Antibacterial mechanism of kojic acid and tea polyphenols against Escherichia coli O157:H7 through transcriptomic analysis

Escherichia coli O157:H7 is one of the major foodborne pathogenic bacterial that cause infectious diseases in humans.The previous found that a combination of kojic acid and tea polyphenols exhibited better activity against E.coli O157:H7 than using either alone.This study aimed to explore responses underlying the antibacterial mechanisms of kojic acid and tea polyphenols from the gene level.The functional enrichment analysis by comparing kojic acid and tea polyphenols individually or synergistically against E.coli O157:H7 found that acid resistance systems in kojic acid were activated,and the cell membrane and genomic DNA were destructed in the cells,resulting in“oxygen starvation”.The oxidative stress response triggered by tea polyphenols inhibited both sulfur uptake and the synthesis of ATP,which affected the bacteria's life metabolic process.Interestingly,we found that kojic acid combined with tea polyphenols hindered the uptake of iron that played an essential role in the synthesis of DNA,respiration,tricarboxylic acid cycle.The results suggested that the iron uptake pathways may represent a novel approach for kojic acid and tea polyphenols synergistically against E.coli O157:H7 and provided a theoretical basis for bacterial pathogen control in the food industry.

The modulatory effect of oolong tea polyphenols on intestinal flora and hypothalamus gene expression in a circadian rhythm disturbance mouse model

The interaction between host circadian rhythm and gut microbes through the gut-brain axis provides new clues for tea polyphenols to improve host health.Our present research showed that oolong tea polyphenols(OTP)improved the structural disorder of the intestinal flora caused by continuous darkness,thereby modulating the production of metabolites related to pyruvate metabolism,glycolysis/gluconeogenesis,and tryptophan metabolism to alleviate the steady-state imbalance.After fecal microbiota transplantation from the OTP group,the single-cell transcriptomic analysis revealed that OTP significantly increased the number of hypothalamus cell clusters,up-regulated the number of astrocytes and fibroblasts,and enhanced the expression of circadian rhythm genes Cry2,Per3,Bhlhe41,Nr1d1,Nr1d2,Dbp and Rorb in hypothalamic cells.Our results confirmed that OTP can actively improve the intestinal environmental state as well as internal/peripheral circadian rhythm disorders and cognitive impairment,with potential prebiotic functional characteristics to notably contribute to host health.

Tea Polyphenols Reduce Inflammation of Orbital Fibroblasts in Graves’Ophthalmopathy via the NF-κB/NLRP3 Pathway

Objective:This study aimed to explore the effects of tea polyphenols(TP)on inflammation of orbital fibroblasts in Graves’ophthalmopathy(GO)and to provide new ideas for GO treatment.Methods:Primary orbital fibroblasts were extracted from orbital adipose/connective tissues of patients with and without GO.Real-time quantitative PCR(RT-qPCR)was used to detect the expression of interleukin(IL)-6,IL-1β,and monocyte chemotactic protein(MCP)-1 in non-GO and GO orbital fibroblasts.The CCK-8 assay was used to determine the appropriate concentration of TP for subsequent experiments.RT-qPCR and enzyme-linked immunosorbent assay(ELISA)were performed to investigate the effects of TP on lipopolysaccharide(LPS)-induced production of inflammatory cytokines.Nuclear factor-κB(NF-κB)expression was measured using Western blotting analysis.NOD-like receptor 3(NLRP3)expression was detected using both Western blotting analysis and immunofluorescence staining.Results:The mRNA levels of IL-6,IL-1β,and MCP-1 in GO orbital fibroblasts were significantly higher than those in non-GO cells.TP treatment significantly inhibited LPS-induced production of inflammatory factors,including IL-6,IL-1β,and MCP-1.TP also inhibited the expression levels of NF-κB and NLRP3.Inflammation in the GO orbital fibroblasts was higher than that in non-GO cells.TP inhibited the production of inflammatory cytokines in GO orbital fibroblasts in vitro through the NF-κB/NLRP3 pathway.Conclusion:These findings suggest that TP may have a potential role in GO treatment.

