白茶乙醇提取物体外抗氧化活性研究

钱波; 廖衫; 刘斯悦; 潘彩琳; 何仲文; 宋家乐

doi:10.13386/j.issn1002-0306.2018.08.008

白茶乙醇提取物体外抗氧化活性研究

In vitro antioxidant capability of white tea ethanol extracts

摘要

摘要: 研究福鼎白茶乙醇提取物的体外抗氧化能力及其对人结肠腺癌Caco-2细胞氧化损伤保护效果。采用化学比色法测定白茶提取物中茶多酚和总黄酮物质含量。利用二苯代苦味酰基自由基(1,1-diphenyl-2-picrylhydrazyl,DPPH)和超氧阴离子(O₂^-)自由基清除率及总还原力来评价白茶乙醇提取物的体外抗氧化能力。此外,建立过氧化氢(H₂O₂,150 μmol/L)诱导的人Caco-2细胞氧化损伤模型来评估白茶乙醇提取物对氧化损伤细胞的保护效果。MTT法测定白茶提物对细胞生存率的影响。细胞内超氧化物歧化酶(superoxide dismutase,SOD)和谷胱甘肽过氧化酶(glutathione peroxidase,GSH-Px)水平按说明书使用试剂盒测定。丙二醛(malondiadehycle,MDA)的含量以硫代巴比妥酸法(thiobarbituric acid reactive substance,TBARS)测定。结果表明,白茶乙醇提取物含较丰富的茶多酚(343.00±27.90 mg没食子酸/g)与黄酮类(24.95±0.56 mg芦丁/g)物质,并具有良好的DPPH自由基(半清除浓度为330.63 μg/mL)、超氧阴离子清除力(半清除浓度为342.90 μg/mL)及较强的总还原力。同时,白茶乙醇提取物可抑制H₂O₂对Caco-2细胞所造成氧化损伤并提高其生存率至85.6%。白茶乙醇提取物还能提高受损细胞内SOD和GSH-Px的活性,并能降低由于氧化应激损伤所导致的细胞损伤标记物MDA水平的升高。综合而言,白茶乙醇提取物具有较强的体外抗氧化能力并对氧化损伤细胞有较好的保护作用。白茶提取物对氧化应激损伤细胞的保护作用可能与其所含有的茶多酚和黄酮类物质有关。

Abstract: To investigate the antioxidant capability and cellular protective effect of Fuding white tea ethanol extracts(WTEE). Total tea polyphenols and flavonoids in WTEE were determinedby chemical colorimetry assay.The antioxidant capability of WTEE was evaluated according to the 1,1-diphenyl-2-picrylhydrazyl(DPPH)scavenging assay,superoxide anion scavenging assay and reducing power assay,respectively. Cellular protective effect of WTEE was investigated using a model of hydrogenperoxide(H₂O₂,150 μmol/L)induced oxidativestress in intestinal epithelial Caco-2 cells.Cell viability was determined by MTT assay. The cellular levels of superoxide dismutase(SOD),and glutathione peroxidase(GSH-Px)were determined by commercial assay kits according the manuscripts.The cellular levels of malondiadehycle(MDA)were determined by thiobarbituric acid reactive substance(TBARS)assay. WTEE were enriched in total tea polyphenols(343.00±27.90 mg gallic acid/g)and flavonoids(24.95±0.56 mg rutin/g). WTEE exhibited a great DPPH(ES₅₀ 330.63 μg/mL)and superoxide anion scavenging activity(EC₅₀ 342.90 μg/mL)and total reducing power. In addition,WTEE was able to increase the cell viability(to 85.6%)in oxidative damaged Caco-2 cells exposed to H₂O₂. The WTEE treatment also increased the cellular levels of SOD and GSH-Px,and reduced the oxidative damaged related MDA generation in H₂O₂ treated Caco-2 cells. Overall,the great in vitro antioxidant capability and cellular protective effect of WTEE was associated with the high levels of total tea polyphenols and flavonoids.