A fluorescence ionic probe utilizing Cu2+ assisted competition for detecting glyphosate abused in green tea

Food fraud caused by the violation of glyphosate use in tea is frequently exposed, posing a potential health risk to consumers and undermining trust in food safety. In the work, an ionic fluorescent probe "[P66614] [4HQCA]-Cu2+ (PHQCA-Cu2+)" was constructed using Cu2+ and ionic liquids coordination through a competitive coordination strategy to detect glyphosate. This probe exhibited a prominent "turn-on" fluorescence response in glyphosate detection. PHQCA-Cu2+was destroyed by glyphosate with its strong coordination capability, and a new complex re-formed simultaneously between glyphosate and the Cu2+ in it, where Cu2+ served as an "invisible indicator" influencing fluorescence changes. Remarkably, PHQCA-Cu2+formed rapidly within 5 s, demonstrated exceptional sensitivity and selectivity, and satisfactory detection performance on paper strips impregnated withPHQCA-Cu2+.Importantly,PHQCA-Cu2+showed excellent recoveries in various green tea, which offered a viable method for identifying contaminated products from the supply chain quickly to enhance overall food safety surveillance.

The manufacturing process provides green teas with differentiated nonvolatile profiles and influences the deterioration of flavor during storage at room temperature

Hundreds of green tea products are available on the tea market and exhibit different characteristics. In the present study, seven types of green tea were processed, and their nonvolatile profiles were analyzed by liquid chromatography-mass spectrometry. Non-spreading green tea contained higher concentrations of catechins and flavonoid glycosides, but lower concentrations of amino acids, caffeine, and theaflavins. Non-rolling green teas with a straight appearance contained higher concentrations of flavonoid glycosides and theaflavins. In contrast, leaf-rolling green teas contained much lower concentrations of flavonoid glycosides and catechins. These seven green tea qualities all decreased following prolonged storage, concurrent with increasing concentrations of proanthocyanidins, catechins dimers, theaflavins, and organic acids. The leaf-rolling green teas exhibited reduced levels of deterioration during storage in terms of their nonvolatile profile and sensory quality. Findings show that moderate destruction on tea leaves during green tea processing is beneficial to both tea flavor and quality maintenance during storage.

Anji white tea relaxes precontracted arteries, represses voltage-gated Ca2+ channels and voltage-gated K+ channels in the arterial smooth muscle cells: Comparison with green tea main component (-)-epigallocatechin gallate

ETHNOPHARMACOLOGICAL RELEVANCE

Tea (Camellia sinensis) is a favorite drink worldwide. Tea extracts and green tea main component (-)-epigallocatechin gallate (EGCG) are recommended for various vascular diseases. Anji white tea is a very popular green tea. Its vascular effect profile, the mechanisms, and the contribution of EGCG to its integrated effect need elucidation.

AIM

To characterize the vasomotion effects of Anji white tea and EGCG, and to explore possible involvement of voltage-gated Ca2+ channels (VGCCs) and voltage-gated K+ (Kv) channels in their vasomotion effects.

MATERIALS AND METHODS

Anji white tea water soaking solution (AJWT) was prepared as daily tea-making process and concentrated to a concentration amounting to 200 mg/ml of dry tea leaves. The tension of rat arteries including aorta, coronary artery (RCA), cerebral basilar artery (CBA), intrarenal artery (IRA), intrapulmonary artery (IPA) and mesenteric artery (MA) was recorded with myographs. In arterial smooth muscle cells (ASMCs) freshly isolated from RCA, the levels of intracellular Ca2+ were measured with Ca2+-sensitive fluorescent probe fluo 4-AM, and Kv currents were recorded with patch clamp. The expressions of VGCCs and Kv channels were assayed with RT-qPCR and immunofluorescence staining.

RESULTS

At 0.4-12.8 mg/ml of dry tea leaves, AJWT profoundly relaxed all tested arteries precontracted with various vasoconstrictors about half with a small transient potentiation on the precontractions before the relaxation. KCl-induced precontraction was less sensitive than precontractions induced by phenylephrine (PE), U46619 and serotonin (5-HT). IPA was less sensitive to the relaxation compared with other arteries. AJWT pretreatment for 1 h, 24 h and 72 h time-dependently inhibited the contractile responses of RCAs. In sharp contrast, at equivalent concentrations according to its content in AJWT, EGCG intensified the precontractions in most small arteries, except that it induced relaxation in PE-precontracted aorta and MA, U46619-precontracted aorta and CBA. EGCG pretreatment for 1 h and 24 h did not significantly affect RCA contractile responses. In RCA ASMCs, AJWT reduced, while EGCG enhanced, intracellular Ca2+ elevation induced by depolarization which activates VGCCs. Patch clamp study showed that both AJWT and EGCG reduced Kv currents. RT-qPCR and immunofluorescence staining demonstrated that both AJWT and EGCG reduced the expressions of VGCCs and Kv channels.

CONCLUSION

AJWT, but not EGCG, consistently induces vasorelaxation. The vasomotion effects of either AJWT or EGCG vary with arterial beds and vasoconstrictors. Modulation of VGCCs, but not Kv channels, contributes to AJWT-induced vasorelaxation. It is suggested that Anji white tea water extract instead of EGCG may be a promising food supplement for vasospastic diseases.

Effects of processing technology on tea quality analyzed using high-resolution mass spectrometry-based metabolomics

Fixation is a crucial step in green tea processing that can impact quality. In this study, we explored the differences in the chemical components of steamed and fried green teas made from the same batch of fresh tea leaves using different fixing methods. Results showed that concentrations of sucrose and free amino acids were significantly higher in steamed green tea. Abundances of 12 compounds including purine nucleoside, pyrimidine nucleoside derivatives, and catechins were higher in fried green tea, while 34 compounds such as amino acids and their derivatives, benzofurans and flavonoids were higher in steamed green tea. Thus, steaming retained more compounds associated with sweet and fresh tastes, such as free amino acids, while frying produced more compounds with bitter tastes, such as catechin. This might explain why steamed green tea is mellower than fried tea.

An efficient artificial intelligence algorithm for predicting the sensory quality of green and black teas based on the key chemical indices

The key components dominating the quality of green tea and black tea are still unclear. Here, we respectively produced green and black teas in March and June, and investigated the correlations between sensory quality and chemical compositions of dry teas by multivariate statistics, bioinformatics and artificial intelligence algorithm. The key chemical indices were screened out to establish tea sensory quality-prediction models based on the result of OPLS-DA and random forest, namely 4 flavonol glycosides of green tea and 8 indices of black tea (4 pigments, epigallocatechin, kaempferol-3-O-rhamnosyl-glucoside, ratios of caffeine/total catechins and epi/non-epi catechins). Compared with OPLS-DA and random forest, the support vector machine model had good sensory quality-prediction performance for both green tea and black tea (F1-score > 0.92), even based on the indices of fresh tea leaves. Our study explores the potential of artificial intelligence algorithm in classification and prediction of tea products with different sensory quality.

A sensor array based on a nanozyme with polyphenol oxidase activity for the identification of tea polyphenols and Chinese green tea

Green tea is popular among consumers because of its high nutritional value and unique flavor. There is often a strong correlation among the type of tea, its quality level and the price. Therefore, the rapid identification of tea types and the judgment of tea quality grades are particularly important. In this work, a novel sensor array based on nanozyme with polyphenol oxidase (PPO) activity is proposed for the identification of tea polyphenols (TPs) and Chinese green tea. The absorption spectra changes of the nanozyme and its substrate in the presence of different TPs were first investigated. The feature spectra were scientifically selected using genetic algorithm (GA), and then a sensor array with 15 sensing units (5 wavelengths × 3 time) was constructed. Combined with the support vector machine (SVM) discriminative model, the discriminative rate of this sensor array was 100% for different concentrations of typical TPs in Chinese green tea with a detection limit of 5 μM. In addition, the identification of different concentrations of the same tea polyphenols and mixed tea polyphenols have also been achieved. Based on the above study, we further developed a facile and efficient new method for the category differentiation and adulteration identification of green tea, and the accuracy of this array was 96.88% and 100% for eight types of green teas and different adulteration ratios of Biluochun, respectively. This work has significance for the rapid discrimination of green tea brands and adulteration.

Potential therapeutic effects of green tea (Camellia sinensis) in eye diseases, a review

This review aims to evaluate the therapeutic potential of green tea (GT), scientifically named Camellia sinensis, in treating eye diseases. We provide an overview of the ingredients and traditional use of Camellia sinensis, followed by a detailed discussion of its therapeutic uses in various eye diseases, including ocular surface diseases (allergic diseases, dry eye, pterygium, and infections), cataract, glaucoma, uveitis, retinal diseases, and optic nerve diseases. The pharmacologic activities related to ocular diseases, such as anti-vascular endothelial growth factor, aldose reductase inhibitor activity, anti-bacterial, anti-inflammatory, and antioxidant effects are also explored in this review. The dose and route of administration of GT in various studies are discussed. Safety issues related to the use of GT, such as the side effects associated with high doses and long-term use, are also addressed. The review highlights the potential of GT as a natural therapeutic agent for a variety of ocular diseases. Its various pharmacologic activities make it a promising treatment option. However, more well-designed studies are needed to determine the optimal dose and route of administration and to assess its long-term safety and efficacy. Overall, GT appears to be a promising adjunct therapy for various ocular diseases.

