Optimization of microwave-assisted extraction of green tea polyphenols by response surface methodology / 药学实践杂志

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.

A novel technology to reduce astringency of tea polyphenols extract and its mechanism / 中草药·英文版

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.

Protective mechanism of tea polyphenols in potassium dichromate-induced acute renal injury in mice / 中国职业医学

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.

Effect of tea polyphenols on diabetic nephropathy mice by regulating Nrf-2/ARE signaling pathway / 国际生物医学工程杂志

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.

Tea polyphenols induce S phase arrest and apoptosis in gallbladder cancer cells

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.

Effect of tea polyphenois on the growth of human papilIomavirus 16 subgenes-immortalized human cervical epithelial cells / 中华皮肤科杂志

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.

Tea polyphenols delays human glomerular mesangial cells senescence induced by high glucose via regulating STAT3/miR-126/telomere signaling pathway activation / 中国中药杂志

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.

The protective effect of tea polyphenols on chronic alcoholic liver injury in rats / 中国应用生理学杂志

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.

Tea polyphenols down-regulate JNK phosphorylation to inhibit neuron apoptosis in rats with cardiac arrest / 中华危重病急救医学

Objective To study the effect of tea polyphenols (TP) on c-Jun N-terminal kinase 1/2 (JNK1/2) phosphorylation and cell apoptosis in brain tissues in rats with cardiac arrest (CA) following cardiopulmonary resuscitation (CPR). Methods Healthy male Sprague-Dawley (SD) rats were randomly divided into sham group (n = 6), CA group (n = 12), and TP group (n = 12). The rats in CA and TP groups were induced ventricular fibrillation (VF) via esophagus stimulation with alternating current. Five minutes after CA, CPR was performed. Once restoration of spontaneous circulation (ROSC) was gained, normal saline (NS) and TP were injected intravenously in CA and TP groups with 10 mg/kg, respectively. Cortex of 6 rats in each group was harvested at 12 hours and 72 hours after ROSC. Cortex of sham group was harvested at 72 hours after operation without VF induction. The expressions of phosphorylated JNK1/2 (p-JNK1/2), JNK1/2, caspase-3, Bax and Bcl-2 were measured by Western Blot. Cell apoptosis was detected by TdT-mediated dUTP nick end labeling (TUNEL), and p-JNK/TUNEL double positive cells were detected by fluorescence double staining. Results Compared with sham group, the expressions of p-JNK, caspase-3 and Bax were increased, the expression of Bcl-2 was declined, and the apoptotic cells were significantly increased at 72 hours after ROSC in CA group. Compared with CA group, the phosphorylation of JNK was significantly declined at 12 hours and 72 hours after ROSC in TP group (the ratio of p-JNK1/2 and JNK1/2: 3.200±0.060 vs. 5.700±0.210, 1.400±0.060 vs. 5.400±0.090, both P < 0.05), the expressions of caspase-3 and Bax were decreased [caspase-3 (gray value): 42.00±5.23 vs. 54.00±7.84, 38.74±4.60 vs. 58.68±7.19; Bax (gray value): 38.04±6.21 vs. 68.76±6.08, 58.84±7.99 vs. 70.03±7.36, all P < 0.05], the expression of Bcl-2 was increased (gray value: 37.36±3.11 vs. 28.47±7.46, 48.78±6.55 vs. 29.54±3.13, both P <0.05); the cell apoptosis rate was reduced at 72 hours [(31.14±4.51)% vs. (45.87±3.95)%, P < 0.01], and p-JNK/TUNEL double positive cells/TUNEL cells ratio was significantly decreased (10.00±0.85 vs. 52.70±3.05, P < 0.01).Conclusion The inhibition of neuron apoptosis caused by TP after CPR in rats with CA is related to the inhibition of JNK1/2 phosphorylation.

