Synergistic Renoprotective Effects of Green Tea Extract and Gemigliptin against Tacrolimus-Induced Nephrotoxicity in Mice / Efectos Renoprotectores Sinérgicos del Extracto de Té Verde y Gemigliptina contra la Nefrotoxicidad Inducida por Tacrolimus en Ratones

SUMMARY: Although tacrolimus (TAC) significantly reduces allograft rejection incidence in solid-organ transplantation, its long-term use is associated with an increased risk of TAC-induced nephrotoxicity. In this study, we investigated the renoprotective effects of green tea extract (GTE) with or without the dipeptidyl peptidase 4 inhibitor, gemigliptin, by assessing serum creatinine levels, the amount of proteinuria, and histopathology in TAC-induced nephrotoxicity. TAC-induced nephrotoxicity was induced by intraperitoneal TAC injection, GTE was administered via subcutaneous injection, and gemigliptin was administered orally. Mice with TAC-induced nephrotoxicity exhibited a significant increase in both serum creatinine levels and 24-hour urine protein. However, when treated with GTE via subcutaneous injection, mice showed a decrease in serum creatinine levels and the amount of proteinuria. When GTE was combined with gemigliptin, further renoprotective effects were observed in biochemical assessments, consistent with the attenuation of TAC-induced nephrotoxicity in histopathology. The expression of p53 protein was lower in the mice treated with the combination of GTE and gemigliptin compared to mice with TAC-induced nephrotoxicity. Our results demonstrate that the combination of GTE and gemigliptin treatment reveals synergistic renoprotective effects by decreasing the expression of p53 protein. These findings suggest that the combination of GTE and gemigliptin could potentially be used as a prophylactic or therapeutic strategy for TAC-induced nephrotoxicity.

Aunque tacrolimus (TAC) reduce significativamente la incidencia de rechazo de aloinjertos en trasplantes de órganos sólidos, su uso a largo plazo se asocia con un mayor riesgo de nefrotoxicidad inducida por TAC. En este estudio, investigamos los efectos renoprotectores del extracto de té verde (GTE) con o sin el inhibidor de la dipeptidil peptidasa 4, gemigliptina, mediante la evaluación de los niveles de creatinina sérica, la cantidad de proteinuria y la histopatología en la nefrotoxicidad inducida por TAC. La nefrotoxicidad inducida por TAC se indujo mediante inyección intraperitoneal de TAC, el GTE se administró mediante inyección subcutánea y la gemigliptina se administró por vía oral. Los ratones con nefrotoxicidad inducida por TAC mostraron un aumento significativo tanto en los niveles de creatinina sérica como en la proteína en orina de 24 horas. Sin embargo, cuando se trataron con GTE mediante inyección subcutánea, los ratones mostraron una disminución en los niveles de creatinina sérica y en la cantidad de proteinuria. Cuando se combinó GTE con gemigliptina, se observaron efectos renoprotectores adicionales en las evaluaciones bioquímicas, lo que concuerda con la atenuación de la nefrotoxicidad inducida por TAC en histopatología. La expresión de la proteína p53 fue menor en los ratones tratados con la combinación de GTE y gemigliptina en comparación con los ratones con nefrotoxicidad inducida por TAC. Nuestros resultados demuestran que la combinación de tratamiento con GTE y gemigliptina revela efectos renoprotectores sinérgicos al disminuir la expresión de la proteína p53. Estos hallazgos sugieren que la combinación de GTE y gemigliptina podría usarse potencialmente como estrategia profiláctica o terapéutica para la nefrotoxicidad inducida por TAC.

A novel optimized eco-friendly simple spectrofluorimetric method for the determination of total catechins in green tea extract: Application to commercial tablet.

