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In recent years, oxidation and antioxidant research has become the forefront of modern life sciences and hot, evaluation and screening have antioxidant activity of natural resources has become a new trend in biology, medicine, and food science. Probiotic lactic acid bacteria can not only adjust the balance of intestinal flora, reduce serum cholesterol, inhibit and reduce the risk of tumor and immunostimulatory role. Recently, some studies also found that lactic acid bacteria has anti-aging, anti-oxidation, and other important biological functions, is an important resource for the development of natural antioxidants. In this paper, the traditional fermented dairy lactic acid bacteria isolated 43 as the research object, screened out the two have a strong antioxidant capacity of Lactobacillus SY13 and LJJ and comprehensive evaluation of its in vitro antioxidant properties and antioxidant factors affecting the initial analysis, the use of the API 50CH biochemical methods and 16S rDNA sequence analysis identified two strains. To further confirm the antioxidant effect, SY13 mice Antioxidant verification experiment. In vitro antioxidant experiments, respectively, the use of Lactobacillus SY13 and LJJ intact cells and cell-free extracts of the inhibitory effect of linoleic acid peroxidation, DPPH radical, hydroxyl radical, superoxide anion radical scavenging, hydrogen peroxide tolerability and chelating ability and reducing activity of the ferrous ions was studied. The results show that the SY13 and LJJ linoleic acid peroxidation inhibition rate reached 62.95% and 66.16%, respectively; cell-free extracts of the two strains Clear superoxide anion and hydroxyl radicals better, SY13 and LJJ Clear superoxide anion and hydroxyl radical, respectively reached 31.38%, 30.24% and 31.19%, 10.01%, no scavenging the LJJ intact cells of the superoxide anion and hydroxyl radical; SY13 and LJJ intact cells scavenge DPPH capacity of 27.5% and 23.99, respectively, ferrous ion chelating ability of 34.12% and 50.55%, respectively; reduction activity equivalent to 305μmol / L and 294μmol / L L-cysteine. Indicators measured above results suggest that these two lactobacilli has good antioxidant capacity, with potential applications. API 50CH identification system and 16S rDNA sequence analysis, the final identification results SY13 Lactobacillus casei subsp.casei, LJJ of Lactobacillus delbrueckii subsp.bulgaricus. Impact factors to conduct a preliminary analysis of the antioxidant activity of the SY13, LJJ two strains. Two strains trend is basically the same, the incubation time of 18 h, they Hydroxyl Radical Scavenging achieve the maximum effect; clear effect is also increasing with the number of viable cells progressively elevated; made cell-free extract test temperature and time combination of two inactivated gradient of 65 ° C for 30 min and 100 ° C, 30 min Hydroxyl Radical Scavenging declined as the temperature rises, this may be due to the heat treatment of 100 ° C, the bacteria in vivo antioxidant enzyme deactivation. Further research found that the use of the SY13 viable preparations were fed by the D-galactose induced aging model ICR mice can effectively improve the antioxidant levels in aging mice, enhanced antioxidant enzyme activity, reduce lipid peroxide content and reduce the level of oxidative stress, and can reduce blood lipid levels, improve blood lipid metabolism, reduce the risk of atherosclerosis. Performance can significantly improve aging serum and liver tissue glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity, reduce the content of malondialdehyde (MDA) . In addition, significantly lower total triglycerides (TG) in aging mice serum and liver tissue of low density lipoprotein (LDL), high-density lipoprotein cholesterol level (HDL), on oxidation in mice - antioxidant levels and lipid levels are closely related.
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