Effect and Mechanism of Tea Polyphenols on Morphine-induced Constipation / 医药导报

Objective To explore the preventive effect and mechanism of tea polyphenols on morphine-induced constipation. Methods Female Kunming mice were randomly divided into 4 groups ( 10 mice per group) , including blank control group, model control group, tea polyphenols group and tea polyphenols+morphine group. Tea polyphenols group and tea polyphenols + morphine group were pretreated with 100 mg·kg-1 of tea polyphenols for 4 days, meanwhile blank control group and model control group were preteated with 0.1 mL·kg-1 of 0.5% CMC-Na for 4 days. On the fourth day model control group and tea polyphenols + morphine group were intraperitoneal injected 20 mg kg-1 morphine, otherwise blank control group and tea polyphenols group were injected with 0.1 mL·kg-1 of 0.9% sodium chloride solution. Then mice were given 0.2 mL of 5% inksolution by intragastric administration 15 min later. The latency to paw licking was detected in hot plate test to evaluate the effect of tea polyphenols on morphine analgesia. The levele of motilin (MLT), substance P (SP) and somatostatin (SS) in intestinal tissue were determined by enzyme-linked immunosorbent assay ( ELISA) among groups. Results Compared with the blank control group, the length of propelling ink and the propelling rate of ink were significantly lower in the model control group ( P<0.01) , meanwhile tea polyphenols group were much higher ( P<0. 05 ) . Compared with model control group, the length of propelling ink and the propelling rate of ink were significantly higher in tea polyphenols + morphine group mice ( P<0.05) . The first paw licking time of control group and tea polyphenols group were (8.64 + 2.72)s and (9.11 + 2.13) s, and the time of model control group and tea polyphenols + morphine group were (18.79±3.58)s and (20.10±3.72) s. The contents of MLT and SP were reduced in model control group (P<0.05), but significantly increased in tea polyphenols group (P<0.05) compared with blank control group. Compared with the model control group, MLT and SP had an obviously increase in tea polyphenols +morphine group (P<0.05). Compared with blank control group, the content of SS was increased in model control group, but decreased markedly in tea polyphenols group and tea polyphenols+morphine group ( P<0.05) . Conclusion Tea polyphenols can prevent the morphine-induced constipation without decreasing the analgesic effect of morphine, which is related to the regulation of the content of MLT, SP and SS.

Effect and Mechanism of Tea Polyphenols on Morphine-induced Constipation / 医药导报

Objective To explore the preventive effect and mechanism of tea polyphenols on morphine-induced constipation. Methods Female Kunming mice were randomly divided into 4 groups ( 10 mice per group) , including blank control group, model control group, tea polyphenols group and tea polyphenols+morphine group. Tea polyphenols group and tea polyphenols + morphine group were pretreated with 100 mg·kg-1 of tea polyphenols for 4 days, meanwhile blank control group and model control group were preteated with 0.1 mL·kg-1 of 0.5% CMC-Na for 4 days. On the fourth day model control group and tea polyphenols + morphine group were intraperitoneal injected 20 mg kg-1 morphine, otherwise blank control group and tea polyphenols group were injected with 0.1 mL·kg-1 of 0.9% sodium chloride solution. Then mice were given 0.2 mL of 5% inksolution by intragastric administration 15 min later. The latency to paw licking was detected in hot plate test to evaluate the effect of tea polyphenols on morphine analgesia. The levele of motilin (MLT), substance P (SP) and somatostatin (SS) in intestinal tissue were determined by enzyme-linked immunosorbent assay ( ELISA) among groups. Results Compared with the blank control group, the length of propelling ink and the propelling rate of ink were significantly lower in the model control group ( P<0.01) , meanwhile tea polyphenols group were much higher ( P<0. 05 ) . Compared with model control group, the length of propelling ink and the propelling rate of ink were significantly higher in tea polyphenols + morphine group mice ( P<0.05) . The first paw licking time of control group and tea polyphenols group were (8.64 + 2.72)s and (9.11 + 2.13) s, and the time of model control group and tea polyphenols + morphine group were (18.79±3.58)s and (20.10±3.72) s. The contents of MLT and SP were reduced in model control group (P<0.05), but significantly increased in tea polyphenols group (P<0.05) compared with blank control group. Compared with the model control group, MLT and SP had an obviously increase in tea polyphenols +morphine group (P<0.05). Compared with blank control group, the content of SS was increased in model control group, but decreased markedly in tea polyphenols group and tea polyphenols+morphine group ( P<0.05) . Conclusion Tea polyphenols can prevent the morphine-induced constipation without decreasing the analgesic effect of morphine, which is related to the regulation of the content of MLT, SP and SS.

