不同乳酸菌胞外分泌物抗氧化活性的研究

以1,1-二苯基-2-三硝基苯肼（DPPH）自由基、羟自由基、超氧阴离子自由基清除能力和还原能力为评价指标，以维生素C作阳性对照，分析不同来源的28株乳酸菌的胞外分泌物体外抗氧化活性，并研究不同抗氧化活性测定方法间的相关性。结果表明，菌株GB8、WC5和GC2抗氧化能力较强，其中菌株GB8对超氧阴离子自由基清除率（98.26%）和还原能力最高（0.964），菌株WC5对DPPH自由基的清除率最高，为74.90%；菌株GC2对羟自由基、DPPH自由基及超氧阴离子自由清除率分别为58.67%、73.09%、87.50%，还原能力为0.806，表现出最强的综合抗氧化能力。4种体外抗氧化活性分析方法的相关性结果表明，羟自由基与DPPH自由基（R2=0.633）、超氧阴离子与还原能力（R2=0.488）方法间达到了极显著相关（P＜0.01）；羟自由基与还原能力（R2=0.295）方法间达到了显著相关（P＜0.05）。

Antioxidant activity of extracellular secretions of different lactic acid bacteria

Using the scavenging ability of DPPH free radical, hydroxyl free radical, superoxide anion radical and reducing power capacity as evaluation indexes, and vitamin C as positive control, the antioxidant activity of extracellular secretions of 28 lactic acid bacteria isolated from different sources was analyzed, and the correlation between different methods for antioxidant activity detection was studied. The results showed that the strains GB8, WC5 and GC2 had strong antioxidant capacity. Among them, the superoxide anion radical scavenging rate (98.26%) and reducing power capacity (A700 nm value was 0.964) of the strain GB8 were the highest; the DPPH radical scavenging rate (74.90%) of the strain WC5 was the highest. The strain GC2 had strongest comprehensive antioxidant activity, and the hydroxyl radical, DPPH free radical, superoxide anion radical scavenging rate and antioxidant activity were 58.67%, 73.09%, 87.50% and 0.806, respectively. The results of correlation between 4 kinds of methods for the antioxidant activity in vitro analysis showed that there was extremely significant (P＜0.01) correlation between the hydroxyl radical and DPPH free radical method (R2=0.633), superoxide anion and reducing power capacity method (R2=0.488), and there was significant (P＜0.05) correlation between hydroxyl radical and reduction capacity method (R2=0.295).