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Objective:To explore the protective mechanism of tea polyphenols (TP) on mouse oral cancer.Methods:A total of 50 mice were divided into control group, model group, TP group, Selisistat group, TP+ Selisistat group, with 10 mice in each group. The control group was gavaged with physiological saline, while the model group, TP group, Selisistat group, and TP+ Selisistat group were gavaged with 300 mg/L 4-NQO to establish a mouse oral cancer model. Physiological saline, 200 mg/kg TP, 0.01 mg/kg Selisistat, and 200 mg/kg TP+ 0.01 mg/kg Selisistat were gavaged respectively. The weight changes of each group of mice were compared; HE staining was used to observe the morphology of mouse oral tumor tissue; Enzyme linked immunosorbent assay was used to detect the levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in serum; Immunoblotting and immunohistochemistry were used to detect the expression of silencing information regulatory factor (Sirt1) and nuclear factor E2 related factor 2 (Nrf2) proteins in mouse oral tissues.Results:Compared with the control group, the model group mice had a decrease in body weight [(23.19±1.36)g], a decrease in serum SOD level [(91.64±8.75)U/ml], an increase in MDA level [(5.18±0.46)nmol/ml], a decrease in Sirt1 (0.38±0.05) and Nrf2 (0.36±0.05) protein expression in oral tissue, and an increase in Nrf2 acetylation level (0.84±0.11) (all P<0.05). Compared with the model group, the TP group mice had an increase in body weight [(25.28±1.25)g], elevated serum SOD levels [(121.24±10.68)U/ml], decreased MDA levels [(3.89±0.42)nmol/ml], increased expression of Sirt1 (0.61±0.09) and Nrf2 (0.58±0.06) proteins in oral tissue, and decreased Nrf2 protein acetylation levels (0.39±0.05); The Selisistat group mice showed a decrease in body weight [(21.41±1.07)g], a decrease in serum SOD levels [(72.16±7.43)U/ml], an increase in MDA levels [(5.87±0.41)nmol/ml], a decrease in Sirt1 (0.23±0.04) and Nrf2 protein (0.24±0.03) expression in oral tissue, and an increase in Nrf2 acetylation levels (1.12±0.14) ( P<0.05). The body weight [(23.32±1.27)g], serum SOD levels [(92.58±8.13)U/ml], and oral Sirt1 (0.41±0.06) and Nrf2 (0.38±0.05) protein expression in the TP+ Selisistat group mice were higher than those in the Selisistat group, while MDA [(5.11±0.38)nmol/ml] and Nrf2 acetylation levels (0.82±0.09) were lower than those in the Selisistat group (all P<0.05). Conclusions:Tea polyphenols can alleviate oral tissue damage and alleviate oxidative stress in mice with oral cancer, and their mechanism may be related to the upregulation of the Sirt1/Nrf2 pathway.
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Objective To optimize the microwave-assisted extraction process of green tea polyphenols. Methods The extraction yield of tea polyphenols was figured up by building the standard curve of gallic acid and examining the concentration of tea polyphenols in green tea extract with the introduction of a correction factor. The effects of four single factor levels of microwave extraction time, microwave output power, liquid-to-material yield, and ethanol volume fraction on the extraction yield of tea polyphenols were primarily studied in this experiment. The response surface was applied to further optimize the extraction process of green tea polyphenols after exploring the appropriate range of four single factor levels. Results The optimal extraction process was as follows: extraction time 37 s, microwave output power 350 w, material - liquid yield 1∶45 (g/ml), ethanol volume fraction 55%, and the actual extraction yield of tea polyphenols was 25.65%, which was not much different from the theoretical value. Conclusion The microwave-assisted green tea polyphenol extraction process optimized by response surface methodology is time-saving and practicable, and the extraction yield is high.
