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New flavan-3-ol dimer from green tea produced from Camellia taliensis in the Ai-Lao mountains of Southwest China.

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TLDR
One new flavan-3-ol dimer, talienbisflavan A (1), was isolated from green tea prepared from the leaves of C. taliensis collected from the east side of the Ai-Lao mountains, Yuanjiang county of Yunnan province, China.
Abstract
Camellia taliensis (W. W. Smith) Melchior, belonging to the genus Camellia sect. Thea (Theaceae), is an endemic species distributed from the west and southwest of Yunnan province, China, to the north of Myanmar. Known as a wild tea tree, its leaves have been used commonly for producing tea beverages by the local people of its growing area. One new flavan-3-ol dimer, talienbisflavan A (1), was isolated from green tea prepared from the leaves of C. taliensis collected from the east side of the Ai-Lao mountains, Yuanjiang county of Yunnan province, China. In addition, five hydrolyzable tannins (2-6), five flavonols and flavonol glycosides (9-13), three flavan-3-ols (14-16), nine simple phenolic compounds and glycosides (7, 8, and 17-23), and caffeine (24) were identified. Their structures were determined by detailed spectroscopic analysis. All of the isolated phenolic compounds were tested for their antioxidant activities by DPPH and ABTS(+) radical scavenging assays. The contents of its main chemical compositions were also compared with those collected from the Lincang area of Yunnan province by high-performance liquid chromatography analysis.

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Microbial bioconversion of the chemical components in dark tea.

TL;DR: An overview of the most recent advances in the knowledge of the microbial bioconversion of the chemical components indark tea, including the chemical composition of dark tea, microbial community composition and dynamics during the fermentation process, and the role of microorganisms in biotransformation of chemical constituents is provided.
Journal ArticleDOI

Phenolic compounds from Origanum vulgare and their antioxidant and antiviral activities

TL;DR: Six new phenolic compounds along with five known ones were isolated from the ethanol extract of the whole plants of Origanum vulgare, and two new compounds exhibited significant antioxidant activity comparable to that of ascorbic acid.
Journal ArticleDOI

Plant Resources, Chemical Constituents, and Bioactivities of Tea Plants from the Genus Camellia Section Thea

TL;DR: The geographical distribution of tea plants and the chemical constituents reported from the genus Camellia section Thea and some tea products that have ever been studied between 1970 and 2018 have been summarized, taking species as the main hint, and the main biological activities are also discussed.
Journal ArticleDOI

Simultaneous determination of caffeine and some selected polyphenols in Wuyi Rock tea by high-performance liquid chromatography.

TL;DR: The results showed that hydrolysis at 2 mol/L HCl solution and at 90 °C for 1 h was an optimizing condition for hydrolyzing flavonoid glycosides to myricetin and quercetin in Wuyi Rock tea.
Journal ArticleDOI

Antioxidative Flavan-3-ol Dimers from the Leaves of Camellia fangchengensis.

TL;DR: The results suggested that the leaves of C. fangchengensis, rich in flavan-3-ol oligomers and monomers as potent antioxidants, could be a valuable plant resource for the production of tea and natural beverages.
References
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Journal ArticleDOI

The correlation between active oxygens scavenging and antioxidative effects of flavonoids

TL;DR: The flavonoids tested now, except monohydroxy flavones, were more or less inhibitive to the superoxide anion (O2) generation in the hypoxanthine-xanthine oxidase system.
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Phenolic antioxidants from clonal oregano (Origanum vulgare) with antimicrobial activity against Helicobacter pylori

TL;DR: The antioxidant activity of phenolic-enriched clonal oregano extracts, and their antimicrobial activity against ulcer-associated Helicobacter pylori have been evaluated.
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Antioxidative polyphenols from walnuts (Juglans regia L.)

TL;DR: Three hydrolyzable tannins, glansrins A-C, together with adenosine, adenine, and 13 known tANNins were isolated from the n-BuOH extract of walnuts and characterized as ellagitannins with a tergalloyl group, or related polyphenolic acyl group, based on spectral and chemical evidence.
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In vitro scavenger activity of some flavonoids and melanins against O2

TL;DR: It is shown that the presence of hydroxyl groups in the B ring of flavonoids is essential for their scavenger activity, and the existence of a hydroxYL at C-3 enhances the scavenger ability of Flavonoids.
Journal ArticleDOI

Tannins and related compounds. XV. A new class of dimeric flavan-3-ol gallates, theasinensins A and B, and proanthocyanidin gallates from green tea leaf (1)

TL;DR: In this article, the identification of three new monomeric acylated flavan-3-ols (asinensins A and B) from green tea leaves was confirmed.
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