Ability of intestinal lactic bacteria to bind or/and metabolise phenol and p-cresol
- 215 Downloads
Intestinal microflora can contribute to colon cancer by the production of substances playing a role in carcinogenesis. Metabolites of protein fermentation in the colon, such as ammonia, H2S, indole, phenol, skatole are toxic. Lactic bacteria existing in the colon may exert an anti-carcinogenic action, but the mechanism is poorly understood. In the present study the ability of intestin|al lactobacilli to bind or metabolise phenol and p-cresolin vitro was determined.Lactobacillus strains were cultivated in MRS and in a modified MRS broth with reduced concentrations of carbon source. Phenol and p-cresol content in the media were from 2 to 10 μg/ml. In MRS medium lactobacilli could decrease the concentration of phenol and p-cresol and it was 0.2-5.8 μg/ml for phenol and 0.2-1.4 μg/ml for p-cresol. After cultivation in a modified MRS broth, the decrease was 0.5-2.0 μg/ml for phenol and 0.5-2.4 μg/ml for p-cresol. The binding capacity of bacterial cells was rather low. After incubation of non-growing bacteria the decrease of phenol concentration was 0.1-0.5 μg/ml and p-cresol 0.1-2.8 μg/ml. But the ability of growing lactobacilli to metabolise the compounds cannot be excluded. After interaction of lactobacilli with 10 μg/ml of phenol they displayed a lower genotoxicity, as evaluated by the alkaline comet assay. The phenomenon not always depended on the decrease of phenol concentration, but on the medium, the strain of bacteria and for phenol it ranged from 32 to 48%.Lactobacillus strains tested did not lower the genotoxicity of p-cresol.
Key wordsphenol p-cresol intestinal microflora Lactobacillus DNA damage
Unable to display preview. Download preview PDF.
- Chung K.T., Fulk G.E., Stein M.W. (1975). Tryptophanase of fecal flora as a possible factor in the etiology of colon cancer. J. Natl. Cancer Inst., 554: 1073–1078.Google Scholar
- Commane D., Hughes R., Shortt C., Rowland I. (2005). The potential mechanisms involved in anti-carcinogenic action of probiotics. Mut. Res., 591: 276–289.Google Scholar
- Kikugawa K., Kato T. (1986). Formation of a mutagenic diazoquinone by interaction of phenol with nitrite. Food Chem. Toxicol., 26: 209–214.Google Scholar
- Priebe M.G., Vonk R.J., Sun X., He T., Harmsen H.J., Welling G.W. (2002). The physiology of colonic metabolism. Possibilities for interventions with pre- and probiotics. Eur. J. Nutr., 1: 2–10.Google Scholar
- Seltzer R. (1986). Phenols help form nitrosamines from NO(2). Chem. Engin. News, 64: 30.Google Scholar
- Shephard S.E., Schlatter C., Lutz W.K. (1987). Model risk analysis of nitrosable compounds in the diet as precursors of potential endogenous carcinogens. In Bartsch H., O’Neill I.K., Schultz-Hermann Eds, The relevance of N-nitroso compounds to human cancer: exposures and mechanisms. IARC Scientific Publication, Lyon, no. 84.Google Scholar