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OBJECTIVE: To explore the protective effect of tea polyphenols and its mechanism in potassium dichromate(PD)-induced acute renal injury in mice. METHODS: The specific pathogen free weaned Kunming mice were divided into control group, model group and low-, middle-and high-dose tea polyphenols groups, with 12 mice in each group. Mice in the control group were given 0.9% sodium chloride solution, and mice in other four groups were given PD solution with 4.275 mg/kg body weight every morning by intragastric administration. Then, mice in the control group and model group were given 0.9% sodium chloride solution in the afternoon, while mice in the low-, middle-and high-dose tea polyphenols groups were given 0.3 mL tea polyphenols solution with a dose of 200, 400 or 600 mg/kg body weight, respectively by gavage, once a day for two consecutive weeks. The body mass of mice was weighed during the experiment. At the end of the experiment, the mice were sacrificed. The kidneys were removed and weighed. The kidney organ coefficients were calculated. The levels of urea nitrogen and creatinine in serum were determined by two-point method, the activities of catalase(CAT) and glutathione peroxidase(GSH-Px) in serum of mice were detected by colorimetry. The pathological change of kidney in mice was observed. RESULTS: The body weight of mice in the model group decreased(P<0.05), while the kidney mass, renal organ coefficient, serum levels of urea nitrogen and creatinine increased(all P<0.05), and the serum activities of CAT and GSH-Px decreased(all P<0.05) compared with the control group. The body weight of mice in the three tea polyphenols groups increased(all P<0.05), while the kidney mass, renal organ coefficient, urea nitrogen and creatinine levels in serum decreased(all P<0.05), and the activities of CAT and GSH-Px in serum increased with the increasing intervention dose of tea polyphenols(all P<0.05) compared with the model group. The change of acute renal injury was mainly caused by renal tubular injury in the model group. The pathological changes of renal tissue in the three tea polyphenols intervention groups were improved compared to that in the model group, and the improvement showed a dose-effect relationship with the intervention of tea polyphenols. CONCLUSION: Tea polyphenols have a protective effect on PD-induced acute renal injury with a dose-effect relationship. Its mechanism of action is related to the fact that tea polyphenols can reduce or reverse oxidative stress and inflammation in the kidney.
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Objective: Tea polyphenols are natural extracts used widely throughout the world. However, the severe astringency of tea polyphenols has reduced patient compliance. Based on the analysis of the formation mechanism of astringency, this paper hopes to propose a new method to control the astringency of tea polyphenols and improve patient compliance without changing its effect. Methods: Artificial saliva was used to prepare the tea polyphenols solution with different pH, using β-casein to imitate salivary protein, and preparing 1.2 mg/mL β-casein solution. A fluorescence quenching test was used to study the interaction between tea polyphenols and β-casein, combined with the stability test results of the compound, we can choose the pH with weak binding but good stability as the best pH for masking astringency. The taste-masking tablets were prepared under the best pH conditions, and the Xinnaojian Original Tablets were prepared according to the conventional preparation method. The disintegration time limit and solubility were tested respectively. The astringency of Xinnaojian original tablets and taste-masking tablets was evaluated by visual analogue scale (VAS). Results: The result of the fluorescence quenching test prompted that the combination force was the weakest when the pH was 4.9. Further synchronous fluorescence analysis showed that an increase in pH resulted in a decrease of the binding sites between tea polyphenols and β-casein, and this decrease was closely related to changes in tryptophan residues in β-casein. Both original and taste-masking Xinnaojian Tablets were prepared. Volunteers’ VAS scores illustrated that the astringency improved significantly with the masking tablets (P < 0.05). Conclusion: This pH-adjusting masking treatment had little effect on the recovery of polyphenols from the tablets or the dissolution of the tablets. This study provides a novel and feasible astringency masking technology for tea polyphenols and its preparation.