Effects of tea addition on antioxidant capacity, volatiles, and sensory quality of beer

Green tea has great potential to enhance the quality of beer. In this study, green tea was added at different stages of beer brewing, and evaluated the antioxidant capacity, volatile components, as well as sensory quality. The results showed that the addition of green tea during the start of boiling has great potential for application, and the green tea beer (GTB) had remarkable antioxidant properties (ABTS radical scavenging ability, 8.67 mmol TE/L; DPPH radical scavenging ability, 3.97 mmol TE/L; reducing power, 3.28 mmol TE/L), and an excellent sensory quality (acceptance, 6.09/9). HPLC analysis indicated that the principal phenolics in GTB were catechin and caffeic acid, in addition, the relative amounts of ferulic acid, gallic acid can be used to differentiate between GTB and beer. HS-SPME-GC-MS analyses showed that ethyl caprylate, ethyl nonanoate, ethyl caprate, linalool, and phenethyl alcohol were potentially significant for the aroma profile of GTB.

Green tea and hyaluronic acid gel enhance fibroblast activation and improves the gingival healing post-third molar extraction

This study evaluates the effects of a green tea (Camellia sinensis) and hyaluronic acid gel on fibroblast activity and alveolar bone repair following third molar extractions. By examining the gene expression related to cell survival, proliferation, and angiogenesis, the study bridges in vitro findings with clinical outcomes in a split-mouth randomized trial. Human fibroblasts were exposed to the treatment gel, analysing gene expression through RT-qPCR. Twenty participants undergoing bilateral third molar extractions received the test gel on one side and a placebo on the other. Assessments included patient-reported outcomes, professional evaluations, and radiographic analyses at multiple postoperative intervals. The test gel significantly enhanced AKT, CDKs, and VEGF gene expressions, indicating a positive effect on angiogenesis and cell proliferation. Clinically, it resulted in reduced exudate, swelling, and secondary interventions, with radiographs showing improved alveolar bone density after 90 days. The green tea and hyaluronic acid gel significantly improves soft tissue and bone healing post-extraction, offering a promising adjunctive therapy for enhancing postoperative recovery. This gel represents a novel adjuvant treatment option for facilitating improved healing outcomes after third molar extractions, highlighting its potential utility in clinical dental practice.

Insight into the effect of cultivar and altitude on the identification of EnshiYulu tea grade in untargeted metabolomics analysis

The accurate identification of tea grade is crucial to the quality control of tea. However, existing methods lack sufficient generalization ability in identifying tea grades due to the effect of temporal and spatial factors. In this study, we analyzed the effect of cultivar and altitude on EnshiYulu (ESYL) tea grades and established a robust model to evaluate their quality. Principal component analysis (PCA) revealed that differences in variety and elevation can mask grade differences. Orthogonal projection to latent structure-discriminant analysis (OPLS-DA) was used for grade identification of samples from different altitudes. For ESYL tea samples above and below 800 m altitude, 75 and 35 grade differentiated metabolites were discovered, with 14 common differentiated metabolites. Based on reconstructed OPLS-DA models, the grades of multi-altitude sources ESYL were discriminated with a rate > 85%. These results demonstrate the potential of a grade discrimination model based on common differential metabolites, which exhibits generalization ability.

Unveiling the presence of fluoride in commercial tea infusion: Factors influencing its release and its adsorptive elimination by indigenously developed nanoadsorbents

Drinking tea, which is globally one of the most widely consumed beverages, is a potential source of fluoride toxicity. This research aimed at fluoride estimation in the infusions of commercial black tea and green tea samples, purchased from the local Indian market, systematic evaluation of the factors influencing the fluoride release and the adsorptive removal of fluoride using the indigenously developed nanoadsorbents. All the prepared infusions had fluoride content above the permissible WHO limits. Various factors, which affect the release of fluoride from tea leaves into the infusion include type of water, tea dosage and brewing time. The investigations revealed that, the fluoride content in the black tea infusions was much higher than the green tea infusions. Further, it also depended on the amount of tea leaves used for brewing. The fluoride, present in tea leaves, is released gradually and within just 1 min of brewing, the concentration of fluoride in the infusions was well above the permissible WHO limits. It was also observed that, the dried unprocessed tea leaves, when brewed in water, had high fluoride content. This further confirmed the presence of fluoride in tea infusion, which demands an efficient remediation technique. The developed nanoadsorbents exhibited efficient defluoridation of groundwater, and were therefore tested for their efficiency in defluoridating tea infusions as well. These nanoadsorbents could efficiently eliminate fluoride from both green and black tea infusions, bringing down the fluoride content below the WHO limits, thereby rendering the infusions safe. They exhibited rapid kinetics with high efficiency in adsorbing fluoride from tea infusions. These properties make them potential adsorbents for defluoridating tea infusion, which provides a probable solution to the problem of fluoride toxicity from drinking tea. This is one of the first reports on a technique for eliminating fluoride from tea infusions.

Phytocompounds-based therapeutic approach: Investigating curcumin and green tea extracts on MCF-7 breast cancer cell line

BACKGROUND

Breast cancer (BC) has transcended lung cancer as the most common cancer in the world. Due to the disease's aggressiveness, rapid growth, and heterogeneity, it is crucial to investigate different therapeutic approaches for treatment. According to the World Health Organization (WHO), Plant-based therapeutics continue to be utilized as safe/non-toxic complementary or alternative treatments for cancer, even in developed countries, regardless of how cutting-edge conventional therapies are. Despite their low bioavailability, curcumin (CUR) and green tea (GT) represent safer therapeutic options. Due to their potent molecular-modulating properties on various cancer-related molecules and signaling pathways, they are considered gold-standard therapeutic agents and have been incorporated into the development of one or more therapeutic strategies of BC treatment.

METHODS

We investigated the modulatory role of CUR and GT extracts on significant multi molecular targets in MCF-7 BC cell line to assess their potential as BC multi-targeting agents. We analyzed the phytocompounds in GT leaves using High-performance liquid chromatography (HPLC) and Gas chromatography-mass spectrometry (GC-MS) techniques. The mRNA expression levels of Raf-1, Telomerase, Tumor necrosis factor alpha (TNF-α) and Interleukin-8 (IL-8) genes in MCF-7 cells were quantified using quantitative real-time PCR (qRT-PCR). The cytotoxicity of the extracts was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the released Lactate dehydrogenase (LDH), a valuable marker for identifying the programmed necrosis (necroptosis). Additionally, the concentrations of the necroptosis-related proinflammatory cytokines (TNF-α and IL-8) were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

In contrast to the GT, the results showed the anticancer and cytotoxic properties of CUR against MCF-7 cells, with a relatively higher level of released LDH. The CUR extract downregulated the oncogenic Raf-1, suppressed the Telomerase and upregulated the TNF-α and IL-8 genes. Results from the ELISA showed a notable increase in IL-8 and TNF-α cytokines levels after CUR treatment, which culminated after 72 h.

CONCLUSIONS

Among both extracts, only CUR effectively modulated the understudy molecular targets, achieving multi-targeting anticancer activity against MCF-7 cells. Moreover, the applied dosage significantly increased levels of the proinflammatory cytokines, which represent a component of the cytokines-targeting-based therapeutic strategy. However, further investigations are recommended to validate this therapeutic approach.

Association of green tea consumption with prediabetes, diabetes and markers of glucose metabolism in rural Vietnam: a cross-sectional study

The literature on green tea consumption and glucose metabolism has reported conflicting findings. This cross-sectional study examined the association of green tea consumption with abnormal glucose metabolism among 3000 rural residents aged 40-60 years in Khánh Hòa province in Vietnam. Multinomial logistic regression analysis was conducted to examine the association of green tea consumption (0, < 200, 200-< 400, 400-< 600 or ≥ 600 ml/d) with prediabetes and diabetes (based on the American Diabetes Association criteria). Linear regression analysis was performed to examine the association between green tea consumption and the log-transformed homeostatic model assessment of insulin resistance (HOMA-IR) (a marker of insulin resistance) and the log-transformed homeostatic model assessment of β-cell function (HOMA-β) (a marker of insulin secretion). The OR for prediabetes and diabetes among participants who consumed ≥ 600 ml/d v. those who did not consume green tea were 1·61 (95 % CI = 1·07, 2·42) and 2·04 (95 % CI = 1·07, 3·89), respectively. Higher green tea consumption was associated with a higher level of log-transformed HOMA-IR (Pfor trend = 0·04) but not with a lower level of log-transformed HOMA-β (Pfor trend = 0·75). Higher green tea consumption was positively associated with the prevalence of prediabetes, diabetes and insulin resistance in rural Vietnam. The findings of this study indicated prompting the need for further research considering context in understanding the link between green tea consumption and glucose metabolism, especially in rural settings in low- and middle-income countries.

Association between green tea intake and digestive system cancer risk in European and East Asian populations: a Mendelian randomization study

PURPOSE

Previous observational studies have shown that green tea consumption is associated with a reduced incidence of digestive system cancers (DSCs). However, the observed association could be due to confounding factors. Therefore, we used a two-sample Mendelian randomization (MR) approach to assess the causal effect of green tea intake on the risk of five common DSCs.