Research progress in mechanisms of functional components in tea on lung cancer / 中草药

Lung cancer has the highest incidence among all of the world’s cancer diseases. Since the incidence and mortality of lung cancer have been increasing year after year, how to prevent and control it arouses general concern in the world. Tea is a healthy drink and has sweet-bitter flavor. It is also slightly cold and non-toxic. Many experimental studies show that a variety of functional components included in tea can be used for preventing, directly intervening and assistantly treating lung cancer or other malignant tumors, so they will be a potential candidate for natural antitumor drugs. For example, tea polyphenols, caffeine, tea pigment, theanine and tea polysaccharide can well inhibit the proliferation of tumor cells, induce apoptosis of tumor cells as well as regulate the expression of related gene and protein. The paper reviews some major researches of prevention and treatment on lung cancer by functional components of tea since 1970, in order to provide reference of systematically cognizing tea’s mechanism on opposing lung cancer, using tea and functional components to resist lung cancer in a safe and effective way, cultivating new varieties of tea armed with high level of specific components and developing new tea products.

Effect of tea polyphenols on the mRNA and nuclear protein expression of Nrf2/Bach1 in human skin fibroblasts / 中华皮肤科杂志

Objective To evaluate effects of tea polyphenols on the mRNA and nucleoprotein expression of Nrf2/Bach1 in human skin fibroblasts (HSFs).Methods Some HSFs were incubated with tea polyphenols at different concentrations of 0,2.5,5,10,20 and 40 mg/L for 24 hours.Methyl thiazolyl tetrazolium (MTT) assay was conducted to evaluate the proliferative activity of HSFs to screen the optimal concentration of tea polyphenols.Then,some other HSFs were treated with tea polyphenols at this optimal concentration for 24 hours.Real-time quantitative PCR (RT-qPCR) was performed to determine mRNA expression of Nrf2 and Bach1,Western blot analysis to measure nuclear expression of Nrf2 and Bach1 proteins,and immunofluorescence assay to determine the distribution of Nrf2 and Bach1 protein in the cell nucleus.Results MTT assay showed that 5 mg/L tea polyphenols had no obvious effects on the proliferation of HSFs,so 5 mg/L was chosen as the optimal concentration of tea polyphenols for subsequent experiments.HSFs cultured without tea polyphenols served as control group.After the treatment,the 5-mg/L tea polyphenol group showed significantly decreased mRNA and nuclear protein expression of Bach 1 (mRNA:0.629 ± 0.077 vs.0.940 ± 0.033,t =6.397,P ＜ 0.05;protein:1.424 ± 0.171 vs.16.966 ± 1.702,t =15.730,P ＜ 0.05),but significantly increased mRNA and nuclear protein expression of Nrf2 (mRNA:1.467 ± 0.076 vs.0.977 ± 0.091,t =7.133,P ＜ 0.05;protein:6.929 ± 0.121 vs.3.537 ± 0.126,t =33.636,P ＜ 0.05) compared with the control group.Immunofluorescence assay showed increased accumulation of Nrf2 protein,but decreased accumulation of Bach1 protein in the nucleus.Conclusion Tea polyphenols can promote the mRNA and nuclear protein expression as well as nuclear distribution of Nrf2,but suppress the mRNA and nuclear protein expression as well as nuclear distribution of Bach 1,finally exerting antioxidative effects.

Effect of green tea polyphenols on uric acid level in potassium oxonate-induced hyperuricemic mice and mechanism / 中国药理学通报

Aim To investigate the effect of green tea polyphenols(GTP)on serum level of uric acid in potas-sium oxonate (PO)-induced hyperuricemic mice,and explore the potential mechanism.Methods PO and GTP were intragastricly administered to mice for seven consecutive days.Uric acid level in serum was exam-ined.Meanwhile,activity and expressions of xanthine oxidase(XOD)in liver were tested.In additon,ex-pressions of urate transporters including urate-anion transporter (URAT ) 1 , organic anion transporter (OAT)1 and 3 in kidney were analyzed.Results GTP significantly decreased the serum level of uric acid in PO-induced hyperuricemic mice.At the same time, GTP markedly reduced the activity and expression of XOD in liver of hyperuricemic mice.Finally,GTP markedly reduced the expression of URAT1 ,OAT1 and OAT3 in kidney of hyperuricemic mice.Conclusion GTP has the effect of lowering uric acid in PO-induced hyperuricemic mice through both decreasing the uric acid production and increasing uric acid excretion.

