副干酪乳杆菌胞外多糖抗氧化活性分析

为评价干酪乳杆菌生物合成胞外多糖(exopolysaccharides,EPS)抗氧化活性,本文分离纯化高产胞外多糖的三株副干酪乳杆菌(3号、5号和7号)的胞外多糖,并对其DPPH·、·OH和O₂-清除率分别进行测定,评价其体外抗氧化活性。通过分析EPS对H₂O₂诱导氧化损伤293T细胞的保护作用,评价其胞内抗氧化活性。结果表明,当EPS浓度为400 μg/mL时,其DPPH·、·OH和O₂-的清除率最高,分别为8.87%(5号)、88.94%(7号)和34.55%(7号),其中对·OH清除能力高于抗坏血酸(65.87%),且三株菌株之间没有明显差异。3号副干酪乳杆菌所产EPS显著提高超氧化物歧化酶(SOD)活性、总抗氧化能力(T-AOC)活性并抑制了丙二醛(MDA)的生成(P<0.05),且与多糖浓度呈正相关。因此,3株副干酪乳杆菌胞外多糖具有良好的抗氧化活性,作为天然抗氧化剂具有良好的应用潜力。

Antioxidant Activity Analysis of Exopolysaccharide from Lactobacillus paracasei Strains

In order to evaluate the antioxidant activity of exopolysaccharides(EPS)which synthesized by Lactobacillus casei,the EPSs were isolated and purified from three L. casei strains(No. 3,5 and 7)with higher EPS production. Antioxidant activities(superoxide anion(O₂-·),hydroxyl radical(·OH)and DPPH· radicals)of EPS were evaluated in vitro. Furthermore,the protective effect of EPS on H₂O₂-induced 293T cells oxidative injury was investigated. The results showed that EPS produced by the three strains had the highest scavenging rates when the EPS concentration was up to 400 μg/mL,and the scavenging rates were 8.87%(No. 5),88.94%(No. 7)and 34.55%(No. 7),respectively. The scavenging ability of hydroxyl free radical was better than that of ascorbic acid(65.87%). However,there was no significantly difference among the strains. Moreover,the EPS which was biosynthesized by L. paracasei No. 3 strain significantly raised the activities of superoxide dismutase(SOD)and total antioxidant capacity(T-AOC)and inhibited the formation of malondialdehyde(MDA)(P<0.05),which positively correlated with EPS concentration. The experimental results provide a basis for its use as an additive to enhance the antioxidant activity of food.