National R&D Center for Freshwater Fish Processing, and Engineering Research Center of Freshwater Fish High-value Utilization of Jiangxi Province, College of Life Science , Jiangxi Normal University , Nanchang , Jiangxi 330022 , China.
State Key Laboratory of Food Science and Technology , Nanchang University , Nanchang , Jiangxi 330047 , China.
J Agric Food Chem. 2019 Jan 9;67(1):236-246. doi: 10.1021/acs.jafc.8b06075. Epub 2018 Dec 31.
Quercetin has been reported to suppress protein glycation or the formation of advanced glycation end-products (AGEs), but the inhibition mechanism related to protein structure and glycation sites and the influence on physicochemical properties remain unclear. The aim of the current research was to investigate the mechanism of quercetin against glycation with BSA-fructose as model by spectroscopic and spectrometric techniques. Changes in physicochemical properties were evaluated by antioxidant activity and emulsifying properties. The results indicated that quercetin dose-dependently inhibited the glycation of BSA by attenuating the alteration of conformational structure and microenvironment induced by glycation. It could also suppress the cross-linking or aggregation of glycated BSA, which reflected in the decreased molecular weight determined by SDS-PAGE and MALDI-TOF. Nanoliquid chromatography coupled to Q-Exactive tandem mass spectrometry analysis revealed the mapping of 20, 23, 19, and 19 glycation sites in glycated BSA with 0, 0.5, 1.5, and 3.0 mM quercetin, respectively. Quercetin changed the glycation sites of BSA, but it could not reduce the number greatly. In addition, quercetin reduced the antioxidant ability and increased the emulsifying properties of BSA, while negligible efficiency was observed on the antioxidant activity and emulsifying activity index of glycated BSA.
槲皮素已被报道可抑制蛋白质糖化或晚期糖基化终产物（AGEs）的形成，但与蛋白质结构和糖化位点相关的抑制机制以及对理化性质的影响仍不清楚。本研究旨在通过光谱和光谱技术研究以 BSA-果糖为模型的槲皮素对糖化的抑制机制。通过抗氧化活性和乳化性能评估理化性质的变化。结果表明，槲皮素通过减弱糖化引起的构象结构和微环境的改变，剂量依赖性地抑制 BSA 的糖化。它还可以抑制糖化 BSA 的交联或聚集，这反映在 SDS-PAGE 和 MALDI-TOF 测定的分子量降低。纳米液相色谱与 Q-Exactive 串联质谱联用分析表明，分别用 0、0.5、1.5 和 3.0 mM 槲皮素处理后，糖化 BSA 中有 20、23、19 和 19 个糖化位点被定位。槲皮素改变了 BSA 的糖化位点，但不能大大减少糖化位点的数量。此外，槲皮素降低了 BSA 的抗氧化能力并增加了 BSA 的乳化性能，而对糖化 BSA 的抗氧化活性和乳化活性指数的影响可以忽略不计。
