迷迭香多酚对模拟胃肠消化中脂质氧化产物生成、细胞毒性的抑制及机理研究

Lipid oxidation occurs readily in foods, and the generated toxic lipid oxidation products may cause a broad range of adverse health effects. The present studies mainly focus on lipid oxidation reactions during processing and storage of foods, but not enough attention is paid to the formation and cytotoxicity of lipid oxidation products in foods digestive processes. Firstly, the inhibitory effects of rosemary polyphenols on lipid oxidation products formation in rapeseed oil during simulated gastrointestinal digestion (SGD) process will be evaluated by measuring the levels of thiobarbituric acid reactive substances and peroxide value. Secondly, the possible mechanisms underlying inhibitory effects of rosemary polyphenols on lipid oxidation during SGD will be further investigated via measuring the free radical-scavenging activities and heme-binding abilities of rosemary polyphenols after SGD treatment. Finally, the Caco-2 cells injury model induced by oxidation products of rapeseed oil generated in SGD process will be built. The inhibitory effects and underling mechanisms of rosemary polyphenols on oxidative damage in Caco-2 cells induced by oxidation products of rapeseed oil will be investigated through measuring cell viability, protein expression levels of antioxidant enzymes, and activation of Keap1-Nrf2-ARE signaling pathway. This project investigates the inhibitory effects and underling mechanisms of rosemary polyphenols on the formation and cytotoxicity of lipid oxidation products in simulated gastrointestinal digestion model, which will provide scientific evidence for the research on control of lipid oxidation during foods digestive processes and its negative health effects by improving the dietary patterns.

食品容易发生脂质氧化反应，产生的毒性氧化产物会危害人体健康。目前，脂质氧化研究多集中于食品的加工和贮藏过程，而对胃肠消化过程中脂质氧化产物生成及毒性的研究相对较少。本课题首先以硫代巴比妥酸反应物浓度和过氧化值为指标，评价迷迭香多酚对模拟胃肠消化（SGD）过程中菜籽油氧化产物生成的抑制作用；其次，通过检测迷迭香多酚经SGD模型处理后的自由基清除能力、血红素结合能力等指标，探讨其抑制SGD过程中脂质氧化的机理；最后，建立菜籽油经模拟胃肠消化形成的氧化产物诱导Caco-2细胞损伤模型，通过检测细胞活力、抗氧化酶蛋白表达、Keap1-Nrf2-ARE信号通路激活等指标，研究迷迭香多酚对菜籽油氧化产物诱导细胞损伤的影响及机理。本课题研究了迷迭香多酚对模拟胃肠消化中脂质氧化产物生成、细胞毒性的抑制作用及机理，将为通过改善膳食结构等方式控制食物消化过程中的脂质氧化及其健康危害方面的研究奠定基础。

研究证实，油脂和富含脂质的食品极易在胃肠道消化过程中发生氧化反应，产生的丙二醛、4-羟基-2-己烯醛（4-HHE）等氧化产物对机体造成健康危害。本项目研究了迷迭香多酚对模拟胃肠消化（SGD）过程中脂质氧化的抑制作用及机制。（1）研究表明，迷迭香提取物能够有效抑制鱼肝油在模拟消化过程中发生的脂质氧化。当添加浓度为1.0 mg/mL时，迷迭香提取物处理组鱼肝油经模拟胃和模拟肠道消化后丙二醛含量比对照组分别下降了41.28%和42.62%，这可能与其具有较强体外抗氧化活性有关；（2）迷迭香提取物消化产物中总酚含量随模拟胃消化时间的延长而升高，而在模拟肠消化过程中显著降低。经模拟胃消化180 min后，总酚含量显著升高了17.88%，而经模拟肠消化120 min后，总酚含量显著降低了19.64%；（3）经模拟胃消化后，迷迭香提取物对DPPH•、超氧阴离子的清除能力及铁还原能力（FRAP）均显著升高，而经模拟肠消化后，迷迭香提取物抗氧化活性显著降低。经模拟胃消化180 min，消化产物对DPPH•和超氧阴离子的清除能力分别显著提高了20.36%和22.07%，FRAP值显著提高了11.76%。而经模拟肠消化120 min后，消化产物对DPPH•和超氧阴离子的清除能力分别显著降低了74.08%和50.00%，FRAP显著降低了52.13%。此外，迷迭香提取物消化产物的抗氧化活性与其总酚含量之间存在良好的正相关性；（4）迷迭香提取物显著抑制模拟胃消化过程中猪肉制品发生的脂质氧化，其抑制作用随添加浓度的升高而增强。上述抑制作用可能与迷迭香提取物螯合Fe2+、结合血红素及清除自由基等活性有关。本课题研究了迷迭香多酚对模拟胃肠消化中脂质氧化产物生成的抑制作用及机理，将为通过改善膳食结构等方式控制食物消化过程中的脂质氧化及其健康危害方面的研究奠定基础。