METHODS

Independent genetic variants strongly associated with green tea consumption in European and East Asian populations were selected as instrumental variables in genome-wide association studies involving up to 64,949 European individuals and 152,653 East Asian individuals, respectively. The associations between genetic variants and DSCs were extracted from the FinnGen study and the Japan Biobank. The primary analysis was performed using random-effects inverse variance weighting (IVW). Other MR analyses, including weighted mode-based estimate, weighted-median, MR-Egger regression, Mendelian Randomization-Pleiotropy Residual Sum and Outlier (MR-PRESSO) analysis, were used for sensitivity analyses. In addition, a multivariate MR design was performed to adjust for smoking and alcohol consumption.

RESULTS

The IVW results showed no causal relationship between tea intake and DSCs risk in European population (esophagus cancer: odds ratio (OR) = 1.044, 95% confidence interval (CI) 0.992-1.099, p = 0.096; stomach cancer: OR = 0.988, 95% CI 0.963-1.014, p = 0.368; colorectal cancer: OR = 1.003, 95% CI 0.992-1.015, p = 0.588; liver cancer: OR = 0.996, 95% CI 0.960-1.032, p = 0.808; pancreatic cancer: OR = 0.990, 95% CI 0.965-1.015, p = 0.432). The MR-Egger regression, MR-PRESSO analysis and other methods also confirmed the reliability of the conclusion. Similarly, no significant association was found between green tea consumption and the incidence of DSCs among East Asians. This relationship is not significant even after adjusting for smoking and alcohol consumption (P > 0.05).

CONCLUSION

Our study provides evidence that genetically predicted green tea intake is not causally associated with the development of DSCs in the European and East Asian population.

Green tea consumption and incidence of cardiovascular disease in type 2 diabetic patients with overweight/obesity: a community-based cohort study

BACKGROUND

Green tea has been reported to be potentially protective against the development of cardiovascular disease (CVD). This study aimed to investigate the association between green tea consumption and incident CVD in type 2 diabetes (T2D) patients with overweight/obesity.

METHODS

A total of 4756 Chinese overweight/obese T2D patients were recruited and followed up for 6.27 years. Information on green tea consumption was collected at baseline using interviewer-administered questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) for incident CVD according to green tea consumption were estimated using the Cox proportional hazards model.

RESULTS

Compared with non-habitual consumers, participants who consumed > 5 g/day of green tea leaves reduced the risk of CVD by 29% (95%CI: 0.55-0.92), stroke by 30% (95%CI: 0.51-0.95) and coronary heart disease (CHD) by 40% (95%CI: 0.40-0.89). Similarly, participants who consumed green tea for ≥ 40 years reduced the risk of CVD by 31% (95%CI: 0.54-0.88), stroke by 33% (95%CI: 0.50-0.90) and CHD by 39% (95%CI: 0.42-0.88). Among participants with < 5-year history of T2D, > 5 g/day of tea leaves and > 40 years of tea consumption were associated with 59% (95%CI: 0.23-0.72) and 57% (95%CI: 0.26-0.74) reduced risk of stroke, respectively. However, among participants with ≥ 5-year history of T2D, > 5 g/day of tea leaves and > 40 years of tea consumption were associated with a 50% (95%CI: 0.30-0.82) and 46% (95%CI: 0.35-0.85) reduced risk of CHD, respectively.

CONCLUSIONS

Green tea consumption is associated with reduced risk of CVD, stroke, and CHD in overweight/obese T2D patients.

Dietary supplementation with green tea extract improves the antioxidant status and oocyte developmental competence in Italian Mediterranean buffaloes

The aim of this work was to assess the antioxidant status and the developmental competence of oocytes recovered by ovum pick-up (OPU) in Italian Mediterranean buffaloes supplemented with green tea extracts (GTE) for 90 days. Buffalo cows (n = 16) were randomly assigned to a control group receiving no supplement and a treatment group, receiving GTE starting 90 days before OPU, carried out for five consecutive sessions. Blood samples were collected before the start of supplementation with GTE (T0) and at day 45 (T1) and day 90 (T2) of supplementation, to measure ferric reducing activity (FRAP), total antioxidant capacity (TAC), superoxide dismutase (SOD) and catalase (CAT). The antioxidant status of follicles was measured as TAC on the follicular fluid collected from the dominant follicle just prior OPU, coinciding with T2, and at the end of five repeated OPU sessions (T3). Another objective was to assess in vitro the protective effects of green tea extracts on hepatic cells exposed to methanol insult. Different concentrations of GTE (0.5 μM and 1 μM) were tested on cultured hepatic cells and viability, morphology and SOD activity were assessed at 24, 48 and 72 h. Supplementation with GTE increased (P < 0.05) the number of total follicles (8.7 ± 0.5 vs 6.9 ± 0.5), the number and the percentage of Grade A + B cumulus-oocyte complexes (COCs) compared with the control (3.7 ± 0.4 vs 2.3 ± 0.3 and 57.5 ± 4.2 vs 40.4 ± 4.9 %, respectively). Oocyte developmental competence was improved in the GTE group as indicated by the higher (P < 0.05) percentages of Grade 1,2 blastocysts (44.8 vs 29.1 %). In the GTE group, plasma TAC was higher both at T1 and T2, while FRAP increased only at T2, with no differences in SOD and CAT. The TAC of follicular fluid was higher (P < 0.05) in the GTE compared to the control both at T2 and at T3 The in vitro experiment showed that co-treatment with methanol and 1 μM GTE increased (p < 0.01) cell viability at 24 h (P < 0.01), 48 h (P < 0.05) and 72 h (P < 0.01) compared with the methanol treatment co-treatment with 1 μM GTE prevented the decrease in SOD activity observed with methanol at 24 and 48 h of culture. In conclusion, the results of in vivo and in vitro experiments suggest that supplementation with GTE increases buffalo oocyte developmental competence, by improving oxidative status and liver function.

Screening Commercial Tea for Rapid Inactivation of Infectious SARS-CoV-2 in Saliva

SARS-CoV-2 infects the oral mucosa and is shed in salivary fluids. Traditionally, tea has been used by various cultures to treat respiratory ailments. The objective of this study was to identify commercially available teas that can rapidly inactivate infectious SARS-CoV-2 in saliva. Initially, tea (n = 24) was prepared as 40 mg/mL infusions and incubated with SARS-CoV-2 resuspended in water, for 5 min at 37 °C. Then, five teas that showed >3 log reduction in virus infectivity were further investigated at 40 and 10 mg/mL infusions for 60 and 10 s contact time with SARS-CoV-2 resuspended in saliva. Tea polyphenols were measured using the Folin-Ciocalteu assay. SARS-CoV-2 infectivity was quantified on Vero-E6 cell line using TCID50 assay. At 10 mg/mL infusion, black tea showed the highest reduction (3 log, i.e., 99.9%) of infectious SARS-CoV-2 within 10 s. Green, mint medley, eucalyptus-mint, and raspberry zinger teas showed similar inactivation of SARS-CoV-2 (1.5-2 log, i.e., 96-99% reduction). At 40 mg/mL infusions, all five teas showed >3 log reduction in virus infectivity within 10 s. Tea polyphenol but not pH was significantly correlated to virus reduction. Time-of-addition assay revealed that the five teas displayed preventive effects (0.5-1 log, i.e., 68-90% reduction) against SARS-CoV-2 infection of Vero-E6 cells as well as during post-virus infection (1.2-1.9 log, i.e., 94-98%). However, the highest inhibitory effect was observed when the teas were added at the time of virus infection (2-3 log, i.e., 99-99.9%). Our results provide insights into a rapid at-home intervention (tea drinking or gargling) to reduce infectious SARS-CoV-2 load in the oral cavity which might also mitigate infection of the oral mucosa.

The Control and Comprehensive Safety Assessment of Heavy Metal Impurities (As, Pb, and Cd) in Green Tea Camellia sinensis (L.) Samples (Infusions) Available in Poland

Tea is the world's most common drink after water, and the world's annual sales exceed $43 billion, of which more than $11 billion is green tea (Camellia sinensis (L.)). Increasing evidence continues to show that green tea consumption and its ingredients have a variety of potential health benefits. The aim of the study was to control and assess the toxicological risk (TRA) of three heavy metals (As, Pb, and Cd) in infusions of green tea (n = 12) from Polish markets. We applied the method of inductive coupled plasma mass spectrometry (ICP-MS) to determine the selected heavy metal and designed a specific toxicological risk assessment with three crucial tiers. The first tier of our strategy was to determine the elements investigated (heavy metal impurities, µg/L). The second step was to estimate the weekly intake of green tea infusions (µg/week) based on weekly consumption. The third tier was to estimate the weekly intake per weight (µg/L/week/bw), based on the average weekly intake of green tea infusion per adult compared to the provisional weekly intake (PTWI) established by the FAO/WHO Joint Food Additives Expert Committee (JECFA). The levels of the investigated heavy metals occur at different levels in all of the investigated green tea infusions. The heavy metal profile indicated that As (0.0721-10.585 µg/L), Pb (0.386-1.695 µg/L), and Cd (0.126-0.346 µg/L) were present in all samples. Basic analysis of general content shows that As (average = 0.325 µg/L) was at a level similar to Cd (average = 0.214 µg/L). Surprisingly, the Pb content (average 0.891 µg/L) was approximately 2.75-4 times higher than that of As and Cd, respectively. The application of our proposed safety assessment methodology (three tiers) provides satisfactory results for regulatory purposes. The evaluation of the investigated heavy metals in all products analysed from green tea samples (infusions) showed that there were no health hazards to consumers due to weekly exposure. The results indicated that after drinking green tea infusions from Polish markets, the amount of investigated elements in weekly doses does not represent any health risks to consumers.

