Some lactobacilli strains had beneficial effects on human beings due to their antioxidant activities. In this study lactobacilli strains stored in our laboratory were screened for potential antioxidant activities by investigating their 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity, oxygen radical absorbance capacity, resistance to H₂O₂, and hydroxyl free radical scavenging activity; then the antioxidant activities of the screened strains were evaluated by cellular antioxidant assay and protection for HT-29 cells against H₂O₂ injury assay. The results showed that Lactobacillus plantarum Y44 could scavenge oxygen free radicals, inhibit the production of intracellular reactive oxygen species without creating obvious cytotoxic effects, and protect HT-29 cells against H₂O₂ injury evidenced by the significant decrease of the Bcl-2-associated X protein (Bax)/B-cell lymphoma 2 (Bcl-2) ratio and heat shock protein 70 expression, increase of superoxide dismutase and glutathione peroxidase activities, and decrease of malondialdehyde level of HT-29 cells damaged by H₂O₂. It was speculated that L. plantarum Y44 protect HT-29 cells against oxygen radical injury through scavenging reactive oxygen species and activating intracellular antioxidant enzymes. A significant correlation was observed among the results of the hydroxyl radical scavenging assay, protection assay for HT-29 cells against H₂O₂ injury, and the cellular antioxidant assay. The findings indicated that L. plantarum Y44 could be a probiotic candidate with antioxidant properties and combining several chemical antioxidant methods and antioxidant cellular models could be an effective procedure to screen lactobacilli strains with antioxidant activity.

一些乳酸菌菌株由于其抗氧化活性而对人类具有有益的作用。在这项研究中，我们调查了储存在我们实验室中的乳酸杆菌菌株的潜在抗氧化活性，方法是调查它们的1,1-二苯基-2-吡啶并肼基自由基清除活性，氧自由基吸收能力，对H ₂ O _2的抗性和羟自由基清除活性; 然后通过细胞抗氧化试验评估筛选菌株的抗氧化活性，并针对HT-29细胞对抗H ₂ O ₂损伤的保护作用进行评估。结果表明植物乳杆菌Y44可以清除氧自由基，抑制细胞内活性氧的产生而不会产生明显的细胞毒性作用，并保护HT-29细胞免受H ₂ O ₂伤害，这是由Bcl-2相关X蛋白（Bax）的显着减少所证明的/ B细胞淋巴瘤2（Bcl-2）的比率和热休克蛋白70的表达，超氧化物歧化酶和谷胱甘肽过氧化物酶活性的增加，以及被H ₂ O ₂损伤的HT-29细胞的丙二醛水平降低。据推测，植物乳杆菌Y44通过清除活性氧并激活细胞内的抗氧化酶来保护HT-29细胞免受氧自由基的伤害。在羟基自由基清除试验，HT-29细胞抵抗H ₂ O ₂损伤的保护试验和细胞抗氧化剂试验的结果之间观察到显着相关性。研究结果表明，植物乳杆菌Y44可能是具有抗氧化特性的益生菌候选物，结合多种化学抗氧化方法和抗氧化细胞模型可能是筛选具有抗氧化活性的乳酸菌菌株的有效方法。