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PubMed1977

A colorimetric study of coffee and tea staining of four composite resins.

Colorimetric measurements were made on four composite resins before and after controlled immersion treatments. The four composite resins were: Adaptic (Johnson and Johnson), Prestige (Lee Pharmaceuticals), Addent XV (3M Mfg. Co.) and Smile (Kerr Mfg. Co.). Specimens of each material were prepared with mylar surfaces and with abraded finished surfaces. Separate groups of specimens of the four materials were immersed in three separate solutions for 12 days at 55c. The three solutions used were: a control solution of distilled water and coffee and a solution of distilled water and tea. For all materials and surface finishes, immersion in coffee and tea produced significantly greater colour changes than distilled water. Coffee produced significantly greater colour changes than tea with the exception of 'Prestige' and 'Addent XV' with finished surfaces. When immersed in a tea solution, specimens of the same material with differing surface finishes showed greater differences in colour change than when immersed in control and coffee solutions. The relative colour changes of the four materials due to the immersion procedures were as follows: 'Adaptic' showed the least colour changes and "Smile' showed the most. 'Addent XV' and 'Prestige' tended to vary between the former two. Comparison and correlation of colorimetry results with visual assessment scores allowed for the expression of the objective measures in subjective terms suitable for clinical purposes.

Coffee↗

PubMed1979

[TEA-resistant outward current in the somatic membrane of perfused nerve cells].

The outward currents remaining after addition of 20-50 mM tetraethylammonium (TEA) to the extracellular solution were studied on perfused isolated neurons from Helix pomatia. A potassium-carried noninactivating outward current with potential-dependence and kinetics different from those of TEA-sensitive potassium currents was found. This TEA-resistant current includes a component depending on the presence of the inward calcium current. It could be abolished by replacing extracellular calcium by magnesium ions, by blocking the calcium channels with extracellular cadmium ions and their distruction by intracellular fluorid ions. An increase in the level of intracellular free carcium (by perfusing the cell with solutions containing Ca-EGTA buffer) potentiated the TEA-resistant component of the outward current and the removal of free calcium by EGTA decreased it. A conclusion is made that the somatic membrane contains outward current channels which can be activated only when calcium ions are bound to its inner surface.

Animals↗

PubMed2026

Metagenomic Insights Into Microbial Diversity of Tea Rhizosphere of the Kangra Valley.

This study provides the first metagenomic assessment of microbial diversity from the tea rhizosphere of the Kangra valley. Tea rhizosphere soil samples were collected from 4 locations (Dharamshala, Baijnath, Palampur, and Joginder Nagar) of the Kangra valley. DNA extracts of rhizosphere samples were analysed for bacterial and Archaeal diversity using amplicon sequencing (V3-V4) region of the 16S rRNA gene and Fungal diversity using ITS1 and ITS2 regions. Baijnath and Palampur samples showed the highest bacterial richness, while Dharamshala and Palampur had the highest fungal richness. Proteobacteria was a dominant phylum in all the rhizosphere samples, followed by Firmicutes, Actinobacteria, Acidobacteria, and Bacteroidetes. A total of 11 fungal phyla were identified among all the locations, with abundance of Ascomycota and Basidiomycota. For the Archaea domain, uncultured archaeon and Aeropyrum camini were the most common found among all the locations. A small fraction (< 0.5%) of Bacillus and Pseudomonas species were observed among all the locations. Alpha and beta diversity indices displayed notable differences within and between microbial diversities. Soil factors were variably associated with microbial diversity, with nitrogen positively aligned with fungal diversity, while EC and K were associated with Archaeal diversity. Soil pH and OM% showed moderate associations with bacterial diversity. These findings provided valuable and comprehensive insights into tea rhizosphere microbial ecology and could be used to better understand microbial functions and their role in plant health.

Rhizosphere↗

PubMed1979

Iron absorption in the thalassemia syndromes and its inhibition by tea.

To determine the hemoglobin concentration at which iron absorption is minimal, five subjects with thalassemia major and one with thalassemia intermedia underwent a series of iron-absorption studies. The effect of tea as an inhibitor of non-heme iron absorption was also tested. Iron absorption increased as the hemoglobin concentration decreased, although iron absorption was much higher at any given hemoglobin level in the subject with thalassemia intermedia. In the subjects with thalassemia major, iron absorption averaged 10 per cent at hemoglobin concentrations between 9 and 10 and 2.7 per cent between 11 and 13 g per deciliter. The percentage of iron absorbed could be accurately predicted from the nucleated red-cell count (r = 0.91, P less than 0.001). Tea produced a 41 to 95 per cent inhibition of iron absorption. Since patients with thalassemia intermedia may absorb a large percentage of dietary iron, inhibitors of iron absorption, such as tea, may be useful in their management.

