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Oolong tea, a semi-fermented tea, has a prominent fruity and floral aroma, resembling green tea's astringency and pungency but lacking black tea's mellowness. Oolong tea incorporating black tea fermentation techniques (OT-IBTFT) not only retained its excellent floral and fruity aroma but also reduced astringency and enriched taste. However, metabolite changes remain unknown. In this study, widely targeted metabolomic analysis showed OT-IBTFT reduced prunin, gallocatechin, methyl gallate, and increased loliolide by changing the flavonoid biosynthesis and biosynthesis of secondary metabolites pathways, thereby reducing the astringency and increasing the mellow taste and richness to improve oolong tea quality. In addition, Wrap-rolling 5 times increased fermentation, improving the color and aroma of oolong tea by increasing theaflavic acid and 2-furoic acid, is more significant than wrap-rolling once. In conclusion, these findings provide a theoretical basis for the improvement of oolong tea processing techniques and flavor and quality control.
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The sensory quality of black tea (BT) influenced by various factors, among which tree age is particularly significant. People prefer BT produced by fresh leaves from old tea trees, yet the correlation between tree age and tea quality has not been thoroughly investigated. In this study, we analyzed the quality of BT from young trees (H-JYH) and old trees (H-OJYH) using e-tongue technology and sensory evaluation. Our findings revealed that H-OJYH had stronger sweetness and sourness, richer flavor, and diminished bitter-astringency compared to H-JYH. 1231 non-volatile metabolites and 504 volatile metabolites were discovered by ultra-performance liquid chromatography (UPLC) and gas chromatography-mass spectrometry (GC-MS). L-tartaric acid and trans-citridic acid were found to contribute to increase acidity, and 7,8-dihydroxy-6-methoxycoumarin and d-fructose 6-phosphate were associated with enhanced sweetness in H-OJYH. Additionally, lower levels of octyl gallate and vanillic acid in H-OJYH contributed to the diminished bitter-astringency. ß-ionone, 2-phenylethanol and phenylacetaldehyde merged as characteristic compounds of older tree BT with stronger floral and sweet aroma. Our study serves as a guideline to explore the relationship between tree age and tea quality.
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The bioactivity of tea polysaccharides (TPs) has been widely reported, but studies to date have focused on green tea. Some human health investigations have implied that black tea may possess potential antidiabetic effects, but less is known about their potential role and related antidiabetic mechanism. The present study was, therefore, conducted to investigate the chemical properties and antidiabetic activity of TPs from black tea. Monosaccharide composition revealed that Alduronic acid (77.8 mol%) considerably predominated in the fraction. TP conformation analysis indicated that three components in TPs were all typical of high-branching structures. Oral administration of TPs could effectively alleviate fasting blood glucose in type 2 diabetes mellitus (T2D) mice, with the values 23.6 ± 1.42, 19.6 ± 2.25, and 16.4 ± 2.07 mmol/L in the 200, 400, and 800 mg/kg·BW groups, respectively. Among these TPs groups, the 800 mg/kg·BW groups significantly decreased by 37.88% when compared with the T2D+water group (p < 0.05). Further studies demonstrated that TP treatment upregulated the expression of p-Akt/p-PI3K (p < 0.001). Additionally, TP treatment significantly promoted glucose transporter protein 2 (GLUT2) translocation in the liver (p < 0.001). These findings suggest that TPs from black tea protect against T2D by activating PI3K/Akt/GLUT2 signaling and might serve as a novel therapeutic candidate for T2D.
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Yellow tea (YT) has an additional process of yellowing before or after rolling than green tea (GT), making YT sweeter. We analyzed the variations of composition and taste throughout the withering, fixing and rolling steps using UPLC-MS/MS and sensory evaluation, and investigated the influence of various yellowing times on flavor profile of YT. 532 non-volatile metabolites were identified. Withering and fixing were the important processes to form the taste quality of GT. Withering, fixing and yellowing were important processes to form flavor profile of YT. Withering mainly regulated bitterness and astringency, and fixing mainly regulated bitterness, astringency and sweetness of YT and GT. Yellowing mainly regulated sweetness of YT. Trans-4-hydroxy-L-proline and glutathione reduced form as the key characteristic components of YT, increased significantly during yellowing mainly through Arginine and proline metabolism and ABC transporters. The paper offers a systematic insight into intrinsic mechanisms of flavor formation in YT and GT.
