發(fā)布時間：2018-02-10 05:18

  本文關鍵詞： 乳酸菌 抗氧化活性 自由基 超氧化物歧化酶 胱甘肽過氧化物酶 植物乳桿菌　出處：《江南大學》2007年碩士論文　論文類型：學位論文

【摘要】： 生命活動的氧化代謝過程中不斷產生各種活性氧自由基會引起生物大分子的損傷,從而引發(fā)一些疾病。盡管人的機體有抗氧化防御系統(tǒng),但是這些系統(tǒng)并不能完全有效地抵御或修復氧化作用帶來的損傷。外加一些抗氧化劑對協(xié)助體內氧代謝的平衡是很有幫助的,而具有抗氧化活性的天然產物越來越受到人們的青睞。近年來,國內外對乳酸菌的生理活性有大量的研究報道。但對乳酸菌抗氧化活性的報道較少。 本研究以體外過氧化氫耐受能力為指標,從發(fā)酵食品中篩選出2株能夠耐受高達1mmol/L過氧化氫的乳酸菌。研究了兩株乳酸菌完整細胞和無細胞提取物的DPPH·自由基和羥自由基清除能力。研究結果表明,菌體為濃度為109cfu/mL的L1001完整細胞和無細胞提取物的DPPH·自由基清除率分別為36.2%和37.9%,同樣濃度的F12完整細胞和無細胞提取物對DPPH·自由基的清除率分別為24.4%和27.0%;清除羥自由基實驗表明,濃度為109cfu/mL的細胞清除羥自由基能力與同體積的1mmol/L抗壞血酸相當,總抗氧化活性是以菌株抑制亞油酸過氧化能力判斷的,兩菌株與空白對照相比都表現出一定抑制亞油酸過氧化的能力。 對乳酸菌L1001的生長特性的研究結果顯示:菌株的最低生長溫度為20℃,最高生長溫度為40℃,菌株以35℃-37℃的生長溫度為佳,最高和最低初始生長pH為9.0和4.0,最適生長初始pH為6.0;L1001菌株的延遲期相對較短,4h左右開始進入對數生長期,l2h就達到穩(wěn)定期。采用生理生化鑒定,形態(tài)特征、培養(yǎng)性狀等鑒定手段對篩選所得的具有抗氧化活性的菌株L1001進行鑒定,最終確定為植物乳桿菌(Lactobacillus plantarum)。 進一步研究發(fā)現L.plantarum L1001的無細胞提取物SOD活性為1.20±0.26U/mL,GSH-Px活性為54.94±12.54活力單位。且L.plantarum L1001中SOD的活性并不受培養(yǎng)基中氧氣濃度的影響。通過菌體生長不同階段SOD活性的研究發(fā)現:L.plantarum L1001的SOD活性在12小時后(對數生長期末)已經達到最大值。培養(yǎng)基中錳離子、亞硒酸鈉濃度對L.plantarum L1001的抗氧化活性有一定的影響。 通過動物實驗,研究抗氧化活性較高的L.plantarum L1001對機體抗氧化指標的影響,包括超氧化物歧化酶(SOD)、谷胱甘肽過氧化物酶(GSH-Px)、過氧化氫酶(CAT)和血漿丙二醛(MDA)含量。結果顯示:灌胃抗壞血酸和L.plantarum L1001的小鼠實驗組相對于空白對照組其紅細胞SOD活力,全血GSH-Px活力血漿CAT活力有所升高,其中灌胃抗壞血酸和的高劑量組L.plantarum L1001小鼠實驗組相對于對照組,其血漿CAT活性顯著升高(P0.05);血漿MDA含量比空白對照組低。L.plantarum L1001能夠改善小鼠的抗氧化能力,從而對機體細胞起到保護作用。
[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，

本文編號：1499747