Plant-inspired biomimetic hybrid PVDF membrane co-deposited by tea polyphenols and 3-amino-propyl-triethoxysilane for high-efficiency oilin-water emulsion separation

Membrane pollution caused by separating oily wastewater is a big challenge for membrane separation technology.Recently,plant-/mussel-inspired interface chemistry has received more and more attention.Herein,a high antifouling poly(vinylidene fluoride)(PVDF)membrane,coated with tea polyphenols(TP,extracted from green tea)and 3-amino-propyl-triethoxysilane(APTES),was developed to purify oil-inwater emulsions.ATR-FTIR,XPS and SEM were used to demonstrate the evolution of surface biomimetic hybrid coatings.The performances of the developed membranes were investigated by pure water permeability and oil rejection for various surfactant-stabilized oil-in-water emulsions.The experimental results revealed that the membrane deposited with a mass ratio of 0.1/0.2 exhibited ultrahigh pure water permeability(14570 L·m^(-2)·h^(-1)·bar^(-1),1 bar=0.1 MPa)and isooctane-in-water emulsion permeability(5391 L·m^(-2)·h^(-1)·bar^(-1))with high separation efficiency(>98.9%).Even treated in harsh environment(acidic,alkaline and saline)for seven days,the membrane still maintained considerable underwater oleophobic property(148°–153°).The fabricated plant-inspired biomimetic hybrid membranes with excellent performances light a broad application prospect in the field of oily wastewater treatment.

Green tea polyphenols alleviate di-(2-ethylhexyl)phthalate-induced liver injury in mice

BACKGROUND Di(2-ethylhexyl)phthalate(DEHP)is a common plasticizer known to cause liver injury.Green tea is reported to exert therapeutic effects on heavy metal exposureinduced organ damage.However,limited studies have examined the therapeutic effects of green tea polyphenols(GTPs)on DEHP-induced liver damage.AIM To evaluate the molecular mechanism underlying the therapeutic effects of GTPs on DEHP-induced liver damage.METHODS C57BL/6J mice were divided into the following five groups:Control,model[DEHP(1500 mg/kg bodyweight)],treatment[DEHP(1500 mg/kg bodyweight)+GTP(70 mg/kg bodyweight),oil,and GTP(70 mg/kg bodyweight)]groups.After 8 wk,the liver function,blood lipid profile,and liver histopathology were examined.Differentially expressed micro RNAs(miRNAs)and mRNAs in the liver tissues were examined using high-throughput sequencing.Additionally,functional enrichment analysis and immune infiltration prediction were performed.The miRNA-mRNA regulatory axis was elucidated using the starBase database.Protein expression was evaluated using immunohistochemistry.RESULTS GTPs alleviated DHEP-induced liver dysfunction,blood lipid dysregulation,fatty liver disease,liver fibrosis,and mitochondrial and endoplasmic reticulum lesions in mice.The infiltration of macrophages,mast cells,and natural killer cells varied between the model and treatment groups.mmu-miR-141-3p(a differentially expressed miRNA),Zcchc24(a differentially expressed mRNA),and Zcchc24(a differentially expressed protein)constituted the miRNA-mRNA-protein regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage in mice.CONCLUSION This study demonstrated that GTPs mitigate DEHP-induced liver dysfunction,blood lipid dysregulation,fatty liver disease,and partial liver fibrosis,and regulate immune cell infiltration.Additionally,an important miRNAmRNA-protein molecular regulatory axis involved in mediating the therapeutic effects of GTPs on DEHP-induced liver damage was elucidated.

Preparation and Drug-Release Property of Polycaprolactone (PCL)/Polyglycolic Acid (PGA) Composite Masterbatch with Drug of Tea Polyphenols (TPs)

In order to effectively control the drug-release rate of medical textiles,biodegradable polycaprolactone(PCL) and polyglycolic acid(PGA) were blended at various mass ratios to prepare composite masterbatches for medical textiles.The surface morphology and the chemical structure of the masterbatches were analyzed.The crystallization,mass losses,strengths and drug-release rates of the composite masterbatches at different PCL/PGA mass ratios were explored.The results show that the degradation rate of the PGA carrier is obvious higher than that of the PCL carrier,and PCL,PGA and the tea polyphenol(TP) drug just physically mix without chemical reaction.During the degradation,the strength of the composite masterbatches gradually decreases.In addition,the drug-release rates of composite masterbatches at different mass ratios are different,and the more the PGA in the composite masterbatches,the faster the drug release of the composite masterbatches.The drug-release rate of the composite masterbatches can be controlled by adjusting the contents of PCL and PGA.

