Trends of tea in cardiovascular health and disease: A critical review

Assessment of carcinogenic and non-carcinogenic risk of exposure to potentially toxic elements in tea infusions: Determination by ICP-OES and multivariate statistical data analysis

BACKGROUND

The perennial evergreen tea (Camellia sinensis) plant is one of the most popular nonalcoholic drinks in the world. Fertilizers and industrial, agricultural, and municipal activities are the usual drivers of soil contamination, contaminating tea plants with potentially toxic elements (PTEs). These elements might potentially accumulate to larger amounts in the leaves of plants after being taken up from the soil. Thus, frequent monitoring of these elements is critically important.

METHODS

The present study intended to determine PTEs (Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb) in both tea leaves and infusions using ICP-OES. Various multivariate data analysis methods such as principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed to elucidate the potential sources of PTEs contamination, whether from anthropogenic activities or natural origins. Additionally, Pearson's correlation coefficient (PCC) was calculated to assess the relationships between the variables under study.

RESULTS

The mean contents (mg/L) of all studied elements in tea infusions decreased in order Mn (150.59 ± 1.66) > Fe (11.39 ± 0.99) > Zn (6.62 ± 0.89) > Cu (5.86 ± 0.62) > Co (3.25 ± 0.64) > Ni (1.69 ± 0.23) > Pb (1.08 ± 0.16) > Cr (0.57 ± 0.09) > Cd (0.46 ± 0.09) > Al (0.05 ± 0.008), indicating that Mn exhibits the highest abundance. The mean concentration trend in tea leaf samples mirrored that of infusions, albeit with higher concentrations of PTEs in the former. The tolerable dietary intake (TDI) value for Ni and provisional tolerable monthly intake (PTMI) value for Cd surpassed the standards set by the WHO and EFSA. Calculated hazard index (HI < 1) and cumulative cancer risk (CCR) values suggest negligible exposure risk.

CONCLUSION

Elevated levels of PTEs in commonly consumed tea products concern the public and regulatory agencies.

Antidiabetic Potential of Tea and Its Active Compounds: From Molecular Mechanism to Clinical Evidence

Diabetes mellitus (DM) is a chronic endocrine disorder that poses a long-term risk to human health accompanied by serious complications. Common antidiabetic drugs are usually accompanied by side effects such as hepatotoxicity and nephrotoxicity. There is an urgent need for natural dietary alternatives for diabetic treatment. Tea (Camellia sinensis) consumption has been widely investigated to lower the risk of diabetes and its complications through restoring glucose metabolism homeostasis, safeguarding pancreatic β-cells, ameliorating insulin resistance, ameliorating oxidative stresses, inhibiting inflammatory response, and regulating intestinal microbiota. It is indispensable to develop effective strategies to improve the absorption of tea active compounds and exert combinational effects with other natural compounds to broaden its hypoglycemic potential. The advances in clinical trials and population-based investigations are also discussed. This review primarily delves into the antidiabetic potential and underlying mechanisms of tea active compounds, providing a theoretical basis for the practical application of tea and its active compounds against diabetes.

Effects of electromagnetic roller-hot-air-steam triple-coupled fixation on reducing the bitterness and astringency and improving the flavor quality of green tea

Despite the importance of fixation in determining green tea quality, its role in reducing the bitter and astringent taste of this beverage remains largely unknown. Herein, an electromagnetic roller-hot-air-steam triple-coupled fixation (ERHSF) device was developed, and its operating parameters were optimized (steam volume: 20 kg/h; hot-air temperature: 90 °C; hot-air blower speed: 1200 r/min). Compared with conventional fixation treated samples, the ratio of tea polyphenols to free amino acids and ester-catechins to simple-catechins in ERHSF-treated samples was reduced by 11.0% and 3.2%, reducing bitterness and astringency of green tea; amino acids, soluble sugars, and chlorophyll contents were significantly increased, enhancing the freshness, sweetness, and greenness; the color indexes, such as L/L* value of brightness and -a/-a* value of greenness, were also improved, and ERHSF-treated samples had the highest sensory scores. These results provided theoretical support and technical guidance for precise quality improvement of summer-autumn green tea.

Causal Association Between Tea Consumption and Gout: A Mendelian Randomization Study

OBJECTIVE

Evidence from prospective studies on the consumption of tea and risk of gout is conflicting and limited. We aimed to investigate the potential causal effects of tea intake on gout using Mendelian randomization (MR).

METHODS

Genome-wide association studies in UK Biobank included 349 376 individuals and successfully discovered single-nucleotide polymorphisms linked to consumption of one cup of tea per day. Summary statistics from the Chronic Kidney Disease Genetics consortium included 13 179 cases and 750 634 controls for gout. Two-sample MR analyses were used to evaluate the relationship between tea consumption and gout risk. The inverse-variance weighted (IVW) method was used for primary analysis, and sensitivity analyses were also conducted to validate the potential causal effect.

