The ellagitannin composition and the total content of ellagitannins in different types of tea were studied by high-performance liquid chromatography/ion-trap mass spectrometry. Strictinin and seven other isomers, tellimagrandin I, and ellagic acid were identified from tea infusions. The ellagitannin content in tea infusions was determined after acid hydrolysis and ranged from 0.15 to 4.46 mg of ellagic acid equivalent/g of tea in the infusions. The intake of ellagic acid after drinking a cup of tea brewed with 4 g of tea could range between 0.59 and 17.89 mg. These results indicate that tea can be a significant contributor to the dietary intake of ellagitannins. Urolithins, the gut microbiota metabolites produced in vivo from ellagic acid and ellagitannins, were detected in human urine after dietary tea beverage intake. Urolithin metabotypes A, B, and 0 were identified in volunteers after tea intake. These results suggest that the daily intake of ellagitannins from tea can have a role in tea health effects.

Tea Is a Significant Dietary Source of Ellagitannins and Ellagic Acid.

This paper describes a total synthesis of (-)-strictinin, an ellagitannin that is 1-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl (HHDP)-β-D-glucose. In the study, total efficiency of the synthesis was improved to produce a 78% overall yield in 13 steps from D-glucose. In the synthesis, formation of the 4,6-(S)-HHDP bridge including the 11-membered bislactone ring was a key step, in which intramolecular aryl-aryl coupling was adopted. The coupling was oxidatively induced by CuCl2-n-BuNH2 with perfect control of the axial chirality, and the reaction conditions of this coupling were optimized thoroughly to achieve the quantitative formation of the bridge.

High-yield total synthesis of (-)-strictinin through intramolecular coupling of gallates.

Summary Tea trichomes synthesize numerous specialized metabolites to protect plants from environmental stresses and contribute to tea flavours, but little is known about the regulation of trichome development. Here, we showed that CsMYB1 is involved in the regulation of trichome formation and galloylated cis‐catechins biosynthesis in tea plants. The variations in CsMYB1 expression levels are closely correlated with trichome indexes and galloylated cis‐catechins contents in tea plant populations. Genome resequencing showed that CsMYB1 may be selected in modern tea cultivars, since a 192‐bp insertion in CsMYB1 promoter was found exclusively in modern tea cultivars but not in the glabrous wild tea Camellia taliensis. Several enhancers in the 192‐bp insertion increased CsMYB1 transcription in modern tea cultivars that coincided with their higher galloylated cis‐catechins contents and trichome indexes. Biochemical analyses and transgenic data showed that CsMYB1 interacted with CsGL3 and CsWD40 and formed a MYB‐bHLH‐WD40 (MBW) transcriptional complex to activate the trichome regulator genes CsGL2 and CsCPC, and the galloylated cis‐catechins biosynthesis genes anthocyanidin reductase and serine carboxypeptidase‐like 1A. CsMYB1 integratively regulated trichome formation and galloylated cis‐catechins biosynthesis. Results suggest that CsMYB1, trichome and galloylated cis‐catechins are coincidently selected during tea domestication by harsh environments for improved adaption and by breeders for better tea flavours.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1111/nph.18026

CsMYB1 integrates the regulation of trichome development and catechins biosynthesis in tea plant domestication

Defensive strategies in Geranium sylvaticum. Part 1: Organ-specific distribution of water-soluble tannins, flavonoids and phenolic acids

Untargeted and targeted methodologies in the study of tea (Camellia sinensis L.)

The polyphenolic composition of Camellia irrawadiensis, which is a closely related species of Camellia sinensis (cultivated tea), was investigated. The most predominant polyphenol, a kind of ellagitannin, was isolated from leaves of C. irrawadiensis. Its structure was established as 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-D-glucose (2) on the basis of spectral and chemical evidence. Moreover, the polyphenols [catechins, strictinin (1), compound 2, theogallin, and gallic acid] and two methylxanthines (theobromine and caffeine) in leaves of C. irrawadiensis were determined by HPLC-Photodiode array detector analysis, and were compared to those in C. sinensis and Camellia taliensis. Total catechin content in C. irrawadiensis was lower than that in C. sinensis and C. taliensis. Theobromine content in C. irrawadiensis was higher than that in C. sinensis and C. taliensis. The content of 2 in C. irrawadiensis was 8.4% of dry leaf weight and comprised approximately 60% of the total polyphenols detected, while the compound was not detected in C. sinensis and was reported to be 2.4% in C. taliensis.

Identification of a major polyphenol and polyphenolic composition in leaves of Camellia irrawadiensis.

Highly efficient synthesis of theaflavins by tyrosinase from mushroom and its application to theaflavin related compounds

PROBLEM TO BE SOLVED: To provide a black tea extract moderating unpleasant astringency and sharp bitterness remaining in a mouth after ingestion, further assuming a refreshing taste without an off-flavor, having excellent solubility with little change in color tone, and hardly causing creaming down even when preserved over a long period of time. SOLUTION: The black tea extract comprises following ingredients (A), (B), (C), (D), and (E): (A) catechin, (B) caffeine, (C) gallic acid, (D) a polyphenol, and (E) theaflavin. The content weight and content weight ratio thereof based on solids satisfy following (i), (ii), and (iii): (i) [(A)+(B)+(C)]/(D)=0.001-0.3; (ii) (D)=≤50 wt.%; and (iii) (E)=0.001-3 wt.%. COPYRIGHT: (C)2009,JPO&INPIT

Black tea extract

PROBLEM TO BE SOLVED: To provide packaged tea beverage suppressed in or prevented from occurrence of flock while retaining flavor inherited from tea. SOLUTION: The packaged tea beverage contains quinic acid-3-gallate as (A) component and aluminum as (B) component at the weight ratio of [(A)/(B)] of 0.60 to 35. COPYRIGHT: (C)2007,JPO&INPIT

Packaged tea beverage

PROBLEM TO BE SOLVED: To provide a method for appraising tea leaves using theogalline as an index by which raw material tea leaves for a packaged tea beverage prevented from flocking during long storage and excellent in flavor are selected. SOLUTION: The method for appraising tea leaves using theogalline as an index appraises raw tea leaves for a packaged beverage in reference to a theogalline concentration to a tannin concentration in tea leaf extract liquid to select tea leaves hardly causing flock. COPYRIGHT: (C)2008,JPO&INPIT

Method for appraising tea leaf using theogalline as index

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