Research Progress on the Therapeutic Mechanism of Tea Polyphenols in Neurodegenerative Diseases

In recent years, the incidence of neurodegenerative diseases, mainly Alzheimer’s disease, Parkinson’s disease, vascular dementia, and cerebral ischemia, has been rising gradually, which has a serious impact on the physiological state and quality of life of human beings in old age, and the current clinical drugs are unsatisfactory in terms of therapeutic efficacy and healing, which has made this kind of diseases become a social medical problem. Tea polyphenols are the main functional components of tea and have great potential in neuroprotection. In this paper, we review the research on tea polyphenols in neurodegenerative diseases, with the aim of providing a new entry point for the treatment of neurodegenerative diseases.

A review of pharmacological activity and application potential in food of tea polyphenols

Tea polyphenols(TP)is a class of polyhydroxy compounds isolated from tea.Modern biological and medical studies have shown that TP has many pharmacological activities,such as anti-inflammatory,anti-virus,anti-oxidation,anti-tumor and anti-radiation.Furthermore,these substances can be used as a potential drug component to positively guide the occurrence and development of certain diseases.Furthermore,because of the activities of TP,such as anti-oxidation and anti-bacteria,it can be applied in food preservation,color preservation,deodorization,and treatment of food processing by-products.Based on the research progress of TP in recent years,this paper summarizes the pharmacological activities of TP and expounds on its application potential in the field of food.In order to provide a theoretical reference for the research,development and utilization of TP.

ROS-related Enzyme Expressions in Endothelial Cells Regulated by Tea Polyphenols

Objective Elevation of reactive oxygen species (ROS), especially the level of superoxide is a key event in many forms of cardiovascular diseases. To study the mechanism of tea polyphenols against cardiovascular diseases, we observed the expressions of ROS-related enzymes in endothelial cells. Methods Tea polyphenols were co-incubated with bovine carotid artery endothelial cells (BCAECs) in vitro and intracellular NADPH oxidase subunits p22phox and p67phox, SOD-1, and catalase protein were detected using Western blot method. Results Tea polyphenols of 0.4 ug/mL and 4.0 ug/mL (from either green tea or black tea) down-regulated NADPH oxidase p22phox and p67phox expressions in a dose-negative manner (P<0.05), and up-regulated the expressions of catalase (P<0.05). Conclusions Tea polyphenols regulate the enzymes involved in ROS production and elimination in endothelial cells, and may be beneficial to the prevention of endothelial cell dysfunction and the development of cardiovascular diseases.

Green tea polyphenols ameliorate non-alcoholic fatty liver disease through upregulating AMPK activation in high fat fed Zucker fatty rats

AIM To investigate protective effects and molecular mechanisms of green tea polyphenols(GTP) on nonalcoholic fatty liver disease(NAFLD) in Zucker fatty(ZF) rats.METHODS Male ZF rats were fed a high-fat diet(HFD) for 2 wk then treated with GTP(200 mg/kg) or saline(5 m L/kg) for 8 wk, with Zucker lean rat as their control. At the end of experiment, serum and liver tissue were collected for measurement of metabolic parameters, alanine aminotransferase(ALT) and aspartate aminotransferase(AST), inflammatory cytokines and hepatic triglyceride and liver histology. Immunoblotting was used to detect phosphorylation of AMP-activated protein kinase(AMPK) acetyl-Co A carboxylase(ACC), and sterol regulatory element-binding protein 1c(SREBP1c). RESULTS Genetically obese ZF rats on a HFD presented with metabolic features of hepatic pathological changes comparable to human with NAFLD. GTP intervention decreased weight gain(10.1%, P = 0.052) and significantly lowered visceral fat(31.0%, P < 0.01). Compared with ZF-controls, GTP treatment significantly reduced fasting serum insulin, glucose and lipids levels. Reduction in serum ALT and AST levels(both P < 0.01) were observed in GTP-treated ZF rats. GTP treatment also attenuated the elevated TNFα and IL-6 in the circulation. The increased hepatic TG accumulation and cytoplasmic lipid droplet were attenuated by GTP treatment, associated with significantly increased expression of AMPK-Thr172(P < 0.05) and phosphorylated ACC and SREBP1c(both P < 0.05), indicating diminished hepatic lipogenesis and triglycerides out flux from liver in GTP treated rats. CONCLUSION The protective effects of GTP against HFD-induced NAFLD in genetically obese ZF rats are positively correlated to reduction in hepatic lipogenesis through upregulating the AMPK pathway.