Purification, structural characteristics and anti-atherosclerosis activity of a novel green tea polysaccharide

A new homogeneous polysaccharide (TPS3A) was isolated and purified from Tianzhu Xianyue fried green tea by DEAE-52 cellulose and Sephacryl S-500 column chromatography. Structural characterization indicated that TPS3A mainly consisted of arabinose, galactose, galacturonic acid and rhamnose in a molar ratio of 5.84: 4.15: 2.06: 1, with an average molecular weight of 1.596 × 104 kDa. The structure of TPS3A was characterized as a repeating unit consisting of 1,3-Galp, 1,4-Galp, 1,3,6-Galp, 1,3-Araf, 1,5-Araf, 1,2,4-Rhap and 1-GalpA, with two branches on the C6 of 1,3,6-Galp and C2 of 1,2,4-Rhap, respectively. To investigate the preventive effects of TPS3A on atherosclerosis, TPS3A was administered orally to ApoE-deficient (ApoE-/-) mice. Results revealed that TPS3A intervention could effectively delay the atherosclerotic plaque progression, modulate dyslipidemia, and reduce the transformation of vascular smooth muscle cells (VSMCs) from contractile phenotype to synthetic phenotype by activating the expression of contractile marker alpha-smooth muscle actin (α-SMA) and inhibiting the expression of synthetic marker osteopontin (OPN) in high-fat diet-induced ApoE-/- mice. Our findings suggested that TPS3A markedly alleviated atherosclerosis by regulating dyslipidemia and phenotypic transition of VSMCs, and might be used as a novel functional ingredient to promote cardiovascular health.

Antiviral Effects and Mechanisms of Green Tea Catechins on Influenza: A Perception on Combating Symptoms from COVID-19

Over the centuries, influenza and its associated epidemics have been a serious public health problem. Although vaccination and medications (such as neuraminidase inhibitors) are the mainstay of pharmacological approaches to prevent and treat influenza, however, frequent mutations in the influenza genome often result in treatment failure and resistance to standard medications which limit their effectiveness. In recent years, green tea catechins have been evaluated as potential anti-influenza agents. Herein, in this review, we highlighted the effects and mechanisms underlying the inhibitory effects of epigallocatechin 3-gallate (EGCG), the most abundant ingredient in green tea, against different influenza viral infections, and their clinical benefits toward prevention and treatment. In addition, as the severe acute respiratory syndrome coronavirus 2 (SARSCoV- 2) causes the outbreak of COVID-19 pandemic, our review also delineates the current perspective on SARS-CoV-2 and future insights as to the potential application of EGCG on suppressing the flu-like symptoms caused by COVID-19.

The intestinal-level metabolic benefits of green tea catechins: Mechanistic insights from pre-clinical and clinical studies

BACKGROUND

The intestinal-level host-microbiota interaction has been implicated in the pathogenesis of chronic diseases. The current review is intended to provide a comprehensive insight into deciphering whether intestinal-level bioactivities mediate the overall metabolic health benefits of green tea catechins.

PURPOSE

We have comprehensively discussed pre-clinical and clinical evidences of intestinal-level changes in metabolism, microbiota, and metabolome due to catechin-rich green tea treatments, ultimately limiting metabolic diseases. Exclusive emphasis has been given to purified catechins and green tea, and discussions on extraintestinal mechanisms of metabolic health benefits were avoided.

METHODS

A literature search for relevant pre-clinical and clinical studies was performed in various online databases (e.g., PubMed) using specific keywords (e.g., catechin, intestine, microbiota). Out of all the referred literature, ∼15% belonged to 2021-2023, ∼51% were from 2011-2020, and ∼32% from 2000-2010.

RESULT

The metabolic health benefits of green tea catechins are indeed influenced by the intestinal-level bioactivities, including reduction of mucosal inflammation and oxidative stress, attenuation of gut barrier dysfunction, decrease in intestinal lipid absorption and metabolism, favorable modulation of mucosal nuclear receptor signaling, alterations of the luminal global metabolome, and mitigation of the gut dysbiosis. The results from the recent clinical studies support the pre-clinical evidences. The challenges and pitfalls of the currently available knowledge on catechin bioactivities have been discussed, and constructive directions to harness the translational benefits of green tea through future interventions have been provided.

CONCLUSION

The metabolism, metabolome, and microbiota at the intestinal epithelia play critical roles in catechin metabolism, pharmacokinetics, bioavailability, and bioactivities. Especially the reciprocal interaction between the catechins and the gut microbiota dictates the metabolic benefits of catechins.

Epigallocatechin-3-gallate and its nanoformulation in cervical cancer therapy: the role of genes, MicroRNA and DNA methylation patterns

Green tea, a popular and healthy nonalcoholic drink consumed globally, is abundant in natural polyphenols. One of these polyphenols is epigallocatechin-3-gallate (EGCG), which offers a range of health benefits, such as metabolic regulation, antioxidant properties, anti-inflammatory effects, and potential anticancer properties. Clinical research has shown that EGCG can inhibit cancers in the male and female reproductive systems, including ovarian, cervical, endometrial, breast, testicular, and prostate cancers. Further research on cervical cancer has revealed the crucial role of epigenetic mechanisms in the initiation and progression of this type of cancer. These include changes to the DNA, histones, and non-coding RNAs, such as microRNAs. These changes are reversible and can occur even before genetic mutations, making them a potential target for intervention therapies. One promising approach to cancer prevention and treatment is the use of specific agents (known as epi-drugs) that target the cancer epigenome or epigenetic dysregulation. Phytochemicals, a group of diverse molecules, have shown potential in modulating cancer processes through their interaction with the epigenetic machinery. Among these, green tea and its main polyphenol EGCG have been extensively studied. This review highlights the therapeutic effects of EGCG and its nanoformulations on cervical cancer. It also discusses the epigenetic events involved in cervical cancer, such as DNA methylation and microRNA dysregulation, which may be affected by EGCG.

Effects of brewing water on the volatile composition of tea infusions

There is a huge demand for brewing water in tea consumption, and the sensory flavor of tea infusion is significantly affected by the water used for brewing. To investigate the impact of brewing water on the aroma of tea infusions made from Camelia senensis, the three tea infusions of green, oolong and black tea brewed by six different drinking waters were analyzed by sensory evaluation, solid-phase microextraction, gas chromatography-mass spectrometry, and chemometrics. Brewing water with high pH values (>8.10) and high TDS content (>140 ppm) resulted in a lower overall aroma acceptability for tea infusion, where HCO3-, Ca2+ and Mg2+ were key influencing ions. A total of 86, 106, and 131 volatiles were identified in green, oolong and black tea infusions, respectively, which were strongly influenced by six different brands of waters. Decanal, dimethyl sulfide, β-ionone and linalool were potent volatiles in tea aroma changes caused by brewing water.

Consumption of herbal infusions/decoctions and tea in Greece: a Planeterranean perspective on the results of Hydria survey

BACKGROUND

The consumption of various herbal infusions was and is common in the traditional Mediterranean diet, and apparently are used in many other regions of the world outside of the Mediterranean region. The present study aimed to investigate the consumption of herbal infusions/decoctions and tea in a nationally representative sample of Greece, considering also their Planetary use.

METHODS

3951 adult participants of the HYDRIA Survey (2013-2014) were included from the 13 regions of Greece. The diet of participants was assessed by two 24-h dietary recalls (24-HDR) and the Food Propensity Questionnaire (FPQ). All food items were analyzed through the HYDRIA Food Composition Tables. Information on socio-demographics, lifestyle, and health characteristics during the baseline was also provided.

RESULTS

26.9% of herbal infusions and decoctions consumers are ≥ 75 years old, pensioners with a low level of education, and residents of urban areas. However, 22.2% of tea consumers belong to the 18-34-year age group, being employed with an intermediate level of education and living in an urban area. Elderly men and women use more herbal infusions/decoctions (55.4%; 40.6%) compared to tea (41.8%; 25.2%). According to FPQ, 7.1% of men and 9.7% of women use herbal infusions and decoctions four times or more per week, while 7.1 and 10.9% of men and women, respectively, consume tea at the same frequency. Green tea, mountain tea (Sideritis spp.), and black tea are reported most frequently. In addition, mountain tea (61.2%), black tea (60.3%), mixed herbal infusions/decoctions (58.4%), and sage (59.4%) are consumed mostly at breakfast, while chamomile was reported mainly at dinner or during the night (42.4%).

CONCLUSIONS

Based on the FPQ results, the moderate and high consumption of herbal infusions/decoctions and tea is low in Greece, especially among adults (18-64 years). Thus, our results indicate the existence of a generation gap to the attachment to the traditional Med Diet and the consumption of herbal infusions. The present study could encourage future research to focus on herbal infusions and decoctions consumption by other populations for cross-cultural comparison, as well as on emphasizing the value of consuming locally available herbs in a Planeterranean perspective.

