Antioxidative ability of lactic acid bacteria

Nineteen strains of lactic acid bacteria were investigated for antioxidativ e activity. These included Lactobacillus acidophilus B, E, N1, 4356, LA-1, and Farr; Lactobacillus bulgaricus 12 278, 448, 449, Lb, 1006, and 11 842; Streptococcus thermophilus 821, MC, 573, 3641, and 19 987; and Bifidobacter ium longum B6 and 15 708. Intracellular cell-free extract of all strains de monstrated antioxidative activity with inhibition rates of ascorbate autoxi dation in the range of 7-12%. Antioxidative mechanisms including metal ion chelating ability, scavenge of reactive oxygen species, enzyme inhibition, and reducing activity of intracellular cell-free extract of lactic acid bac teria were studied. S. thermophilus 821 had the highest metal ion chelating ability for Fe2+, and B. longum 15 708 showed the highest Cu2+ chelating a bility among the 19 strains-tested. All strains demonstrated reactive oxyge n species scavenging ability. L. acidophilus E showed, the highest hydroxyl radical scavenging ability, and B. longum B6 had the best hydrogen peroxid e scavenging ability. Reducing activity was also found in all strains, Most of the strains tested demonstrated excellent reducing activity. B. longum B6 showed the highest reducing activity among the 19 strains tested. In enz yme inhibition, superoxide dismutase activity was not found in these 19 str ains, and the activity of superoxide dismutase was not induced when metal i on Mn2+, Fe2+, or Cu2+Zn2+ was present.