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Objective:To investigate the effect of Shentai Tea Polyphenols on memory and its underlying mechanism in healthy elderly adults.Methods:According to the randomized, double blind and placebo-controlled prospective experimental design, 240 healthy middle-aged or elderly subjects with normal objective cognition were recruited in our hospital from April to December 2019 through advertising, and they were randomly divided into an experimental group ( n=120) and a control group ( n=120). Oral administration of Shentai Tea Polyphenols or placebo capsules (lasting for 90 d, 2 times/d, 2 capsules/time) was given to subjects in the two groups. The neuropsychological scale scores and near-infrared brain imaging data of all subjects were collected before and after intervention, and the mean time from baseline data collection before intervention to follow-up data collection after medication was controlled within 6 months. Results:In patients from the experimental group, as compared with those before intervention, scores of delayed recall and recognition memory in the auditory verbal learning test (Huashan version) and Boston naming test, scores of Montreal cognitive assessment scale (basis version) were significantly higher, and scores of Hamilton anxiety scale, shape trails test A and rapid-eye-movement sleep behavior disorder screening questionnaire were significantly lower after intervention ( P<0.05); however, only scores of delayed recall in the auditory verbal learning test (Huashan version) were significantly increased in the control group ( P<0.05). A total of 23 pairs of differences of brain function connection before and after intervention in the experimental group were significantly higher than those in the control group ( P<0.05), mainly involving the function connection of forehead peak network (FPN), and function connection of FPN-default network, function connection of FPN-somatosensory movement network, function connection of FPN-dorsal attention network and function connection of FPN-visual network, as well as the function connection of default network and somatosensory movement network. Conclusion:Shentai Tea Polyphenols can improve cognitive performances including memory, language and executive function, anxiety mood and sleep quality in healthy middle aged or elderly subjects by affecting the functional connections of the networks in the brain.
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Objective To investigate the effects of tea-polyphenols on diabetic nephropathy (DN) mice by regulating nuclear factor E2-related factor 2/antioxidant response element (Nrf-2/ARE) signaling pathway. Methods A total of ten male 9-week-old normal (db/m) mice were randomly and equally divided into blank control group and tea-polyphenol control group, and ten male 9-week-old homologous type 2 diabetes (db/db) mice were randomly divided into model group and tea polyphenol treatment group. The animals in the tea-polyphenol control group and the treatment group were given 50 mg/(kg·d) tea-polyphenols by oral gavage, and the animals in the blank control group and model group were given same volume of double distilled water. The administration was once a day for 8 weeks. The blood glucose and 24-hour urine protein quantization (24 h-UP) were measured and recorded at 0, 4, and 8 weeks. After 8 weeks of the treatment, the mice were sacrificed. The intraocular blood stasis samples were collected for renal function indicators (serum creatinine and urea nitrogen), and kidney tissue samples were also collected for the tests of superoxide dismutase (SOD), reactive oxygen species, and malondialdehyde. Periodic acid Schiff reaction (PAS) staining was used to observe glomerular injury and scored. Western blot was used to detect the expression of Nrf-2 and hemeoxygenase-1 (HO-1) protein. Results Compared with the blank control group, the blood glucose and 24 h-UP of the mice in the model group and the tea-polyphenol treatment group increased after 4 and 8 weeks of the treatment (all P<0.01). Compared with the blank control group, after 8 weeks of the treatment, the serum creatinine and blood urea nitrogen of the model group and the tea-polyphenol treatment group increased (all P<0.01), the content of SOD in the renal tissue decreased (all P<0.01), the content of active oxygen and malondialdehyde, the relative expression of Nrf-2 and HO-1 protein increased (all P<0.01), and the glomerular injury aggravated (all P<0.01). However, there were no significant differences in all the indexes between the tea-polyphenol control group and the blank control group (all P>0.05). Conclusions Renal tissue of DN mice will undergo significant oxidative stress injury. Tea-polyphenols may reduce the oxidative stress injury in DN mice by regulating the Nrf-2/ARE signaling pathway, and play a protective role in the kidney.