Tea polyphenols and their chemopreventive and therapeutic effects on colorectal cancer

Colorectal cancer(CRC),a multifactorial disease,is usually induced and developed through complex mechanisms,including impact of diet and lifestyle,genomic abnormalities,change of signaling pathways,inflammatory response,oxidation stress,dysbiosis,and so on.As natural polyphenolic phytochemicals that exist primarily in tea,tea polyphenols(TPs)have been shown to have many clinical applications,especially as anticancer agents.Most animal studies and epidemiological studies have demonstrated that TPs can prevent and treat CRC.TPs can inhibit the growth and metastasis of CRC by exerting the antiinflammatory,anti-oxidative or pro-oxidative,and pro-apoptotic effects,which are achieved by modulations at multiple levels.Many experiments have demonstrated that TPs can modulate several signaling pathways in cancer cells,including the mitogen-activated protein kinase pathway,phosphatidylinositol-3 kinase/Akt pathway,Wnt/β-catenin pathway,and 67 kDa laminin receptor pathway,to inhibit proliferation and promote cell apoptosis.In addition,novel studies have also suggested that TPs can prevent the growth and metastasis of CRC by modulating the composition of gut microbiota to improve immune system and decrease inflammatory responses.Molecular pathological epidemiology,a novel multidisciplinary investigation,has made great progress on CRC,and the further molecular pathological epidemiology research should be developed in the field of TPs and CRC.This review summarizes the existing in vitro and in vivo animal and human studies and potential mechanisms to examine the effects of tea polyphenols on CRC.

Antioxidant and anti-inflammatory roles of tea polyphenols in inflammatory bowel diseases

Polyphenols,including phenolic acids,flavonoids,and procyanidins,are abundant in food and beverage derived from plants.Tea(Camellia sinensis)is particularly rich in polyphenols(e.g.,catechins,theaflavins,thearubigins,gallic acid,and flavonols),which are thought to contribute to the health benefits of tea.High intake of tea polyphenols has been described to prevent and/or attenuate a variety of chronic pathological conditions like cardiovascular diseases,neurodegenerative diseases,diabetes,and cancer.This review focuses on established antioxidant and anti-inflammatory properties of tea polyphenols and underlying mechanisms of their involvement in inflammatory bowel diseases(IBD).Tea polyphenols act as efficient antioxidants by inducing an endogenous antioxidant defense system and maintaining intracellular redox homeostasis.Tea polyphenols also regulate signaling pathways such as nuclear factor-κB,activator protein 1,signal transducer and activator of transcriptions,and nuclear factor E2-related factor 2,which are associated with IBD development.Accumulating pieces of evidence have indicated that tea polyphenols enhance epithelial barrier function and improve gut microbial dysbiosis,contributing to the management of inflammatory colitis.Therefore,this study suggests that supplementation of tea polyphenols could prevent inflammatory conditions and improve the outcome of patients with IBD.

Focusing on the recent progress of tea polyphenol chemistry and perspectives

Myriad evidence attests to the health-promoting benefits of tea drinking.While there are multiple factors of tea influencing the effective biological properties,tea polyphenols are the most significant and valuable components.The chemical characterization and physical characteristics of tea polyphenols have been comprehensively studied over the previous years.Still the emergence of new chemistry in tea,particularly the property of scavenging reactive carbonyl species(RCS)and the newly discovered flavoalkaloid compounds,has drawn increasing attention.In this review,we summarize recent findings of a new class of compounds in tea-flavonoid alkaloids(flavoalkaloids),which exist in fresh tea leaves and can be generated during the process of post-harvesting,and also postulate the formation mechanism of flavoalkaloids between catechins and theanine-derived Strecker aldehyde.Additionally,we detail the up-to-date research results of tea polyphenols regarding their ability to trap RCS and their in vivo aminated metabolites to suppress advanced glycation ends products(AGEs).We further raise questions to be addressed in the near future,including the synthetic pathways for the generation of flavoalkaloids and AGEs in fresh tea leaves before processing and the concentrations of tea polyphenols that affect their RCS scavenging capability due to their pro-oxidant nature.More intensive research is warranted to elucidate the mechanisms of action underlying the biological activity of flavoalkaloids and the pharmacological application of tea polyphenols in scavenging RCS and impeding detrimental AGEs.

