Nie Guangjun, Jin Chaofang, Cao Yuanlin, Shen Shengrong, Zhao Baolu
Laboratory of Visual Information Processing, Department of Molecular and Cell Biophysics, Institute of Biophysics, Academia Sinica, Beijing 100101, China.
Arch Biochem Biophys. 2002 Jan 1;397(1):84-90. doi: 10.1006/abbi.2001.2636.
Green tea polyphenols have aroused considerable attention in recent years for preventing oxidative stress related diseases including cancer, cardiovascular disease, and degenerative disease. Neurodegenerative diseases are cellular redox status dysfunction related diseases. The present study investigated the different effects of the five main components of green tea polyphenols on 6-hydroxydopamine (6-OHDA)-induced apoptosis in PC12 cells, the in vitro model of Parkinson's disease (PD). When the cells were treated with five catechins respectively for 30 min before exposure to 6-OHDA, (-)-epigallocatechins gallate (EGCG) and (-)-epicatechin gallate (ECG) in 50-200 microM had obvious concentration-dependent protective effects on cell viability, while (-)-epicatechin (EC), (+)-catechin ((+)-C), and (-)-epigallocatechin (EGC) had almost no protective effects. The five catechins also showed the same pattern described above of the different effects against 6-OHDA-induced cell apoptotic characteristics as analyzed by cell viability, fluorescence microscopy, flow cytometry, and DNA fragment electrophoresis methods. The present results indicated that 200 microM EGCG or ECG led to significant inhibition against typical apoptotic characteristics of PC12 cells, while other catechins had little protective effect against 6-OHDA-induced cell death. Therefore, the classified protective effects of the five catechins were in the order ECG> or = EGCG>>EC> or = (+)-C>>EGC. The antiapoptotic activities appear to be structurally related to the 3-gallate group of green tea polyphenols. The present data indicate that EGCG and ECG might be potent neuroprotective agents for PD.
近年来，绿茶多酚因预防包括癌症、心血管疾病和退行性疾病在内的氧化应激相关疾病而备受关注。神经退行性疾病是与细胞氧化还原状态功能障碍相关的疾病。本研究调查了绿茶多酚的五种主要成分对6-羟基多巴胺（6-OHDA）诱导的PC12细胞凋亡的不同影响，PC12细胞是帕金森病（PD）的体外模型。当细胞在暴露于6-OHDA之前分别用五种儿茶素处理30分钟时，50-200微摩尔的（-）-表没食子儿茶素没食子酸酯（EGCG）和（-）-表儿茶素没食子酸酯（ECG）对细胞活力具有明显的浓度依赖性保护作用，而（-）-表儿茶素（EC）、（+）-儿茶素（（+）-C）和（-）-表没食子儿茶素（EGC）几乎没有保护作用。通过细胞活力、荧光显微镜、流式细胞术和DNA片段电泳方法分析，这五种儿茶素对6-OHDA诱导的细胞凋亡特征的不同影响也呈现上述相同模式。目前的结果表明，200微摩尔的EGCG或ECG可显著抑制PC12细胞的典型凋亡特征，而其他儿茶素对6-OHDA诱导的细胞死亡几乎没有保护作用。因此，这五种儿茶素的分类保护作用顺序为ECG≥EGCG>>EC≥（+）-C>>EGC。抗凋亡活性似乎在结构上与绿茶多酚的3-没食子酸基团有关。目前的数据表明，EGCG和ECG可能是治疗PD的有效神经保护剂。