Green tea extract (GTE) contains antioxidants that are present in green tea. The active constituents of green tea extract are catechins. This study demonstrates a spectrofluorimetric method for measuring GTE's catechin concentration based on its native fluorescence. To design a quick, sensitive, and ecological spectrofluorimetric approach, all features were investigated and adjusted. This method relies on determining the GTE ethanolic solution's native fluorescence at 312 nm after excitation at 227 nm. The calibration graph displayed a linear regression for values between 0.05 and 1.0 µg mL-1. The detection and quantification limits of the proposed technique were 0.008 and 0.026 µg mL-1, respectively. Two pure catechins present in GTE, (-)-epicatechin and (-)-epigallocatechin gallate, were examined by the proposed method. The analytical estimation of GTE in the pharmaceutical tablet was achieved effectively using this approach. An adequate degree of agreement was found when the findings were compared to those obtained by the comparative technique. Therefore, the novel strategy may be used in the GTE quality control study with minimal risks to people or the environment. The quantum yields of catechins were estimated. The validated technique was accepted by the International Council of Harmonization criteria.

Effects of post-fermentation addition of green tea extract for sulfur dioxide replacement on Sauvignon Blanc wine phenolic composition, antioxidant capacity, colour, and mouthfeel attributes.

This study examines the feasibility of replacing SO2 in a New Zealand Sauvignon Blanc wine with a green tea extract. The treatments included the control with no preservatives (C), the addition of green tea extract at 0.1 and 0.2 g/L (T1 and T2), and an SO2 treatment at 50 mg/L (T3). Five monomeric phenolic compounds were detected in the green tea extract used for the experiment, and their concentrations ranged in the order (-)-epigallocatechin gallate > (-)-epigallocatechin > (-)-epicatechin > (-)-epicatechin gallate > gallic acid. At the studied addition rates, these green tea-derived phenolic compounds contributed to ∼70% of the antioxidant capacity (ABTS), ∼71% of the total phenolic index (TPI), and âˆ¼ 84% of tannin concentration (MCPT) of the extract dissolved in a model wine solution. Among wine treatments, T1 and T2 significantly increased the wine's colour absorbance at 420 nm, MCPT, gallic acid and total monomeric phenolic content. TPI and ABTS were significantly higher in wines with preservatives (i.e., T2 > T1 â‰… T3 > C, p < 0.05). These variations were observed both two weeks after the treatments and again after five months of wine aging. Additionally, an accelerated browning test and a quantitative sensory analysis of wine colour and mouthfeel attributes were performed after 5 months of wine aging. When exposed to excessive oxygen and high temperature (50 °C), T1 and T2 exhibited ∼29% and 24% higher browning capacity than the control, whereas T3 reduced the wine's browning capacity by ∼20%. Nonetheless, the results from sensory analysis did not show significant variations between the treatments. Thus, using green tea extract to replace SO2 at wine bottling appears to be a viable option, without inducing a negative impact on the perceptible colour and mouthfeel attributes of Sauvignon Blanc wine.

CdAl4O7/CdO nanocomposites: green tea extract-mediated sol-gel auto-combustion synthesis, characterization, and study as a potential hydrogen storage material.

In this article, we present the synthesis of binary CdAl4O7/CdO nanocomposites using green tea extracts and green chemistry methods for high-performance hydrogen storage. The green tea extract contains bioactive compounds (polyphenols) that act as reducing agents, which facilitate the reaction between metal ions and water. By examining the structural and morphological characteristics of the obtained substrates using scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR), it was demonstrated that the nanocomposites were successfully synthesized. We evaluated the electrochemical performance of the synthesized CdAl4O7/CdO nanocomposites using a three-electrode chronopotentiometry system. According to the results, the synthesized nanocomposites are capable of storing 1750 mAh/g of hydrogen at a constant current of 1 Amp. By using green tea extract as a natural structure-directing agent, the CdAl4O7/CdO nanocomposite can be developed more sustainably as high-performance hydrogen storage materials. Ultimately, this work contributes to the advancement of sustainable energy storage through the synthesis of a promising new material.

Antimicrobial and antioxidant activity of encapsulated tea polyphenols in chitosan/alginate-coated zein nanoparticles: a possible supplement against fish pathogens in aquaculture.