RESULTS

In this study, the genetically predicted increase in tea consumption per cup was associated with a lower risk of gout in the IVW method (OR: 0.90; 95% CI: 0.82-0.98). Similar results were found in weighted median methods (OR: 0.88; 95% CI: 0.78-1.00), while no significant associations were found in MR-Egger (OR: 0.89; 95% CI: 0.71-1.11), weighted mode (OR: 0.80; 95% CI: 0.65-0.99), and simple mode (OR: 1.01; 95% CI: 0.75-1.36). In addition, no evidence of pleiotropy was detected by MR-Egger regression (P=0.95) or MR-PRESSO analysis (P=0.07).

CONCLUSION

This study provides evidence for the daily consumption of an extra cup of tea to reduce the risk of gout.

Dose-response relationships of tea and coffee consumption with gout: a prospective cohort study in the UK Biobank

OBJECTIVES

The association of tea or coffee consumption with gout is inconsistently reported. Few prospective studies have explored their dose-response relationship. Therefore, we aimed to quantitatively investigate the association between tea, coffee and the risk of developing gout.

METHODS

The study included 447 658 participants in the UK Biobank who were initially free of gout. Tea and coffee consumption were assessed at baseline. We used Cox proportional hazards models to estimate the associations between tea/coffee consumption and incident gout, with restricted cubic spline added to the Cox models to evaluate the dose-response relationships.

RESULTS

During a median follow-up period of 13.42 years, we recorded 3,053 gout cases. The associations between tea, coffee and gout were nonlinear, with a significant reduction in the risk by ∼ six cups/day of tea and three cups/day of coffee. Compared with those who were not tea and coffee drinkers, those who consumed >6 cups/day of tea or coffee were associated with 23% (HR 0.77, 95% CI, 0.66, 0.91) and 40% (HR 0.60, 95% CI, 0.47, 0.77) lower risks of gout, respectively, and both caffeinated and decaffeinated coffee consumption were associated with a decreased risk. Moreover, hyperuricaemia may modify the association between coffee and gout. Compared with non-coffee consumers with hyperuricaemia, those with ≥4 cups/day coffee intake without hyperuricaemia had the lowest risk (HR 0.34, 95% CI, 0.28, 0.41).

CONCLUSION

Consumption of tea or coffee had a strong nonlinear association in gout risk reduction. Hyperuricaemia status had a potential effect modification on the association of coffee intake with gout.

Determination of Dicofol in Tea Using Surface-Enhanced Raman Spectroscopy Coupled Chemometrics

Dicofol is a highly toxic residual pesticide in tea, which seriously endangers human health. A method for detecting dicofol in tea by combining stoichiometry with surface-enhanced Raman spectroscopy (SERS) technology was proposed in this study. AuNPs were prepared, and silver shells were grown on the surface of AuNPs to obtain core-shell Au@AgNPs. Then, the core-shell Au@AgNPs were attached to the surface of a PDMS membrane by physical deposition to obtain a Au@AgNPs/PDMS substrate. The limit of detection (LOD) of this substrate for 4-ATP is as low as 0.28 × 10^-11 mol/L, and the LOD of dicofol in tea is 0.32 ng/kg, showing high sensitivity. By comparing the modeling effects of preprocessing and variable selection algorithms, it is concluded that the modeling effect of Savitzky-Golay combined with competitive adaptive reweighted sampling-partial least squares regression is the best (Rp = 0.9964, RPD = 10.6145). SERS technology combined with stoichiometry is expected to rapidly detect dicofol in tea without labels.

Flavor components detection and discrimination of isomers in Huaguo tea using headspace-gas chromatography-ion mobility spectrometry and multivariate statistical analysis

Aroma components are one of the crucial factors in dynamic processes analysis, quality control, and origin traceability. Various categories of Huaguo Tea possessed different taste due to the generation of aroma. In this study, a comprehensive analysis of volatiles was conducted for five popular Huaguo Tea samples (Lemon Slices, Bitter Gourd Slices, Citri Reticulatae Pericarpium, Red Lycium Barbarum, and Black Lycium Barbarum) via gas chromatography-ion mobility spectrometry (GC-IMS) combining with multivariate statistical strategies. Comparison analysis was achieved with the properties of visually and intuitively by drawing of topography plots. A total of one hundred and eighty volatiles were distinguished. Aliphatic isomers were identified simultaneously by fingerprint spectra. Alcohols, aldehydes, esters, and ketones were the most abundant volatiles in Huaguo Tea samples. To characterize the Huaguo Tea precisely and establish an analysis model for their classification, multivariate statistical analysis was applied to distinguish different Huaguo Tea. Satisfied discrimination was obtained by principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) based on the HS-GC-IMS results with the robustness parameter (R²Y) of 99.4%, and prediction ability parameter (Q²) of 98.6%, respectively. The results provide a theoretical basis for aroma discrimination, isomer identification, and categories analysis of Huaguo Tea.