Biochar effects on early decomposition of standard litter in a European beech forest (northern Italy)

The release of biochar (BC) on forest soil is a strategy aimed at increasing carbon reserves and forest productivity. The effect of BC amendments on the decomposition of different quality litter is, however, poorly understood. With this study we investigate the effects of wood-derived BC applications on early decomposition in a European beech (Fagus sylvatica L.) forest through the burial of standard material, i.e. green tea and rooibos tea (high- and low-quality litter surrogates, respectively). Two main questions were addressed: 1) Do BC applications influence the decomposition of high- and low-quality standard litter and, if so, in what way? and 2) Does this effect (if measurable) depend on where the sample is placed with respect to the BC application layer? To test BC amendment effects, four application percentages were employed (0, 10, 20 and 100 %), after which standard litter mass loss was recorded. To investigate the effects of sample position, only three BC application percentages were used (0, 10 and 20 %), with teabags buried at three different depths - within the BC amended layer, between this layer and the unamended soil, and below the latter. Results show that early decomposition of high-quality standard litter was not influenced by BC applications, while a significant reduction in mass loss of low-quality standard litter was observed when the percentage of BC application was higher, specifically of litter within the 20 % and 100 % BC amended layers. Decomposition was also affected by sample position relative to the BC layer, exhibiting higher levels of mass loss when samples were placed within the BC amended layer. Overall, BC applications on beech forest soils not only seem to produce negligible effects on the early decomposition rate of high-quality standard litter, but such applications also seem to have the ability to reduce carbon loss following plant material degradation.

L-Theanine adjunct to risperidone in the treatment of chronic schizophrenia inpatients: a randomized, double-blind, placebo-controlled clinical trial

RATIONALE

Inadequate responses to current schizophrenia treatments have accelerated research into novel therapeutic approaches.

OBJECTIVES

This study investigated the efficacy and tolerability of adjunctive L-theanine, an ingredient with neuroimmunomodulatory and neuroprotective properties, for chronic schizophrenia.

METHODS

Eighty chronic schizophrenia inpatients were equally assigned to receive risperidone (6 mg/day) plus either L-theanine (400 mg/day) or matched placebo in this 8-week, randomized, parallel-group, double-blind, placebo-controlled trial. The participants were assessed using the Positive and Negative Syndrome Scale (PANSS) by recording the results of subscales at baseline and weeks 4 and 8 to measure treatment efficacy. Additionally, the participants were assessed for the Hamilton Depression Rating Scale (HDRS) and adverse events, including the Extrapyramidal Symptom Rating Scale (ESRS).

RESULTS

Sixty patients, 30 in each group, were included in the analyses. All baseline demographic and clinical characteristics were comparable between the groups (p-values > 0.05). The reduction rates from baseline to endpoint in negative, general psychopathology, and total scores of PANSS were greater in the L-theanine group (p-values = 0.03, 0.01, and 0.04, respectively). Regarding general psychopathology scores, the reduction in the L-theanine group was also greater until week 4 (p-value < 0.01). The time × treatment interaction effect was significant on negative (p-value = 0.03), general psychopathology (p-value < 0.01), and total (p-value = 0.04) scores of PANSS, indicating additional improvements in the L-theanine group. The HDRS and side effects were comparable between the groups (p-values > 0.05).

CONCLUSIONS

L-Theanine adjunct to risperidone safely and tolerably outperformed adjunctive placebo for schizophrenia, and promising evidence indicated its effects on primary negative symptoms, which need to be scrutinized in further studies.

TRIAL REGISTRATION

The study protocol was registered and published prospectively in the Iranian Registry of Clinical Trials ( http://www.irct.ir ; registration number: IRCT20090117001556N133) on 2020-12-12.

Catechin Composition, Phenolic Content, and Antioxidant Properties of Commercially-Available Bagged, Gunpowder, and Matcha Green Teas

The leaves of the Camellia sinensis plant are used to produce many different types of teas, and green tea is particularly noted for its health promoting properties which are attributed to high concentrations of phenolic compounds known as catechins. Green tea is available in forms such as bagged, gunpowder (rolled leaf), and matcha, a fine powder. This study evaluated the phenolic content, catechin composition, caffeine concentration, and antioxidant properties of fifteen commercially-available green teas with an emphasis on identifying differences between ceremonial and culinary matcha. Gunpowder and bagged green teas had higher total phenolic contents and greater CUPRAC (cupric ion reducing antioxidant capacity) and ORAC (oxygen radical absorbance capacity) antioxidant capacities than matcha teas. Among matcha samples, less expensive culinary teas had greater total phenolic contents and higher antioxidant capacities than ceremonial products. Hierarchical cluster analysis was used to determine similarities and differences in catechin composition and revealed that bagged and gunpowder green teas had the highest levels of the stereoisomers epi/catechin gallate, which correlated with their strong antioxidant properties. Bagged and gunpowder teas were the lowest cost products in this study, indicating that they are an economical choice for consumers who want a green tea beverage with high catechin content, although they generally had lower caffeine levels than matcha.

Effect of fluid replacement with green tea on body fluid balance and renal responses under mild thermal hypohydration: a randomized crossover study

PURPOSE

Maintaining an appropriate hydration level by ingesting fluid in a hot environment is a measure to prevent heat-related illness. Caffeine-containing beverages, including green tea (GT), have been avoided as inappropriate rehydration beverages to prevent heat-related illness because caffeine has been assumed to exert diuretic/natriuretic action. However, the influence of caffeine intake on urine output in dehydrated individuals is not well documented. The aim of the present study was to examine the effect of fluid replacement with GT on body fluid balance and renal water and electrolyte handling in mildly dehydrated individuals.

METHODS

Subjects were dehydrated by performing three bouts of stepping exercise for 20 min separated by 10 min of rest. They were asked to ingest an amount of water (H2O), GT, or caffeinated H2O (20 mg/100 ml; Caf-H2O) that was equal to the volume of fluid loss during the dehydration protocol; fluid balance was measured for 2 h after fluid ingestion.

RESULTS

The dehydration protocol induced hypohydration by ~ 10 g/kg body weight (~ 1% of body weight). Fluid balance 2 h after fluid ingestion was significantly less negative in all trials, and the fluid retention ratio was 52.2 ± 4.2% with H2O, 51.0 ± 5.0% with GT, and 47.9 ± 6.2% with Caf-H2O; those values did not differ among the trials. After rehydration, urine output, urine osmolality, and urinary excretions of osmotically active substances, sodium, potassium and chloride were not different among the trials.

CONCLUSION

The data indicate that ingestion of GT or an equivalent caffeine amount does not worsen the hydration level 2 h after ingestion and can be effective in reducing the negative fluid balance for acute recovery from mild hypohydration.

TRIAL REGISTRATION

ISRCTN53057185; retrospectively registered.

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.

Comparison of volatile and nonvolatile metabolites in green tea under hot-air drying and four heat-conduction drying patterns using widely targeted metabolomics

Hot-air and heat-conduction drying are the most common drying patterns in green tea production. However, the differences between them in terms of the resulting green tea chemical compounds have not been illustrated systematically. In this study, 515 volatile and 204 nonvolatile metabolites were selected to compare the differences between hot-air drying green tea (HAGT) and four heat-conduction drying green teas (HCDGTs) using widely targeted metabolomics. The results showed notable changes in volatile compounds; for example, two kinds of HCDGTs preferred to form chestnut-like and caramel-like key odorants. In addition, 14 flavonol glycosides, 10 catechins, 9 phenolic acids, 8 amino acids, 7 flavonols, and 3 sugars were significantly changed between HAGT and HCDGTs (p < 0.05), presenting a tremendous discrepancy in the transformation of nonvolatile compounds. Our results provide clear guidance for the precise manufacturing of green tea by four common heat-drying patterns and hot air-drying patterns.

The formation mechanism of aroma quality of green and yellow teas based on GC-MS/MS metabolomics

Aroma is a crucial determinant of tea quality. While some studies have examined the aroma of yellow tea, there are no reports of the difference and formation mechanism of aroma quality between yellow and green teas from the same tea tree variety. This study employed gas chromatography-mass spectrometry to investigate the difference and formation mechanism of the aroma of yellow and green tea at the omics level, based on sensory evaluation. The sensory evaluation revealed that green tea has a distinct faint scent and bean aroma, while yellow tea, which was yellowed for 48 h, has a noticeable corn aroma and sweet fragrance. A total of 79 volatile metabolites were detected in the processing of yellow and green tea, covering 11 subclasses and 27 were differential volatile metabolites. Benzoic acid, 2-(methylamino-), methyl ester, terpinen-4-ol ethanone, 1-(1H-pyrrol-2-yl-), 3-penten-2-one, 4-methyl- and benzaldehyde were characteristic components of the difference in aroma quality between green and yellow teas. Eleven volatile metabolites significantly contributed to the aroma quality of green and yellow teas, especially acetic acid, 2-phenylethyl ester, with rose and fruity aromas. KEGG enrichment analysis showed that the arginine and proline metabolism might be the key mechanism of aroma formation during green and yellow teas' processing. These finding provide a theoretical basis way for the aroma formation of green and yellow teas.

Thermoneutrality or standard temperature: is there an ideal housing temperature to study the antisteatotic effects of green tea in obese mice?

