鲈鱼抗氧化肽的稳定性分析及其对细胞氧化损伤的保护作用

目的:探究鲈鱼蛋白酶解物（Lateolabrax maculatus protein hydrolysates，LPH）的体外抗氧化活性及稳定性。方法:采用化学实验测定LPH的抗氧化活性以及分析pH、温度、金属离子（K+、Ca2+、Cu2+、Zn2+）和模拟胃肠道消化对其稳定性的影响，并利用过氧化氢诱导的Caco-2细胞氧化损伤模型探究LPH对细胞氧化损伤的保护作用。结果:LPH具有较强的自由基清除活性，其DPPH和ABTS+自由基清除能力的IC₅₀值分别为2.13 mg/mL和31.53 μg/mL。LPH对pH（2.0~12.0）、温度（25~100 ℃）和K+（0.25~2 mmol/L）稳定，0.25~2 mmol/L的Ca2+和Cu2+能够提升其DPPH自由基清除率，而1 mmol/L以上的Zn2+会降低DPPH自由基清除率。此外，LPH具有良好的胃肠道稳定性。在过氧化氢诱导的Caco-2细胞模型中，LPH能够将氧化损伤的细胞存活率由58.02%显著增加至83.40%（P<0.05），显著抑制细胞内活性氧的释放（P<0.05）并恢复细胞线粒体膜电位至正常水平。此外，LPH能够显著抑制细胞上清中乳酸脱氢酶水平至模型组的19.34%（P<0.05）并显著增加细胞内超氧化物歧化酶和过氧化氢酶活力（P<0.05）。结论:LPH具有较好的抗氧化活性及稳定性，在食品保健领域具有良好的应用前景。

Stability Analysis of Antioxidant Peptides from Lateolabrax maculatus and Their Protective Effect Against Cellular Oxidative Damage

Objective: The study aimed to explore the antioxidant activity and stability of Lateolabrax maculatus protein hydrolysates (LPH) in vitro. Methods: Chemical experiments were used to determine the antioxidant activity of LPH and analyze the effects of pH, temperature, metal ions (K+, Ca2+, Cu2+, Zn2+) and simulated gastrointestinal digestion on its stability. And the oxidative damage model of Caco-2 cells induced by hydrogen peroxide was used to explore the protective effect of LPH against cellular oxidative damage. Results: LPH had strong free radical scavenging activity against DPPH and ABTS and the IC₅₀ values were 2.13 mg/mL and 31.53 μg/mL respectively. LPH was stable to pH(2.0~12.0), temperature (25~100 ℃) and K+ (0.25~2 mmol/L). Ca2+ and Cu2+ at 0.25~2 mmol/L improved DPPH scavenging rate of LPH, while Zn2+ above 1 mmol/L decreased it. In addition, LPH had good gastrointestinal stability. In the Caco-2 cell model induced by hydrogen peroxide, LPH significantly increased cell viability from 58.02% to 83.40% (P<0.05), significantly inhibited the release of intracellular reactive oxygen species (P<0.05) and restored mitochondrial membrane potential to normal level. Furthermore, LPH significantly inhibited the activity of lactate dehydrogenase in supernatant to 19.34% of model group (P<0.05) and significantly increased the activities of superoxide dismutase and catalase in cells (P<0.05). Conclusion: LPH had good antioxidant activity and stability, suggesting a good application prospect in the area of functional nutritious food.