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Black tea (BT), the most consumed tea worldwide, can alleviate hyperlipidemia which is a serious threat to human health. However, the quality of summer BT is poor. It was improved by microbial fermentation in a previous study, but whether it affects hypolipidemic activity is unknown. Therefore, we compared the hypolipidemic activity of BT and microbially fermented black tea (EFT). The results demonstrated that BT inhibited weight gain and improved lipid and total bile acid (TBA) levels, and microbial fermentation reinforced this activity. Mechanistically, both BT and EFT mediate bile acid circulation to relieve hyperlipidemia. In addition, BT and EFT improve dyslipidemia by modifying the gut microbiota. Specifically, the increase in Lactobacillus johnsonii by BT, and the increase in Mucispirillum and Colidextribacter by EFT may also be potential causes for alleviation of hyperlipidemia. In summary, we demonstrated that microbial fermentation strengthened the hypolipidemic activity of BT and increased the added value of BT.
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Camellia sinensis , Hiperlipidemias , Humanos , Chá , Hiperlipidemias/tratamento farmacológico , Hiperlipidemias/prevenção & controle , Fermentação , Ácidos e Sais BiliaresRESUMO
Fermentation durations are crucial in determining the quality of black tea flavour. The mechanism underlying the degradation of black tea flavour caused by inappropriate fermentation duration remains unclear. In this study, the taste of black teas with different fermentation durations (BTFs) was analysed using sensory evaluation, electronic tongue, and metabolomics. The results revealed significant differences in 46 flavour profile components within the BTFs. Notably, metabolites such as gallocatechin gallate, gallocatechin, and epigallocatechin were found to be primarily reduced during fermentation, leading to a reduction in the astringency of black tea. Conversely, an increase in d-mandelic acid and guanine among others was observed to enhance the bitter flavour of black tea, while 3-Hydroxy-5-methylphenol nucleotides were found to contribute to sweetness. Furthermore, succinic acid and cyclic-3',5'-adenine nucleotides were associated with diminished freshness. This study offers a theoretical foundation for the regulation of flavour quality in large leaf black tea.
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Camellia sinensis , Chá , Chá/metabolismo , Paladar , Fermentação , Camellia sinensis/metabolismo , Metabolômica/métodos , Folhas de Planta/metabolismoRESUMO
The reasons for the change in volatile metabolites and aroma of black tea during storage remain unclear. Therefore, we used HS-SPME and GC-MS methods to analyze the aroma compounds of new tea (2021) versus aged tea groups (2015, 2017, and 2019). A total of 109 volatile components were identified. During storage, 36 metabolites mainly with floral and fruity aromas decreased significantly, while 18 volatile components with spicy, sour, and woody aromas increased significantly. Linalool and beta-ionone mainly contributed to sweet and floral aromas of freshly-processed and aged black tea, respectively. Isovaleric acid and hexanoic acid mainly caused sour odor of aged black tea. The monoterpene biosynthesis and secondary metabolic biosynthesis pathways might be key metabolic pathways leading to changes in the relative content of metabolites during storage of black tea. Our study provides theoretical support for fully understanding the changes in the aroma quality of black tea during storage.
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Aroma is one of the significant quality factors of dark tea (DT). However, for a single large-leaf tea variety, there are few studies analyzing the effect of pile-fermentation on the aroma quality of DT. The GC × GC-QTOFMS, electronic nose (E-nose) and GC-olfactometry (GC-O) techniques were employed to analysis the difference of tea products before and after pile-fermentation. A total of 149 volatile metabolites (VMs) were identified, with 92 VMs exhibiting differential characteristics. Among these, 31 VMs with OAV > 1.0 were found to be correlated with E-nose results (|r| > 0.8). Additionally, GC-O analysis validated seven major differential metabolites. Notably, naphthalene, 2-methylnaphthalene, and dibenzofuran were found to enhance the woody aroma, while (Z)-4-heptenal, 2-nonenal and 1-hexanol were associated with an increase in mushroom, fatty and sweet odors, respectively. Moreover, 1-octen-3-ol was linked to reducing pungent fishy smell. These findings could provide a certain theoretical basis for understanding the influence of pile-fermentation on the aroma quality of dark tea.
