Different polysaccharide-enhanced probiotic and polyphenol dual-functional factor co-encapsulated microcapsules demonstrate acute colitis alleviation efficacy and food fortification.

Probiotics and polyphenols have multiple bioactivities, and developing co-encapsulated microcapsules (CM) is a novel strategy to enhance their nutritional diversity. However, the development of CMs is challenged by complicated processing, single types, and unclear in vivo effects and applications. In this study, the co-microencapsulations of polyphenol and probiotic were constructed using pectin, alginate (WGCA@LK), and Fu brick tea polysaccharides (WGCF@LK), respectively, with chitosan-whey isolate proteins by layer-by-layer coacervation reaction, and their protective effects, in vivo effectiveness, and application potential were evaluated. WGCA@LK improved the encapsulation rate of polyphenols (42.41 %), and remained high viability of probiotics after passing through gastric acidic environment (8.79 ± 0.04 log CFU/g) and storage for 4 weeks (4.59 ± 0.06 log CFU/g). WGCF@LK exhibited the highest total antioxidant activity (19.40 ± 0.25 µmol/mL) and its prebiotic activity removed the restriction on probiotic growth. WGCA@LK showed strong in vitro colonic adhesion, but WGCF@LK promoted in vivo retention of probiotics at 48 h. WGCF@LK showed excellent anti-inflammatory effects and alleviated symptoms of acute colitis in mice. These findings provide unique insights into the fortification of probiotic-polyphenol CMs by different polysaccharides and the development of novel health foods with rich functional hierarchies and superior therapeutic effects.

Unveiling the total catechin profile in tea leaves: a novel one-step extraction method empowered by UPLC-IDX-Orbitrap mass spectrometry.

More catechins are found in green tea than in any other type of tea, with its predominant production taking place in Asian nations. Consumption of green tea has been strongly correlated with a reduced risk of many diseases. This study introduces a new, efficient, and reliable method for extracting total catechins using ultra-high-performance liquid chromatography coupled with an ID-X-Orbitrap Mass spectrometer (UHPLC-IDX-Orbitrap-MS). The method was then applied to quantify the catechin content in green tea, yielding results comparable to previously published studies. Among the various sources of green tea analyzed, the lowest average catechin content was observed in Vietnam, Japan (2: Matcha), and Morocco, ranging between 346 and 322 mg/L. Conversely, the highest average catechin content (between 424 and 422 mg/L) was found in Sri Lanka and Japan (1: Sencha). For the remaining green tea extracts, the catechin levels ranged from 367 to 410 mg/L, exhibiting similar values. These findings demonstrate the high reproducibility of the proposed extraction procedure, with a relative standard deviation (RSD) error of less than 15% for the catechin standard. Additionally, the limit of detection for catechins was determined to be 1 ng mL-1. This study serves as a pilot investigation for extracting catechins from various green tea sources. Future research will focus on identifying all active compounds present. Furthermore, it is worth noting that this study aligns with the goals set forth in Saudi Vision 2030, which aims to diversify the country's economy and promote scientific advancements in various fields, including healthcare and agriculture.

Fabrication and characterization of tea seed starch-tea polyphenol complexes.

This study investigates the complexation between tea seed starch (TSS) and tea polyphenols (TPs) at varying concentrations (2.5, 5.0, 7.5, and 10.0 %). The objectives can expand the knowledge of TSS, which is a novel starch, and to examine how TPs influence the structure and physicochemical properties of the complexes. Results indicate that TPs interact with TSS through hydrogen bonding, altering granule morphology and disrupting ordered structure of starch. Depending on the concentration, TPs induce either V-type or non-V-type crystal structures within TSS, which had bearing on iodine binding capacity, swelling, pasting, gelatinization, retrogradation, rheology, and gel structure. In vitro digestibility analysis reveals that TSS-TPs complexes tend to reduce readily digestible starch while increasing resistant starch fractions with higher TP concentrations. Thus, TSS-TPs complexes physicochemical and digestibility properties can be modulated, providing a wide range of potential applications in the food industry.

Caffeine consumption of medical students in Korea: amount and symptoms based on a 2023 survey.