Adolescent↗

PubMed1976

[Purification and properties of peroxidase from tea leaves].

Purification of fractions of tea leaves peroxidase is described. During ion-exchange chromatography on DEAE- and CM-cellulose peroxidase is eluted into six fractions, differing in their electrophoretic properties. The enzyme showed optimal activity at pH 4.1-5.0, when the enzyme fractions of guaiacol adsorbed on DEAE-cellulose were used as a substrate; in case of enzyme fractions adsorbed on CM-cellulose it was observed within pH range of 5.4-6.2. The dependence curves of the initial rate of the reaction on the substrate concentration were S-shaped in case of the latter fractions. Peroxidase is shown to catalyze the oxidation of tea catechins; its activity is inhibited by the products of their condensation. The catalytic effect of the enzyme on the oxidation of phenolic acids, e.g. chlorogenic, caffeic and gallic, was far stronger than on that of tea catechins, pyrogallol and pyrocatechin. It was established that two fractions of the enzyme possess predominantly the phloroglucinol oxidase activity, whereas the other fractions do not catalyze the oxidation of phloroglucin. The molecular weights of some peroxidase fractions estimated by polyacryl amide gel electrophoresis are 26.000+/-1.100, 45.00+/-1.200 and 50.000+/-1.500.

Catechin↗

PubMed1979

[Efficacy and tolerance of Uroflux, a bladder and kidney tea, in the treatment of urinary tract infections, especially in diabetes mellitus].

In an open study the use of Uroflux tea and sugar coated tablets individually and in combination with chemotherapeutic or antibiotic therapy in 52 patients is described. Urine analysis showed improvement rates of 92 and 93 per cent respectively. A blind trial was carried out separately in diabetic patients over a period of 14 days in order to evaluate the effects on daily blood sugar levels of Uroflux tea against a comparative product. It was clearly shown, that the patients on Uroflux tea showed no changes in daily blood sugar profiles. Contrary to this is was noteworthy that blood sugar concentrations in patients receiving the comparative product were elevated in the morning before breakfast as well as one hour after the midday meal. There were no side effects observed with any of the Uroflux dosage forms; even patients complaining of "sensitive stomach" reported excellent tolerance.

Aged↗

PubMed2026

Enhancement flavor quality in Zhao'an Baxian oolong tea through enhanced turning-over process.

A systematical investigation on the effects of turning-over intensity on the flavor formation of Zhao'an Baxian oolong tea (ZBT) was performed, through a comparative analysis of heavy turning-over (HT) and light turning-over (LT) treatments in this study. The tea samples were subjected to proteomic and metabolomic analyses, combined with quantitative descriptive analysis (QDA) and electronic sensory (E-tongue/E-nose) evaluation. The results demonstrate that HT significantly reduced the content of bitter and astringent compounds, such as catechins and flavonol glycosides, while promoting the accumulation of umami-related amino acids. Concurrently, HT enhanced the biosynthesis of key floral and fruity volatiles, such as β-ocimene, geraniol, benzaldehyde, jasmone by activating stress-responsive metabolic pathways. These coordinated biochemical changes, driven by enzyme-catalyzed reactions in response to prolonged mechanical wounding and environmental stress, collectively improved the overall sensory profile of ZBT. These findings provide a mechanistic foundation for improving ZBT production, with clear implications for quality control and flavor-oriented product development.

Tea↗

PubMed1977

Toxicity from tea ingestion in an infant: a computer simulation analysis.

A seven-week-old infant presented with tonic posturing and nervous irritability after concentrated tea ingestion. The tea was analyzed and found to contain caffeine, a methylxanthine central nervous system stimulant. With the aid of a computer, projected blood levels were calculated over a thirty-hour time period and comared to the infant's clinical status. It is recommended that beverages containing xanthines be given to infants and small children with caution.

Caffeine↗

PubMed2026

Cis-regulatory evolution of CsANS1 drives cultivar variation in anthocyanin accumulation in tea plants.

Anthocyanins, a ubiquitous class of water-soluble phytochemicals renowned for their chromatic diversity and potent bioactivity, are integral to the phenotypic and metabolic plasticity of higher plants. Using an integrative multi-omics approach that combines transcriptomic and metabolomic profiling, we identified anthocyanin synthase (CsANS1) as the key genetic determinant responsible for interspecific variation in anthocyanin accumulation among tea plants. Architectural comparison of promoter regions revealed a 192-bp variation insertion in the CsANS1 cis-regulatory region with potential functional significance. This insertion was strictly conserved in anthocyanin-rich (purple-leaf) cultivars, including both natural and hybrid genotypes, but entirely missing in anthocyanin-deficient (green-leaf) cultivars. Dual-luciferase assays confirmed that this insertion enhances promoter activity. Additionally, we delineated a tripartite regulatory axis comprising CsmiR156b, CsSPL9, and CsMYB75 which orchestrates the spatiotemporal modulation of CsANS1 expression and, consequently, anthocyanin biosynthesis. Collectively, these findings provide a mechanistic paradigm for anthocyanin polymorphism in tea plants, implicating both cis-regulatory evolution and transcriptional network synergy as pivotal drivers of phytochemical diversification.

