金银花叶黄酮体外抗氧化能力及对H_2O_2诱导RAW264.7巨噬细胞损伤的保护作用

目的:研究金银花叶黄酮的体外抗氧化能力和对H2O2诱导RAW264.7巨噬细胞损伤的保护作用。方法:金银花叶粉经提取纯化后得到金银花叶黄酮粉,以抗坏血酸为阳性对照,测定金银花叶黄酮的总还原力,对羟自由基、超氧阴离子自由基及1,1-二苯基-2-三硝基苯肼自由基的清除能力。体外培养RAW264.7巨噬细胞,实验分为空白组、模型组、对照组和金银花叶黄酮低、中、高剂量组,用H2O2诱导损伤RAW264.7细胞,噻唑蓝法测定细胞存活率,试剂盒法测定细胞和细胞培养液中丙二醛、谷胱甘肽含量及超氧化物歧化酶、乳酸脱氢酶活力。结果:金银花叶黄酮的总还原力及对各自由基的清除能力较强,并在足够质量浓度下等同于对照品抗坏血酸。金银花叶黄酮呈剂量依赖性保护H2O2引起的RAW264.7细胞的损伤,降低细胞及细胞培养液中丙二醛含量,提高超氧化物歧化酶活力及谷胱甘肽含量,提高细胞内乳酸脱氢酶活力。结论:金银花叶黄酮抗氧化能力较强,可修复H2O2诱导的RAW264.7巨噬细胞的损伤,其作用可能与调节细胞氧化还原系统、清除自由基、提高细胞内抗氧化酶系的活力有关。

Antioxidant Activity in Vitro and Protective Effect of Flavonoids from Lonicera japonica Thunb. Leaves on H2O2-Induced Toxicity in RAW264.7 Cells

Objective: To evaluate the in vitro antioxidant capacity of flavonoids from Lonicera japonica Thunb. leaves and their protective effect against oxidative damage induced by H2O2 in RAW264.7 cells. Methods: Flavonoids from Lonicera japonica Thunb. leave powder were obtained by extraction and purification. Total reducing power and scavenging capacity against hydroxyl (·OH), superoxide anion (O2-·) and DPPH free radicals were determined by using ascorbic acid as a positive control. RAW264.7 cells were cultured in vitro, and the experiment was divided into blank, model, control, and low-, medium- and high-dose flavonoid groups. RAW264.7 cells were injured by H2O2. The cell viability was measured by the methyl thiazolyl tetrazolium (MTT) assay, and the contents of malondialdehyde (MDA) and glutathione (GSH) and the activities of superoxide dismutase (SOD) and lactate dehydrogenase (LDH) in cells and culture supernatant were determined using commercial kits. Results: The flavonoids at sufficient concentrations had strong total reducing power and free radical scavenging ability equivalent to that of ascorbic acid. The flavonoids from Lonicera japonica Thunb. leaves could protect against H2O2-induced toxicity in RAW 264.7 cells in a dose-dependent manner, reduce MDA content in cells and culture supernatant, improve SOD activity and GSH content and increase intracellular lactate dehydrogenase activity. Conclusion: The flavonoids from Lonicera japonica Thunb. leaves has a strong antioxidant capacity, and can repair H2O2-induced toxicity in RAW264.7 cells likely by regulating cell redox system, scavenging free radicals and enhancing the activity of intracellular antioxidant enzymes.