PURPOSE: To investigate the form and level of daily caffeine intake recommended above 400 mg in medical students expected to consume caffeinated beverages to enhance their performance. METHODS: From May to June 2023, freshman through senior medical students at a medical school in Korea were administered a seven-item questionnaire designed to measure the amount of caffeine-containing foods consumed, the weekly interval between consumption, the reason for consumption, and the level of caffeine-induced symptoms experienced. RESULTS: Out of 443 students, 361 responded (81.5%). The most commonly consumed caffeine beverages were coffee (79.2%), followed by soda (33.2%), tea (27.4%), chocolate (25.2%), and energy drinks (20.5%). The estimated (average±standard deviation) daily intake was estimated to 274.6±276.5 mg, and they consumed caffeine on an average of 4.25±2.26 days per week. Students who consumed 400 mg or more of caffeine daily consumed 19.9%. The primary motivation for caffeine intake was "to improve academic performance" (60.9%) and "preferred food" (51.8%). Among the responders, 98% of them replied they had symptoms that could be caused by caffeine, in order of palpitations (47.4%), frequent urination (42.9%), anxiety (27.1%), indigestion (17.5%), and excitement (17.5%). A total of 45.7% reported two symptoms, and 24.7% reported three or more. CONCLUSION: Caffeinated beverage consumption was routine among current medical students, with 20% consuming more than the recommended daily amount. Most students experienced at least one caffeine-induced symptom, with two symptoms in half, suggesting the need for policy measures and warnings about caffeine-containing foods.

Data set for Gambung green tea aroma using on electronic nose.

OBJECTIVES: In recent years, there has been much discussion and research on electronic nose (e-nose). This topic has developed mainly in the medical and food fields. Typically, e-nose is combined with machine learning algorithms to predict or detect multiple sensory classes in each tea sample. Therefore, in e-nose systems, e-nose signal processing is an important part. In many situations, a comprehensive set of experiments is required to ensure the prediction model can be generalized well. This data set specifically focuses on two main goals such as classification of green tea quality and prediction of organoleptic score. In this experiment, Gambung dry green tea samples were used. The challenge is that dry tea does not emit as strong an aroma as tea infusions, making it more difficult for the e-nose system to detect and identify the aromas. This data set offers a valuable resource for researchers and developers to conduct investigations and experiments by classifying and detecting organoleptic scores that aim to categorize and identify organoleptic ratings. This enables a deeper understanding of the quality of dry green tea and encourages further integration of e-nose technology in the tea industry. DATA DESCRIPTION: This experiment focused on analyzing green tea aroma using six gas sensors. Seventy-eight green tea samples were tested, each observed three times, using a tea chamber connected to a sensor chamber via a hose and an intake micro air pump. Air flowed from the tea chamber to the sensor chamber for 60 s, followed by 60 s of aroma data recording. This data was saved into CSV files and labeled according to the Indonesian National Standard (SNI) 3945:2016, which includes special and general requirements for green tea quality. An organoleptic test by a tea tester further labeled the data set into "good" or "quality defect" for classification and provided organoleptic scores based on dry appearance, brew color, taste, aroma, and dregs of brewing for continuous label.

Nonrestorative sleep and its associated factors in Chinese adolescents and the moderation effects of coffee or tea consumption.

BACKGROUND: Nonrestorative sleep (NRS) is related to numerous adverse outcomes. There is rare evidence of its associated factors, especially in Chinese adolescents. This study aimed to explore the factors associated with NRS in Chinese adolescents and the potential moderation effects of coffee or tea consumption. METHODS: This cross-sectional study invited adolescents attending Grades 7-11 in Nanjing, China, to complete a self-administered questionnaire, including their NRS, stress, anxiety, physical symptoms, depression, sociodemographics, and lifestyles. Linear regressions were applied to investigate the associated factors of their NRS, with the moderation effects of coffee or tea consumption and other characteristics being tested by additionally including their interactions. RESULTS: Totally 481 adolescents (49% male, age 15.5 ± 1.5 years) were enrolled, with the average global NRS score of 42.16 ± 7.57. Higher family income (ß = 2.01, P = 0.007), longer sleep duration (ß = 2.33, P = 0.011), and moderate after-class activity (ß = 1.50, P = 0.044) contributed less NRS, while higher educational level (ß = -2.60, P = 0.033), more coffee or tea consumption (ß = -1.68, P = 0.013), physical symptoms (ß = -3.85, P < 0.001), stress (ß = -0.23, P = 0.005), anxiety (ß = -1.54, P = 0.045), and depression (ß = -0.13, P = 0.014) contributed more NRS. Females (ß = 0.82, P = 0.005), older age (ß = -0.46, P = 0.029), and higher education level (ß = -1.68, P < 0.001) contributed less refreshment from sleep, more physical/medical symptoms of NRS, and less daytime function, respectively. Coffee or tea consumption moderated the associations of somatic symptoms (ß = 0.25, P = 0.021), stress (ß = 0.29, P = 0.022), anxiety (ß = 0.27, P = 0.005), and depression (ß = 0.17, P = 0.021) with NRS. CONCLUSIONS: Longer sleep duration, moderate after-class activity, reduced coffee or tea consumption, and promotion of physical and mental health may help reduce adolescents' NRS. Coffee or tea consumption may help buffer the negative associations of somatic symptoms, stress, anxiety, and depression with NRS.

