lactobacillus rhamnosus GG (LGG) and Lactobacillus sp. Fn001 were successively decreasing. LGG and Fn032 significantly decreased hydroxyl radicals (P < 0.01) in colonic fermentation model, in which considerable hydroxyl radicals occurred spontaneously. Addition of ferrous ion induced the production of hydroxyl radicals, which could be significantly inhibited by LGG, Fn032 (P < 0.01) and Fn001 (P < 0.05). Ferrous ion significantly induced the growth of Enterococcus and Escherichia coli, which could be inhibited by all three Lactobacillus strains. Escherichia coli and Enterococcus show significantly positive correlation with hydroxyl radicals with R of 0.96 (P = 0.0002) and 0.91 (P = 0.0017), respectively.
  
  
  CONCLUSIONS
  Antioxidative Lactobacillus could modulate redox state in colonic fermentation system, which is related to their free radical-scavenging ability or antibacterial effect.
  
  
  CONCLUSIONS
  This study proves that Lactobacillus strain could influence the redox state of gut chyme. Evaluation of antioxidative ability might be a powerful method for screening probiotic Lactobacillus strains.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi Jiangsu Province, China.
authors.forename: J
authors.initials: J
authors.lastname: Sun
authors.forename: X-L
authors.initials: XL
authors.lastname: Hu
authors.forename: G-W
authors.initials: GW
authors.lastname: Le
authors.forename: Y-H
authors.initials: YH
authors.lastname: Shi
mesh_terms: D000898:Antibiosis; D003106:Colon / Q000382:microbiology*; D016983:Enterococcus / Q000254:growth & development*; D004926:Escherichia coli / Q000254:growth & development*; D005285:Fermentation; D005296:Ferrous Compounds / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000378:metabolism; D007778:Lactobacillus / Q000378:metabolism*; D015227:Lipid Peroxidation; D010084:Oxidation-Reduction; D019936:Probiotics; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D005296:Ferrous Compounds; D007502:Iron Chelating Agents; D017665:Hydroxyl Radical; D013482:Superoxide Dismutase