Regulatory Effects and Molecular Mechanisms of Tea and Its Active Compounds on Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD), the most common chronic liver disease, is a multifactorial disease resulting from the interaction between environment, genetic background, and metabolic stress. Most treatments for NAFLD include dietary intervention and exercise show limited efficacy due to the complex mechanisms involved in NAFLD. Meanwhile, drug therapy is accompanied by serious side effects. The development of high-efficiency natural supplements is a sustainable strategy for the prevention and treatment of NAFLD. As the second most consumed beverage, tea has health benefits that have been widely recognized. Nevertheless, the intervention of tea active compounds in NAFLD has received limited attention. Tea contains abundant bioactive compounds with potential effects on NAFLD, such as catechins, flavonoids, theanine, tea pigments, and tea polysaccharides. We reviewed the intrinsic and environmental factors and pathogenic mechanisms that affect the occurrence and development of NAFLD, and summarized the influences of exercise, drugs, diet, and tea drinking on NAFLD. On this basis, we further analyzed the potential effects and molecular regulatory mechanisms of tea active compounds on NAFLD and proposed future development directions. This review hopes to provide novel insights into the development and application of tea active compounds in the prevention and treatment of NAFLD.

In Vitro Antithrombotic, Antitumor and Antiangiogenic Activities of Green Tea Polyphenols and Its Main Constituent Epigallocatechin-3-gallate

The balance between embolic risk and bleeding represents a clinical challenge in cancer patient treatment, encouraging studies on adjuvant oncologic treatments. Thereby, this study evaluated the in vitro effect of green tea extract (GTE) and epigallocatechin-3-gallate (EGCG) on hemostasis modulation and the antineoplastic effect on melanoma cells (B16-F10) by applying platelet aggregation, angiogenesis and viability cell assays. The results displayed a significant platelet antiaggregant effect, corresponding to 50 and 80% for the extract and EGCG, respectively, compared to the negative control. Furthermore, both GTE and EGCG exhibited antitumor effects by reducing melanoma cell growth by 25 and 50%, respectively, verified by cellular apoptosis. Regarding angiogenesis, these substances inhibited blood vessel formation, reaching about 25% and 99% for GTE and EGCG at 100 μg/mL, respectively. Moreover, TNF-α cell stimulation evidenced VEGF and IL-8 secretion inhibition at 55 and 20% with GTE, while EGCG promoted an inhibition around 78% for both VEGF and IL-8. The results indicate the promising performance of GTE and EGCG as an option for treating cancer and its side effects. Nonetheless, further studies are required to elucidate their action mechanism on clotting, cell death and angiogenesis.

Solving Tea Blending Problems Using Interactive Fuzzy Multi-Objective Linear Programming

Blending is a classical and well-known optimization problem that has been applied in the food, steel, and composite material industries. However, tea blending is more complicated than general problems due to the variety of products, processes, and sources of raw materials and semi-products. So, in this research, a fuzzy multi-objective model for the tea blending problem was proposed to minimize the total production cost and the deviation of quality target score; it provides a more robust and flexible method than existing models for complex real-world problems. Existing research works of a blending problem consider only raw material cost, but semi-product cost and processing cost are included in the proposed model that matches the actual case. Losses that occur during production are also incorporated. The selection of appropriate raw materials and semi-product sources can be obtained with the preferred levels of cost and quality by the proposed algorithm. The interactive fuzzy multi-objective programming to solve the problem has advantages over existing interactive programming methods. It is easy to manipulate interactively to obtain more efficient solutions than existing methods and both balanced and unbalanced solutions can be selected. The comparison of the results of an existing approach and the interactive fuzzy multi-objective programming algorithm for the tea industry is illustrated.

Comparative Transcriptomic and Metabolomic Analyses Reveal the Regulatory Effect and Mechanism of Tea Extracts on the Biosynthesis of Monascus Pigments

