玉簪多糖对细胞氧化应激损伤的保护作用机制

Protective Mechanism of Polysaccharide from Hosta ventricosa against Oxidative Damage in Cells

本实验以紫萼玉簪(Hosta ventricosa)为原材料,采用响应面法优化其根系多糖(Hosta ventricosa root polysaccharide,HVRP)的提取工艺,探索HVRP对叔丁基过氧化氢(tert-butyl hydroperoxide,t-BHP)诱导的HepG2细胞氧化应激损伤的保护作用机制。结果表明:在提取温度84℃、提取时间3 h、料液比1∶31条件下,HVRP平均提取率达到23.9%;HVRP中还原性糖、蛋白质、糖醛酸的质量分数分别为11.17%、0.6%、12.31%,含有多糖类物质的特征吸收峰,不存在三螺旋构象。体外抗氧化和细胞实验结果表明,HVRP具有较强的抗氧化活性,能显著或极显著降低t-BHP诱导氧化损伤HepG2细胞内活性氧、丙二醛含量并提高过氧化氢酶、超氧化物歧化酶、还原型谷胱甘肽及谷胱甘肽过氧化物酶水平(P<0.05、P<0.01)。通过实时荧光定量聚合酶链式反应和蛋白质免疫印迹分析发现,HVRP可通过调控Kelch样环氧氯丙烷相关蛋白1/核因子E2相关因子2/抗氧化反应元件信号通路促进抗氧化酶表达,从而改善t-BHP诱导的HepG2细胞氧化损伤。本研究可为阐明HVRP抗氧化作用机制及其在功能性食品中的应用提供理论依据。

In this study,the extraction process of Hosta ventricosa root polysaccharide(HVRP)was optimized by response surface methodology(RSM),and the protective effect of HVRP on oxidative injury induced by tert-butyl hydroperoxide(t-BHP)in HepG2 cells was explored.Under the optimized conditions:extraction temperature 84℃,extraction time 3 h and solid-to-liquid ratio 1:31,the average extraction yield of HVRP was 23.9%,The mass fractions of reducing sugar,protein and uronic acid in HVRP were 11.17%,0.6%and 12.31%,and HVRP showed absorption peaks characteristic of polysaccharides but no triple-helical conformation.HVRP had strong in vitro antioxidant activity and could significantly reduce the contents of reactive oxygen species(ROS)and malondialdehyde(MDA)and increase the activity of catalase(CAT),superoxide dismutase(SOD),reduced glutathione(GSH)and glutathione peroxidase(GPx)(P<0.05,P<0.01).The results of real-time quantitative polymerase chain reaction(qPCR)and Western blot analysis showed that HVRP could promotes the expression of antioxidant enzymes and consequently protect HepG2 cells from t-BHP-induced oxidation damage by regulating the Kelch-like epichlorohydrin-associated protein 1/nuclear factor erythroid 2-related factor 2/antioxidant response element(Keap1/Nrf2/ARE)signaling pathway.This study provides a theoretical basis for clarifying the antioxidant mechanism of HVRP and its application in functional foods.