Differential effects of polystyrene microplastics on the adsorption of cadmium and ciprofloxacin by tea leaf litter-derived magnetic biochar: Influencing factors and mechanisms.

Water pollution involves the coexistence of microplastics (MPs) and traditional pollutants, and how can MPs influence the adsorption of other pollutants by biochar during the treatment process remains unclear. This study aimed to investigate the influence of polystyrene microplastics (PS MPs) on the adsorption of cadmium (Cd) and ciprofloxacin (CIP) by magnetic biochar (MTBC) in the single and binary systems. MTBC was prepared using tea leaf litter; the effects of time, pH, and salt ions on the adsorption behaviors were investigated; and X-ray photoelectronic spectroscopy (XPS) and density flooding theory analysis were conducted to elucidate the influence mechanisms. Results indicated that PS MPs reduced the pollutants adsorption by MTBC due to the heterogeneous aggregation between PS MPs and MTBC and the surface charge change of MTBC induced by PS MPs. The effects of PS MPs on heavy metals and antibiotics adsorption were distinctly different. PS MPs reduced Cd adsorption on MTBC, which were significantly influenced by the solution pH and salt ions contents, suggesting the participation of electrostatic interaction and ion exchange in the adsorption, whereas the effects of PS MPs on CIP adsorption were inconspicuous. In the hybrid system, PS MPs reduced pollutants adsorption by MTBC with 66.3% decrease for Cd and 12.8% decrease for CIP, and the more remarkable reduction for Cd was due to the predominated physical adsorption, and CIP adsorption was mainly a stable chemisorption. The influence of PS MPs could be resulted from the interaction between PS MPs and MTBC with changing the functional groups and electrostatic potential of MTBC. This study demonstrated that when using biochar to decontaminate wastewater, it is imperative to consider the antagonistic action of MPs, especially for heavy metal removal. PRACTITIONER POINTS: Magnetic biochar (MTBC) was prepared successfully using tea leaf litter. MTBC could be used for cadmium (Cd) and ciprofloxacin (CIP) removal. Polystyrene microplastics (Ps MPs) reduced Cd/CIP adsorption by MTBC. Ps MPs effects on Cd adsorption were more obvious than that of CIP. Ps MPs changed the functional groups and electrostatic potential of MTBC, thus influencing MTBC adsorption.

Olfactory analysis of oolong tea sensory quality using composite nano-colorimetric sensor array.

Chinese oolong tea is famous for its rich and diverse aromas, which is an important indicator for sensor quality evaluation. To accurately and rapidly evaluate sensory quality, a novel colorimetric sensor array (CSA) was developed to detect volatile organic compounds (VOCs) in oolong tea. We further explored the binding mechanism between colorimetric dyes that trigger changes in charge transfer and visible color changes. Based on this, we modified and optimized the CSA to improve the sensitivity by 17.1-234.9% and the stability by 8.7-33.3%. The study also assessed the effectiveness of this method by comparing two linear and two non-linear classification models, with the support vector machine (SVM) model achieving the highest accuracy, identifying different flavor intensity and grades with rates of 100% and 95.83%, respectively. These findings sufficiently demonstrated that the novel CSA, integrated with the SVM model, has promising potential for predicting the sensory quality of oolong tea.

Characterization of the key differential aroma compounds in five dark teas from different geographical regions integrating GC-MS, ROAV and chemometrics approaches.