Metabolic-associated fatty liver disease (MAFLD) is a condition characterized by excessive accumulation of triglycerides in hepatocytes, currently considered the number one cause of chronic liver disease. MAFLD is strongly associated with obesity, type 2 diabetes, hyperlipidaemia, and hypertension. Emphasis has been placed on the use of green tea (GT), produced from the Camellia sinensis plant, rich in antioxidants as polyphenols and catechins, on obesity and MAFLD treatment/prevention. Studies carried out in rodent models housed at a standard temperature (ST, 22°C) are being questioned as ST is a determining factor on generating changes in the physiology of immune response, and energy metabolism. On the other hand, it seems that thermoneutrality (TN, 28°C) represents a closer parallel to human physiology. In this perspective, we investigated the effects of GT (500 mg/kg of body weight, over 12 weeks, 5 days/week) by comparing mice housed at ST or TN in a model of MAFLD of diet-induced obese males C57Bl/6 mice. We show that the liver phenotype at TN exhibits a more severe MAFLD while GT ameliorates this condition. In parallel, GT restores the expression of genes involved in the lipogenic pathway, regardless of temperature, with slight modifications in lipolysis/fatty acid oxidation. We observed an increase promoted by GT in PPARα and PPARγ proteins independently of housing temperature and a dual pattern of bile acid synthesis. Thus, animals' conditioning temperature is a key factor that can interfere in the results involving obesity and MAFLD, although GT has beneficial effects against MAFLD independently of the housing temperature of mice.

Revelation of volatile contributions in green teas with different aroma types by GC-MS and GC-IMS

Aroma types of green teas associate with their commercial prices and consumer acceptance, mainly including floral-like (HX), chestnut-like (LX), and fresh (QX) aromas. However, the volatile differences and specificities in these aroma types are still unclear. Herein, Taiping Houkui green teas with HX, LX, and QX aromas were processed separately with the same fresh tea leaves. Ninety-four and seventy-eight volatiles were detected and identified by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS), respectively. Candidate differential volatiles among the tea samples were determined by the variable importance in projection (VIP) of the partial least squares-discriminant analysis (PLS-DA) and were further confirmed by the relative odor activity value (ROAV) and odor description. The volatiles 1-hexanol, linalool oxide (furanoid), linalool, geraniol, (E)-β-ionone, isoamyl acetate, and 2-methylpropanal enriched in HX and contributed to the floral-like aroma, while 3-methylbutanal, 2-ethyl-1-hexanol, indole, β-damascone, and cedrol enriched in LX and contributed to the chestnut-like aroma. This study reveals the specificities and contributions of volatiles in green teas with different aromas, thus providing new insights into the molecular basis of different flavored teas, benefiting for their precision processing and targeted quality control.

Influence of green tea on alcohol aggravated neurodegeneration of cortex, cerebellum and hippocampus of STZ-induced diabetic rats

The main aim of this study was to evaluate the cytotoxic effects of chronic alcohol consumption on various regions of diabetic brain and preventive role of GTE. Clinical, experimental and histopathological observations indicate chronic, excessive alcohol consumption aggravates the free radical-mediated oxidative and nitrosative stress in several tissues including brain. Treatment with Epigallocatechin gallate (EGCG) significantly reduced the levels of oxidative/nitrosative stress paradigms, increased glutathione (GSH) levels and enhanced the activities of antioxidant enzymes. Histopathology evaluation revealed the possible influence of EGCG in reversing alcohol exacerbated diabetes-induced damage in cortex, cerebellum and hippocampus of brain. Furthermore, these studies have provided evidence to show how EGCG can exactly occupy the position in functional sites of nNOS (neuronal nitric oxide synthase) and induce a conformational change, inhibition of enzymatic activity and prevention of neurodegeneration/necrotic changes of tissue, in comparison with the rosiglitazone and glibenclamide. To summarise, this research has offered useful information on the action of EGCG that would provide potential protection against ethanol exacerbated diabetic brain damageand additional evidence for the use of EGCG as a lead compound for drug discovery.

The types of brewing water affect tea infusion flavor by changing the tea mineral dissolution

The effects of different brewing water samples, including natural drinking water (NDW), pure water (PW), mineral water (MW), distilled water (DW), and tap water (TW) on flavor and quality of green tea infusion were investigated. The results showed the dissolution rate of mineral substances varied greatly depend on the type of water used. Notably, the tea infusion brewed with MW showed the highest taste response and darker but higher brightness in color. Furthermore, the content of volatile compounds was highest in tea infusion brewed with NDW and lowest in tea infusion brewed with MW. The mineral substances content and pH were the main factors affecting volatile compounds in green tea infusion. Thereinto, Ca²⁺ and Fe³⁺ remarkably affected the content of alcohols and aldehydes in volatile compounds. These results suggested that water with a neutral pH value and lower mineral substance content is more conducive for brewing green tea.

Effect of chamomile (Matricaria chamomilla L.), linden (Tilia cordata Mill.), and green tea (Camellia sinensis L.) aqueous extract administration in the drinking water during pre-slaughter feed withdrawal period in broiler chickens

Feed withdrawal (FW) and other pre-slaughter stressors have detrimental effects on the meat quality of broiler chickens. Herbal extracts can be used for their sedative effects to reduce the harmful impacts of pre-slaughter stress on broiler chickens. This study aimed to investigate the effect of chamomile (CAE), linden (LAE), and green tea (GAE) aqueous extracts (AE) in drinking water during the pre-slaughter FW period on the meat and liver quality, serum corticosterone level, and some cecal microorganisms of broilers. A total of 450 male and female 42-day-old chickens were allocated to a completely randomized design with five treatment groups and two sexes in six replicates, 12 birds (six male and six female) for each replicate. Treatment groups were chickens offered ad libitum feed and drinking water (control, CT), broilers exposed to FW for 10 h before the slaughter with unsupplemented drinking water (FW), with drinking water supplemented 50 ml/L CAE, LAE, and GAE. Chickens that experienced FW had lower (P < 0.001) slaughter body weight, carcass, gastrointestinal tract (GIT) and inner organ weights, and GIT length (P = 0.002). However, the dressing percentage was higher (P < 0.001) in FW and AE groups than CT group. The FW increased (P < 0.001) the ultimate pH of thigh meat compared with the CT group. The FW also decreased (P = 0.026) the lightness (L*) value of thigh meat of broilers, although CAE and LAE did not change the L* value compared with the CT group. Similarly, the redness (a*) value of thigh meat was lower (P = 0.003) in chickens exposed to FW but was not affected by GAE administration. However, FW or AE did not impact the serum corticosterone level and cecal microbial loads in broiler chickens. The obtained result showed that CAE, LAE, or GAE can be used in drinking water to reduce the harmful effects of FW on the meat quality of broiler chickens.

Laccase-assisted colouration of wool fabric using green tea extract for imparting antioxidant, antibacterial, and UV protection activities

The demand for natural dyes for imparting sustainable dyeing effects to textiles is increasing. Metal mordants generate an unstainable impact in the natural dyeing of textiles. In order to avoid the toxic effect due to the use of metal mordants, the present work uses enzyme for sustainable natural dyeing of wool. The current study is aimed at preparing multifunctional wool fabric using natural dye green tea (Camellia sinensis). Laccase (an enzyme) was used to polymerise the phenolic compounds of Camellia sinensis in situ on wool. The in situ colouration of wool fabric was performed at various varying dyeing conditions (temperature, time, and concentrations) using laccase. Colouration properties (colour values and strength) were examined to estimate the appearance of dyed fabrics. The evaluation of dyed fabrics for functional properties such as antibacterial, antioxidant, and UV protection was done. The efficient functional properties viz, antibacterial activity (> 75%), antioxidant property (> 90%), and excellent UV protection, were obtained. FTIR analysis of separately prepared polymeric dye and the dyed fabric was also done to confirm the laccase-assisted polymerisation. Thus, a novel approach of enzymatic functional natural dyeing of wool was explored.

The effect of green tea supplementation on the anthropometric outcomes in overweight and obese women: a time and dose-response meta-analysis of randomized controlled trials

Inconsistencies are evident within the literature regarding the role of Green Tea (GT) supplementation on women living with obesity. To address this, we conducted to determine the impact of GT supplementation on the weight, body mass index (BMI), and waist circumference (WC) in overweight and obese women using time and dose-response meta-analysis of randomized controlled trials (RCTs). This meta-analysis searched electronic Scopus, Web of Science, Embase, and PubMed/Medline databases from inception to December 1^st, 2022. Data were reported as weighted mean difference (WMD) with 95% confidence interval (CI). A total of 2061 references were identified, and 15 articles with 16 RCT arms on body weight, 17 RCT arms on BMI, and 7 RCT arms on WC were included in the meta-analysis. GT supplementation significantly decreases body weight (WMD: -1.23 kg, 95% CI: -2.13 to -0.33, p = 0.007), BMI (WMD: -0.47 kg/m², 95% CI: -0.87 to -0.07, p = 0.020) and WC (WMD: -3.46 cm, 95% CI: -6.75 to -0.16, p = 0.040). In subgroup analyses, GT consumption demonstrated lowered body weight with dosaes ≥1000 mg/day (WMD: -1.38 kg), in the RCTs, which lasted ≥8 wk (WMD: -1.24 kg). The non-linear dose-response assessment detected a negative correlation between the changes in body weight and BMI in green tea consumption of more than 1000 (mg/day). The GT supplementation reduced the weight, BMI, and WC in overweight and obese women. In clinical practice, healthcare professionals can recommend using GT with dosages ≥ 1000mg/day and duration ≥ 8 wk in obese women.