Regulation of antibiotic use in aquaculture calls for the emergence of more sustainable alternative treatments. Tea polyphenols (GTE), particularly epigallocatechin gallate (EGCG), have various biological activities. However, tea polyphenols are susceptible to degradation. In this work, EGCG and GTE were encapsulated in zein nanoparticles (ZNP) stabilized with alginate (ALG) and chitosan (CS) to reduce the degradation effect. ALG-coated ZNP and ALG/CS-coated ZNP encapsulating EGCG or GTE were obtained with a hydrodynamic size of less than 300 nm, an absolute ζ-potential value >30 mV, and an encapsulation efficiency greater than 75%. The antioxidant capacity of the encapsulated substances, although lower than that of the free ones, maintained high levels. On the other hand, the evaluation of antimicrobial activity showed greater efficiency in terms of growth inhibition for ALG/CS-ZNP formulations, with average overall values of around 60%, reaching an inhibition of more than 90% for Photobacterium damselae. These results support encapsulation as a good strategy for tea polyphenols, as it allows maintaining significant levels of antioxidant activity and increasing the potential for antimicrobial activity, in addition to increasing protection against sources of degradation.

Combined treatment of human mesenchymal stem cells and green tea extract on retinal ganglion cell regeneration in rats after optic nerve injury.

Retinal ganglion cell (RGC) death and axonal loss cause irreversible vision loss upon optic nerve (ON) injury. We have independently demonstrated that mesenchymal stem cells (MSCs) and green tea extract (GTE) promote RGC survival and axonal regeneration in rats with ON injury. Here we aimed to evaluate the combined treatment effect of human bone marrow-derived MSCs (hBM-MSCs) and GTE on RGC survival and axonal regeneration after ON injury. Combined treatment of hBM-MSCs and GTE promoted RGC survival and neurite outgrowth/axonal regeneration in ex vivo retinal explant culture and in rats after ON injury. GTE increased Stat3 activation in the retina after combined treatment, and enhanced brain-derived neurotrophic factor secretion from hBM-MSCs. Treatment of 10 µg/mL GTE would not induce hBM-MSC apoptosis, but inhibited their proliferation, migration, and adipogenic and osteogenic differentiation in vitro with reducing matrix metalloproteinase secretions. In summary, this study revealed that GTE can enhance RGC protective effect of hBM-MSCs, suggesting that stem cell priming could be a prospective strategy enhancing the properties of stem cells for ON injury treatment.

Antioxidants green tea extract and nordihydroguaiaretic acid confer species and strain-specific lifespan and health effects in Caenorhabditis nematodes.

The Caenorhabditis Intervention Testing Program (CITP) is an NIH-funded research consortium of investigators who conduct analyses at three independent sites to identify chemical interventions that reproducibly promote health and lifespan in a robust manner. The founding principle of the CITP is that compounds with positive effects across a genetically diverse panel of Caenorhabditis species and strains are likely engaging conserved biochemical pathways to exert their effects. As such, interventions that are broadly efficacious might be considered prominent compounds for translation for pre-clinical research and human clinical applications. Here, we report results generated using a recently streamlined pipeline approach for the evaluation of the effects of chemical compounds on lifespan and health. We studied five compounds previously shown to extend C. elegans lifespan or thought to promote mammalian health: 17α-estradiol, acarbose, green tea extract, nordihydroguaiaretic acid, and rapamycin. We found that green tea extract and nordihydroguaiaretic acid extend Caenorhabditis lifespan in a species-specific manner. Additionally, these two antioxidants conferred assay-specific effects in some studies-for example, decreasing survival for certain genetic backgrounds in manual survival assays in contrast with extended lifespan as assayed using automated C. elegans Lifespan Machines. We also observed that GTE and NDGA impact on older adult mobility capacity is dependent on genetic background, and that GTE reduces oxidative stress resistance in some Caenorhabditis strains. Overall, our analysis of the five compounds supports the general idea that genetic background and assay type can influence lifespan and health effects of compounds, and underscores that lifespan and health can be uncoupled by chemical interventions.

Effects of matcha tea extract on cell viability and estrogen receptor-ß expression on MCF-7 breast cancer cells.

