Milk and milk-derived products are a relevant source of bioactive peptides, which are also potential components of functional foods. Bioactive peptides exert multiple actions including an antioxidant role. In the present paper, four synthetic peptides (NPYVPR, AVPYPQR, KVLPVPEK, and ARHPHPHLSFM), corresponding to milk-derived peptides were studied. Although with different features, as revealed by RP-HPLC chromatography and MS analysis, the obtained peptides were shown to be taken up by Caco-2 cells arranged in an epithelial monolayer formation. The four peptides were all able to preserve cell viability against induced oxidative stress indicating that they might have a role in the control of oxidative stress. Therefore, an estimation of total thiols and glutathione content was performed after cell treatment with oxidants like hydrogen peroxide (H₂O₂) or tert-butyl hydroperoxide (TbOOH). The peptides were able to prevent the decrease of both total thiols and glutathione induced by H₂O₂ or TbOOH, and, in addition, they showed a protective effect on the thiol-related antioxidant enzymes thioredoxin reductase and glutathione reductase. Finally, they caused a decrease of ROS production induced by TbOOH in Caco-2 cells. The reported results highlight the relevant antioxidant role played by bioactive peptides in cells, which adds to other previously known properties.

中文翻译：

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牛奶来源的生物活性肽可保护Caco-2细胞模型中的氧化应激†

牛奶和牛奶来源的产品是生物活性肽的重要来源，它们也是功能性食品的潜在成分。生物活性肽发挥多种作用，包括抗氧化作用。在本文中，研究了四种合成肽（NPYVPR，AVPYPQR，KVLPVPEK和ARHPHPHLSFM），它们对应于牛奶衍生的肽。尽管具有不同的特征，如通过RP-HPLC色谱法和MS分析所揭示的，但显示出所获得的肽被排列在上皮单层形成中的Caco-2细胞吸收。这四种肽都能够保持细胞抵抗诱导的氧化应激的活性，表明它们可能在氧化应激的控制中起作用。因此，在用过氧化氢（H）等氧化剂进行细胞处理后，进行了总硫醇和谷胱甘肽含量的估算₂ O ₂）或叔丁基氢过氧化物（TbOOH）。该肽能够防止H ₂ O ₂或TbOOH诱导的总硫醇和谷胱甘肽的减少，此外，它们对与硫醇相关的抗氧化酶硫氧还蛋白还原酶和谷胱甘肽还原酶显示出保护作用。最后，它们导致了Tacoh诱导的Caco-2细胞中ROS的产生减少。报道的结果突出了生物活性肽在细胞中发挥的相关抗氧化作用，这增加了其他先前已知的特性。