Screening And Study Of Lactic Acid Bacteria With Antioxidative Activity

In recent years, oxidation and antioxidation have become the hot topics in modern life sciences and appraisal and selection of natural resources with strong antioxidative activities have become the new trends of biology, medical science, food science and technology. Lactic acid bacteria have some probiotic functions, such as adjusting the balancing of intestinal flora, reducing serum cholesterol, inhibiting and reducing the risk of tumors, and revitalizing the immune system etc. Lately, the study also found that some lactic acid bacteria strains have other important biological functions such as anti-aging and antioxidative activities. It is an important natural resources for exploiting antioxidant.We use 43 strains lactic acid bacteria, which isolated from traditional femented dairy products, to evaluate antioxidative effect and some influencing factors. Meanwhile, two higher antioxidative strains of SY13 and LJJ were identified using API biochemical method and 16S rDNA homology analysis method. In order to further confirming antioxidative effect, we use SY13 to feed ICR mice, verify antioxidative effect in vivo. Both intact cells and cell-free extract of Lactobacillus casei subsp.casei SY13 and Lactobacillus delbrueckii subsp.bulgaricus LJJ were used to study the inhibited effect of linoleic acid peroxidation, the ability of scavenging 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide anion radical, the ability of tolerancing hydrogen peroxide and the chelating capacity of ferrous ion and reducting activity. Lactobacillus casei subsp.casei SY13 and Lactobacillus delbrueckii subsp.bulgaricus LJJ demonstrated highest inhibition on linoleic acid peroxidetion by 62.95% and 66.16%, respectively. The cell-free extract showed excellent scavenging superoxide anion and hydroxyl radicals activity. However, the intact cells of Lactobacillus delbrueckii subsp.bulgaricus LJJ scavenging superoxide and hydroxyl radicals capacity were not detected. The intact cells of Lactobacillus casei subsp.casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ on 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability and chelating ferrous ion capacity were superior to cell-free extract. The highest reduced activety was equivalent to 305μmol/L and 294μmol/L L-cysteine. Two latobacilli strains had good antioxidant capacity. As potential probiotics, it can be used in future.The animal experiment showed that SY13 biogen can effectively improve the aging mice antioxidative level and increase the activity of antioxidant enzymes, reduce lipid peroxidation level, lower the levels of oxidative stress, can effectively reduce small rat serum lipid levels and improve lipid metabolism and reduce atherosclerosis risk. Notable mainly for the incease in aging mice in serum and liver of superoxide dismutase and glutathione peroxidase activity, reduce lipid peroxidation MAD. In addition, a significant reduction in total triglyceride and low density lipoprotein, raise the level of high density lipprotein cholesterol. The results showed oxidation-antioxidation levels and lipid levels were closely interrelated.