Monascus pigments (MPs) are natural edible pigments with high safety and strong function, which have been widely used in food and health products. In this study, different types of tea extracts (rich in polyphenols) were used to regulate the biosynthesis of MPs. The results showed that 15% ethanol extract of pu-erh tea (T11) could significantly increase MPs production in liquid fermentation of Monaco’s purpureus M3. Comparative transcriptomic and metabolomic analyses combined with reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to further explore the regulatory mechanism of T11 on the biosynthesis of MPs. Comparative transcriptomic analysis showed that there were 1503 differentially expressed genes (DEGs) between the Con group and the T11 group, which were mainly distributed in carbohydrate metabolism, amino acid metabolism, energy metabolism, lipid metabolism, metabolism of terpenoids and polyketides, etc. A total of 115 differential metabolites (DMs) identified by metabolomics between the Con and T11 groups were mainly enriched in glutathione metabolism, starch and sucrose metabolism, alanine, aspartic acid and glutamate metabolism and glycine, serine and threonine metabolism, etc. The results of metabolomics were basically consistent with those of gene transcriptomics, indicating that the regulatory effect of T11 on the biosynthesis of MPs is mainly achieved through affecting the primary metabolic pathway, providing sufficient energy and more biosynthetic precursors for secondary metabolism. In this study, tea extracts with low economic value and easy access were used as promoters of MPs biosynthesis, which may be conducive to the application of MPs in large-scale industrial production. At the same time, a more systematic understanding of the molecular regulatory mechanism of Monascus metabolism was obtained through multi-omics analysis.

Consumer Choices and Habits Related to Tea Consumption by Poles

Tea is one of the most consumed beverages in the world. In the literature, much attention is paid to the influence of tea and its components on human health and consumer purchasing behavior. The aim of the study was to analyze the habits of Polish consumers regarding tea consumption, brewing methods, and their choices related to tea, to describe the characteristics of tea consumers, and present their segmentation based on consumer choices and habits regarding tea consumption. The study was performed using the computer-assisted web interviewing (CAWI) method on a group of 1700 adult consumers of tea. Information about consumer choices and habits related to tea consumption was collected, including brewing method, place of tea consumption, and factors determining tea choices. Using cluster analysis, six groups of tea consumers were identified. These are “Occasional tea gourmets”, “Yerba mate drinkers”, “Tea gourmets”, “Occasional consumers”, “Undemanding tea consumers,” and “Occasional strong tea consumers”. In summary, it can be said that Poles are not tea gourmets; they prefer black tea, in bags, brewed in cups or glasses for up to 3 min, and usually drink teas without any additives, at home, several times a week, during breakfast and between meals. The most popular brand among the respondents was Lipton. Consumers have little knowledge of the health benefits of tea.

The Stress Detection and Segmentation Strategy in Tea Plant at Canopy Level

As compared with the traditional visual discrimination methods, deep learning and image processing methods have the ability to detect plants efficiently and non-invasively. This is of great significance in the diagnosis and breeding of plant disease resistance phenotypes. Currently, the studies on plant diseases and pest stresses mainly focus on a leaf scale. There are only a few works regarding the stress detection at a complex canopy scale. In this work, three tea plant stresses with similar symptoms that cause a severe threat to the yield and quality of tea gardens, including the tea green leafhopper [Empoasca (Matsumurasca) onukii Matsuda], anthracnose (Gloeosporium theae-sinensis Miyake), and sunburn (disease-like stress), are evaluated. In this work, a stress detection and segmentation method by fusing deep learning and image processing techniques at a canopy scale is proposed. First, a specified Faster RCNN algorithm is proposed for stress detection of tea plants at a canopy scale. After obtaining the stress detection boxes, a new feature, i.e., RGReLU, is proposed for the segmentation of tea plant stress scabs. Finally, the detection model at the canopy scale is transferred to a field scale by using unmanned aerial vehicle (UAV) images. The results show that the proposed method effectively achieves canopy-scale stress adaptive segmentation and outputs the scab type and corresponding damage ratio. The mean average precision (mAP) of the object detection reaches 76.07%, and the overall accuracy of the scab segmentation reaches 88.85%. In addition, the results also show that the proposed method has a strong generalization ability, and the model can be migrated and deployed to UAV scenarios. By fusing deep learning and image processing technology, the fine and quantitative results of canopy-scale stress monitoring can provide support for a wide range of scouting of tea garden.

Tea (Camellia sinensis): A Review of Nutritional Composition, Potential Applications, and Omics Research

Tea (Camelliasinensis) is the world’s most widely consumed non-alcoholic beverage with essential economic and health benefits since it is an excellent source of polyphenols, catechins, amino acids, flavonoids, carotenoids, vitamins, and polysaccharides. The aim of this review is to summarize the main secondary metabolites in tea plants, and the content and distribution of these compounds in six different types of tea and different organs of tea plant were further investigated. The application of these secondary metabolites on food processing, cosmetics industry, and pharmaceutical industry was reviewed in this study. With the rapid advancements in biotechnology and sequencing technology, omics analyses, including genome, transcriptome, and metabolome, were widely used to detect the main secondary metabolites and their molecular regulatory mechanisms in tea plants. Numerous functional genes and regulatory factors have been discovered, studied, and applied to improve tea plants. Research advances, including secondary metabolites, applications, omics research, and functional gene mining, are comprehensively reviewed here. Further exploration and application trends are briefly described. This review provides a reference for basic and applied research on tea plants.

