Novel Theaflavin-Type Chlorogenic Acid Derivatives Identified in Black Tea

Abstract

Consumption of black tea contributed to many health benefits including the prevention of heart disease and certain types of cancer. However, the chemical composition of black tea has not been fully explored. Most studies have examined different interactions between the four major tea catechins, and limited studies have investigated the interaction between catechins and other components in tea. In the present study, we tested our hypothesis that the ortho-dihydroxyl structure of chlorogenic acid (CGA) could react with the vic-trihydroxy structure of (-)-epigallocatechin 3-gallate (EGCG) and (-)-epigallocatechin (EGC) to generate theaflavin-type of compounds during black tea fermentation. The reaction between CGA and EGCG or EGC was catalyzed by horseradish peroxidase (POD) in the presence of HO. Two theaflavin-type compounds EGCG-CGA and EGC-CGA were purified using a Sephadex LH-20 column. Their structures were elucidated on the basis of the analysis of their MS and 1D- and 2D-NMR spectroscopic data. Furthermore, the existence of these two novel compounds was characterized by LC/MS/MS analysis. We also found that EGCG-CGA and EGC-CGA had very similar inhibitory effects on the growth of human colon cancer cells with that of theaflavin 3,3'-digallate. These findings shed light on the interactions between the major bioactive compounds, catechins, and other minor compounds in tea. The confirmation of the presence of this type of reaction in black tea may provide more understanding of the complexity of black tea chemistry.

Tea polyphenols as a strategy to control starch digestion in bread: the effects of polyphenol type and gluten

“…6 Theaflavins have benzotropolone structures and therefore give a red colour to a black tea infusion and thearubigins are polymeric polyphenols. 7 Previously, the inhibitory effect of tea polyphenols on digestive enzymes has been characterized by determination of the half inhibition concentration (IC 50 ), kinetics of inhibition, and fluorescence quenching to further explain the inhibition type and mechanism. 8 Most studies tested the inhibition in a simple reaction system (a simple mixture of a digestive enzyme and a substrate), ignoring the influence of the interactions among polyphenols, digestive enzymes, starch and other food components on starch digestibility.…”

Neuroprotective and Anti-Amyloid β Effect and Main Chemical Profiles of White Tea: Comparison Against Green, Oolong and Black Tea

“…ECG‘’3Me and 8- C -ascorbyl-EGCG are two catechin derivatives that have similar structures with their catechin precursors, and were shown to have the highest levels in WT (Figure 7 and Figure S2). Catechin derivatives with new structures and activities have been occasionally reported from diverse tea cultivars or tea types [31,32]. Interestingly, in a recent study, two N -ethyl-2-pyrrolidinone-substituted catechin derivatives were found in aged white teas for the first time [33].…”

Untargeted mass spectrometry-based metabolomics approach unveils molecular changes in raw and processed foods and beverages

“…As expected, caffeine was also annotated in tea samples. Theaflavin, a polyphenol formed during fungal oxidation and its analogues, often associated with black tea (Zhang et al, 2018), were detected in white, green, black and oolong tea samples. Theaflavin increased in relative concentration over time, as shown in Fig.…”