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Odorantes , Compostos Orgânicos Voláteis , Odorantes/análise , Nariz Eletrônico , Fermentação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Orgânicos Voláteis/análise , Folhas de Planta/química , CháRESUMO
Niudali (Callerya speciosa) is commonly grown in southeastern regions of China and consumed as a food ingredient. Although Niudali root extracts showed various biological activities, the hepatoprotective effects of Niudali root phytochemicals are not fully studied. Herein, we prepared two Niudali root aqueous extracts, namely, c and Niudali polysaccharides-enriched extract (NPE), and identified an alkaloid, (hypaphorine) in NEW. The hepatoprotective effects of NWE, NPE, and hypaphorine were evaluated in an acute liver injury model induced by carbon tetrachloride (CCl4) in mice. Pathohistological examination and blood chemistry assays showed that treatment of NWE, NPE, and hypaphorine alleviated CCl4-induced liver damage by lowering the liver injury score (by 75.51%, 80.01%, and 41.22%) and serum aspartate and alanine transaminases level (by 63.24%, 85.22%, and 49.74% and by 78.73%, 80.08%, and 81.70%), respectively. NWE, NPE, and hypaphorine also reduced CCl4-induced hepatic oxidative stresses in the liver tissue by decreasing the levels of malondialdehyde (by 40.00%, 51.25%, and 28.75%) and reactive oxygen species (by 30.22%, 36.14%, and 33.54%) while increasing the levels of antioxidant enzymes including superoxide dismutase (by 21.36%, 21.64%, and 8.90%), catalase (by 22.13%, 33.33%, and 5.39%), and glutathione (by 84.87%, 90.65%, and 80.53%), respectively. Mechanistic assays showed that NWE, NPE, and hypaphorine alleviated liver damage by mediating inflammatory biomarkers (e.g., pro-inflammatory cytokines) via the signaling pathways of mitogen-activated protein kinases and nuclear factor-κB. Findings from our study extend the understanding of Niudali's hepatoprotective effects, which is useful for its development as a dietary intervention for liver inflammation.
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Tea is the most popular and widely consumed beverage worldwide, especially black tea. Summer tea has a bitter and astringent taste and low aroma compared to spring tea due to the higher content of polyphenols and lower content of amino acids. Microbial fermentation is routinely used to improve the flavor of various foods. This study analyzed the relationship between the quality of black tea, metabolic characteristics, and microbial communities after microbial stuck fermentation in summer black tea. Stuck fermentation decreased the bitterness, astringency sourness, and freshness, and increased the sweetness, mellowness, and smoothness of summer black tea. The aroma also changed from sweet and floral to fungal, with a significant improvement in overall quality. Metabolomics analysis revealed significant changes in 551 non-volatile and 345 volatile metabolites after fermentation. The contents of compounds with bitter and astringent taste were decreased. Sweet flavor saccharides and aromatic lipids, and acetophenone and isophorone that impart fungal aroma showed a marked increase. These changes are the result of microbial activities, especially the secretion of extracellular enzymes. Aspergillus, Pullululanibacillus, and Bacillus contribute to the reduction of bitterness and astringency in summer black teas after stuck fermentation, and Paenibacillus and Basidiomycota_gen_Incertae_sedis contribute positively to sweetness. In addition, Aspergillus was associated with the formation of fungal aroma. In summary, our research will provide a suitable method for the improvement of tea quality and utilization of summer tea, as well as provide a reference for innovation and improvement in the food industry.