Dark tea (DT) holds a rich cultural history in China and has gained sizeable consumers due to its unique flavor and potential health benefits. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), relative odor activity value (ROAV), and chemometrics approaches were used to detect and analyze aroma compounds differences among five dark teas from different geographical regions. The results revealed that the five DTs from different geographical regions differed in types, quantities, and relative concentrations of volatile compounds. A total of 1372 volatile compounds of were identified in the 56 DT samples by HS-SPME-GC-MS. Using ROAV and chemometrics approaches, based on ROAV>1 and VIP>1. Eighteen key aroma compounds can be used as potential indicators for DT classification, including dihydroactinidiolide, linalool, 1,2,3-trimethoxybenzene, geranyl acetone, 1,2,4-trimethoxybenzene, cedrol, 3,7-dimethyl-1,5,7-octatrien-3-ol, ß-ionone, 4-ethyl-1,2-dimethoxybenzene, methyl salicylate, α-ionone, geraniol, linalool oxide I, linalool oxide II, 6-methyl-5-hepten-2-one, α-terpineol, 1,2,3-trimethoxy-5-methylbenzene, and 1,2-dimethoxybenzene. These compounds provide a certain theoretical basis for distinguishing the differences in five DTs from different geographical regions. This study provides a potential method for identifying the volatile substances in DTs and elucidating the differences in key aroma compounds. Abbreviations: DT, dark tea; FZT, Fuzhuan tea; LPT, Guangxi Liupao tea; QZT, Hubei Qingzhuan tea; TBT, Sichuan Tibetan tea; PET, Yunnan Pu-erh tea; ROAV, Relative odor activity value; OT, Odor threshold; HS-SPME, Headspace solid-phase microextraction; GC-MS, Gas chromatography-mass spectrometry; PCA, Principal components analysis; PLS-DA, Partial least squares-discriminant analysis; HCA, Hierarchical clustering analysis.

Gastrointestinal digestion of yerba mate, rosemary and green tea extracts and their subsequent colonic fermentation by human, pig or rat inocula.

Polyphenolic compounds are common constituents of human and animal diets and undergo extensive metabolism by the gut microbiota before entering circulation. In order to compare the transformations of polyphenols from yerba mate, rosemary, and green tea extracts in the gastrointestinal tract, simulated gastrointestinal digestion coupled with colonic fermentation were used. For enhancing the comparative character of the investigation, colonic fermentation was performed with human, pig and rat intestinal microbiota. Chemical analysis was performed using a HPLC system coupled to a diode-array detector and mass spectrometer. Gastrointestinal digestion diminished the total amount of phenolics in the rosemary and green tea extracts by 27.5 and 59.2 %, respectively. These reductions occurred mainly at the expense of the major constituents of these extracts, namely rosmarinic acid (-45.7 %) and epigalocatechin gallate (-60.6 %). The yerba mate extract was practically not affected in terms of total phenolics, but several conversions and isomerizations occurred (e.g., 30 % of trans-3-O-caffeoylquinic acid was converted into the cis form). The polyphenolics of the yerba mate extract were also the least decomposed by the microbiota of all three species, especially in the case of the human one (-10.8 %). In contrast, the human microbiota transformed the polyphenolics of the rosemary and green extracts by 95.9 and 88.2 %, respectively. The yerba mate-extract had its contents in cis 3-O-caffeoylquinic acid diminished by 78 % by the human microbiota relative to the gastrointestinal digestion, but the content of 5-O-caffeoylquinic acid (also a chlorogenic acid), was increased by 22.2 %. The latter phenomenon did not occur with the rat and pig microbiota. The pronounced interspecies differences indicate the need for considerable caution when translating the results of experiments on the effects of polyphenolics performed in rats, or even pigs, to humans.

Mechanism of aroma formation in white tea treated with solar withering.

Withering is a crucial process that determines the quality of white tea (WT). Solar withering (SW) is reported to contribute to the aroma quality of WT. However, the mechanism by which aroma is formed in WT subjected to SW remains unclear. In this study, through headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and transcriptomics, we found that 13 key genes enriched in the mevalonic acid and methylerythritol phosphate pathways, such as those of 1-deoxy-D-xylulose-5-phosphate synthase and terpineol synthase, were significantly upregulated, promoting the accumulation of α-terpinolene, geraniol, and nerolidol, which imparted floral and fruity odors to WT subjected to SW. Additionally, the significant upregulation of lipoxygenases enriched in the lipoxygenase pathway promoting the accumulation of hexanol, 1-octen-3-ol, (E, Z)-3,6-nonadien-1-ol, and nonanal, which contributed to the green and fresh odor in WT subjected to SW. This study provided the first comprehensive insight into the effect mechanism of SW on aroma formation in WT.