PURPOSE: In the following work, we investigated the effect of matcha green tea extract (MTE) on MCF-7 breast cancer cell viability and estrogen receptor-beta expression (ERß). METHODS: MCF-7 cells were stimulated with MTE at concentrations of 5 and 10 µg/ml. Cell viability was assessed using a water-soluble tetrazolium assay (WST-1 assay) after an incubation time of 72 h. ERß was quantified at gene level by real-time polymerase chain reaction (PCR). A western blot (WB) was carried out for the qualitative assessment of the expression behavior of on a protein level. RESULTS: The WST-1 test showed a significant inhibition of viability in MFC-7 cells after 72 h at 10 µg/ml. The WB demonstrated a significant quantitative decrease of ERß at protein level with MTE concentrations of 10 µg/ml. In contrast, the PCR did not result in significant downregulation of ERß. CONCLUSION: MTE decreases the cell viability of MCF-7 cells and furthermore leads to a decrease of ERß at protein level.

Stability of Flavan-3-ols, Theaflavins, and Methylxanthines in 30 Industrial Green, Black, and White Tea (Camellia sinensis L.) Extracts Characterized via Liquid Chromatography Techniques.

Commercially available tea extracts for dietary supplements and nutraceuticals are standardized to characteristic components of Camellia sinensis L., such as epigallocatechin gallate (EGCG) and total catechins or polyphenols. However, since most commercial tea extracts are highly concentrated into only one molecule such as EGCG, the comparatively less stable catechin, the oxidative stability of the extract during the 24-month shelf life was questioned. It was hypothesized that the overall oxidative stability is reduced for highly purified/concentrated tea extracts due to the absence of other natural antioxidants stabilizing the complex mixture. Via liquid chromatographic analysis, the individual chromatographic profiles of 30 commercial white, green, and black tea extracts were evaluated and compared regarding oxidative stability and functional properties. The contents of bioactive flavan-3-ols, theaflavins, and methylxanthines differed much from what was claimed by the suppliers. At the end of the product shelf life, most of the commercial green and black tea extracts showed a decrease in the flavan-3-ol content, the main bioactive components of tea. A high EGCG content to the detriment of other possibly stabilizing flavan-3-ols or antioxidants in tea was found to explain the lower oxidative stability of such tea extract products. A natural overall composition of molecular structures was found to be superior to a strong enrichment in just one molecule.

A comparative study on feeding timing and additive types of broilers in a high-temperature environment.

Antioxidants such as vitamin C (VC) and green tea extract (GTE) have been reported to have various antioxidant functions and are used as one of the nutritional approaches to alleviate heat stress (HS) in chickens. However, studies on the feeding timing that can produce optimal effects have not been reported. In this study, the stress-relieving effect of VC and GTE addition timing was investigated in high-temperature broiler chickens. A total of 880 1-d-old male chickens were used, and the treatments were as follows: no feed additives provided, CON; VC 250 mg/kg added from 1 d, VC1; GTE 600 mg/kg added from 1 d, GTE1; VC 250 mg/kg added from 22 d, VC22; GTE 600 mg/kg added from 22 d, GTE22. The HS environment was provided for 2 wk from the 22 d and was set at 33 ± 1 °C, 55 ± 10% for 24 h. Feed and water were provided ad libitum. Broiler production was similar in all treatments. In chicken meat quality, the addition of VC and GTE had an effect on meat color and pH (P < 0.05). In particular, GTE had a positive effect on the antioxidant capacity and quality preservation of breast meat (P < 0.05). In blood characteristics, GTE1 significantly lowered the level of total cholesterol, and VC1 affected AST and IgM (P < 0.05). Interestingly, the VC1 group had a positive effect on the maintenance and development of intestinal morphology, a lower rectal temperature, and showed to relieve stress. In conclusion, the addition of VC and GTE has been shown to alleviate the high-temperature stress of broilers, and in the case of VC in particular, feeding from 1 d appeared to alleviate stress more effectively. This study suggests that it is important to determine the appropriate timing of addition of functional substances in order to effectively reduce various stresses that occur in livestock rearing.

