College of Pharmacy and Integrated Research Institute of Pharmaceutical Sciences, The Catholic University of Korea, Bucheon, 14662, Republic of Korea.
College of Pharmacy, Dongduk Women's University, Seoul, 02748, Republic of Korea.
Phytochemistry. 2019 Apr;160:11-18. doi: 10.1016/j.phytochem.2018.12.013. Epub 2019 Jan 17.
Thirty-three phenolic compounds were identified from the extract of fermented tea (Camellia sinensis L.), including three undescribed flavonoids, namely quamoreokchaside I-II and kamoreokchaside I, along with thirty known compounds. All isolates were tested to evaluate their inhibitory effects against amyloid-beta (Aβ) aggregation through thioflavin-T (ThT) fluorescence-based assay and transmission electron microscopy (TEM). Among the isolates, three tea polyphenols, including (-)-catechin gallate (CG), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), significantly decreased Aβ aggregation at a concentration of 10 μg ml, compared to the positive control, Aβ alone. The anti-Aβ aggregation effects of CG, ECG, and EGCG were confirmed again via TEM, which were consistent with the ThT fluorescence-based assay. Moreover, CG and ECG provided stronger protection on SH-SY5Y cells against Aβ-induced cytotoxicity than EGCG. Remarkably, CG showed more potent inhibitory activity than EGCG, the best-known anti-Aβ aggregation agent from tea products.
从发酵茶（茶树）提取物中鉴定出 33 种酚类化合物，包括三种未描述的类黄酮，即 quamoreokchaside I-II 和 kamoreokchaside I，以及三十种已知化合物。所有分离物均经过测试，以通过硫代黄素-T（ThT）荧光测定法和透射电子显微镜（TEM）评估它们对淀粉样蛋白-β（Aβ）聚集的抑制作用。在分离物中，三种儿茶素多酚，包括（-）-没食子酸儿茶素（CG）、（-）-表儿茶素没食子酸酯（ECG）和（-）-表没食子儿茶素没食子酸酯（EGCG），在 10μg/ml 的浓度下，与阳性对照物（单独的 Aβ）相比，明显降低了 Aβ 的聚集。CG、ECG 和 EGCG 通过 TEM 再次证实了抗 Aβ 聚集作用，这与 ThT 荧光测定法一致。此外，CG 和 ECG 对 SH-SY5Y 细胞提供了比 EGCG 更强的 Aβ 诱导细胞毒性保护作用。值得注意的是，CG 表现出比 EGCG 更强的抑制活性，而 EGCG 是茶产品中最知名的抗 Aβ 聚集剂。
