Resistance of Lactobacillus plantarum KCTC 3099 from Kimchi to oxidative stress

The antioxidative capacity of two lactic acid bacteria isolated from Kimchi, a Korean fermented food, was evaluated by measuring the resistance to reactive oxygen species (ROS) and compared with that of Lactobacillits rhamnosus GG as a positive control. Both intact cells and cell-free extracts of Lactobacillus plantartan KCTC 3099 exhibited higher antioxidative activity in inhibiting lipid peroxidation among the strains evaluated with an inhibitory level of 38.6% and 48.5%, respectively. To evaluate the resistance of the two lactic acid bacteria to ROS, we tested their survival in the presence of I mM hydrogen peroxide, 0.4 mM hydroxyl radicals, and superoxide anions induced by 10 mM paraquat. L. plantarum KCTC 3099 was viable even after 8 hours in the presence of both I mM hydrogen peroxide and 0.4 mM hydroxyl radicals. Moreover. the survival of L. plantarum KCTC 3099 was not affected by superoxide anions generated by using paraquat, indicating that it has resistance to superoxide anions. To define the antioxidative mechanism, superoxide dismutase (SOD) and metal ion chelating activities were determined. L. plantarton KCTC 3099 presented little SOD activity, but had the higher level of chelatinc, activity for both Fe2+ CU2+ C and metal ions at 13.6 ppm and 23.9 ppm, respectively. These results suggested that the antioxidative capacity of L. plantarton KCTC 3099 is apparently caused by chelating metal ions rather than by SOD activation.