Anthocyanins↗

PubMed2026

Network pharmacology-based prediction and experimental validation of the anti-hyperuricemic effects of oolong tea polyphenols.

OBJECTIVE: This study aimed to identify candidate therapeutic targets of oolong tea polyphenols (TP) against hyperuricemia (HUA) using network pharmacology and bioinformatics, and to validate the predicted molecular mechanism through in vivo experimentation. METHODS: Drug and disease targets were retrieved from public databases, and overlapping targets were identified by Venn diagram analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed on the shared targets, and a protein-protein interaction (PPI) network was constructed to identify hub genes. For in vivo validation, an HUA mouse model was established by 15 days of oral potassium oxonate (PO) administration. Model mice then received TP by gavage at low (0.5 g⋅kg-1⋅d-1), medium (1 g⋅kg-1⋅d-1), or high (2 g⋅kg-1⋅d-1) doses for an additional 15 days. Serum biochemical markers, histopathological changes, and pathway-related protein expression were assessed by enzyme-linked immunosorbent assay (ELISA), hematoxylin and eosin (HE) staining, and western blot analysis, respectively. RESULTS: Network pharmacology analysis identified 59 overlapping targets between TP and HUA; GO and KEGG enrichment analyses revealed that these targets were primarily associated with hormone metabolism and the PI3K-AKT signaling pathway. In the animal experiment, TP dose-dependently reduced serum uric acid (SUA) levels in hyperuricemic mice. At the molecular level, low and medium doses of TP suppressed phosphorylation of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR), whereas the high dose paradoxically activated this pathway and concomitantly elevated interleukin-1β levels. These findings indicate that TP modulates uric acid metabolism through a non-monotonic, dose-dependent mechanism. CONCLUSION: By combining network pharmacology with animal experiments, this study identified the PI3K/AKT/mTOR signaling pathway as a likely mediator of the anti-hyperuricemic action of oolong tea polyphenols (TP). A medium dose of TP achieved the most balanced outcome, attenuating inflammation and preserving hepatic and renal architecture; the high dose, by contrast, paradoxically elevated interleukin-1β (IL-1β) and overactivated PI3K/AKT/mTOR signaling, underscoring the importance of dose calibration. These data suggest that a medium dose of TP may represent a feasible dietary strategy against hyperuricemia. Further work-including monomer identification, direct target validation, and clinical evaluation-is warranted to confirm and extend these preclinical findings.

PI3K/Akt/mTOR signaling pathway↗

PubMed1975

The mechanism of the inhibition of iron absorption by tea.

Previous human studies have shown that drinking tea during meals significantly inhibits the absorption of both food iron and medicinal iron. This study provides evidence from experiments with rats that the tannins in the tea are responsible for the inhibition, probably by forming non-absorbable complexes with the iron within the intestinal lumen. The molar ratio of tannin: iron is dependent on the pH, being 1:1 at pH 2,0 2:1 at pH 5,5 and 3:1 at pH 8,0. Since tannins are present in many vegetable foods the formation of such complexes may be a factor in the poor availability for absorption of much food iron.

Chemical Phenomena↗

PubMed1978

Modified K-channel gating by exhaustion and the block by internally applied TEA+ and 4-aminopyridine in muscle.

Voltage clamp experiments on frog sartorius muscle fibres suggest that the large increase in resting potassium conductance during metabolic exhaustion is due to a change in the gating of activated potassium channels to a permanently open state. gK in exhausted fibres is less sensitive to externally applied blockers as Zn2+ and 4-aminopyridine (4-AP) while TEA+, Rb+ and Ba2+ act similarly, both in normal and exhausted fibres. In addition, injection experiments provide evidence that TEA+ and 4-AP applied internally to normal fibres effectively block potassium outward current, whereas in exhausted fibres the block seems to be smaller. These results suggest modifications in the structure of the potassium channels during metabolic exhaustion.

Animals↗

PubMed1976

A case of veno-occlusive disease of the liver in Britain associated with herbal tea consumption.

Veno-occlusive disease of the liver with clinical and pathological features similar to those of the condition occurring in the Caribbean is described in a young woman resident in Britain. The diagnosis was made from liver biopsies and hepatic venography and was confirmed at necropsy. Small amounts of pyrroliziding alkaloids were recovered from a sample of mate (Paraguay) tea, owned by the patient, to which she was addicted. It seems probable that the consumption of large amounts of this tea over a period of years was the cause of the hepatic disease.