Health Risk Assessment of Exposure to Trace Elements from Drinking Black and Green Tea Marketed in Three Countries

Although tea can be beneficial for our health, consuming excess trace elements in tea can be harmful. In this study, the carcinogenic and noncarcinogenic health risk for trace elements in tea influenced by the country of origin, tea type, and infusion process was assessed. Tea (Camellia sinensis) purchased from China, India, and the USA, including black and green tea, were analyzed for essential micronutrients (Cu, Se, and Zn) and nonessential trace elements (Ag, As, Ba, Cd, Cr, and Pb) in leaves and three types of infusions. The results showed that country of origin, tea type, and infusion process had a significant influence on the trace element contents in tea leaves and infusions, also on health risk. Country of origin had a significant influence on Ba, Cr, Pb, and Zn contents in tea leaves and on As, Ba, Cd, Cr, Pb, and Zn contents in tea infusions. Black tea had significantly higher (p < 0.05) Cr and Cu content in tea leaves than green tea, but only Cr content was significantly higher (p < 0.05) than that of green tea in tea infusion. The trace element contents were the highest in the first infusion and decreased as the number of infusion steps increased. The results showed that the consumption of tea infusion was not likely to cause noncarcinogenic risk. However, the carcinogenic risk for As was of concern. Our results indicate that avoiding drinking the first infusion can help to reduce both carcinogenic and noncarcinogenic health risks for trace elements.

Halawa T, Ahmed Wani ِF. Epigallocatechin gallate ameliorates tetrahydrochloride-induced liver toxicity in rats via inhibition of TGFβ / p-ERK/p-Smad1/2 signaling, antioxidant, anti-inflammatory activity

Chronic liver disease is a worldwide health problem. Carbon tetra hydrochloride is an environmental toxin which is regarded as highly toxic and a potential human carcinogen. It can cause liver damage through the generation of metabolites and production of free radicals. Green tea contains catechins such as Epigallocatechin gallate which has been found to reduce the inflammation, oxidative stress, and fibrosis in experimental animal models. Hence, it represents a good source to prevent or ameliorate several chronic diseases. Silymarin is extracted from milk thistle seeds and has been found to be an effective agent to reduce the oxidative stress and free radical production and thereby exert protective effects in chronic liver conditions. The present study was planned to keep in view the above-mentioned facts. We included thirty rats in our study and divided them into five groups, each having six rats and the study continued for 8 weeks. Group I received normal saline; Group 2 received i.p. CCl4 injections; Group 3 received CCl4 i.p. injection and Epigallocatechin gallate (EGCG) oral gavage, Group 4 received CCl4 i.p. injection and silymarin by oral gavage; and Group 5 received CCl4 i.p. injection and combined EGCG + silymarin by oral gavage. The study found that in group 2, CCl4 induced significant elevation of ALT and MDA and reduced GSH thereby signifying increased oxidative stress. CCl4 also significantly increased inflammatory (TNFα, NFκB, IL1β, and TGFβ) as well as fibrotic markers (p-ERK and p-Smad1/2 protein expression). EGCG and silymarin significantly reversed the previously mentioned parameters either alone or in combination; however, the effect was more pronounced in case of EGCG. We conclude that EGCG and silymarin possess liver protective effects through their antioxidant, anti-inflammatory, and antifibrotic action.

The chemistry, processing, and preclinical anti-hyperuricemia potential of tea: a comprehensive review

Hyperuricemia is an abnormal purine metabolic disease that occurs when there is an excess of uric acid in the blood, associated with cardiovascular diseases, hypertension, gout, and renal disease. Dietary intervention is one of the most promising strategies for preventing hyperuricemia and controlling uric acid concentrations. Tea (Camellia sinensis) is known as one of the most common beverages and the source of dietary polyphenols. However, the effect of tea on hyperuricemia is unclear. Recent evidence shows that a lower risk of hyperuricemia is associated with tea intake. To better understand the anti-hyperuricemia effect of tea, this review first briefly describes the pathogenesis of hyperuricemia and the processing techniques of different types of tea. Next, the epidemiological and experimental studies of tea and its bioactive compounds on hyperuricemia in recent years were reviewed. Particular attention was paid to the anti-hyperuricemia mechanisms targeting the hepatic uric acid synthase, renal uric acid transporters, and intestinal microbiota. Additionally, the desirable intake of tea for preventing hyperuricemia is provided. Understanding the anti-hyperuricemia effect and mechanisms of tea can better utilize it as a preventive dietary strategy.HighlightsHigh purine diet, excessive alcohol/fructose consumption, and less exercise/sleep are the induction factors of hyperuricemia.Tea and tea compounds showed alleviated effects for hyperuricemia, especially polyphenols.Tea (containing caffeine or not) is not associated with a higher risk of hyperuricemia.Xanthine oxidase inhibition (reduce uric acid production), Nrf2 activation, and urate transporters regulation (increase uric acid excretion) are the potential molecular targets of anti-hyperuricemic effect of tea.About 5 g tea intake per day may be beneficial for hyperuricemia prevention.

