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.

Effect of Green Tea Polyphenols on N-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine Induced Dopaminergic Neurodegeneration in Mice / 中国康复理论与实践

@#Objective To investigate the protective effects of green tea polyphenols(GTPs)on dopamine neuron loss in substantia nigra concomitant with a depletion of dopamine in corpus striatum induced by the N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine(MPTP)in mice as a model of Parkinson disease.Methods Male C57BL/6 mice were intraperitoneally injected with saline + saline(group A),saline + GTPs(group B),saline+MPTP(group C)and GTP+MPTP(group D)at 2-hour intervals for a total of 3 doses for MPTP and 5 doses for GTPs(10 or 50 mg/kg delivered).The animals were sacrificed 7 d after the last injection.Levels of dopamine and its metabolites in the corpus striatum were measured with high-performance liquid chromatography with an electrochemical detector(HPLC-ECD).Results Level of dopamine and its metabolites in the corpus striatum in group C decreased significantly compared with group A or B;however,those in group D(both 10 and 50 mg/kg)prevented these effects.Conclusion GTPs can protect the dopamine neurons from loss in MPTP-induced mice.

Protective Effects of Green Tea Polyphenols Against Parkinson's Disease / 生物化学与生物物理进展

About 70% of Parkinson's pathogenesis comes from environment factor and one important of which is oxidative stress although the genetic factor plays an important role. The antioxidant of green tea polyphenols(GTP) and they can enter into plasma even penetrate blood brain barie provides an important condition for the protective effects of GTP against Parkinson's Disease(PD). In cellular model the protective mechanisms of GTP on PC12 and SH-SY5Y cells against apoptosis induced by 6-hydroxydopamine (6-OHDA) were investigated. GTP attenuated 6-OHDA-induced early apoptosis, prevented the decrease in mitochondrial membrane potential, suppressed accumulation of reactive oxygen species (ROS) and of intracellular free Ca2+. GTP also counteracted 6-OHDA-induced nitric oxide increase and over-expression of nNOS and iNOS, and decreased the level of protein bound 3-Nitro-tyrosine (3-NT). Using PD rat model injected by 6-OHDA, the effect of GTP were investigated on animal model. Results showed that GTP attenuated the injury in a dose and time dependent manner. Pretreatment of the animals with GTP decreased ROS and NO production, thiobarituric acid reactive substances content, nitrite/nitrate concentration, and protein bound 3-Nitro-tyrosine (3-NT) in brain homogenate of midbrain and striatum in a concentration and time dependent manner. NOS participated in the neuron death induced by 6-OHDA and it was found that the pretreatment with GTP could decrease the protein level of nNOS and iNOS. More neurons survived and less cells suffered apoptosis in the substantia nigra pars compacta (SNc) of GTP treated animal brain. These results suggest that oral administration of GTP increases the antioxidant level in the brain and protects the brain against cell death caused by 6-OHDA. The experimental results of present study support the neuroprotection of GTP and provided new strategy of preventing and curing Parkinson's diseases by ROS-NO pathway.

Experimental study on nerve allografts stored in green tea polyphenol solution / 中国矫形外科杂志

[Objective]To explore the outcome of repairing nerve defects with nerve allografts stored in green tea polyphenol solution.[Method]Forth-eight male mice were randomly divided into 4 groups of nerve grafting,with 12 rats in each group.A 1.0 cm sciatic nerve segment,5 mm away from infrapiriform foramen,was removed and repaired by 4 kinds of nerve allografts.Group A:autografts.Group B:allografts.Group C:cryopreserved nerve allografts.Group D:nerve allografts stored in green tea polyphenol solution.At 6 weeks and 12 weeks,a series of examinations were performed,including the gross appearance,electrophysiological test,histological observation,electron microscopic study and quantitative analysis with image analysis system.[Result]All the parameters of groups A and D were better than those in groups B and C(P

