School of Biotechnology and Biological Sciences, West Bengal University of Technology, Kolkata, India.
J Environ Pathol Toxicol Oncol. 2012;31(2):155-66. doi: 10.1615/jenvironpatholtoxicoloncol.v31.i2.70.
Myriad research has contributed significantly toward the understanding and identification of health benefits stemming from tea polyphenols and many other naturally occurring flavonoids present in fruits and vegetables. These flavonoids are known to mitigate reactive oxygen species-induced damage by scavenging them. In this study, hot-water black tea extract rich in flavonoids is evaluated as a supplementary antioxidant. The antioxidant efficacy of black tea extract was investigated by evaluating radioprotection conferred to pBR322 DNA, calf thymus DNA, and normal lymphocytes during gamma irradiation. The protection was measured by gel electrophoresis, fluorimetric study, cell viability assay, cytokinesis-blocked micronuclei assay, and comet assay. The 2,2-diphenyl-1-picrylhydrazyl scavenging ability of the tea extract used increased in a dose-dependent manner (IC50: 182.45 µg/mL). Positive correlation of radioprotection with antioxidant activity of black tea extract was observed in all systems. Maximum protection against radiation-induced damage was observed in pBR322 DNA and calf thymus DNA at ≥200 µg/mL of black tea extract. At a dose of black tea extract as low as 5 µg/mL, efficient radioprotection was observed in normal lymphocytes, which is encouraging and can be tested in the future as a natural antioxidant supplement during radiotherapy.
众多研究极大地促进了对茶多酚和水果和蔬菜中其他许多天然类黄酮的健康益处的理解和识别。这些类黄酮通过清除它们来减轻活性氧诱导的损伤。在这项研究中，富含类黄酮的热水红茶提取物被评估为一种补充抗氧化剂。通过评估 pBR322 DNA、小牛胸腺 DNA 和正常淋巴细胞在伽马辐射下的辐射防护作用来研究红茶提取物的抗氧化功效。通过凝胶电泳、荧光研究、细胞活力测定、胞质分裂阻断微核试验和彗星试验来测量保护作用。所使用的茶提取物的 2,2-二苯基-1-苦基肼清除能力呈剂量依赖性增加（IC50：182.45 µg/mL）。在所有系统中都观察到红茶提取物的抗氧化活性与辐射防护之间存在正相关。在 pBR322 DNA 和小牛胸腺 DNA 中，在≥200 µg/mL 的红茶提取物下观察到对辐射诱导损伤的最大保护。在红茶提取物的剂量低至 5 µg/mL 时，在正常淋巴细胞中观察到有效的辐射防护作用，这令人鼓舞，可以在未来作为放射治疗期间的天然抗氧化补充剂进行测试。