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OBJECTIVE@#To investigate the protective effects and potential mechanisms of tea polyphenols intervention on excess alcohol intake induced liver injury in rats. This study established the animal model of chronic liver injury rats induced by alcohol. Our results will provide experimental evidence for the effects of tea polyphenol on chronic alcoholic liver injury.@*METHODS@#Alcohol-induced liver injury rat models were established, and the tea polyphenols intervention was performed in the meantime. After 8 weeks, rats were anesthetized, and visceral fat and liver samples were separated, weighted and stored. Visceral fat content was evaluated in fat/body weight ratio. Liver lipid accumulation was assessed by liver index and the result of Oil Red O staining. Hepatic superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, total antioxidant capacity assay (T-AOC) and glutathione peroxidase (GSH-Px) activity were detected. And fatty acid translocase (FAT/CD36) protein level in liver was detected.@*RESULTS@#Compared with the control group rats, the fat/body weight ratio, SOD/MDA, T-AOC and GSH-Px activity of chronic liver injury rats were decreased significantly (<0.05,<0.01). Meanwhile the liver index, FAT/CD36 protein level and lipid deposition in liver of chronic liver injury rats were increased (<0.01). Compared with chronic liver injury rats, the tea polyphenols intervention increased fat/body weight ratio (<0.05), and significantly increased SOD/MDA, T-AOC and GSH-Px activity (<0.01). Meanwhile the tea polyphenols intervention reduced liver index (<0.01), FAT/CD36 protein level (<0.01) and lipid deposition in liver.@*CONCLUSIONS@#Tea polyphenols intervention can improve lipid deposition and oxidative stress in chronic alcoholic liver, which is concurrent with decreased FAT/CD36 protein expression on the hepatocyte membrane.
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Animals , Rats , Antioxidants , Liver , Malondialdehyde , Polyphenols , Superoxide Dismutase , TeaABSTRACT
The aim of this paper was to explore the effects and possible mechanisms in vitro of tea polyphenols (TP) delaying human glomerular mesangial cells (HGMCs) senescence induced by high glucose (HG). HGMCs were cultured in vitro and divided into the normal group (N, 5.5 mmol·L⁻¹ glucose), the mannitol group(MNT, 5.5 mmol·L⁻¹ glucose plus 24.5 mmol·L⁻¹ mannitol), the high dose of D-glucose group (HG, 30 mmol·L⁻¹ glucose), the low dose of TP group (L-TP, 30 mmol·L⁻¹ glucose plus 5 mg·L⁻¹ TP) and the high dose of TP group (H-TP, 30 mmol·L⁻¹ glucose plus 20 mg·L⁻¹ TP), which were cultured in 5% CO₂ at 37 °C, respectively. Firstly, the effects of TP on the cell morphology of HGMCs were observed after 72 h-intervention. Secondly, the cell cycle, the positive rate of senescence-associated-β-galactosidase (SA-β-gal) staining and the telomere length were detected, respectively. Finally, the protein expressions of p53, p21 and Rb in the p53-p21-Rb signaling pathway were investigated, respectively. And the expressions of p-STAT3 and miR-126 were examined severally. The results indicated that HG not only arrested the cell cycle in G₁ phase but also increased the positive rate of SA-β-gal staining, and shortened the telomere length. HG led to the protein over-expressions of p53, p21 and Rb and HGMCs senescence by activating the p53-p21-Rb signaling pathway. In addition, L-TP delayed HGMCs senescence by improving the cell cycle G₁ arrest, reducing SA-β-gal staining positive rate and lengthening the telomere length. L-TP reduced the protein over-expressions of p53, P21 and Rb induced by HG and inhibited the telomere-p53-p21-Rb signaling pathway. Moreover, the expression of p-STAT3 was increased and the expression of miR-126 was decreased in HGMCs induced by HG. L-TP reduced the expression of p-STAT3 and increased the expression of miR-126 in HGMCs. In conclusion, HG could induce HGMCs senescence by activating the telomere-p53-p21-Rb signaling pathway in vitro. L-TP could delay HGMCs senescence through regulating STAT3/miR-126 expressions and inhibiting the telomere-p53-p21-Rb signaling pathway activation. These findings could provide the effective interventions in clinic for preventing and treating renal cell senescence in diabetic kidney disease.
