Peng Shi-Ya, Lu Naihao, Tian Rong
College of Chemistry and Materials, Key Laboratory of Green Catalysis of Jiangxi Education Institutes, Jiangxi Normal University, Nanchang, China.
College of Chemistry and Materials, Key Laboratory of Green Catalysis of Jiangxi Education Institutes, Jiangxi Normal University, Nanchang, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Sep 5;337:126096. doi: 10.1016/j.saa.2025.126096. Epub 2025 Mar 22.
Myoglobin (Mb) is an efficient inducer for lipid oxidation in muscle foods and protein-polyphenol binding is a well-known phenomenon. The effects of the interaction between quercetin (one of the most common flavonoids in natural plants and human diet) and Mb on lipid oxidation were scarcely elucidated. In this study, the interactions between quercetin and Mb were systematically investigated by multi-spectroscopic techniques (fluorescence, UV-vis absorption, circular dichroism (CD) spectra) and molecular docking, to demonstrate the structural mechanisms whereby bioactive quercetin influenced Mb redox state and stability. Quercetin bound into Mb central pocket to generate Mb-quercetin complex with one binding site, and binding process was spontaneous where hydrophobic interaction played a major role. Heme stability and free hemin (but not inorganic iron) liberated from Mb was vital to Mb oxidation and Mb-mediated lipid oxidation, and quercetin significantly inhibited Mb-mediated lipid oxidation in liposomes or muscles. The inhibitory mechanisms of quercetin were possibly attributable to that the binding of quercetin promoted the compactness of Mb and narrowed the crevice surrounding heme group, which resulted in the reduction of met-Mb to oxy-Mb state and suppression of free hemin loss. In agreement with its weaker properties to bind Mb and scavenge free radicals, rutin (a natural quercetin derivative) did not affect the redox state and stability of Mb, and then, it lesser attenuated Mb-induced lipid oxidation than quercetin. Collectively, our results about the interaction of quercetin with Mb suggest a new mechanism for the antioxidant capability of natural flavonoids and are beneficial to the nutritional application of quercetin in the freshness and good quality of hemeprotein-containing foods.
肌红蛋白（Mb）是肌肉食品中脂质氧化的有效诱导剂，蛋白质 - 多酚结合是一种众所周知的现象。槲皮素（天然植物和人类饮食中最常见的黄酮类化合物之一）与Mb之间的相互作用对脂质氧化的影响鲜有阐明。在本研究中，通过多光谱技术（荧光、紫外 - 可见吸收、圆二色（CD）光谱）和分子对接系统地研究了槲皮素与Mb之间的相互作用，以阐明生物活性槲皮素影响Mb氧化还原状态和稳定性的结构机制。槲皮素结合到Mb中心口袋中形成具有一个结合位点的Mb - 槲皮素复合物，结合过程是自发的，其中疏水相互作用起主要作用。从Mb释放的血红素稳定性和游离血红素（而非无机铁）对Mb氧化和Mb介导的脂质氧化至关重要，并且槲皮素显著抑制脂质体或肌肉中Mb介导的脂质氧化。槲皮素的抑制机制可能归因于槲皮素的结合促进了Mb的紧凑性并缩小了血红素基团周围的缝隙，这导致高铁肌红蛋白还原为氧合肌红蛋白状态并抑制了游离血红素的损失。与其结合Mb和清除自由基的能力较弱一致，芦丁（一种天然槲皮素衍生物）不影响Mb的氧化还原状态和稳定性，因此，它对Mb诱导的脂质氧化的减弱作用小于槲皮素。总体而言，我们关于槲皮素与Mb相互作用的结果揭示了天然黄酮类化合物抗氧化能力的新机制，并且有利于槲皮素在含血红素蛋白食品的新鲜度和品质方面的营养应用。