Tracing the origin of Taiping Houkui green tea using 1H NMR and HS-SPME-GC-MS chemical fingerprints, data fusion and chemometrics

The narrow geographical traceability of green tea is both important and challenging. This study aimed to establish multi-technology metabolomic and chemometric approaches to finely discriminate the geographic origins of green teas. Taiping Houkui green tea samples were analyzed by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry and ¹H NMR of polar (D₂O) and non-polar (CDCl₃). Common dimension, low-level and mid-level data fusion approaches were tested to verify if the combination of several analytical sources can improve the classification ability of samples from different origins. In assessments of tea from six origins, the single instrument data test set results in 40.00% to 80.00% accuracy. Data fusion improved single-instrument performance classification with mid-level data fusion to obtain 93.33% accuracy in the test set. These results provide comprehensive metabolomic insights into the origin of TPHK fingerprinting and open up new metabolomic approaches for quality control in the tea industry.

Quantitative fusion omics reveals that refrigeration drives methionine degradation through perturbing 5-methyltetrahydropteroyltriglutamate-homocysteine activity

Postharvest senescence and quality deterioration of fresh tea leaves occurred due to the limitation of processing capacity. Refrigerated storage prolongs the shelf life of fresh tea. In this study, quantitative fusion omics delineated the translational landscape of metabolites and proteins in time-series (0-12 days) refrigerated tea by UHPLC-Q-Orbitrap HRMS. Accurate quantification results showed the content of amino acids, especially l-theanine, decreased with the lengthening of the storage duration (15.57 mg g^-1 to 7.65 mg g^-1) driven by theanine synthetase. Downregulation of enzyme 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase expression led to methionine degradation (6.29 µg g^-1 to 1.78 µg g^-1). Refrigerated storage inhibited serine carboxypeptidase-like acyltransferases activity (59.49 % reduction in 12 days) and induced the polymerization of epicatechin and epigallocatechin and generation of procyanidin dimer and δ-type dehydrodicatechin, causing the manifestation of color deterioration. A predictive model incorporating zero-order reaction and Arrhenius equation was constructed to forecast the storage time of green tea.

Green tea leaf constituents inhibit the formation of lysozyme amyloid aggregates: An effect of mutual interactions

Amyloidoses represent a group of pathological conditions characterized by amyloid fibrils accumulating in the form of deposits in intra- or extracellular space, leading to tissue damage. The lysozyme from hen egg-white (HEWL) is often used as a universal model protein to study the anti-amyloid effects of small molecules. The in vitro anti-amyloid activity and mutual interactions of green tea leaf constituents: (-)-epigallocatechin gallate (EGCG), (-)-epicatechin (EC), gallic acid (GA), caffeine (CF) and their equimolar mixtures were studied. The inhibition of HEWL amyloid aggregation was monitored by a Thioflavin T fluorescence assay and atomic force microscopy (AFM). The interactions of the analyzed molecules with HEWL were interpreted by ATR-FTIR and protein-small ligand docking studies. EGCG was the only substance efficiently inhibiting amyloid formation (IC₅₀ ~ 193 μM), slowing the aggregation process, reducing the number of fibrils and partially stabilizing the secondary structure of HEWL. Compared to EGCG alone, EGCG-containing mixtures displayed lower overall anti-amyloid efficacy. The decrease in efficiency results from (a) the spatial interference of GA, CF and EC with EGCG while binding to HEWL, (b) the propensity of CF to form a less active adduct with EGCG, which participates in interactions with HEWL in parallel with pure EGCG. This study confirms the importance of interaction studies, revealing the possible antagonistic behavior of molecules when combined.

Discrimination of Chinese green tea according to tea polyphenols using fluorescence sensor array based on Tb (III) and Eu (III) doped Zr (IV) metal-organic frameworks

A facile and rapid fluorescence sensor array based on Tb (III) and Eu (III) doped Zr (IV) metal-organic frameworks was proposed for Chinese green tea discrimination. According to large porosity of Tb@UiO-66-(COOH)₂ and Eu@UiO-66-(COOH)₂, phenolic hydroxyl groups of tea polyphenols could coordinate with free carboxylic acid groups and was captured into the pores, which led to the disturbance of electronic structure of ligand and inhibited the energy transfer efficiency from ligand to Tb (III) and Eu (III) center, causing the fluorescence quenching effect. Based on Hierarchy Cluster Analysis and Linear Discrimination Analysis, the fluorescence sensor array was employed for successful tea polyphenols classification through the analysis of different fluorescence quenching effect to tea polyphenols. Green tea samples within different categories and grades were also successfully discriminated using this assay according to tea polyphenols, providing a new method for Chinese green tea identification.

Gut microbiota-mediated associations of green tea and catechin intakes with glucose metabolism in individuals without type 2 diabetes mellitus: a four-season observational study with mediation analysis

This four-season observational study aimed to examine the mediating role of the gut microbiota in the associations between green tea and catechin intakes and glucose metabolism in individuals without type 2 diabetes mellitus (T2DM). In each of the 4 seasons, 85 individuals without T2DM (56 male [65.9%]; mean [standard deviation] age: 43.3 [9.4] years) provided blood samples, stool samples, 3-day weighed dietary records, and green tea samples. Catechin intake was estimated by analyzing the tea samples. Linear mixed-effects model analysis showed that green tea intake was negatively associated with fasting blood glucose and insulin levels, even after considering the seasonal variations. Of the gut microbial species associated with green tea intake, the mediation analysis revealed that Phocaeicola vulgatus mediated the association between green tea intake and fasting blood glucose levels. These findings indicate that green tea can improve glucose metabolism by decreasing the abundance of P. vulgatus that is associated with elevated blood glucose levels in individuals without T2DM.

Can antioxidant treatment replace delay in bracket bonding? An in vitro study

BACKGROUND

Deterioration in shear bond strength has been reported after immediate bracket bonding following hydrogen peroxide bleaching. This study compared the effectiveness of three antioxidant agents, namely, alpha-tocopherol, green tea extract, and sodium ascorbate, in reversing the bleaching effect and as possible alternatives to delayed bonding.

METHODS

A total of 105 extracted human premolars were arbitrarily assigned to 7 groups (n = 15 each), including group 1 as the unbleached control group and six experimental groups, which were bleached with 40% hydrogen peroxide in three sessions of 15 min each. In experimental group 2, bonding was performed immediately after bleaching, whereas in groups 3 and 4, bonding was delayed for 1 and 2 weeks, respectively; meanwhile, the specimens were immersed in artificial saliva at 37 °C. Groups 5, 6, and 7 were treated immediately after bleaching with 10% of alpha-tocopherol, green tea extract, and sodium ascorbate solutions, respectively, for 15 min. Specimens were processed using 500 thermal cycles between 5 and 55 °C, with a dwell time of 30 s after 24 h of bracket bonding, and then tested for shear bond strength. The adhesive remnant index was examined to evaluate fracture mode. One-way analysis of variance, Kruskal-Wallis H, and post hoc Tukey's honestly significant difference tests were used to compare the data. Significant results were subjected to pairwise comparisons with Bonferroni's correction-adjusted of p values ≤ 0.050.

RESULTS

Shear bond strength was significantly lower (p < 0.001) in the immediate bonding and 1-week delay groups than in the control group. However, no significant difference was detected among the 2-week delay, antioxidant-treated, and control groups (p > 0.05).

CONCLUSIONS

Application of 10% alpha-tocopherol, green tea extract, or sodium ascorbate for 15 min could restore shear bond strength after 40% hydrogen peroxide bleaching as an alternative to delay in bracket bonding.

Green tea consumption and the risk of coronary heart disease: A systematic review and meta-analysis of cohort studies

BACKGROUND AND AIMS

Conflicting evidence exists regarding the association between green tea consumption and the risk of coronary heart disease (CHD). We performed a meta-analysis to determine whether an association exists between them in cohort studies.

METHODS AND RESULTS

We searched the PubMed and EMBASE databases for studies conducted until September 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence intervals (CIs) for the association were included. Study-specific risk estimates were combined using a random-effects model. A total of seven studies, with 9211 CHD cases among 772,922 participants, were included. We observed a nonlinear association between green tea consumption and the risk of CHD (P for nonlinearity = 0.0009). Compared with nonconsumers, the RRs (95% CI) of CHD across levels of green tea consumption were 0.89 (0.83, 0.96) for 1 cup/day (1 cup = 300 ml), 0.84 (0.77, 0.93) for 2 cups/day, 0.85 (0.77, 0.92) for 3 cups/day, 0.88 (0.81, 0.96) for 4 cups/day, and 0.92 (0.82, 1.04) for 5 cups/day.

CONCLUSIONS

This updated meta-analysis of studies from East Asia suggests that green tea consumption may be associated with a reduced risk of CHD, especially among those with low-to-moderate consumption. Additional cohorts are still needed before we could draw a definitive conclusion.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022357687.

A case-control study of drinking beverages and the risk of multiple sclerosis in Iran

BACKGROUND

There is no study in the world on the relationship between consuming black and green tea as beverages containing polyphenols and the risk of MS. This study aimed to determine the association between the consumption of green and black tea, coffee, non-alcoholic beer, milk, fruit juices and carbonated beverages with the risk of MS.

METHODS AND MATERIALS

This case-control study was performed on 150 patients with MS and 300 healthy individuals as a control group among patients who were referred to the ophthalmology ward of a referral hospital in Ahvaz with the groups matching for age. The data collection tool was a researcher-made questionnaire including demographic information and beverage consumption. Analysis was performed using univariate and multiple logistic regression models.