The increasing frequency of exposure to high-temperature environments has prompted research into nutritional approaches to alleviate heat stress in chickens, but little research has been reported on feeding timing. The aim of this study was to determine the effect of feeding timing on the effectiveness of the natural antioxidants vitamin C (VC) and green tea extract (GTE). Production was similar among all treatments, and GTE fed from 1 d of age increased antioxidant capacity, including DPPH, FRAP, and MDA in carcass quality. VC fed from 1 d of age decreased AST and increased IgM in the blood, and increased villus height (VH), with a positive effect on intestinal development. In conclusion, feeding VC and GTE from 1 d of age has been shown to effectively alleviate stress by increasing antioxidant capacity in breast meat, positively changing total cholesterol, AST, and IgM in the blood, and maintaining intestinal morphology, and it is important to set the timing of feeding to increase the effectiveness of the additives.

Synergistic Effects of Heat-Treated Green Tea Extract and Enzymatically-Modified Isoquercitrin in Preventing Obesity.

Previous research has shown that both heat-treated green tea extract (HTGT) and enzymatically modified isoquercitrin (EMIQ) have anti-obesity effects. Given the absence of in vivo evidence demonstrating their synergistic effects, our study aimed to elucidate the combined obesity prevention potential of HTGT and EMIQ in mice. Mice were treated with these compounds for 8 weeks, while being fed a high-fat diet, to investigate their preventive anti-obesity effects. We demonstrated that the co-treatment of HTGT and EMIQ results in a synergistic anti-obesity effect, as determined by a Kruskal-Wallis test. Furthermore, the combined treatment of HTGT and EMIQ was more effective than orlistat in reducing body weight gain and adipocyte hypertrophy induced by high-fat diet. The co-treatment also significantly reduced total body fat mass and abdominal fat volume. Additionally, the group receiving the co-treatment exhibited increased energy expenditure and higher glucose intolerance. We observed a dose-dependent upregulation of genes associated with mitochondrial oxidative metabolism and PKA signaling, which is linked to lipolysis, in response to the co-treatment. The co-treatment group displayed elevated cAMP levels and AMPK activation in adipose tissue and increased excretion of fecal lipids. The results indicate that the co-treatment of HTGT and EMIQ holds the potential to be a promising combination therapy for combating obesity. To further validate the anti-obesity effect of the combined treatment of HTGT and EMIQ in human subjects, additional clinical studies are warranted.

The hepatoprotective effects of Herbt Tea Essences on phenanthrene-induced liver damage in mice.

Phenanthrene (Phe), one of the most frequently occurring pollutants in nature, can cause substantial damage to the human liver. Herbt Tea Essences (HTE), a kind of black tea extract with strong anti-inflammatory activity, can protect humans against disease. Currently, whether HTE can protect the liver from Phe-induced hepatotoxicity remains unclear. Herein, we explore the protective effects of HTE against Phe-induced hepatotoxicity. Our results showed that Phe exposure could significantly induce liver damage and increase serum hepatic enzyme levels in mice. HTE could prevent liver damage and recover the expression levels of inflammatory factors. Furthermore, we found that HTE suppressed the excessive activation of the nuclear transcription factor kappa-B and transforming growth factor-ß/SMAD signaling pathways to alleviate Phe-induced liver inflammation and fibrosis. Overall, our data showed that HTE treatment could be a new preventive means for Phe-induced liver disease.

Green tea extract supplementation does not modify plasma concentration of F2-isoprostanes in women who are postmenopause: Findings from a randomized controlled trial.

