Ability of Intestinal Lactic Acid Bacteria to Bind and/or Metabolise Indole
Adriana Nowak1*, Michał Arabski2 and Zdzisława Libudzisz1
1Institute of Fermentation Technology and Microbiology, Department of Biotechnology and Food Sciences, Technical University of Lodz, Wolczanska 171/173, PL-90-924 Lodz, Poland
2Department of Molecular Genetics, University of Lodz, Banacha 12/16, PL-90-237 Lodz, Poland
Article history:
Received April 13, 2007
Accepted April 7, 2008
Key words:
indole, intestinal microbiota, Lactobacillus, DNA damage
Summary:
Intestinal microbiota can contribute to the development of colon cancer by the production of many substances playing a role in carcinogenesis. Metabolites of protein fermentation in the colon, such as ammonia, amines, indole, phenol, skatole and their derivatives are toxic. On the other hand, lactic acid bacteria (LAB) existing in the colon may exert an anticarcinogenic action, but the mechanism is still poorly understood. In the present study, the aim is to determine the ability of intestinal lactobacilli to adsorb or metabolise indole in vitro. Lactobacillus strains were cultivated in MRS and a modified MRS broth with reduced concentrations of nitrogen and carbon. Indole concentration in the media was from 2 to 20 μg/mL. The decrease in indole concentration was from 1 to 10 μg/mL after cultivation in MRS broth, and from 4.3 to 6.7 μg/mL after cultivation in a modified MRS broth. It was shown that the higher concentration of indole in the medium, the higher reduction of its level. Killed bacteria displayed slight binding capacity. After the interaction of alive lactobacilli with 10 μg/mL of indole, it displayed a lower genotoxicity, as evaluated by the alkaline comet assay. The phenomenon did not depend on the decrease of indole concentration, but on the culture medium and the strain of LAB and ranged from 7 to 96 %.
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