Role of Shh-PARP-1 signaling pathway in the protective effects of tea polyphenols against fatty acid-induced injury to islet microvessel endothelial function / 第二军医大学学报

Objective To investigate the role of Shh-PARP-1 signaling pathway in the protective effects of tea polyphenols against the fatty acid-induced islet microvessel endothelial function injury. Methods Mouse islet microvessel endothelial MS-1 cells were used in this study, and the cells were divided into normal control group, solvent group, fatty acid group (0. 25 mmol/L palmitic acid + 0. 5 mmol/L oleic acid), tea polyphenols group (25 μmol/L), fatty acid + tea polyphenols group, PARP-1 inhibitor (8 μmol/L BYK204165) + fatty acid group, PARP-1 inhibitor + fatty acid + tea polyphenols group, Shh inhibitor (2. 5 μmol/L cyclopamine) + fatty acid group, Shh inhibitor + fatty acid + tea polyphenols group and inhibitors of Shh and PARP-1 + fatty acid +tea polyphenols group. The changes of cell viability, apoptosis, nitric oxide (NO) synthesis and oxidative stress related indicators were examined in each group. Results After fatty acid treatment, the survival rate ofMS-1 cells was decreased, and the level of apoptosis was significantly increased (P0. 05). Conclusion Fatty acid can directly trigger islet microvessel endothelial function injury, and tea polyphenols shows a protective effect against the toxicity of fatty acid, which can be enhanced by inhibiting Shh-PARP-1 signal pathway.

Protection of tea polyphenols against pulmonary ischemia-reperfusion injury in rats / 国际中医中药杂志

Objective To investigate the protection of tea polyphenols (TP) against pulmonary ischemia-reperfusion injury in rats. Methods A total of 100 rats were randomly devided into five groups:the sham operation group, the model control group, the high-, medium-and low-dose TP groups. Two hours after reperfusion, the PO2 and the lung tissue wet/dry (W/D) ratio were examined; the apoptosis index (AI) was analysised;the activity of SOD, CAT and the content of MDA in lung tissue were determined. Results Compared with the model control group, the W/D (5.7 ± 0.4, 5.5 ± 0.4 vs. 6.5 ± 0.5) and the AI (19.3%± 1.8%, 14.2%± 1.4%vs. 31.2%± 2.4%) of the high-, medium-dose groups were significantly decreased (P<0.05 or P<0.01);the activity of SOD (115.2 ± 18.1 U/mg, 128.7 ± 20.9 U/mg vs. 94.7 ± 12.1 U/mg), CAT (1.3 ± 0.2 U/mg, 1.7 ± 0.4 U/mg vs. 0.9 ± 0.2 U/mg) in lung tissue of the the high-, medium-dose groups groups were significantly increased (P<0.05 or P<0.01), and the content of MDA (1.1 ± 0.3 nmol/L, 1.0 ± 0.3 nmol/L vs. 1.6 ± 0.5 nmol/L) were significantly decreased (P<0.05 or P<0.01). The PO2 (93.4%± 4.0%vs. 85.9%± 3.4%) of the high-dose group were significantly increased compared to the model group (P<0.01). Conclusion TPs could effectively lower the W/D, increase the PO2, inhibit the hepatocyte apoptosis, lower the AI, suggesting that TPs had protective effects against pulmonary ischemia-reperfusion injury in rats, which perhaps related to its effects of improving antioxidant ability and inhibiting the oxidative stress.

The expression of MMP-1 and MMP-2 of periodontal ligament fibroblasts treated by tea polyphenols and LPS / 实用口腔医学杂志

Objective:To survey the expression of MMP-1,MMP-2 of human periodontal ligament cells(HPDLCs)treated by tea polyphenols(TP)and lipopolysaccharide(LPS).Methods:HPDLCs were in vitro cultured in vitro and treated by TP(200 μg/ml) and /or LPS(100 μg/ml)for 24,48 and 72 h respectively,the secretion of MMP-1 and MMP-2 were examined by ELISA,MMP-1 and MMP-2 mRNA expression was examined by real-time PCR.Results:The secression and mRNA expression of MMP-1 and MMP-2 of HPDLCs increased by LPS treatment and significantly inhibited by TP at the different times.Conclusion:TP can inhibit the col-lagen degradation of HPDLCs mediated by LPS.