Green tea extract (GTE) is a potential mitigator of oxidative stress, and F2-isoprostanes are a reliable biomarker of oxidative stress. Genetic polymorphisms in the catechol-o-methyltransferase (COMT) gene may modify tea catechin metabolism, prolonging exposure. We hypothesized that GTE supplementation would decrease plasma F2-isoprostanes concentrations compared with placebo and that participants with the COMT genotype polymorphisms would experience a more significant expression of this outcome. This study was a secondary analysis of the Minnesota Green Tea Trial, a randomized placebo-controlled, double-blinded trial investigating the effects of GTE in women who were generally healthy and postmenopausal. The treatment group consumed 843 mg of epigallocatechin gallate daily for 12 months versus placebo. Participants in this study had a mean age of 60 years, were predominantly White, and most had a healthy body mass index. GTE supplementation did not significantly change plasma F2-isoprostanes concentrations compared with placebo after 12 months (P for overall treatment = .07). There were no significant interactions between treatment and age, or body mass index, physical activity, smoking history, and alcohol intake. COMT genotype did not modify the effect of GTE supplementation on F2-isoprostanes concentrations in the treatment group (P = .85). Among participants in the Minnesota Green Tea Trial, consuming GTE supplements daily for 1 year did not result in a significant decrease in plasma F2-isoprostanes concentrations. Likewise, the COMT genotype did not modify the effect of GTE supplementation on F2-isoprostanes concentrations.

Postprandial Metabolic Mesponses to High-fat Feeding in Healthy Adults Following Ingestion of Oolong Tea-Derived Polymerized Polyphenols: A Randomized, Double-blinded, Placebo-controlled Crossover Study.

BACKGROUND: Polymerized polyphenols (PP) found in oolong tea can inhibit pancreatic lipase activity in vitro, and pilot work indicates that this may reduce postprandial lipemia. Since tea contains caffeine and catechins, the interactions between these ingredients and PP warrant investigation. OBJECTIVES: To assess whether PP ingested alone or with caffeine and catechins lowers postprandial lipemia. METHODS: Fifty healthy adults [mean (SD) age: 26 (7) y; BMI (in kg/m2): 24.0 (2.7); female: n = 16] completed 4 oral lipid tolerance tests in a placebo-controlled randomized, crossover design. Participants ingested 40 g of fat with either 1) placebo, 2) 100 mg PP, 3) 150 mg PP, or 4) 100 mg PP plus 50 mg caffeine and 63 mg catechins (PP + CC). Blood was sampled for 3 h postprandially to assess concentrations of serum and plasma triacylglycerol and plasma markers of lipid (NEFA; glycerol; LDL and HDL cholesterol; and ApoA-I, A-II, B, C-II, C-III, and E) and glucose metabolism (glucose, insulin, and C-peptide). RESULTS: Serum and plasma triacylglycerol concentrations and lipid metabolism variables generally increased following any test drink ingestion (main effect of time, p < 0.001). Nevertheless, for the lipid metabolism responses, there were no statistically significant condition-time interactions and no statistically significant differences in incremental or total area under the curve between conditions, apart from HDL cholesterol (p = 0.021). Ingesting 100 mg PP + CC lowered peak plasma glucose, insulin, and C-peptide concentrations compared with all other conditions 30 min postingestion (p < 0.001), with persistent alterations in glucose concentrations observed for 90 min compared with placebo and 100 mg PP conditions. CONCLUSIONS: PP ingested at doses ≤150 mg does not clearly alter early-phase postprandial triacylglycerol concentrations in healthy adults, irrespective of the presence or absence of caffeine and catechins. Nevertheless, caffeine and catechins added to PP lowered postprandial glucose and insulin concentrations. This trial was registered in ClinicalTrials.gov as NCT03324191 (https://clinicaltrials.gov/ct2/show/NCT03324191).

Suppressive effect of black tea polyphenol theaflavins in a mouse model of ovalbumin-induced food allergy.

Food allergy is recognized as a global medical problem with increasing prevalence in recent years. Currently, the treatment of food allergy mainly involves avoidance of allergens and allergen-specific immunotherapy. Barring the spontaneous resolution of food allergy during the growth process, this disease is difficult to treat fundamentally. In recent years, the use of functional food ingredients derived from natural products has been attracting attention for their prophylactic use in food allergy. Theaflavins, i.e., black tea polyphenols, are potent antioxidants that have inhibitory effects on a variety of diseases. However, little is known about the preventive effect of theaflavins on food allergy. In this study, we designed a mouse model of food allergy and examined the effect of theaflavins using the severity of diarrhea, a symptom of food allergy, as an indicator. The administration of a black tea extract rich in theaflavins or theaflavin 1 (subgroup of theaflavins) to mice reduced the severity of diarrhea when compared with a normal diet. A reduction in malondialdehyde levels, a key marker of lipid peroxidation, was also observed. Overall, these data suggest that theaflavins may potentially inhibit food allergy by alleviating oxidative stress in the colon and can be a potential food material for prevention of food allergy.

