Puerins A and B, Two New 8-C Substituted Flavan-3-ols from Pu-er Tea

Abstract

Pu-er tea is a special treated fermented tea produced from crude green tea, which is prepared from the leaves of Camellia sinensis var. assamica. It is a traditional beverage having been used in China, particularly the southern areas, for a long time. Chemical investigation led to the identification of two new 8-C substituted flavan-3-ols, puerins A (1) and B (2), and two known cinchonain-type phenols, epicatechin-[7,8-bc]-4alpha-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone (3) and cinchonain Ib (4), together with other seven known phenolic compounds, 2,2',6,6'-tetrahydroxydiphenyl (5), (-)-epicatechin-8-C-beta-d-glucopyranoside (6), (-)-epicatechin (EC) (7), (-)-epigallocatechin (EGC) (8), (+/-)-gallocatechin (GC) (9), gallic acid (10), and myricetin (11), in addition to caffeine (12). Their structures were determined by spectroscopic methods. The compounds 1-5, which might be formed in the postfermentative process of Pu-er tea, were isolated from tea and theaceous plants for the first time.

A new catechin oxidation product and polymeric polyphenols of post-fermented tea

“…In contrast, the post-fermented teas are produced by 4 aerobic or anaerobic microbial fermentation of heat-processed green tea leaves (Gong, Watanabe, Yagi, Etoh, Sakata, Ina, & Liu, 1993;Okada, Takahashi, Ohara, Uchimura, & Kozaki, 1996). During the fermentation process, the levels of tea catechins decrease because of decomposition by microbial enzymes and autoxidation; however, only a few catechin metabolites characteristic to post-fermented tea have been reported (Zhou, Zhang, Xu, & Yang, 2005). Thus we have examined the chemical constituents of a commercially available post-fermented tea product.…”

Secondary Metabolites in Fruits, Vegetables, Beverages and Other Plant‐based Dietary Components

“…Pu'er tea is produced by a microbial fermentation of black tea. Some novel compounds have been isolated and it is suggested that they form during the fermentation (Zhou et al 2005). These include two new 8-C substituted flavan-3-ols, puerins A and B, and two known cinchonain-type phenols, epicatechin-[7,8-bc]-4-(4-hydroxyphenyl)-dihydro-2(3H)-pyranone and cinchonain Ib, and 2,2 ,6,6 -tetrahydroxydiphenyl (Figure 7.56).…”

Influence of postharvest processing and storage on the content of phenolic acids and flavonoids in foods

“…Plums [131,178], sorghum [88], potatoes [76,124], mangos [124,179,180], kernels [138], cherries [13, 42,43,181], spinach [124,156,182], kale [183], broccoli [124,145], cabbage [55], asparagus [156], lettuces [124], oranges [124], arugulas [137], tea [184], artichokes [132], coffee [185], honey [133,186], apricots [187], citrus fruits [136], oranges [142], bush butter fruits [188], radishes [156,189], cabbages [156,124], pepper [156], olive oil [85,190], cowpeas [104], cactus pears [191], Kancolla seeds [192], Pinto beans [193], beans [82], soybeans [99], and lentils [82].…”

“…The major flavonol that occurred in Pu-er tea (a treated fermented tea produced from crude green tea prepared from the leaves of Camellia sinensis) is myricetin [184].…”