A combined analytical-chemometric approach for the in vitro determination of polyphenol bioaccessibility by simulated gastrointestinal digestion

In this study, an integrated characterisation through polyphenol and caffeine content and antioxidant activity was combined with chemometric analysis to assess the effects of simulated in vitro gastrointestinal digestion on the bioaccessibility of these bioactive compounds from nine different tea infusions. Tea infusions were characterised based on total flavonoids, total polyphenols and antioxidant activity, together with the determination of individual polyphenol content. Fourteen phenolic compounds, including phenolic acids, stilbenes and flavonoids, were selected based on their reported bioactivity and high accessibility, attributed to their low molecular weight. Both polyphenols and caffeine were initially monitored in raw tea infusions and through the different digestion stages (salivary, gastric and duodenal) by capillary high performance liquid chromatography coupled to diode array detection (cHPLC-DAD) and/or HPLC coupled to a triple quadrupole mass analyser (HPLC–MS/MS). Multivariate analysis of the studied bioactives, using principal component analysis and cluster analysis, revealed that the decaffeination process seems to increase the stability and concentration of the compounds evaluated during digestion. The greatest transformations occurred mainly in the gastric and duodenal stages, where low bioactivity indices (IVBA) were shown for resveratrol and caffeic acid (IVBA = 0%). In contrast, the polyphenols gallic acid, chlorogenic acid and quercetin gave rise to their availability in white, green and oolong infusion teas (IVBA > 90%). Furthermore, highly fermented black and pu-erh varieties could be designated as less bioaccessible environments in the duodenum with respect to the tested compounds.

Quickly and efficiently remove multiple pesticides in tea infusions by low-cost carbonized bacterial cellulose

Soaking tea leaves make tea consumers exposure to pesticide residues more easily. However, there are few studies on the removal of pesticides in tea infusions. Therefore, a low-cost carbonized bacterial cellulose material was prepared by direct calcination method, and used to remove multiple pesticides in tea infusions quickly and efficiently. CBC-350 has the best removal efficiency for 9 pesticides and then screened the best adsorption conditions. The adsorption isotherm experiment was carried out and indicated that the adsorption process was in consist with the Freundlich model. The thermodynamic parameters are also calculated. Moreover, the adsorption mechanism was discussed, which suggests that π-π interaction and hydrophobic action are the driving force during the adsorption process. Exhilaratingly, the CBC-350 also has excellent adsorption capacity compared to other adsorbents and can be reused at least five times.

PARP-1-Associated Pathological Processes: Inhibition by Natural Polyphenols

Poly (ADP-ribose) polymerase-1 (PARP-1) is a nuclear enzyme involved in processes of cell cycle regulation, DNA repair, transcription, and replication. Hyperactivity of PARP-1 induced by changes in cell homeostasis promotes development of chronic pathological processes leading to cell death during various metabolic disorders, cardiovascular and neurodegenerative diseases. In contrast, tumor growth is accompanied by a moderate activation of PARP-1 that supports survival of tumor cells due to enhancement of DNA lesion repair and resistance to therapy by DNA damaging agents. That is why PARP inhibitors (PARPi) are promising agents for the therapy of tumor and metabolic diseases. A PARPi family is rapidly growing partly due to natural polyphenols discovered among plant secondary metabolites. This review describes mechanisms of PARP-1 participation in the development of various pathologies, analyzes multiple PARP-dependent pathways of cell degeneration and death, and discusses representative plant polyphenols, which can inhibit PARP-1 directly or suppress unwanted PARP-dependent cellular processes.

Establishment of a HPLC-MS/MS Detection Method for Glyphosate, Glufosinate-Ammonium, and Aminomethyl Phosphoric Acid in Tea and Its Use for Risk Exposure Assessment

The tea shrub is grown in long-standing orchards, an environment that is suitable for persistent weed growth, which is increasingly controlled by herbicides. Therefore, there is increasing concern that tea consumers may be exposed to herbicide residues. In this study, the levels of glufosinate-ammonium (GLU), glyphosate [N-(phosphonomethyl) glycine; PMG], and its metabolite aminomethyl phosphoric acid (AMPA) were determined in tea samples by HPLC-MS/MS using several current purification methods and a new method that we developed herein. The matrix effect of our proposed method was between -27.3 and 27.7%, which was lower than that in other methods, indicating that this method effectively reduced the interference of tea matrix in the mass spectrometry process. This method was used to determine the levels of PMG, GLU, and AMPA in 780 samples, including six traditional Chinese teas (green tea, black tea, oolong tea, dark tea, white tea, and yellow tea) and a floral tea, from 14 provinces of China. Probability estimates showed that the 95th percentile risk entropy values of the three pesticide residues were far below the acceptable risk level. The risk assessment results showed that exposure to PMG, GLU, and AMPA caused by drinking tea beverages poses no significant risk to human health.