Lightweight CNN combined with knowledge distillation for the accurate determination of black tea fermentation degree.

Black tea is the second most common type of tea in China. Fermentation is one of the most critical processes in its production, and it affects the quality of the finished product, whether it is insufficient or excessive. At present, the determination of black tea fermentation degree completely relies on artificial experience. It leads to inconsistent quality of black tea. To solve this problem, we use machine vision technology to distinguish the degree of fermentation of black tea based on images, this paper proposes a lightweight convolutional neural network (CNN) combined with knowledge distillation to discriminate the degree of fermentation of black tea. After comparing 12 kinds of CNN models, taking into account the size of the model and the performance of discrimination, as well as the selection principle of teacher models, Shufflenet_v2_x1.0 is selected as the student model, and Efficientnet_v2 is selected as the teacher model. Then, CrossEntropy Loss is replaced by Focal Loss. Finally, for Distillation Loss ratios of 0.6, 0.7, 0.8, 0.9, Soft Target Knowledge Distillation (ST), Masked Generative Distillation (MGD), Similarity-Preserving Knowledge Distillation (SPKD), and Attention Transfer (AT) four knowledge distillation methods are tested for their performance in distilling knowledge from the Shufflenet_v2_x1.0 model. The results show that the model discrimination performance after distillation is the best when the Distillation Loss ratio is 0.8 and the MGD method is used. This setup effectively improves the discrimination performance without increasing the number of parameters and computation volume. The model's P, R and F1 values reach 0.9208, 0.9190 and 0.9192, respectively. It achieves precise discrimination of the fermentation degree of black tea. This meets the requirements of objective black tea fermentation judgment and provides technical support for the intelligent processing of black tea.

Identification and molecular mechanism of novel hypoglycemic peptide in ripened pu-erh tea: Molecular docking, dynamic simulation, and cell experiments.

Ripened pu-erh tea is known to have beneficial hypoglycemic properties. However, it remains unclear whether the bioactive peptides produced during fermentation are also related to hypoglycemic potential. This study aimed to identify hypoglycemic peptides in ripened pu-erh tea and to elucidate their bioactive mechanisms using physicochemical property prediction, molecular docking, molecular dynamics simulations, and cell experiments. Thirteen peptides were identified by liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS). Among them, AADTDYRFS (AS-9) and AGDGTPYVR (AR-9) exhibited high α-glucosidase inhibitory activity, with half-maximal inhibitory concentration (IC50) values of 0.820 and 3.942 mg/mL, respectively. Molecular docking and dynamics simulations revealed that hydrogen bonding, hydrophobic interactions, and van der Waals forces assist peptides AS-9 and AR-9 in forming stable and tight complexes with α-glucosidase. An insulin-resistance (IR)-HepG2 cell model was established. AS-9 was non-toxic to IR-HepG2 cells and significantly increased the glucose consumption capacity, hexokinase, and pyruvate kinase activities of IR-HepG2 cells (p < 0.05). AS-9 alleviated glucose metabolism disorders and ameliorated IR by activating the IRS-1/PI3K/Akt signaling pathway and increasing the expression levels of MDM2, IRS-1, Akt, PI3K, GLUT4, and GSK3ß genes. In addition, no hemolysis of mice red blood cells red blood cells occurred at concentrations below 1 mg/mL. This work first explored hypoglycemic peptides in ripened pu-erh tea, providing novel insights for enhancing its functional value.

Genome-wide epigenetic dynamics of tea leaves under mechanical wounding stress during oolong tea postharvest processing.

