Chinese Name: Pu'er, pu'erh
Origin: To make pu'er tea, fresh tea leaves are dried and then undergo microbial fermentation during processing. Various forms exist from compressed or `brick' teas to rolled loose-leaf. Young pu'ers up to 10 years old often retain an astringent green tea flavour. Older pu'ers take on a rich and complex panoply of flavours, and it is the rare, old pu'ers (30 years plus) which are sought after by health-conscious Chinese tea connoisseurs.
Taste: Poor grades bitter and somewhat earthy, top grades smooth and sweet. Yunnan Pu'er and Anhui Liu An are the most outstanding.
Evid Based Complement Alternat Med. 2005 Jun;2(2):209-215.
Inhibition of SARS-CoV 3C-like Protease Activity by Theaflavin-3,3'-digallate (TF3)
Chen CN, Lin CP, Huang KK, Chen WC, Hsieh HP, Liang PH, Hsu JT.
SARS-CoV is the causative agent of severe acute respiratory syndrome (SARS). The virally encoded 3C-like protease (3CL(Pro)) has been presumed critical for the viral replication of SARS-CoV in infected host cells. In this study, we screened a natural product library consisting of 720 compounds for inhibitory activity against 3CL(Pro). Two compounds in the library were found to be inhibitive: tannic acid (IC(50) = 3 microM) and 3-isotheaflavin-3-gallate (TF2B) (IC(50) = 7 microM). These two compounds belong to a group of natural polyphenols found in tea. We further investigated the 3CL(Pro)-inhibitory activity of extracts from several different types of teas, including green tea, oolong tea, Puer tea and black tea. Our results indicated that extracts from Puer and black tea were more potent than that from green or oolong teas in their inhibitory activities against 3CL(Pro). Several other known compositions in teas were also evaluated for their activities in inhibiting 3CL(Pro). We found that caffeine, (-)-epigallocatechin gallte (EGCg), epicatechin (EC), theophylline (TP), catechin (C), epicatechin gallate (ECg) and epigallocatechin (EGC) did not inhibit 3CL(Pro) activity. Only theaflavin-3,3'-digallate (TF3) was found to be a 3CL(Pro) inhibitor. This study has resulted in the identification of new compounds that are effective 3CL(Pro) inhibitors.