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Humans , Cells, Cultured , Cellular Senescence , Cyclin-Dependent Kinase Inhibitor p21 , Glucose , Mesangial Cells , MicroRNAs , Polyphenols , STAT3 Transcription Factor , Tea , Telomere , Tumor Suppressor Protein p53ABSTRACT
Objective To explore the effect of tea polyphenols on the growth of human papillomavirus 16 (HPV16) subgenes-immortalized human cervical epithelial cells (H8 cells).Methods Cultured H8 cells were divided into 5 groups to be treated with 0 (control group),6.25,12.5,25 and 50 mg/L tea polyphenols respectively for 24,36,and 48 hours,and then cell counting kit-8 (CCK8)assay was performed to detect cell proliferation.After 24 hours of incubation,flow cytometry was conducted to detect cell apoptosis and cell cycle,and fluorescence microscopy to observe the morphology of apoptotic cells.Results After incubation with tea polyphenols at different concentrations for 24,36 and 48 hours,the proliferation of H8 cells was inhibited,and 12.5 mg/L tea polyphenols could inhibit the relative growth rate of H8 cells in a time-dependent manner.Flow cytometry showed that there was a significant difference in cell apoptosis rate among the 6.25-,12.5-,25-,50-mg/L tea polyphenols groups and the control group (52.62％ ± 0.62％,52.22％ ± 0.72％,42.52％ ± 0.90％,45.96％ ± 2.11％,29.96％ ± 0.70％ respectively,F =272.0,P ＜ 0.05).Moreover,all the tea polyphenol groups showed significantly increased cell apoptosis rate compared with the control group (all P ＜ 0.05).Fluorescence microscopy showed karyopyknosis,nuclear fragmentation and other typical apoptotic morphological changes in H8 cells in tea polyphenols groups.There were significant differences in the percentage of cells in G1,G2 phase and cell proliferation index among the 5 groups (all P ＜ 0.05).Compared with the control group,the 6.25-,12.5-,25-mg/L tea polyphenols groups showed significantly increased percentage of cells in G1 phase (55.96％ ± 0.72％,54.12％ ± 3.20％,65.30％ ± 1.51％ respectively,all P ＜ 0.05),but significantly decreased percentage of cells in G2 phase (3.17 ± 1.82％,4.94 ± 1.46％,4.65 ± 4.26％ respectively,all P ＜ 0.05) and lower cell proliferation index(0.44 ± 0.01,0.46 ± 0.02,0.36 ± 0.01 respectively,all P ＜ 0.05).Conclusion Tea polyphenols can inhibit the proliferation of H8 cells,induce cell apoptosis,and block cell cycle progression.
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Gallbladder cancer (GBC) is the most common malignancy in the biliary tract. Without effective treatment, its prognosis is notoriously poor. Tea polyphenols (TPs) have many pharmacological and health benefits, including antioxidant, anti-inflammatory, anti-tumor, anti-thrombotic, antibacterial, and vasodilatory properties. However, the anti-cancer effect of TPs in human gallbladder cancer has not yet been determined. Cell viability and colony formation assay were used to investigate the cell growth. Cell cycle and apoptosis were evaluated by flow cytometry analysis. Western blot assay was used to detect the expression of proteins related to cell cycle and apoptosis. Human tumor xenografts were used to examine the effect of TPs on gallbladder cancer cells in vivo. TPs significantly inhibited cell growth of gallbladder cancer cell lines in a dose- and time-dependent manner. Cell cycle progression in GBC cells was blocked at the S phase by TPs. TPs also induced mitochondrial-related apoptosis in GBC cells by upregulating Bax, cleaved caspase-3, and cleaved PARP expressions and downregulating Bcl-2, cyclin A, and Cdk2 expressions. The effects of TPs on GBC were further proven in vivo in a mouse xenograft model. Our study is the first to report that TPs inhibit GBC cell growth and these compounds may have potential as novel therapeutic agents for treating gallbladder cancer.