Green tea polyphenols inhibit testosterone production in rat Leydig cells

This study investigated the acute effects of green tea extract （GTE） and its polyphenol constituents, （-）-epigallocatechin-3-gallate （EGCG） and （-）-epicatechin （EC）, on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A （PKA） or protein kinase C （PKC） activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin （hCG）, luteinizing hormone releasing hormone （LHRH）, 22（R）-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22（R）- hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22（R）-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17β-hydroxysteroid dehydrogenase function.

Improving the stability and bioavailability of tea polyphenols by encapsulations:a review

Tea polyphenols(TPPs)have attracted significant research interest due to their health benefits.However,TPPs are sensitive to certain environmental and gastrointestinal conditions and their oral bioavailability was found to be very low.Delivery systems made of food-grade materials have been reported to improve the shelf-life,bioavailability and bioefficacy of TPPs.This review discusses the chemistry of TPPs;the setbacks of TPPs for application;and the strategies to counteract application limitations by rationally designing delivery systems.An overview of different formulations used to encapsulate TPPs is provided in this study,such as emulsion-based systems(liposome,nanoemulsion,double emulsion,and Pickering emulsion)and nano/microparticles-based systems(protein-based,carbohydrate-based,and bi-polymer based).In addition,the stability,bioavailability and bioactivities of encapsulated TPPs are evaluated by various in vitro and in vivo models.The current findings provide scientific insights in encapsulation approaches for the delivery of TPPs,which can be of great value to TPPs-fortified food products.Further explorations are needed for the encapsulated TPPs in terms of their applications in the real food industry as well as their biological fate and functional pathways in vivo.

Tea polyphenols inhibit expressions of iNOS and TNF-a and prevent lipopolysaccharide-induced liver injury in rats

BACKGROUND: Tea polyphenols have been shown to protect against carbon tetrachloride ( CCl4) -induced liver injury, liver fibrosis, hepatic ischemia-reperfusion injury. In this study, we examined the effect of tea polyphenols on lipopolysaccharide ( LPS ) -induced liver injury, and explored its mechanisms. METHODS: Sprague-Dawley rats received tea polyphenols (100 mg · kg-1·d-1) or vehicle (water) intragastrically by gavage for 14 days, followed by LPS (5 mg/kg) or saline injection intraperitoneally. Liver injury was assessed by biochemical assay and pathological analysis. Serum tumor necrosis factor-α (TNF-α) levels and liver malondialdehyde (MOA) contents were determined. Inducible nitric oxide synthase (iNOS) protein and TNF-α, iNOS and en-dothelial nitric oxide synthase (eNOS) mRNA expressions in the liver were detected by immunohistochemistry and reverse transcriptase-polymerase chain reaction (RT-PCR), respectively. RESULTS: Administration of LPS resulted in liver injury in rats, evidenced by elevated activities of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), hepatocellular necrosis, and neutrophil infiltration in the liver. These responses were associated with increased serum TNF-α levels, induced iNOS protein, expressions of TNF-α, iNOS mRNA in the liver and elevated lipid peroxidation at 90 minutes or 6 hours after LPS injection. Pretreatment with tea polyphenols attenuated LPS-induced liver injury, and blunted the rises of serum TNF-α levels and lipid peroxidation and the induction of expressions of TNF-α, iNOS in the liver. CONCLUSION: Tea polyphenols prevent LPS-induced liver injury, and the mechanisms may involve the reduction of serum TNF-α levels and lipid peroxidation and the suppression of TNF-α, iNOS expressions in the liver.

