Modulation of cholesterol metabolism by the green tea polyphenol (-)-epigallocatechin gallate in cultured human liver (HepG2) cells
Modulation of cholesterol metabolism by the green tea polyphenol (-)-epigallocatechin gallate in cultured human liver (HepG2) cells
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DOI：
10.1021/jf051736o
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发表时间：
2006-03-08
影响因子：
6.1
通讯作者：
Roach, PD
中科院分区：
文献类型：
--
作者：
Bursill, CA;Roach, PD
流行病学和动物研究发现，绿茶与降低血浆胆固醇有关。本研究旨在进一步阐明绿茶如何调节胆固醇代谢。当HepG2细胞与主要绿茶成分孵育时，儿茶素，表没食子儿茶素没食子酸酯（EGCG）是唯一一种比对照增加LDL受体结合活性（3倍）和蛋白质（2.5倍）的儿茶素。EGCG增加了甾醇调节元件结合蛋白-1 （SREBP-1）向活性形式的转化（+56%），降低了细胞胆固醇浓度（-28%）。在50 μ M时，EGCG显著降低了细胞胆固醇合成，解释了细胞胆固醇的降低。在200 μ M EGCG浓度下，尽管细胞胆固醇较低，但胆固醇合成显著增加，但中等胆固醇显著增加。这表明，在200 μ M时，EGCG增加细胞胆固醇外排。本研究提供了绿茶调节胆固醇代谢的机制，并提示EGCG可能是其活性成分。
Epidemiological and animal studies have found that green tea is associated with lower plasma cholesterol. This study aimed to further elucidate how green tea modulates cholesterol metabolism. When HepG2 cells were incubated with the main green tea constituents, the catechins, epigallocatechin gallate (EGCG) was the only catechin to increase LDL receptor binding activity (3-fold) and protein (2.5-fold) above controls. EGCG increased the conversion of sterol regulatory element binding protein-1 (SREBP-1) to its active form (+56%) and lowered the cellular cholesterol concentration (-28%). At 50 mu M, EGCG significantly lowered cellular cholesterol synthesis, explaining the reduction in cellular cholesterol. At 200 mu M EGCG, cholesterol synthesis was significantly increased even though cellular cholesterol was lower, but there was a significant increase seen in medium cholesterol. This indicates that, at 200 mu M, EGCG increases cellular cholesterol efflux. This study provides mechanisms by which green tea modulates cholesterol metabolism and indicates that EGCG might be its active constituent.