Antioxidative effects of lactic acid bacteria on the colonic mucosa of iron-overloaded mice

The antioxidative effects of lactic acid bacteria on lipid peroxidation in the colonic mucosa were investigated. Among 49 strains of lactic acid bacteria, Streptococcus thermophilus YIT 2001 showed the highest inhibitory activity against lipid peroxidation in liposomes induced by ferrous iron. Feeding a diet containing 0.4% St. thermophilus YIT 2001 (2 x 10(8) colony-forming units per mouse per day) for 2 weeks caused a significant decrease of lipid peroxide (thiobarbituric acid reactive substance) in the colonic mucosa of iron-overloaded mice (0.07% Fe in the diet). The mucosal lipid peroxide level did not correlate with the soluble iron concentration of the cecal contents. Therefore, it is suggested that the antioxidative effect of St. thermophilus YIT 2001 in the colonic mucosa was not due to the removal of ferrous iron from the reaction system of lipid peroxidation.