Determination of perchlorate in tea using SERS with a superhydrophobically treated cysteine modified silver film/polydimethylsiloxane substrate

Perchlorate is a new type of persistent pollutant, which interferes with the synthesis and secretion of thyroxine and affects human health. The EU's limit for perchlorate in tea is 750 μg kg^-1. The surface-enhanced Raman scattering (SERS) technique has the characteristics of a simple pretreatment method, rapid detection, high sensitivity, high specificity and great stability in the detection of perchlorate. This study proposed a novel superhydrophobic SERS substrate, which can be used to detect perchlorate in tea. Firstly, a chemical deposition method was used to deposit a silver film on the surface of a thin layer of polydimethylsiloxane. After drying, the substrate was immersed in 1H,1H,2H,2H-perfluorodecyltriethoxysilane aqueous solution for 15 hours to make the surface of the substrate superhydrophobic. Then cysteine molecules were deposited on the surface of the silver film/polydimethylsiloxane by incubation. The superhydrophobic surface has a unique enrichment effect on the highly diluted solution, and perchlorate has a strong affinity for the amino group of cysteine. We collected the Raman spectra of 9 gradient concentrations (1-100 μmol L^-1) of perchlorate-spiked tea samples on the hydrophobic substrate, and a linear model of the relationship between the SERS spectral intensity and the concentrations of perchlorate in tea was established. This method reached a good limit of detection of 0.0067 μmol L^-1 (0.82 μg kg^-1) in tea, which showed that the developed sensor has high sensitivity and could be used as a fast and simple technique for quantitative detection of perchlorate based on SERS technology.

Opportunities and challenges for the nanodelivery of green tea catechins in functional foods

Green tea, the least processed tea product, is scientifically known for its rich antioxidant content originating from polyphenols, especially catechins. The most potent green tea catechin is epigallocatechin-3-gallate (EGCG), which is responsible for a wide range of health benefits including anticancer, antidiabetics, and anti-inflammatory properties. However, green tea catechins (GTCs) are very labile under both environmental and gastrointestinal conditions; their chemical stability and bioavailability primarily depend on the processing and formulation conditions. Nanocarriers can protect GTCs against such conditions, and consequently, can be applicable for designing nanodelivery systems suitable for GTCs. In this review, the latest findings about both opportunities and limitations for the nanodelivery of GTCs and their incorporation into various functional food products are discussed. The scientific findings so far confirm that nanodelivery of GTCs can be an efficient approach towards the enhancement of their health-promoting effects with a minimal dose, controlled and targeted release, lessening the dose-related toxicity, and the efficient incorporation into functional foods. However, further investigation is yet needed to fully explain the cellular mechanisms of action of GTCs on human health and to elucidate the effect of encapsulation on their bioefficacy using well-designed, systematic, long-term, and large-scale clinical interventions. There also exists a substantial concern regarding the safety of the manufactured nanoparticles, their absorption, and the associated release mechanisms.

Tea consumption and its effects on primary and secondary prevention of coronary artery disease: Qualitative synthesis of evidence from randomized controlled trials

BACKGROUND AND AIMS

There is a general interest in understanding how the consumption of tea impacts cardiovascular function in individuals at risk of developing cardiovascular disease (CVD). The current review focuses on evidence from randomized controlled trials (RCTs) reporting on associations between tea consumption and endothelial function, in the primary and secondary prevention of coronary artery disease (CAD).

METHODS

PubMed, EMBASE, and Google Scholar databases/search engines were used to identify eligible studies. Included studies had to report on the impact of tea supplementation of endothelial function or CAD related markers. In addition to flow-mediated dilation (FMD), makers of oxidative stress and inflammation such as oxidized low-density lipoprotein and C-reactive protein were considered as determinants of endothelial function. A total of 34 RCTs met the inclusion criteria, and these reported on the impact of tea consumption on endothelial function in individuals at risk of CVD or patients with CAD.

RESULTS

The current qualitative synthesis of literature demonstrates that beyond enhancing nitric oxide bioavailability and lowering blood pressure, regular consumption of tea and its active ingredients such as epigallocatechin gallate may be beneficial in reducing markers of oxidative stress and inflammation. Moreover, the reduction of oxidized low-density lipoprotein and C-reactive protein levels, could be a sign of improved endothelial function in individuals at increased risk of developing CVD.