An optimal dose of tea polyphenols protects against global cerebral ischemia/reperfusion injury

Previous studies addressing the protection of tea polyphenols against cerebral ischemia/ reperfusion injury often use focal cerebral ischemia models, and the optimal dose is not unified. In this experiment, a cerebral ischemia/reperfusion injury rat model was established using a modified four-vessel occlusion method. Rats were treated with different doses of tea polyphenols （25, 50, 100, 150, 200 mg/kg） via intraperitoneal injection. Results showed that after 2, 6, 12, 24, 48 and 72 hours of reperfusion, peroxide dismutase activity and total antioxidant capacity in brain tissue gradually increased, while malondialdehyde content gradually decreased after tea polyphenol intervention. Tea polyphenols at 200 mg/kg resulted in the most apparent changes. Terminal deoxynucleotidyl transferase-mediated nick end labeling and flow cytometry showed that 200 mg/kg tea polyphenols significantly reduced the number and percentage of apoptotJc cells in the hippocampal CA1 region of rats after cerebral ischemia/reperfusion injury. The open field test and elevated plus maze experiments showed that tea polyphenols at 200 mg/kg strengthened exploratory behavior and reduced anxiety of cerebral ischemia/reperfusion injured rats. Experimental findings indicate that tea polyphenols protected rats against cerebral ischemia/ reperfusion injury and 200 mg/kg is regarded as the optimal dose.

Tea Polyphenols Exerts Anti-hepatitis B Virus Effects in a Stably HBV-transfected Cell Line

In this study, the anti-HBV effects of tea polyphenols （TP） were examined. After cells were exposed to TP for 3, 6, 9 days, amounts of HBsAg, HBeAg and HBV-DNA released into the supernatant of the cultured HepG2 2.2.15 cells were detected. TP, to some extent, inhibited the secretion of HBsAg and strongly suppressed the secretion of HBeAg in a dose-dependent （P〈0.01） and time-dependent manner, with 50% maximal inhibitory concentration （IC50） value being 7.34μg/mL on the 9th day, but the time-dependence was not significant （P=0.051）. Expression of HBV-DNA in the supernatant of the cell culture also was significantly decreased in a dose-dependent fashion （P〈0.01）. The ICS0 of TP in inhibiting HBV DNA was 2.54 pg/mL. It concluded that TP possessed potential anti-HBV effects and may be used as a treatment alternative for HBV infection.

Scavenging Action of Zinc and Green Tea Polyphenol on Cisplatin and Nickel Induced Nitric Oxide Generation and Lipid Peroxidation in Rats

Objective Toxic metal ions have been implicated in the generation of reactive oxygen species (ROS) and nitric oxide (NO). Metallothionines (MT) and plant flavonoids have been reported in the intervention against oxidative damage. We investigated the effect of zinc induced MT and green tea polyphenol (GTP) in reducing the oxidative responses induced by nickel and platinum. Methods Zinc (10 mg/kg b. wt, sc) was administered to rats twice at a gap of 24hrs and GTP (10 mg/100 mL in drinking water) was fed ad libitum for 8 days. Nickel chloride (150 umol/kgb.wt, ip) and cisplatin (50 mmol/kg b.wt, sc) was administered to rats 24 h after Zn or GTP pre-treatment. Animals of all the groups were sacrificed 16 hrs after treatment and biochemical markers for toxicity were monitored. Results Zinc or GTP pre-treatment caused significant protection against nickel or cisplatin enhanced mortality in rats, and reduction in lipid peroxidation and NO. Conclusion It is proposed that inhibition of ROS and NO by GTP and zinc may prove useful as a selective pharmacological agent in the amelioration of metal toxicity.

Tea polyphenol-gut microbiota interactions:hints on improving the metabolic syndrome in a multi-element and multi-target manner

The metabolic syndrome(MS)has become one of the main problems in public health.Tea polyphenols(TPs),the main bioactive components of tea,has been claimed to have the potential to regulate metabolism and effectively prevent or mitigate the MS.However,many studies into the effects of TPs on MS have provided conflicting findings and the underlying mechanism has been elusive.The predominant TPs in unfermentedand and fermented tea are catechins and oxidized polyphenols(theaflavins and thearubigins),both of which have low bioavailability and reach the colon where most gut microbes inhabit.Gut microbiota has been demonstrated to be tightly associated with host metabolism.The interactions between TPs and gut microbiota will lead to the alterations of gut microbiota composition and the production of metabolites including short chain fatty acids,bile acids,amino acids and TPs derived metabolites,accordingly exerting their biological effects both locally and systemically.This review highlighted the contribution of metabolites and specific gut bacteria in the process of TPs intervention on the MS and further discuss how TPs impact the MS via gut microbiota from the viewpoint of gut organ/tissue axis.