Polyphenol contents of Pu-Erh teas and their abilities to inhibit cholesterol biosynthesis in Hep G2 cell line

Thirty samples of Pu-Erh tea (a microbial fermented Chinese tea) were collected and assayed for cholesterol synthesis inhibitory activity and polyphenol composition. All samples were able to inhibit the cholesterol biosynthesis in Hep G2 cell model and the inhibition ratios ranged from 7% to 35%. The inhibition abilities of tea polyphenol standards were in the order of gallocatechin gallate (GCG) > epigallocatechin gallate (EGCG) > epicatechin gallate (ECG) > gallic acid > epigallocatechin (EGC) > myricetin > quercetin > catechin (C) > epicatechin (EC). It appears that catechins with a galloyl structure on the B ring or a gallic acid moiety in the structure would have better inhibitory activity. In summary, tea polyphenol may play a role on the cholesterol biosynthesis inhibitory ability of Pu-Erh tea.