New Phenolic Components and Chromatographic Profiles of Green and Fermented Teas

Abstract

A standardized profiling method based on liquid chromatography with diode array and electrospray ionization mass spectrometric detection (LC–DAD–ESI/MS) was applied to establish the phenolic profiles of 41 green teas and 25 fermented teas. More than 96 phenolic compounds were identified that allowed the teas to be organized into five groups. Epigallocatechin gallate (EGCG) was the major phenolic component of green tea made from mature leaves (group 2), while green tea made from the younger buds and leaves (group 1) contained lower flavonoid concentrations. Partially fermented teas (group 3) contained one-half the EGCG content of the green tea. Fully fermented black teas (group 4) had a trace of EGCG, but contained theaflavins. Highly overfermented black tea (group 5) contained only trace amounts of flavonol glycosides and theaflavins. Over 30 phenolics are new for tea, and this is the first phenolic profile to simultaneously detect C- and O-glycosylated flavonoids, catechins, proanthocyanidins, phenolic acid derivatives, and purine alkaloids.

Preparation of catechin extracts and nanoemulsions from green tea leaf waste and their inhibition effect on prostate cancer cell PC-3

“…A method based on Lin et al, 19 Vuong et al, 20 and Lin et al 21 was modified. A 0.2 g tea leaf waste powder sample was mixed with 4 mL of 30%, 50%, or 70% ethanol solution, after which each mixture was sonicated at room temperature for 1 hour.…”

Simultaneous determination of eight catechins and four theaflavins in green, black and oolong tea using new HPLC–MS–MS method

“…In addition, considering the contribution of catechin and theaflavin to the quality of tea, a reliable quantitative analysis of these compounds is needed for manufacturers of dietary supplements and the quality control authorities. A variety of analytical methods have been used for the analysis of these phenolic compounds in teas: high-performance liquid chromatography [12][13][14][15][16][17][18] liquid chromatography-mass spectrometry [19][20][21] and liquid chromatography tandem mass spectrometry (LC-MS/MS) [22,23]). HPLC is the most widely used technique [12][13][14][15][16][17][18].…”

Secondary Metabolites

“…The hydrolyzable tannin epigallocatechin gallate was the major phenolic component of green tea and partially fermented teas, while fully fermented black teas had traces of epigallocatechin gallate but contained theaflavins. Glycosylated flavonoids, catechins, proanthocyanidins (condensed tannins) and phenolic acid derivatives were found too (Lin et al, 2008). Aqueous acetonic extract of green tea (C. crassicolumna) further partitioned with ethyl acetate and purified by CC led to the identification of various fractions obtained by CC over Sephadex LH-20 eluted with ethanol.…”