抗氧化益生乳酸菌的筛选

发布时间：2018-02-10 05:18

  本文关键词： 乳酸菌 抗氧化活性 自由基 超氧化物歧化酶 胱甘肽过氧化物酶 植物乳杆菌　出处：《江南大学》2007年硕士论文　论文类型：学位论文

【摘要】： 生命活动的氧化代谢过程中不断产生各种活性氧自由基会引起生物大分子的损伤,从而引发一些疾病。尽管人的机体有抗氧化防御系统,但是这些系统并不能完全有效地抵御或修复氧化作用带来的损伤。外加一些抗氧化剂对协助体内氧代谢的平衡是很有帮助的,而具有抗氧化活性的天然产物越来越受到人们的青睐。近年来,国内外对乳酸菌的生理活性有大量的研究报道。但对乳酸菌抗氧化活性的报道较少。 本研究以体外过氧化氢耐受能力为指标,从发酵食品中筛选出2株能够耐受高达1mmol/L过氧化氢的乳酸菌。研究了两株乳酸菌完整细胞和无细胞提取物的DPPH·自由基和羟自由基清除能力。研究结果表明,菌体为浓度为109cfu/mL的L1001完整细胞和无细胞提取物的DPPH·自由基清除率分别为36.2%和37.9%,同样浓度的F12完整细胞和无细胞提取物对DPPH·自由基的清除率分别为24.4%和27.0%;清除羟自由基实验表明,浓度为109cfu/mL的细胞清除羟自由基能力与同体积的1mmol/L抗坏血酸相当,总抗氧化活性是以菌株抑制亚油酸过氧化能力判断的,两菌株与空白对照相比都表现出一定抑制亚油酸过氧化的能力。 对乳酸菌L1001的生长特性的研究结果显示:菌株的最低生长温度为20℃,最高生长温度为40℃,菌株以35℃-37℃的生长温度为佳,最高和最低初始生长pH为9.0和4.0,最适生长初始pH为6.0;L1001菌株的延迟期相对较短,4h左右开始进入对数生长期,l2h就达到稳定期。采用生理生化鉴定,形态特征、培养性状等鉴定手段对筛选所得的具有抗氧化活性的菌株L1001进行鉴定,最终确定为植物乳杆菌(Lactobacillus plantarum)。 进一步研究发现L.plantarum L1001的无细胞提取物SOD活性为1.20±0.26U/mL,GSH-Px活性为54.94±12.54活力单位。且L.plantarum L1001中SOD的活性并不受培养基中氧气浓度的影响。通过菌体生长不同阶段SOD活性的研究发现:L.plantarum L1001的SOD活性在12小时后(对数生长期末)已经达到最大值。培养基中锰离子、亚硒酸钠浓度对L.plantarum L1001的抗氧化活性有一定的影响。 通过动物实验,研究抗氧化活性较高的L.plantarum L1001对机体抗氧化指标的影响,包括超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)和血浆丙二醛(MDA)含量。结果显示:灌胃抗坏血酸和L.plantarum L1001的小鼠实验组相对于空白对照组其红细胞SOD活力,全血GSH-Px活力血浆CAT活力有所升高,其中灌胃抗坏血酸和的高剂量组L.plantarum L1001小鼠实验组相对于对照组,其血浆CAT活性显著升高(P0.05);血浆MDA含量比空白对照组低。L.plantarum L1001能够改善小鼠的抗氧化能力,从而对机体细胞起到保护作用。
[Abstract]:The constant production of reactive oxygen free radicals in the oxidative metabolism of life activities can cause damage to biological macromolecules, which can lead to some diseases, although the human body has an antioxidant defense system. But these systems are not completely effective in resisting or repairing oxidative damage. The addition of antioxidants helps balance oxygen metabolism in the body. In recent years, there have been a lot of reports on the physiological activities of lactic acid bacteria, but there are few reports on the antioxidant activities of lactic acid bacteria. In this study, hydrogen peroxide tolerance in vitro was used as an index. Two strains of lactic acid bacteria capable of tolerating up to 1 mmol / L hydrogen peroxide were screened from fermented food. The scavenging ability of DPPH 路free radical and hydroxyl radical of two strains of lactic acid bacteria were studied. The scavenging rates of DPPH 路free radicals of intact cells and acellular extracts were 36.2% and 37.9, respectively. The scavenging rates of DPPH 路free radicals of the same concentration of F12 intact cells and acellular extracts were 24.4% and 27.0, respectively. The ability of scavenging hydroxyl radical at 109 cfur / mL was equal to that of ascorbic acid at the same volume, and the total antioxidant activity was judged by the ability of strain to inhibit linoleic acid peroxidation. Compared with the control, the two strains showed the ability to inhibit linoleic acid peroxidation. The study on the growth characteristics of lactic acid bacteria L1001 shows that the minimum growth temperature of the strain is 20 鈩，

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