Adult↗

PubMed1978

[Results later many years after TEA in femoro-popliteal segment (author's transl)].

Our results later many years after 231 TEA in femoro-popliteal segment are based to examinate the indications of this reconstructive operation and to compare with other methods of arterial reconstruction. Resulted: the TEA is always a good method of biological worth without risk. This method authorized to indicate the reconstruction of chronical arterial occlusions. However the method is not to apply to all arterial occlusions without criticism only to selected patients.

Age Factors↗

PubMed2026

Multi-omics insights into aroma formation in congou black tea during fermentation.

This study used multi-omics technologies to analyze aroma formation during Congou black tea fermentation. Volatile compounds were analyzed by headspace solid phase microextraction coupled with gas chromatography mass spectrometry using two columns of different polarity. Fermentation increased total volatile normalized peak area fivefold, with alcohols, aldehydes, and acids increasing over sevenfold. 29 differential metabolites were screened, including amino acid derived phenylacetaldehyde, phenylethanol, and 2-methylbutanal; fatty acid derived (E,E)-2,4-heptadienal, hexanal, and 1-hexanol; and isoprenoid derived linalool, geraniol, and beta ionone. Transcriptomic, proteomic, and enzyme analyses revealed that biosynthesis contributed to early accumulation of amino acid and isoprenoid derived aromas, whereas ortho quinone mediated Strecker degradation and free radical induced fatty acid auto oxidation dominated generation of amino and fatty acid derived aromas during middle and late fermentation. In conclusion, aroma formation during fermentation results from biosynthesis and non-enzymatic oxidation, with the latter possibly dominating amino and fatty acid derived aromas.

Fermentation↗

PubMed2026

Alginate-based edible coating incorporating green tea extract for preserving postharvest quality and safety of white mushrooms (Agaricus bisporus).

This study aimed to evaluate the effects of a sodium alginate based edible coating incorporated with green tea extract (GTE) (Camellia sinensis) on the postharvest quality attributes and antimicrobial activity against Listeria monocytogenes in white mushrooms during refrigerated storage. The phenolic profile of GTE was characterized, and its minimum inhibitory concentration (MIC) against L. monocytogenes (1.6 mg/mL) was determined. Sodium alginate coatings, with (ALG-GTE) or without GTE (ALG) at MIC (1.6 mg/mL), were characterized (functional groups, solubility in water, moisture, thickness, water contact angle and color) for their chemical and physical properties. The effects of ALG-GTE coatings on quality parameters (firmness, weight loss, color, pH, sugars and organic acids), enzymatic activity [polyphenol oxidase (PPO), peroxidase (POD) and pectin methylesterase (PME)], antimicrobial activity against L. monocytogenes (5 log CFU/g), and surface characteristics (3D optical profilometry) were assessed in white mushrooms (Agaricus bisporus) during refrigerated storage (8 days, 4 ± 1 °C, 90-95% RH). The ALG-GTE coatings preserved sugar composition, particularly rhamnose, reduced organic acids accumulation and delayed weight and firmness loss, reduced color changes, and decreased PME activity in coated white mushrooms. L. monocytogenes counts decreased by 1.4 log CFU/g after 1 day, and no viable cells were detected after 2 days (< 1.5 log CFU/g) in ALG-GTE coated white mushrooms. In addition, ALG-GTE coated white mushrooms exhibited smoother surfaces than uncoated samples. These findings highlight the potential of ALG-GTE coatings as a sustainable alternative capable of improving the microbiological safety and delaying the postharvest changes in fresh mushrooms.

Agaricus↗

PubMed1977

Accelerating action of tea on mouse skin carcinogenesis.

The effect of different tannin-containing aqueous solutions on the carcinogenic action of benzo(a)pyrene (BP) on the mouse skin was investigated. It was found that the appearance of tumours was accelerated in mice treated with either tea or an oak extract after a single application of BP. The time of appearance of tumours in mice treated with gallic acid or tannic acid after treatment with BP was similar to that in the group treated with BP alone. The overall incidence of tumours was similar in all five groups.

Animals↗

PubMed1976

A 'TEA+-insensitive' mutant with increased potassium conductance in Paramecium aurelia.

A single-gene mutant of Paramecium aurelia is analysed electrophysiologically. (a) The regenerative Ca-response, triggered by small or moderate current, was smaller and slower in the mutant than in wild type. (b) Input resistance of the mutant membrane is about half of that of wild type bathed in various solutions. This is true for the zero-current input resistance and the chord resistance measured with high depolarizing current. (c) Membrane resistance of the mutant measure with hyperpolarizing currents is smaller than that of wild type only when K+ is the major external cation. (d) Internally applied TEA+ or externally applied Ba+ increases the membrane resistance of the mutant to that of wild type similarly treated. We conclude that the mutant has an increased K conductance.

Action Potentials↗