CONCLUSIONS

The cumulative evidence also suggests that the development of epigallocatechin gallate as a nutraceutical or enriching foods with this bioactive compound could be a feasible strategy to improve endothelial function and lower CVD-risk. However, well-designed RCTs are still necessary to confirm long-term benefits of tea consumption on vascular health.

Nanoselenium foliar application enhances biosynthesis of tea leaves in metabolic cycles and associated responsive pathways

An emerging stress of pesticides in plant and soil is closely watched as it affects crop antioxidant systems, nutritional quality, and flavor. Although selenium (Se) can enhance the resistance of plants, the protective mechanism of nanoselenium is still not known under the long-term pesticide stress in tea trees. In this study, we investigated the potential effects of foliar application of nanoselenium for a two-year field experiment on tea plants under pesticide-induced oxidative stress. Compared to control, nano-Se (10 mg/L) markedly enhanced the protein, soluble sugar, carotenoid, tea polyphenols, and catechins contents. High levels of theanine, glutamic acid, proline, and arginine were found to be induced most likely by adjusting the GS-GOGAT cycle. Se-supplementation may promote tea leaves' secondary metabolism, thus increasing the accumulation of total phenols and flavonoids (apigenin, kaempferol, quercetin, myricetin, and rutin). It also minimized the accumulation of malondialdehyde, hydrogen peroxide, and superoxide anion by activating the antioxidants enzymes including in the AsA-GSH cycle. Selenium-rich tea also showed better fragrance and flavor. In summary, nano-Se can ameliorate the nutrients quality and abiotic stresses resistance of crops.

The effect of black tea supplementation on blood pressure: a systematic review and dose-response meta-analysis of randomized controlled trials

The main goal of this work was to clarify the effects of black tea supplementation on blood pressure (BP) by performing a systematic review according to the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines, followed by a dose-response meta-analysis of randomized controlled trials (RCTs). Electronic search was carried out in PubMed, Embase and the Cochrane Library databases published up to March 2020. To be included, RCTs had to report the effect of black tea supplementation on systolic blood pressure (SBP) or diastolic blood pressure (DBP) in adults. A total of 13 trials, including 22 study arms were eligible for inclusion in the final quantitative analysis. It was observed that black tea supplementation significantly reduced SBP (WMD - 1.04 mmHg; 95% CI - 2.05 to -0.03; and P = 0.04) and DBP (WMD - 0.59 mmHg; 95% CI - 1.05 to -0.13; and P = 0.01) compared to the control. However, nonlinear analysis failed to indicate a significant influence of black tea flavonoid supplementation dose or duration on both SBP and DBP. Sensitivity analysis showed that no individual study had a significant impact on our results. In addition, we found no evidence for the presence of small-study effects among studies for both SBP and DBP. Thus, the favorable effect of black tea supplementation emerging from the current meta-analysis suggests the possible use of this tea as an active compound in order to promote cardiovascular health, mostly when used for longer duration (>7 days) and in men. Furthermore RCTs using different doses of black tea and various durations may contribute to confirming our conclusion.

Epigallocatechin gallate suppresses inflammation in human coronary artery endothelial cells by inhibiting NF-κB

The endothelium is a critical regulator of vascular homeostasis, controlling vascular tone and permeability as well as interactions of leukocytes and platelets with blood vessel walls. Consequently, endothelial dysfunction featuring inflammation and reduced vasodilation are considered central to cardiovascular disease (CVD) pathogenesis and have become a therapeutic area of focus. Type II endothelial cell (EC) activation by stress-related stimuli such as tumor necrosis factor-α (TNF-α) initiates the nuclear factor-κB (NF-κB) signaling pathway, a master regulator of inflammatory responses. Because dysregulated NF-κB signaling has been tightly linked to several CVDs, EC-specific inhibition of NF-κB represents an attractive pharmacological strategy. As accumulating evidence highlights the clinical benefits of tea catechin for multiple diseases including CVDs, we sought to determine whether the tea catechin epigallocatechin gallate (EGCG) that displays antioxidative, anti-inflammatory, hypolipidemic, anti-thrombogenic, and anti-hypertensive properties offers protection against CVDs by suppressing the canonical NF-κB pathway. Our findings indicate that EGCG downregulates multiple components of the TNF-α-induced NF-κB signaling pathway and thereby reduces the consequent increase in inflammatory gene transcription and protein expression. Furthermore, EGCG blocked type II EC activation, evidenced by diminished EC leakage and monocyte adhesion in EGCG-treated cells. In summary, our study advances knowledge of EGCG's anti-inflammatory effects on the NF-κB pathway and hence its benefits on endothelial health, supporting its therapeutic potential for CVDs.