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Aroma is a crucial determinant of tea quality. While some studies have examined the aroma of yellow tea, there are no reports of the difference and formation mechanism of aroma quality between yellow and green teas from the same tea tree variety. This study employed gas chromatography-mass spectrometry to investigate the difference and formation mechanism of the aroma of yellow and green tea at the omics level, based on sensory evaluation. The sensory evaluation revealed that green tea has a distinct faint scent and bean aroma, while yellow tea, which was yellowed for 48 h, has a noticeable corn aroma and sweet fragrance. A total of 79 volatile metabolites were detected in the processing of yellow and green tea, covering 11 subclasses and 27 were differential volatile metabolites. Benzoic acid, 2-(methylamino-), methyl ester, terpinen-4-ol ethanone, 1-(1H-pyrrol-2-yl-), 3-penten-2-one, 4-methyl- and benzaldehyde were characteristic components of the difference in aroma quality between green and yellow teas. Eleven volatile metabolites significantly contributed to the aroma quality of green and yellow teas, especially acetic acid, 2-phenylethyl ester, with rose and fruity aromas. KEGG enrichment analysis showed that the arginine and proline metabolism might be the key mechanism of aroma formation during green and yellow teas' processing. These finding provide a theoretical basis way for the aroma formation of green and yellow teas.
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Odorantes , Espectrometria de Massas em Tandem , Cromatografia Gasosa-Espectrometria de Massas , Metabolômica , ÉsteresRESUMO
Most aged tea has superior sensory qualities and good health benefits. The content of organic acids determines of the quality and biological effects of aged tea, but there are no reports of the effect of storage on the composition and relative proportion of acidic compounds in black tea. This study analyzed and compared the sourness and metabolite profile of black tea produced in 2015, 2017, 2019 and 2021 using pH determination and UPLC-MS/MS. In total, 28 acidic substances were detected, with 17 organic acids predominating. The pH of black tea decreased significantly during storage from pH 4.64 to pH 4.25 with significantly increased in l-ascorbic acid, salicylic acid, benzoic acid and 4-hydroxybenzoic acid. The metabolic pathways ascorbate biosynthesis, salicylate degradation, toluene degradation, etc. were mainly enriched. These findings provide a theoretical basis to regulate the acidity of aged black tea.
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Camellia sinensis , Chá , Chá/química , Cromatografia Líquida , Espectrometria de Massas em Tandem , Camellia sinensis/química , Metabolômica , Folhas de Planta/químicaRESUMO
The gut-liver axis is a bidirectional relationship between the gut with its microbiota and the hepatic. Ulcerative colitis (UC) disrupts the intestinal barrier and influx of intestinal microorganisms and their products into the liver, which trigger liver injury. Tea consumption is associated with a low incidence of UC in Asian countries. In this study, we revealed the mechanisms of six types of tea water extracts (TWEs) obtained from the leaves of Camellia sinensis on the dextran sodium sulfate (DSS)-induced colitis and liver injury in mice. The TWEs significantly restored mucin production and increased the expression levels of tight junction (TJ) proteins such as zonula occludens-1 (ZO-1), occluding, and claudin-1. In addition, TWEs also reduced the levels of pro-inflammatory cytokines in the colon and liver tissue by inactivating the NF-κB/NLRP3. Moreover, TEWs treatment promoted the integrity of the intestinal barrier to reduce serum lipopolysaccharide (LPS) levels, thereby reducing liver injury caused by intestinal microbial translocation and LPS induction. Analysis of 16 S rRNA microbial sequencing revealed that tea water extracts (TWEs) restored the DSS-induced gut dysbiosis. Interestingly, our results showed that the degree of fermentation of tea leaves was negatively associated with the alleviation of DSS-induced colitis effects, and there was also an overall negative trend with colitis-induced liver injury, except for black tea. Taken together, tea consumption mitigated DSS-induced colitis and liver injury in mice via inhibiting the TLR4/NF-κB/NLRP3 inflammasome pathway.
