抗氧化乳酸菌在体外结肠环境清除羟自由基的研究

目的利用鼠肝匀浆经Fe^2＋ -VitC诱导产生丙二醛（MDA）为模型研究29株乳酸菌的抗氧化活性。方法建立体外模拟结肠发酵体系，分析3株具有不同抗氧化能力的乳酸菌（Lactobacillus paracasei Fn032，Laaobacillus rhamnosus GG，Lactobacillus sp．Fn001）在正常结肠和铁过载结肠模型中清除羟自由基效果及对肠球菌增殖的的影响，并检测3株菌螯合亚铁离子能力及其无细胞提取物超氧化物歧化酶（SOD）活性。结果体外结肠体系中羟自由基含量与肠球菌数量有显著相关性。在正常结肠环境中，3株乳酸菌清除羟自由基能力与其SOD活性一致，但与其抑制肠球菌增殖能力和螯合亚铁离子能力不一致。在高铁结肠环境中，3株乳酸菌清除羟自由基能力与它们抑制肠球菌增殖能力和螯合亚铁离子能力一致，但与SOD活性不一致。结论正常条件下乳酸菌可通过产生抗氧化酶来清除结肠自由基，铁过载条件则可增强具有铁螯和能力乳酸菌的抗氧化活性。

Scavenging of hydroxy radical by Lactobacillus spp in mimetic colon conditions

Objective Antioxidative abilities was studied for 29 Lactobacillus spp by their effect on inhibiting liver lipid peroxidation in Fe^2＋ -VitC system. Method An in vitro colon fermentation system was established to analyze scavenging hydroxy radical ability and inhibiting enterococcus ability by three different antioxidative lactobacilli （Lactobacillus paracasei Fn032,Lactobacillus rhamnosus GG, Lactobacillus sp. Fn001 ）. Iron-chelation abilities and SOD activity was also determined for these three strains. Result Hydroxy radical was significantly correlated to enterococcus in colon fermentation system. In normal system, hydroxy radical scavenging ability of them was related to their SOD activity. In iron-overloa- ded system, it was related to their ability of inhibiting enterococcus and chelating iron. Conclusion In normal system, lactobacilli maybe eliminate hydroxy radical mainly by antioxidase, and Fe^2＋ -overloaded system can induce antioxidative ability of LactobaciUus with highly chelated iron.