Departamento de Metabolismo y Nutrición Instituto del Frío-ICTAN (CSIC), José Antonio Novais, 10 28040 Madrid, Spain.
Phytother Res. 2010 Apr;24(4):503-9. doi: 10.1002/ptr.2961.
Flavanols, such as epicatechin (EC), constitute an important part of the human diet; they can be found in green tea, grapes and cocoa and possess different biological activities such as antioxidant, anti-inflammatory and anticarcinogenic. This study investigated the potential chemo-protective effect of EC against oxidative stress induced by tert-butylhydroperoxide (t-BOOH) on human HepG2 cells. Cell viability by lactate dehydrogenase assay and markers of oxidative status: reduced glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS), glutathione peroxidase (GPx) and glutathione reductase (GR) were evaluated. Pretreatment of cells with EC for 20 h prevented the enhanced cell damage and GPx and GR activities as well as the decrease in GSH induced by t-BOOH. The increased ROS generation induced by t-BOOH was also partly prevented by a pretreatment for 20 h with EC. In addition, pretreatment of cells with EC for 20 h recovered the t-BOOH-induced MDA concentration to control values. A pretreatment for 2 h with EC did not reduce cell damage but partly recovered GSH, reduced ROS levels and muffled the increase of GPx and GR after exposure to t-BOOH. Treatment of HepG2 cells with concentrations of EC in the micromolar range confers a significant protection against oxidative stress.
黄烷醇，如表儿茶素（EC），是人类饮食的重要组成部分；它们存在于绿茶、葡萄和可可中，具有不同的生物活性，如抗氧化、抗炎和抗癌。本研究探讨了 EC 对叔丁基过氧化物（t-BOOH）诱导的人 HepG2 细胞氧化应激的潜在化学保护作用。通过乳酸脱氢酶测定法评估细胞活力和氧化状态标志物：还原型谷胱甘肽（GSH）、丙二醛（MDA）、活性氧（ROS）、谷胱甘肽过氧化物酶（GPx）和谷胱甘肽还原酶（GR）。用 EC 预处理细胞 20 h 可防止 t-BOOH 增强的细胞损伤和 GPx 和 GR 活性以及 GSH 的减少。用 EC 预处理 20 h 还部分防止了 t-BOOH 诱导的 ROS 生成增加。此外，EC 预处理 20 h 可将 t-BOOH 诱导的 MDA 浓度恢复至对照值。用 EC 预处理 2 h 不会减少细胞损伤，但可部分恢复 GSH，降低 ROS 水平，并减轻 t-BOOH 暴露后 GPx 和 GR 的增加。用 EC 在微摩尔范围内处理 HepG2 细胞可显著对抗氧化应激。