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Camellia sinensis , Colite Ulcerativa , Colite , Animais , Camundongos , Colite/induzido quimicamente , Colite/tratamento farmacológico , Colite/metabolismo , Sulfato de Dextrana/toxicidade , Modelos Animais de Doenças , Inflamassomos/metabolismo , Lipopolissacarídeos , Fígado/metabolismo , Camundongos Endogâmicos C57BL , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Chá , Proteínas de Junções Íntimas/metabolismo , Receptor 4 Toll-LikeRESUMO
Tea flavonoids are widely recognized as critical flavor contributors and crucial health-promoting bioactive compounds, and have long been the focus of research worldwide in food science. The aim of this review paper is to summarize the major progress in tea flavonoid chemistry, their dynamics of constituents and concentrations during tea processing as well as storage, and their health functions studied between 2001 and 2021. Moreover, the utilization of tea flavonoids in the human body has also been discussed for a detailed understanding of their uptake, metabolism, and interaction with the gut microbiota. Many novel tea flavonoids have been identified, including novel A- and B-ring substituted flavan-3-ol derivatives, condensed and oxidized flavan-3-ol derivatives, and glycosylated and methylated flavonoids, and are found to be closely associated with the characteristic color, flavor, and health benefits of tea. Flavoalkaloids exist widely in various teas, particularly 8-C N-ethyl-2-pyrrolidinone-substituted flavan-3-ols. Tea flavonoids behave significantly difference in constituents and concentrations depending on tea cultivars, plantation conditions, multiple stresses, the tea-specified manufacturing steps, and even the long-term storage period. Tea flavonoids exhibit multiple health-promoting effects, particularly their anti-inflammatory in alleviating metabolic syndromes. Interaction of tea flavonoids with the gut microbiota plays vital roles in their health function.
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Camellia sinensis , Chá , Humanos , Chá/química , Camellia sinensis/química , Flavonoides/análiseRESUMO
Food extract supplements, with high functional activity and low side effects, play a recognized role in the adjunctive therapy of human colorectal cancer. The present study reported a new functional beverage, which is a type of Chinese Hakka stir-fried green tea (HSGT) aged for several years. The extracts of the lyophilized powder of five HSGT samples with different aging periods were analyzed with high-performance liquid chromatography. The major components of the extract were found to include polyphenols, catechins, amino acids, catechins, gallic acid and caffeine. The tea extracts were also investigated for their therapeutic activity against human colorectal cancer cells, HT-29, an epithelial cell isolated from the primary tumor. The effect of different aging time of the tea on the anticancer potency was compared. Our results showed that, at the cellular level, all the extracts of the aged teas significantly inhibited the proliferation of HT-29 in a concentration-dependent manner. In particular, two samples prepared in 2015 (15Y, aged for 6 years) and 2019 (19Y, aged for 2 years) exhibited the highest inhibition rate for 48 h treatment (cell viability was 50% at 0.2 mg/mL). Further, all the aged tea extracts examined were able to enhance the apoptosis of HT-29 cells (apoptosis rate > 25%) and block the transition of G1/S phase (cell-cycle distribution (CSD) from <20% to >30%) population to G2/M phase (CSD from nearly 30% to nearly 10%) at 0.2 mg/mL for 24 h or 48 h. Western blotting results also showed that the tea extracts inhibited cyclin-dependent kinases 2/4 (CDK2, CDK4) and CylinB1 protein expression, as well as increased poly ADP-ribose polymerase (PRAP) expression and Bcl2-associated X (Bax)/B-cell lymphoma-2 (Bcl2) ratio. In addition, an upstream signal of one of the above proteins, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signalling, was found to be involved in the regulation, as evidenced by the inhibition of phosphorylated PI3K and AKT by the extracts of the aged tea. Therefore, our study reveals that traditional Chinese aged tea (HSGT) may inhibit colon cancer cell proliferation, cell-cycle progression and promoted apoptosis of colon cancer cells by inactivating PI3K/AKT signalling.