Effect of tea polyphenols intake on ethanol-induced liver injury / 重庆医学

Objective To establish the cell model of ethanol-induced liver injury and explore the protective effects of tea poly-phenols (TP)on ethanol-induced liver injury .Methods Cell morphology were observed by microscope ,and then alanine aminotrans-ferase (ALT) ,nmda transaminase (AST) ,gamma GGTP ,GGT and ROS changes were detected .Results Alcohol maked L02 hepa-tocyte fatty degeneration .Compared with ethanol group ,steatosis in TP + ethanol group was lighter ,its ALT ,AST ,GGT content and intracellular ROS reduced .Conclusion TP can decrease cell fatty change degree in vitro experiments ,improue the enzymology indexes ,reduce the generation of reactive oxygen species to avoid liver damage .

Contents of fluoride and tea polyphenols in brick tea at fluorosis regions in Inner Mongolia / 中华地方病学杂志

Objective To determine the contents of fluoride and tea polyphenols in brick-tea and to understand the utilization ratio of qualified brick-tea in fluorosis regions in Inner Mongolia.Methods The investigation was carried out in Chenbaerhuqi Country and Eweukeqi Country.Seventy-two households of four villages in Chenbaerhuqi and 11 households of three villages in Ewenkeqi were selected as study subjects.The brick-tea in each household was sampled.The contents of fluoride and tea polyphenols were determined by using fluoride selective electrode method and Forint-Ciocalteu oxidation method,respectively.T test and linear correlation were used to analyze the data.Results The fluoride content in qualified brick tea ranged from 114.82 mg/kg to 290.23 mg/kg with an average value of 171.78 mg/kg,while tea polyphenols content was between 56.15 g/kg and 132.18 g/kg with an average value of 95.44 g/kg.In unqualified brick-tea,the average fluoride content was 459.86 mg/kg with the range from 304.71 mg/kg to 660.76 mg/kg and the average of tea polyphenols was 67.48 g/kg with the range from 36.03 g/kg to 102.15 g/kg.The content of tea polyphenols of qualified brick tea was significantly higher than that of unqualified brick tea (P ＜ 0.05).The content of tea polyphenols was negatively correlated with fluoride content(r =-0.636,P ＜ 0.05).The content of tea polyphenols was 396 times more than that of fluoride in brick tea.The utilization ratio of qualified brick-tea in the investigation areas was 53.0％(44/83).Conclusion The fluoride content in qualified brick-tea was less than unqualified brick-tea,and the tea polyphenols of qualified brick-tea was higher than the unqualified brick-tea.The utilization rate of qualified brick tea is not high and further actions are needed to be taken to supply more qualified brick-tea for controlling of drinking brick-tea type fluorosis.

Protective effects of tea polyphenols against the destruction of melanocytes by CD8+ T ceils from vitiligo patients / 中华皮肤科杂志

Objective To evaluate the protective effects of tea polyphenols against the destruction of melanocytes by CD8+ T cells from vitiligo patients.Methods Skin tissue was resected from the margin of vitiligo lesions followed by the isolation and culture of CD8+ T lymphocytes,and from the normal skin of vitiligo patients followed by the isolation and culture of melanocytes.Flow cytometry was carried out to evaluate the purity of CD8+ T cells.The melanocytes were cocultured with the CD8 + T cells at different ratios followed by the evaluation of killing effect of CD8+ T cells.Various concentrations (200 and 400 μg/ml) of tea polyphenols were added into the co-culture system of CD8+ T cells and melanocytes at a ratio of 5 ∶ 1 followed by an additional culture of 48 hours.Then,flow cytometry was performed to detect the apoptosis in melanocytes in the coculture system.Results CD8+ T lymphocytes were successfully obtained from the marginal area of vitiligo lesions with a purity of more than 90％,which highly expressed the antigens CD137 and CD69.The coculture with CD8+ T cells markedly accelerated the apoptosis in melanocytes,while the accelerative effect was inhibited by tea polyphenols of 200 and 400 μg/ml.Conclusions The CD8+ T cells infiltrating the edge of vitiligo lesions display a potential destructive effect on autologous melanocytes from vitiligo patients,and tea polyphenols have a protective effect against the destruction of melanocytes by CD8+ T cells.