Polyphenol Composition of a Functional Fermented Tea Obtained by Tea-Rolling Processing of Green Tea and Loquat Leaves

Abstract

Phenolic constituents of a new functional fermented tea produced by tea-rolling processing of a mixture (9:1) of tea leaves and loquat leaves were examined in detail. The similarity of the phenolic composition to that of black tea was indicated by high-performance liquid chromatography comparison with other tea products. Twenty-five compounds, including three new catechin oxidation products, were isolated, and the structures of the new compounds were determined to be (2R)-2-hydroxy-3-(2,4,6-trihydroxyphenyl)-1-(3,4,5-trihydroxyphenyl)-1-propanone 2-O-gallate, dehydrotheasinensin H, and acetonyl theacitrin A by spectroscopic methods. In addition, theacitrinin A and theasinensin H were obtained for the first time from commercial tea products. Isolation of these new and known compounds confirms that reactions previously demonstrated by in vitro model experiments actually occur when fresh tea leaves are mechanically distorted and bruised during the production process.

Catechins: Therapeutic Perspectives in COVID-19-Associated Acute Kidney Injury

“…Catechins are natural polyphenolic compounds, belonging to the flavanols group of flavonoids, found in a wide variety of fruits, vegetables and plant-based food and beverages, such as fresh tea leaves, red wines, black grapes, cocoa beans, apricots and others [ 31 , 34 ]. Green tea extract is a recognized rich dietary source of catechins, containing a substantial amount of catechin, (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG).…”

“…Catechins are natural polyphenolic compounds found in a wide variety of fruits, vegetables and plant-based food and beverages. Green tea extract is a recognized rich dietary source of catechins, containing a substantial amount of catechin, (-)-epicatechin (EC), (-)-epicatechin-3-gallate (ECG), (-)-epigallocatechin (EGC) and (-)-epigallocatechin-3-gallate (EGCG) [ 30 , 31 ]. A broad range of pharmacological activities have been reported for catechins, including antiviral and nephroprotective activities, which are strongly associated with their anti-inflammatory and antioxidant properties [ 32 , 33 , 34 , 35 , 36 , 37 ].…”

Production Mechanisms of Black Tea Polyphenols

“…Surprisingly, in 1957, Roberts had already presumed that theasinensin-type oxidation products might be formed by oxidation-reduction disproportionation of dimer quinones. 57,58) Hashimoto et al synthesized galloyl oolongtheanin (17) by oxidation of 2 with K 3 Fe(CN) 6 , 17) and recently a detailed production mechanism of 17 was proposed by Hirose et al 59) Theacitrins A (10) and C (11) are yellow pigments of black tea that were first reported in 1997 by Davis et al 18) Theacitrin C (11) is obtained as a minor product of enzymatic oxidation of 2 together with 16. 19) The stereochemistry was determined in 2016 by Matsuo et al by density functional theory (DFT) calculations of NMR chemical shifts of 11 and time-dependent DFT calculations of the electronic circular dichroism spectra of theacitrinin A (19), which is a degradation product of 11 20) (Chart 3).…”

Evaluating the Reduced Hydrophobic Taste Sensor Response of Dipeptides by Theasinensin A by Using NMR and Quantum Mechanical Analyses

“…Briefly, a solution of EGCG incubated with CuCl 2 and ascorbic acid was applied to a Diaion HP20 column (Mitsubishi Chemical Co., Tokyo, Japan), followed by a stepwise elution with methanol to obtain TSA [ 24 ]. TSB was obtained from a fermented green tea product [ 25 ]. An internal standard (IS), 3-trimethylsilyl-1-propanesulfonic acid- d 6 (DSS- d 6 , 98.0 atom% D) was obtained from Santa Cruz Biotechnology Inc. (Santa Cruz, TX, USA).…”