Understanding the epigenetic responses to mechanical wounding stress during the postharvest processing of oolong tea provides insight into the reprogramming of the tea genome and its impact on tea quality. Here, we characterized the 5mC DNA methylation and chromatin accessibility landscapes of tea leaves subjected to mechanical wounding stress during the postharvest processing of oolong tea. Analysis of the differentially methylated regions and preferentially accessible promoters revealed many overrepresented TF-binding motifs, highlighting sets of TFs that are likely important for the quality of oolong tea. Within these sets, we constructed a chromatin accessibility-mediated gene regulatory network specific to mechanical wounding stress. In combination with the results of the TF-centred yeast one-hybrid assay, we identified potential binding sites of CsMYC2 and constructed a gene regulatory network centred on CsMYC2, clarifying the potential regulatory role of CsMYC2 in the postharvest processing of oolong tea. Interestingly, highly accessible chromatin and hypomethylated cytosine were found to coexist in the promoter region of the indole biosynthesis gene (tryptophan synthase ß-subunit, CsTSB) under wounding stress, which indicates that these two important epigenetic regulatory mechanisms are jointly involved in regulating the synthesis of indole during the postharvest processing of oolong tea. These findings improve our understanding of the epigenetic regulatory mechanisms involved in quality formation during the postharvest processing of oolong tea.

Flavan-3-ols and Vascular Health: Clinical Evidence and Mechanisms of Action.

Cardiovascular diseases (CVDs) are one of the main causes of mortality and morbidity worldwide. A healthy diet rich in plant-derived compounds such as (poly)phenols appears to have a key role in improving cardiovascular health. Flavan-3-ols represent a subclass of (poly)phenols of great interest for their possible health benefits. In this review, we summarized the results of clinical studies on vascular outcomes of flavan-3-ol supplementation and we focused on the role of the microbiota in CVD. Clinical trials included in this review showed that supplementation with flavan-3-ols mostly derived from cocoa products significantly reduces blood pressure and improves endothelial function. Studies on catechins from green tea demonstrated better results when involving healthy individuals. From a mechanistic point of view, emerging evidence suggests that microbial metabolites may play a role in the observed effects. Their function extends beyond the previous belief of ROS scavenging activity and encompasses a direct impact on gene expression and protein function. Although flavan-3-ols appear to have effects on cardiovascular health, further studies are needed to clarify and confirm these potential benefits and the rising evidence of the potential involvement of the microbiota.

Mathematical optimization of multilinear and artificial neural network regressions for mineral composition of different tea types infusions.

The objective of this study was to investigate the change in mineral composition depending on tea variety, tea concentration, and steeping time. Four different tea varieties, black Ceylon (BC), black Turkish (BT), green Ceylon (GC), and green Turkish (GT), were used to produce teas at concentrations of 1, 2, and 3%, respectively. These teas were produced using 7 different steeping times: 2, 5, 10, 20, 30, 45, and 60 min. It was also aimed to optimize the regression equations utilizing these factors to identify parameters conducive to maximizing Zn, K, Cu, Mg, Ca, Na, and Fe levels; minimizing Al content, and maintaining Mn level at 5.3 mg/L. The optimal conditions for achieving a Mn content of 5.3 mg/L in black Turkish tea entailed steeping at a concentration of 1.94% for 11.4 min. Variations in K and Mg levels across teas were inconsistent with those observed for other minerals, whereas variations in Al, Cu, Fe, Mn, Na, and Zn levels exhibited a close relationship. Overall, mineral levels in tea can be predicted through regression analysis, and by mathematically optimizing the resultant equations, the requisite conditions for tea production can be determined to achieve maximum, minimum, or target mineral values.

Theaflavins mitigate diabetic symptoms in GK rats by modulating the INSR/PI3K-Akt/GSK-3 pathway and intestinal microbiota.

Dietary management and interventions are crucial in the clinical management of diabetes. Numerous active dietary components in black tea have demonstrated positive effects on blood glucose levels and metabolic functions. However, limited research has explored the potential of theaflavins (TF), polyphenols in black tea, for diabetes management. In this study, high-purity TF was administered to Goto-Kakizaki (GK) diabetic model rats for four weeks to investigate its impact on diabetic pathology and analyze the underlying mechanisms through liver transcriptomics, hepatocyte metabolomics, and gut microbiome analysis. The findings indicated that continuous administration of TF (100 mg/kg) significantly suppressed blood glucose levels, reduced insulin resistance, and decreased the expression of oxidative stress indicators and inflammatory factors in GK rats. Further analysis revealed that TF might alleviate insulin resistance by improving hepatic glycogen conversion and reducing hepatic lipid deposition through modulation of key pathways, such as peroxisome proliferator-activated receptors and PI3K/AKT/GSK-3 pathways within the liver, thereby ameliorating diabetic symptoms. Additionally, TF intake facilitated the restoration of the intestinal microbial community structure by reducing the abundance of harmful bacteria and increasing the abundance of beneficial bacteria. It also reduced endotoxin lipopolysaccharide production, thereby lowering the chances of insulin resistance development and enhancing its efficacy in regulating blood glucose levels. These findings offer a novel perspective on the potential of black tea and its active constituents to prevent and treat diabetes and other metabolic disorders, providing valuable references for identifying and applying active dietary components from tea.