RESULTS

The mean age of patients at the time of diagnosis was 38.55 ± 8.88 years. The results showed that drinking milk (OR = 5.46), natural juice (OR = 2.49), and carbonated beverages (OR = 16.17) were associated with an increased chance of developing MS. However, drinking non-alcoholic beer (OR = 0.48), black tea (OR = 0.20), green tea (OR = 0.29) and coffee (OR = 0.07) were associated with a reduced chance of developing MS.

CONCLUSION

The results show that drinking black and green tea, non-alcoholic beer, and coffee are associated with a decrease in the chance of developing MS. The results of this study can be used to design interventional research and to change people's lifestyles to prevent MS.

Green tea consumption and the risk of stroke: A systematic review and meta-analysis of cohort studies

OBJECTIVES

Epidemiologic studies are inconsistent regarding the association between green tea consumption and the risk of stroke. We performed a meta-analysis to determine whether an association exists between them in cohort studies.

METHODS

We searched the PubMed and Embase databases for studies conducted from 1966 through September 2022. Prospective cohort studies that provided relative risk (RR) estimates with 95% confidence interval (CI)s for the association were included. Study-specific risk estimates were combined by using a random-effects model.

RESULTS

A total of five studies, with 11 421 stroke cases among 645 393 participants, were included in the meta-analysis. The summary RR indicated a significant association between highest green tea consumption and reduced risk of stroke (summary RR: 0.74; 95% CI, 0.66-0.83). In the dose-response analysis, we observed a nonlinear association between green tea consumption and the risk of stroke (P for nonlinearity = 0.0000). Compared with non-consumers, the RRs (95% CI) of stroke across levels of green tea consumption were 0.91 (0.89-0.94) for 150 mL/d, 0.84 (0.80-0.89) for 300 mL/d, 0.79 (0.74-0.84) for 500 mL/d, 0.77 (0.72-0.82) for 900 mL/d, and 0.84 (0.77-0.91) for 1500 mL/d.

CONCLUSIONS

This meta-analysis suggests that green tea consumption is inversely associated with the risk of stroke, especially among those with moderate consumption. Our results support recommendations for green tea consumption to the primary prevention of stroke.

Bioactivity-boosting strategy based on combination of anti-allergic O-methylated catechin with a Citrus flavanone, hesperetin

Many patients with allergies have anxiety about taking anti-allergic medicines due to their side effects and increased medical expenses. Thus, developing functional foods/agricultural products for allergy prevention is strongly desired. In this study, we revealed that a Citrus flavanone, hesperetin, amplified IgE/antigen-mediated degranulation-inhibitory potency of anti-allergic catechin, (-)-epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3''Me), in the rat basophilic/mast cell line RBL-2H3. Hesperetin also significantly elevated the activation of acid sphingomyelinase (ASM), essential for eliciting anti-allergic effect of EGCG3''Me through the cell surficial protein, 67-kDa laminin receptor (67LR). Furthermore, oral administration of the highly absorbent hesperidin, α-glucosyl hesperidin, also enhanced the inhibitory potency of EGCG3''Me-rich 'Benifuuki' green tea (Camellia sinensis L.) on passive cutaneous anaphylaxis (PCA) reaction evoked by IgE/antigen in BALB/c mice. These observations indicate that hesperetin amplifies the ability of EGCG3''Me to inhibit the IgE/antigen-mediated degranulation through activating ASM signaling.

A comprehensive review on clinically proven medicinal plants in the treatment of overweight and obesity, with mechanistic insights

Background and objectives

Obesity has become a global health issue, more precisely, a pandemic throughout the present world due to its high prevalence in the recent era. Increased risk of morbidity and mortality in obese patients can be attributed to its association with the development of different life-threatening conditions. Plants are considered one of the most important sources of bioactive molecules which are used against a wide range of health disorders. This systematic review explores the efficacy as well as the safety profile of commonly used medicinal plants in the management of obesity that may help people to maintain a healthy weight.

Methods

This review is based on comprehensive literature searches from PubMed, Science Direct, Scopus, and Google Scholar databases using the keywords- "plants in obesity", "plants used in weight reduction" or keywords that are similar to those. Medicinal plants which have been clinically proven for their anti-obesity effect have only been selected for this study and attempts to investigate beneficial effects and adverse effects along with their mechanism of action have also been taken in this review.

Results

A significant reduction of weight in both human and other animals are exhibited by the extracts of Phaseolus vulgaris, green coffee, Yerba Mate, green tea, Gynostemma pentaphyllum, and the combination of Cissus quadrangularis/Irvingia gabonensis. All of those plant extracts seemed to work on different physiological pathways and none of those extracts showed any notable adverse effects in human or animal models.

Conclusion

Our review suggests that the discussed medicinal plants are effective in reducing the weight of obese patients without causing notable adverse reactions. Although further study is necessary to confirm their exact molecular mechanism and safety in human use.

Therapeutic potential of green tea catechin, (-)-epigallocatechin-3-O-gallate (EGCG) in SARS-CoV-2 infection: Major interactions with host/virus proteases

BACKGROUND

The current COVID-19 pandemic from the human pathogenic virus SARS-CoV-2 has resulted in a major health hazard globally. The morbidity and transmission modality of this disease are severe and uncontrollable. As no effective clinical drugs are available for treatment of COVID-19 infection till to date and only vaccination is used as prophylaxis and its efficacy is restricted due to emergent of new variants of SARS-CoV-2, there is an urgent need for effective drugs for its treatment.

PURPOSE

The aim of this review was to provide a detailed analysis of anti-SARS-CoV-2 efficacy of (-)-epigallocatechin-3-O-gallate (EGCG), a major catechin constituent of green tea (Camellia sinensis (L.) Kuntze) beverage to highlight the scope of EGCG in clinical medicine as both prophylaxis and treatment of present COVID-19 infection. In addition, the factors related to poor oral bioavailabilty of EGCG was also analysed for a suggestion for future research in this direction.

STUDY DESIGN

We collected the published articles related to anti-SARS-CoV-2 activity of EGCG against the original strain (Wuhan type) and its newly emerged variants of SARS-CoV-2 virus.

METHODS

A systematic search on the published literature was conducted in various databases including Google Scholar, PubMed, Science Direct and Scopus to collect the relevant literature.

RESULTS

The findings of this search demonstrate that EGCG shows potent antiviral activity against SARS-CoV-2 virus by preventing viral entry and replication in host cells in vitro models. The studies on the molecular mechanisms of EGCG in inhibition of SARS-CoV-2 infection in host cells reveal that EGCG blocks the entry of the virus particles by interaction with the receptor binding domain (RBD) of viral spike (S) protein to host cell surface receptor protease angiotensin-converting enzyme 2 (ACE2) as well as suppression of the expressions of host proteases, ACE2, TMPRSS2 and GRP78, required for viral entry, by Nrf2 activation in host cells. Moreover, EGCG inhibits the activities of SARS-CoV-2 main protease (Mpro), papain-like protease (PLpro), endoribonuclease Nsp15 in vitro models and of RNA-dependent RNA polymerase (RdRp) in molecular docking model for suppression of viral replication. In addition, EGCG significantly inhibits viral inflammatory cytokine production by stimulating Nrf2- dependent host immune response in virus-infected cells. EGCG significantly reduces the elevated levels of HMGB1, a biomarker of sepsis, lung fibrosis and thrombotic complications in viral infections. EGCG potentially inhibits the infection of original (Wuhan type) strain of SARS-CoV-2 and other newly emerged variants as well as the infections of SARS-CoV-2 virus spike-protein of WT and its mutants-mediated pseudotyped viruses . EGCG shows maximum inhibitory effect against SARS-CoV-2 infection when the host cells are pre-incubated with the drug prior to viral infection. A sorbitol/lecithin-based throat spray containing concentrated green tea extract rich in EGCG content significantly reduces SARS-CoV-2 infectivity in oral mucosa. Several factors including degradation in gastrointestinal environment, low absorption in small intestine and extensive metabolism of EGCG are responsible for its poor bioavailability in humans. Pharmacokinetic and metabolism studies of EGCG in humans reveal poor bioavailability of EGCG in human plasma and EGCG-4"-sulfate is its major metabolite. The concentration of EGCG-4"-sulfate in human plasma is almost equivalent to that of free EGCG (Cmax 177.9 vs 233.5 nmol/L). These findings suggest that inhibition of sulfation of EGCG is a crucial factor for improvement of its bioavailability. In vitro study on the mechanism of EGCG sulfonation indicates that sulfotransferases, SULT1A1 and SULT1A3 are responsible for sulfonation in human liver and small intestine, respectively. Some attempts including structural modifications, and nanoformulations of EGCG and addition of nutrients with EGCG have been made to improve the bioavailability of EGCG.

CONCLUSIONS

The findings of this study suggest that EGCG has strong antiviral activity against SARS-CoV-2 infection independent of viral strains (Wuhan type (WT), other variants) by inhibition of viral entry and replication in host cells in vitro models. EGCG may be useful in reduction of this viral load in salivary glands of COVID-19 patients, if it is applied in mouth and throat wash formulations in optimal concentrations. EGCG could be a promising candidate in the development of effective vaccine for prevention of the infections of newly emergent strains of SARS-CoV-2 virus. EGCG might be useful also as a clinical medicine for treatment of COVID-19 patients if its bioavailability in human plasma is enhanced.