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Camellia sinensis , Neoplasias do Colo , Neoplasias Colorretais , Humanos , Apoptose , Camellia sinensis/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/metabolismo , Fosfatidilinositol 3-Quinase , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2 , Chá/químicaRESUMO
Photothermal therapy (PTT) was reported to induce synergistic immunogenic cell death (ICD) which may convert tumor cells into "therapeutic vaccines". However, this is often insufficient to prevent tumor recurrence, in part because of the immunosuppressive microenvironment in tumors. Therefore, remodeling tumor microenvironment is of great importance to enhance the therapeutic efficacy of PTT. We herein fabricated a versatile nano-photosensitizer by assembling quercetin and Ferrum ion (QFN). The released quercetin from QFN could reduce programmed death ligand 1 (PD-L1) in tumor cells by inhibiting the phosphorylation of JAK2 and STAT3, and reshape extracellular matrix (ECM) by down-regulating α-SMA+ fibroblast in tumors. Moreover, QFN could capture tumor antigen and deliver it to the tumor-draining lymph nodes after PTT, which further enhanced the activation of antigen-presenting cells. As a result, QFN-based PTT eliminated melanoma and induced long-term immune memory to prevent tumor metastasis and recurrence. This study provides an effective and translationally feasible photothermic agent for photothermal/immunotherapy. STATEMENT OF SIGNIFICANCE: The efficacy of photothermal therapy (PTT) in cancer treatment is often limited by the immunosuppressive microenvironment in tumors. Herein, we prepared a versatile photosensitizer by assembling quercetin and Ferrum ion (QFN). Upon near-infrared light irradiation, QFN-PTT induced cancer cells destruction and tumor antigen release. QFN then captured antigen and delivered it to the tumor-draining lymph nodes, thus promoting dendritic cell maturation and T cells activation. Quercetin released from QFN in tumors improved T cells infiltration and activation in tumor by regulating immunosuppressive microenvironment. The QFN-PTT-treated mice exhibited significantly elongated survival time, and gained strong anti-tumor immune memory to prevent tumor metastasis and recurrence. Thus, this work provided a simple and versatile photothermic agent, and it has important implications for designing effective and translationally feasible photosensitizers for PTT.
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Nanopartículas , Microambiente Tumoral , Camundongos , Animais , Quercetina/farmacologia , Terapia Fototérmica , Linhagem Celular Tumoral , Recidiva Local de Neoplasia/tratamento farmacológico , Fototerapia , Nanopartículas/uso terapêutico , Fármacos Fotossensibilizantes/uso terapêutico , Imunoterapia , Antígenos de NeoplasiasRESUMO
Objective: In this study, black tea and Citrus maxima (BT-CM), yellow tea and C. maxima (YT-CM), green tea and C. maxima (GT-CM) as subjects, the active ingredient content and antioxidant activity of three tea and C. maxima (T-CM) were analyzed. The effects of three T-CMs on apoptosis of liver cells in vitro and its mechanism were further explored. Methods: National standard method and HPLC were used for active ingredient analysis. MTT, cell flow cytometry and Western blot were used to analyze the effects of three T-CMs on cell proliferation, apoptosis, and its underlying molecular mechanism. Results: The content of tea polyphenols, free amino acids, ratio of polyphenols and amino acids, ester catechins, non-ester catechins and caffeine in YT-CM and GT-CM was significantly higher than that of BT-CM. The in vitro antioxidant capacity of YT-CM and GT-CM was also significantly stronger than that of BT-CM. Three T-CMs had the effects of inhibiting proliferation, arresting cell cycle and inducing apoptosis in HepG2 and Bel7402 cells, especially YT-CM and GT-CM. Western blot analysis showed three T-CMs activated PI3K/AKT/mTOR signaling pathway and regulated the expression levels of apoptosis-related proteins Bax, Bcl-2 and Caspase-3/9. YT-CM and GT-CM had better ability to change the signal pathway than BT-CM. Conclusion: In short, T-CMs, which combined different degrees of fermentation tea with C. maxima, were rich in nutrients and biologically active substances. T-CMs, especially YT-CM and GT-CM, are healthy drinks that help to prevent and treat liver cancer.