Green tea extract reduces viral proliferation and ROS production during Feline Herpesvirus type-1 (FHV-1) infection.

BACKGROUND: Feline Herpesvirus type-1 (FHV-1) is a worldwide spread pathogen responsible for viral rhinotracheitis and conjunctivitis in cats that, in the most severe cases, can lead to death. Despite the availability of a variety of antiviral medications to treat this illness, mainly characterized by virostatic drugs that alter DNA replication, their use is often debated. Phytotherapeutic treatments are a little-explored field for FHV-1 infections and reactivations. In this scenario, natural compounds could provide several advantages, such as reduced side effects, less resistance and low toxicity. The purpose of this study was to explore the potential inhibitory effects of the green tea extract (GTE), consisting of 50% of polyphenols, on FHV-1 infection and reactive oxygen species (ROS) production. RESULTS: Crandell-Reese feline kidney (CRFK) cells were treated with different doses of GTE (10-400 µg/mL) during the viral adsorption and throughout the following 24 h. The MTT and TCID50 assays were performed to determine the cytotoxicity and the EC50 of the extract, determining the amounts of GTE used for the subsequent investigations. The western blot assay showed a drastic reduction in the expression of viral glycoproteins (i.e., gB and gI) after GTE treatment. GTE induced not only a suppression in viral proliferation but also in the phosphorylation of Akt protein, generally involved in viral entry. Moreover, the increase in cell proliferation observed in infected cells upon GTE addition was supported by enhanced expression of Bcl-2 and Bcl-xL anti-apoptotic proteins. Finally, GTE antioxidant activity was evaluated by dichloro-dihydro-fluorescein diacetate (DCFH-DA) and total antioxidant capacity (TAC) assays. The ROS burst observed during FHV-1 infection was mitigated after GTE treatment, leading to a reduction in the oxidative imbalance. CONCLUSIONS: Although further clinical trials are necessary, this study demonstrated that the GTE could potentially serve as natural inhibitor of FHV-1 proliferation, by reducing viral entry. Moreover, it is plausible that the extract could inhibit apoptosis by modulating the intrinsic pathway, thus affecting ROS production.

Antimicrobial effects of epigallocatechin-3-gallate, a catechin abundant in green tea, on periodontal disease-associated bacteria.

OBJECTIVE: Epigallocatechin-3-gallate (EGCG), a catechin abundant in green tea, exhibits antibacterial activity. In this study, the antimicrobial effects of EGCG on periodontal disease-associated bacteria (Porphyromonas gingivalis, Prevotella intermedia, Prevotella nigrescens, Fusobacterium nucleatum, and Fusobacterium periodontium) were evaluated and compared with its effects on Streptococcus mutans, a caries-associated bacterium. RESULTS: Treatment with 2 mg/ml EGCG for 4 h killed all periodontal disease-associated bacteria, whereas it only reduced the viable count of S. mutans by about 40 %. Regarding growth, the periodontal disease-associated bacteria were more susceptible to EGCG than S. mutans, based on the growth inhibition ring test. As for metabolism, the 50 % inhibitory concentration (IC50) of EGCG for bacterial metabolic activity was lower for periodontal disease-associated bacteria (0.32-0.65 mg/ml) than for S. mutans (1.14 mg/ml). Furthermore, these IC50 values were negatively correlated with the growth inhibition ring (r = -0.73 to -0.86). EGCG induced bacterial aggregation at the following concentrations: P. gingivalis (>0.125 mg/ml), F. periodonticum (>0.5 mg/ml), F. nucleatum (>1 mg/ml), and P. nigrescens (>2 mg/ml). S. mutans aggregated at an EGCG concentration of > 1 mg/ml. CONCLUSION: EGCG may help to prevent periodontal disease by killing bacteria, inhibiting bacterial growth by suppressing bacterial metabolic activity, and removing bacteria through aggregation.