Green tea extract enhances retinal ganglion cell survival and axonal regeneration in rats with optic nerve injury.

Current clinical treatments have not yet effectively cured progressive retinal ganglion cell (RGC) death and axonal degeneration after optic nerve (ON) injury. We previously demonstrated green tea extract (GTE) can reduce RGC death in rats after ischemic injury. Here, we aim to determine the prophylactic and therapeutic effects and mechanisms of GTE on RGC survival and axonal regeneration in rats with ON injury. GTE (275 or 550 mg/kg) was administered intragastrically for 7 d before or 14 d post-ON crush surgery in adult Fischer 344 rats. Rats with pre- or post-operative treatment of 275 mg/kg GTE showed significantly higher numbers of RGCs and regenerated axons post-ON injury with improved pupillary light reflex as compared to saline-treated rats. Akt and Erk p42/44 activation was higher in the retina of rats given 275 mg/kg GTE pre-surgery, whereas Stat3 activation was higher in those with 275 mg/kg GTE post-operation. Less activated microglia were observed in rats with pre-treatment of 275 or 550 mg/kg GTE. RNA sequencing analysis identified the downregulation of inflammation, apoptosis, and microglia activation genes in the retina of rats with pre- or post-treatment with 275 mg/kg GTE as compared to the saline-treated rats. In summary, this study revealed the prophylactic and therapeutic treatment effects of GTE on RGC survival and axonal regeneration in rats with ON injury, indicating a potential alternative treatment for traumatic optic neuropathy.

Green tea extract ameliorates macrophage-driven emphysematous lesions in chronic obstructive pulmonary disease induced by cigarette smoke condensate.

Chronic obstructive pulmonary disease (COPD) is an important lung disease characterized by complicated symptoms including emphysema. We aimed to explore the mechanisms underlying the protective effect of green tea extract (GTE) on cigarette smoke condensate (CSC)-induced emphysema by demonstrating the reduction of macrophage-induced protease expression through GTE treatment in vivo and in vitro. Mice were intranasally administered 50 mg/kg CSC once a week for 4 weeks, and doses of 100 or 300 mg/kg GTE were administered orally once daily for 4 weeks. GTE significantly reduced macrophage counts in bronchoalveolar lavage fluid and emphysematous lesions in lung tissues in CSC-exposed mice. In addition, GTE suppressed CSC-induced extracellular signal-regulated kinase (ERK)/activator protein (AP)-1 phosphorylation followed by matrix metalloproteinases (MMP)-9 expression as revealed by western blotting, immunohistochemistry, and zymography in CSC-instilled mice. These underlying mechanisms related to reduced protease expression were confirmed in NCI-H292 cells stimulated by CSC. Taken together, GTE effectively inhibits macrophage-driven emphysematous lesions induced by CSC treatment, and these protective effects of GTE are closely related to the ERK/AP-1 signaling pathway, followed by a reduced protease/antiprotease imbalance. These results suggest that GTE can be used as a supplementary agent for the prevention of emphysema progression in COPD patients.

Reduction in Five Harmful Substances in Fried Potato Chips by Pre-Soaking Treatment with Different Tea Extracts.