THE COMPARATIVE STUDY ON EFFECTS OF GREAN TEA AND BLACK TEA POLYPHENOLS ON GENES RELATED TO ADIPOCYTE DIFFERENTIATION IN RATS / 营养学报

Objective:To compare the anti-obesity effect of green tea and black tea polyphenols and investigate their molecular mechanisms. Method:Rats were divided randomly into four groups:control group,high-fat group,high-fat diet with green tea polyphenols(GTP) supplement group,and high-fat diet with black tea polyphenols(BTP) supplement group. Body weight was determined every 2 w. After 3 months,the changes of epididymal fat tissues weight and serum lipids were observed. Expressions of those genes associated with adipocyte differentiation in epididymal fat tissues of rats were measured by real-time transcription-polymerase chain reaction,including pref-1,aP2,TNF-?,leptin,PPAR-?,C/EBP-? . Results:Both GTP and BTP prevented the increase of body weight and fat induced by high-fat diet and profoundly down-regulated those adipocyte-specific genes,including aP2,TNF-?and leptin. In addition,GTP also up-regulated the pre-adipocye marker — pref-1 and reduced the expression of transcription factor,peroxisome proliferators-activated receptor(PPAR-?) . Conclusion:Tea polyphenols could prevent obesity by reversing the adipocyte differentiation,and GTP possessed stronger inhibitory effect than BTP.

Growth inhibition and induction of apoptosis in cervical cancer cell lines by green tea polyphenols / 대한산부인과학회잡지

OBJECTIVE: The purpose of this article is to estimate the anti-cancer effects of the major components of the green tea (polyphenols, catechin and EGCG) and the mechanism of EGCG on different cervical cancer cell lines. METHODS: Six cervical cancer cell lines (HeLa, HeLaS3, Caski, SiHa, HT3 and C33A) were treated with 20 microgram/ml green tea polyphenols (GTPs), 50 micrometer catechin and various concentrations of (-)-epigallo- catechin-3-gallate (EGCG). The viabilities were determined by trypan blue exclusion assay, neutral red assay and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. DNA fragmentation and nuclear condensation were used to see whether EGCG-induced anti-proliferation effect was due to apoptosis. RESULTS: Both GTPs, catechin and EGCG had growth inhibition effects on cervical cancer cell lines, but EGCG appeared to be the most effective. What's more, the sensitivity of each cell lines to EGCG was different. HT3 cells (HPV negative, mutant type p53) were most sensitive to EGCG (estimate IC50: 10 micrometer). Caski (HPV-16 positive, wild type p53) and HeLaS3 cells (HPV-18 positive, wild type p53) were less sensitive (estimate IC50: 35 and 70 micrometer respectively). EGCG-induced apoptosis can be seen in all the cell lines and it happened as early as 8 hours after EGCG treatment. CONCLUSION: Green tea or EGCG alone will be beneficial to the cervical cancer patients.

The study of green tea polyphenols inhibiting apoptosis of lens epithelial cell in vitro and relevant mechanism / 重庆医科大学学报

Objective: To investigate the inhibitory effect of Green Tea Polyphenols(GTP) on H2O2-induced lens epithelial cell apoptosis and relevant mechanism.Methods: Separated and cultivated lens epithelial cell,disposed that with GTP,then detected the inhibitory effect of GTP by electron transmission microscopy,flow cytometry and DNA fragmentation assay.The bcl-2,Bax and caspase-3 protein expression were measured with Western-blot in various groups.Results: The apoptosis cells and G1 phase cells increased in the group treated with sodium chloride solution,and the DNA "ladder" was found.In the group treated with GTP,the apoptosis cells and G1 phase cells decreased,and no DNA "ladder".The apoptosis protein bcl-2 increased,however,the Bax and caspase-3 protein decreased.Conclusion: The GTP can protect lens epithelial cells from the oxidative injury and restrain the apoptosis rate of lens epithelial cells and the mechanism was nearly correlated with bcl-2,Bax and caspase-3 protein.