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Liver injury is a significant public health issue nowadays. Shibi tea is a non-Camellia tea prepared from the dried leaves of Adinandra nitida, one of the plants with the greatest flavonoid concentration, with Camellianin A (CA) being the major flavonoid. Shibi tea is extensively used in food and medicine and has been found to provide a variety of health advantages. The benefits of Shibi tea and CA in preventing liver injury have not yet been investigated. The aim of this study was to investigate the hepatoprotective effects of extract of Shibi tea (EST) and CA in mice with carbon tetrachloride (CCl4)-induced acute liver injury. Two different concentrations of EST and CA were given to model mice by gavage for 3 days. Treatment with two concentrations of EST and CA reduced the CCl4-induced elevation of the liver index, liver histopathological injury score, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Western blotting and immunohistochemical analysis demonstrated that EST and CA regulated the oxidative stress signaling pathway protein levels of nuclear factor E2-related factor 2 (Nrf2)/heme-oxygenase-1 (HO-1), the expression of inflammatory cytokines, the phosphorylated nuclear factor-kappaB p65 (p-NF-κB)/nuclear factor-kappaB p65 (NF-κB) ratio, the phospho-p44/42 mitogen-activated protein kinase (p-MAPK), and the apoptosis-related protein levels of BCL2-associated X (Bax)/B cell leukemia/lymphoma 2 (Bcl2) in the liver. Taken together, EST and CA can protect against CCl4-induced liver injury by exerting antioxidative stress, anti-inflammation, and anti-apoptosis.
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Doença Hepática Induzida por Substâncias e Drogas , Flavonoides , Chás de Ervas , Animais , Apoptose , Tetracloreto de Carbono/toxicidade , Doença Hepática Induzida por Substâncias e Drogas/tratamento farmacológico , Flavonoides/farmacologia , Inflamação/metabolismo , Fígado/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Estresse Oxidativo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de SinaisRESUMO
Background: The health benefits of tea are as diverse including the reduction of uric acid levels. Xanthine oxidase is the most directly mediated enzyme in the production of uric acid. Objective: To explore the inhibitory effects of different teas and its main bioactive components on the production of uric acid. Design: Experimental study. The experiments were conducted in vitro using human immortalized normal liver cell line HL-7702 (L-02). Results: The inhibition of the xanthine oxidase activities and the expression level of xanthine dehydrogenase mRNA stimulated in the hyperuric hepatocyte cell model showed that the unfermented green tea and th1e lightly fermented yellow tea, white tea, and oolong tea significantly stronger than the highly fermented black tea and dark tea. The main bioactive compound, gallic acid, showed the strongest inhibitory effect on uric acid production, followed by tea polyphenols and theaflavins. Discussion: All teas exhibited significant inhibition of xanthine oxidase activities, and the degree of fermentation of tea may be inversely proportional to its ability to inhibit the production of uric acid. Compared with tea polyphenols rich in tea, gallic acid may be a more potential uric acid-lowering component. Conclusion: In this article, we first compared the effects of six traditional Chinese tea made from a single variety in stabilizing the synthesis of uric acid and found that the lighter the fermentation, the greater the potential for inhibiting the production of uric acid. Furthermore, we analyzed the inhibitory effects of its main biochemical active ingredients and found that the inhibitory effects of polyphenols rich in lightly fermented tea were significantly stronger than caffeine rich in highly fermented tea. Our findings will be helpful for people to choose a proper tea for alleviating hyperuricemia and provide a scientific basis for uric acid-lowering tea processing.
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Hyperuricemia (HUA) is a metabolic disease that threatens human health. Tea is a healthy beverage with an abundance of benefits. This study revealed the uric acid-lowering efficacy of six types of tea water extracts (TWEs) on HUA in mice. The results revealed that under the intervention of TWEs, the expression of XDH, a key enzyme that produces uric acid, was significantly downregulated in the liver. TWE treatment significantly upregulated the expression of uric acid secretion transporters ABCG2, OAT1, and OAT3, and downregulated the expression of uric acid reabsorption transporter URAT1 in the kidney. Furthermore, HUA-induced oxidative stress could be alleviated by upregulating the Nrf2/HO-1 pathway. The intervention of TWEs also significantly upregulated the expression of the intestinal ABCG2 protein. On the other hand, TWE intervention could significantly upregulate the expression of intestinal ABCG2 and alleviate HUA by modulating the gut microbiota. Taken together, tea can comprehensively regulate uric acid metabolism in HUA mice. Interestingly, we found that the degree of fermentation of tea was negatively correlated with the uric acid-lowering effect. The current study indicated that tea consumption may have a mitigating effect on the HUA population and provided a basis for further research on the efficacy of tea on the dosage and mechanism of uric acid-lowering effects in humans.