Effects of supplementation of green tea extract on the milk performance of peripartal dairy cows and the expression of stress response genes in the liver

Background: We hypothesised that supplementation of green tea extract(GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum(ER) stress in the liver of these cows. Thirty Holstein cows with an average parity of 3.06(± 1.31, SD) were divided into a control group and a group that received a daily amount of 10 g of GTE from d 7 before the calving day and a daily amount of 20 g of GTE from the day of calving until d 7 of lactation.Results: Cows supplemented with GTE did not show differences in energy intake or milk yield in weeks 2–7 of lactation. However, these cows had a lower milk fat concentration and a lower energy corrected milk yield than the control cows and showed a trend of improved energy balance. The relative m RNA concentrations of proinflammatory genes, genes involved in the acute phase reaction and antioxidant genes in the liver in weeks 1, 4 and 7 of lactation were not different between the two groups of cows. The concentrations of α-tocopherol and the Trolox equivalent antioxidant capacity in plasma were not different between the two groups. However, the group supplemented with GTE showed significant reductions of some genes of the unfolded protein response(UPR) in week 1 and a trend of lower liver triacylglycerol(TAG) concentrations in the liver compared to the control group.Conclusions: This study shows that supplementation of GTE in dairy cows lowers the fat concentration in the milk but overall has no effect on the expression of inflammatory genes and the antioxidative status in dairy cows during early lactation. The finding of reduced m RNA levels of genes involved in the UPR at week 1, however, supports other results showing that supplementation of polyphenols could prevent the development of ER stress in the liver of cows during early lactation. The finding of a tendency towards a reduced TAG concentration in the liver of cows supplemented with GTE might be due to an improved energy balance in these cows.

Inhibitory Effect of Green Tea Extract on the Carcinogenesis Induced by Asbestos Plus Benzo(a)pyrene in Rat

In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observcd that the incidcnce (16.0%) of lung carcinomas was lowel, and the survival time (376 days) of the first case of carcinoma and the mean survival time (758 days) of the rats with carcinoma were higher in the group of rats drinking 2% green tea extract for life than in the positive group (without drinking green tea extract). The mortality ratio (0.5047) was smaller in the cxperimental group than in the positive control group, and the survival curve of the experimental group significantly raised up, in comparison with the positive group.

Green tea extract:A potential cause of acute liver failure

The use of herbal products has increased significantly in recent years.Because these products are not subject to regulation by the Food and Drug Administration and are often used without supervision by a healthcare provider,the indication for and consumption of these supplements is quite variable.Moreover,their use is generally regarded as safe and natural by the lay-public.Unfortunately,there has been an increase in the number of reported adverse events occurring with the use of herbal products.We present a case of acute impending liver failure in an adolescent male using a weightloss product containing green tea extract.Our case adds to the growing concern surrounding the ingestion of green tea extract and serves to heighten healthcare provider awareness of a potential green tea extract hepatotoxicity.Despite the generally touted benefits of green tea as a whole,clinical concern regarding its use is emerging and has been linked to its concentration in multiple herbal supplements.Interestingly,the suspected harmful compounds are those previously proposed to be advantageous for weight-loss,cancer remedy,and anti-inflammatory purposes.Yet,we emphasize the need to be aware of not just green tea extract,but the importance of monitoring patient use of all dietary supplements and herbal products.

Applications of Green Tea Extract in Bakery Products

Green tea extract(GTE) is a rich source of tea catechins with antioxidative,anticarcinogenic and antiarteriosclerotic activities and it has been applied in food such as bakery products to provide health benefits and extend the shelf life.This review outlines the stability of green tea catechins during baking process of bakery products supplemented with GTE and the effects of GTE on the functional properties,sensory properties,physical characteristics and Maillard reaction of bakery products.