Thermally processed food always contains various types of harmful substances. Control of their levels in food is important for human health. This work used the extracts from green tea dust, old green tea, yellow tea, white tea, oolong tea, and black tea to simultaneously mitigate diverse harmful substances in fried potato chips. The six tea extracts (30 g/L) all showed considerable inhibitory effects on the formation of 5-hydroxymethylfurfural (reduced by 19.8%-53.2%), glyoxal (26.9%-36.6%), and methylglyoxal (16.1%-75.1%). Green tea and black tea extracts exhibited better inhibitory abilities than the other three teas and were further investigated for other harmful compounds by various concentration treatments. Finally, pre-soaking of fresh potato slices in 50 g/L extracts of green tea dust displayed, overall, the most promising inhibitory capacity of HMF (decreased by 73.3%), glyoxal (20.3%), methylglyoxal (69.7%), acrylamide (21.8%), and fluorescent AGEs (42.9%) in fried potato chips, while it exhibited the least impact on the color and texture. The high level of catechins in green tea dust may contribute most to its outstanding inhibitory effect, whereas the distinguished inhibitory effect of black tea extract was speculated to be attributable to the high levels of theaflavins and amino acids in the fully fermented tea. This study indicated that green tea dust, a predominant waste of the tea industry, had great potential to be exploited to improve food quality and safety.

Multifunctional Iron Oxide Nanocarriers Synthesis for Drug Delivery, Diagnostic Imaging, and Biodistribution Study.

The aim of the current study is to design the radiolabeled and drug-loaded nanocarrier with high loading capacity and pH-dependent drug release characteristics that could effectively transport loaded compounds to various organs for efficient diagnostic imaging and chemotherapeutic drug delivery. The aqueous extract of green tea leaves was used to synthesize the small-sized iron oxide nanoparticles (IONPs). The nanoparticles were characterized with UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray analysis (EDX). Iron oxide nanoparticles with sizes smaller than 50 nm were successfully synthesized, making them suitable for in vivo studies. In drug loading trials, 94% of the drug was loaded onto the active surface of iron oxide nanoparticles from the solution. The in vitro drug release study revealed that an acidic environment (pH 4.5) effectively triggers the release of doxorubicin (DOX) from the nanoparticles as compared to a neutral environment (pH 7.4). The gamma-emitting radionuclide 99mTc was successfully labeled with IONPs for biodistribution and imaging studies. The efficiency of radiolabeling was observed to be ≥ 99%. Furthermore, the in vivo biodistribution study of radiolabeled IONPs in rabbit model showed rapid accumulation in various organs such as heart, liver, and kidneys. This work suggested that green synthesized iron oxide nanoparticles are potential nanocarriers for diagnostic imaging and efficiently distributing DOX to specific organs. The aqueous extract of green tea leaves was used for the facile green synthesis of iron oxide nanoparticles (IONPs). Furthermore, the chemotherapeutic drug doxorubicin (DOX) and gamma-emitting radionuclide 99mTc were loaded on these iron oxide nanoparticles to evaluate the in vivo biodistribution and drug delivery studies in the rabbit models.

Green tea extract exhibits antidiabetic effects partly through regulating dipeptidyl peptidase-4 expression in adipose tissue.

The antidiabetic effects of green tea have been demonstrated in clinical trials and epidemiological studies. This study investigated the antidiabetic effects of green tea extract (GTE) and its underlying molecular mechanisms using a leptin receptor-deficient db/db mouse model (Leprdb/db). Treatment with GTE for 2 weeks improved glucose tolerance and insulin sensitivity in Leprdb/db mice. In addition, GTE treatment reduced the body weight and adiposity of Leprdb/db mice. Furthermore, GTE treatment reduced pro-inflammatory gene expression, including nuclear factor kappa B (NF-κB) in white adipose tissue (WAT), and also reduced dipeptidyl peptidase-4 (DPP4) expression levels in WAT as well as in the serum. The promoter region of Dpp4 contains the NF-κB binding site, and DPP4 was found to be a direct target of NF-κB. Consistently, in vitro treatment of cells with GTE or its main constituent epigallocatechin gallate reduced lipopolysaccharide-induced NF-κB/DPP4 expression in 3T3-L1 adipocytes and RAW264.7 cells. Overall, our data demonstrated that GTE exerts an anti-diabetic effect by regulating the expression levels of NF-κB and DPP4 in WAT.