Wang Liying, Ding Long, Yu Zhipeng, Zhang Ting, Ma Shuang, Liu Jingbo
Laboratory of Nutrition and Functional Food, Jilin University, Changchun 130062, People's Republic of China.
College of Food Science and Engineering, Bohai University, Jinzhou 121013, People's Republic of China.
Food Res Int. 2016 Dec;90:33-41. doi: 10.1016/j.foodres.2016.10.023. Epub 2016 Oct 15.
The objective of this study was to investigate the intracellular reactive oxygen species (ROS) scavenging activities and antioxidant enzyme regulating capacities of corn gluten peptide fractions (CPFs) in HepG2 cells. A cellular antioxidant activity (CAA) assay was used to assess their antioxidant activities and revealed that both CPF1 (molecular weight <1kDa) and CPF2 (molecular weight between 1 and 3kDa) exhibited high cellular antioxidant activities with EC values of 2.85±0.19mg/mL and 5.05±0.32mg/mL, respectively. Both CPFs also exhibited cytoprotective effects and intracellular ROS scavenging activities in HepG2 cells subjected to oxidative stress by oxidation with HO. In addition, at concentrations of 2.50mg/mL, the CPFs increased the activity levels of superoxide dismutase (SOD), catalase (CAT), and glutathione reductase (GR), as well as the total glutathione (GSH) levels in oxidized HepG2 cells (from 86.54% to 114.14% (CPF1) or 109.72% (CPF2) for SOD activity; from 71.91% to 107.64% (CPF1) or 106.50% (CPF2) for CAT activity; from 70.52% to 103.01% (CPF1) or 104.10% (CPF2) for GR activity; and from 81.39% to 114.00% (CPF1) or 108.82% (CPF2) for total GSH levels). These results suggested that both CPF1 and CPF2 exhibited positive effects on the activities of the intracellular antioxidant enzymes SOD, CAT and GR, as well as on the total GSH levels in HepG2 cells under conditions of oxidative stress. Furthermore, size exclusion gel chromatography and MALDI-TOF/TOF mass spectrometry revealed that the molecular weights of the antioxidant peptides in CPF1 were between 500Da to 900Da, and a novel antioxidant peptide consisting of GLLLPH (Gly-Leu-Leu-Leu-Pro-His) was identified in CPF1.
本研究的目的是探讨玉米醇溶蛋白肽组分（CPFs）在HepG2细胞中的细胞内活性氧（ROS）清除活性和抗氧化酶调节能力。采用细胞抗氧化活性（CAA）测定法评估其抗氧化活性，结果显示CPF1（分子量<1kDa）和CPF2（分子量在1至3kDa之间）均表现出较高的细胞抗氧化活性，其EC值分别为2.85±0.19mg/mL和5.05±0.32mg/mL。两种CPFs在经HO氧化遭受氧化应激的HepG2细胞中也表现出细胞保护作用和细胞内ROS清除活性。此外，在浓度为2.50mg/mL时，CPFs提高了氧化型HepG2细胞中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和谷胱甘肽还原酶（GR）的活性水平，以及总谷胱甘肽（GSH）水平（SOD活性从86.54%提高到114.14%（CPF1）或109.72%（CPF2）；CAT活性从71.91%提高到107.64%（CPF1）或106.50%（CPF2）；GR活性从70.52%提高到103.01%（CPF1）或104.10%（CPF2）；总GSH水平从81.39%提高到114.00%（CPF1）或108.82%（CPF2））。这些结果表明，在氧化应激条件下，CPF1和CPF2对HepG2细胞内抗氧化酶SOD、CAT和GR的活性以及总GSH水平均具有积极影响。此外，尺寸排阻凝胶色谱和基质辅助激光解吸电离飞行时间/串联飞行时间质谱分析表明，CPF1中抗氧化肽的分子量在500Da至900Da之间，并且在CPF1中鉴定出一种由GLLLPH（甘氨酸-亮氨酸-亮氨酸-亮氨酸-脯氨酸-组氨酸）组成的新型抗氧化肽。