Oxidative Stability of Green Tea Extract-Enriched Rice Bran Oil During Storage

Adding green tea extract to rice bran oil was expected to improve its oxidative stability,so this study was conducted to investigate oxidative stability of green tea extract-enriched rice bran oil(RBOG) during storage at 60℃ for 15 days compared to rice bran oil(RBO),olive(OL),canola(CN),and grape-seed oil(GS).Acid values did not increase during storage,and the highest value was found for OL.The peroxide values of RBOG,RBO,CN,OL,and GS increased for up to 15 days.The highest average rate constant for the change in peroxide value was found for RBO(0.282).TBARS increased continually during storage of RBOG,RBO,CN,and OL;however,the value increased for up to 9 days and then decreased for GS.The highest average rate constant of change in TBARS was found for CN.Overall,the results suggest that green tea extract improves oxidative stability of rice bran oil.

Effects of Black Tea Extract on Transplantable and Solid Tumors in Swiss Albino Mice

The chemopreventive effects of green tea and its polyphenols are well documented in the literature. Epidemiological studies have suggested that green tea consumption might be effective in the prevention of certain human cancers. About 80% of the tea is consumed as black tea. Limited studies have been carried out to assess the usefulness of black tea as anti_carcinogen. The present set of investigations were initiated to study the anti_tumorigenic potential of aqueous black tea extract (ATE) in Swiss albino mice in \%in vivo\% animal bioassay, using 7, 12 dimethyl_benzanthracene (DMBA) as carcinogen. In the experimental group, 2% ATE was given orally as sole source of drinking water, while the control were allowed to drink normal water, \%ad lib.\% The results revealed that drinking of 2% ATE could effectively inhibit the onset of tumorigenesis, cumulative number of tumors and average number of tumors per mouse. In ATE drinking group 44% animals remained tumor free till the termination of experiment, i. e. 26 weeks. In the second set of experiment the preventive efficacy of 2% ATE of different cultivars of black tea, viz orthodox, CTC and dust were tested in Ehrlich Ascites (EA) tumor bearing mice. The preventive effects of ATE were observed in terms of increased life span (ILS). All the cultivars of tea showed more than 25% increase in life span of the animals. Cytotoxic effect of various doses of all three cultivars of black tea was also observed \%in vitro \%on EA cells.

In vivo antioxidant activity and its protective effects of green tea extract on acute myocardial infarction

The antioxidant activity and its protective effects of Green Tea Extract （GTE） from a Chinese green tea, Hangzhou Longjing, on acute myocardial inthrction （AMI） were investigated in rats. Blood, liver and heart were collected to perform DNA damage test, hepatic antioxidant test, gene expression as well as capillary distribution study. A well-known angiotensin II type I receptor antagonist, Losartan was used as control. It was fbund there were significant reductions in certain DNA damage products＇ levels in GTE and Losartan treated groups compared to saline-treated group. In addition, significant increases in antioxidant enzyme activities and antioxidant gene expressions were observed in GTE and Losartan treated groups. Molphological study also demonstrated the cardioprotective effects of GTE on AMI. In conclusion, GTE has potent and similar cardioprotective effect as Losartan that mav due to its ability to scavenge free radicals.

Reducing oxidative stress and hepatoprotective effect of water extracts from Pu-erh tea on rats with high-fat diet

Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.The body weight was measured once a day.The malondialdehyde(MDA)and glucose(Glu)levels and the activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),nitric oxide synthase(NOS),and pyruvate kinase(PK)in serum were determined.Furthermore,the hepatic glycogen level(HGL)and the activities of hepatic total superoxide dismutase(T-SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were also measured after continuous administration for 12 weeks.The result demonstrated that Pu-erh extract caused the decreases in body weight,fat index,MDA and NOS levels,and the increases in hepatic T-SOD,CAT and GSH-Px activities,indicating that the extract may be due to inhibiting the increases of body weight and fat index,reducing oxidant stress state and inhibiting lipid peroxidation,thus decreasing the activities of ALT and AST,and protecting the liver in rat.Meanwhile,the extracts could increase the production of hepatic glycogen and the activity of PK,and reduce glucose level,protecting the liver from the diseases associated with type II diabetes.

Sonme Factors that Affect the Free Radical-scavenging Activity of Tea Extracts

Some factors that affect the free radical-scavenging activety of two tea extracts were studied in vitro. It was found that concentration of tea extract or heating tea extract or treating with activated carbon and diatomite all had obvious effect on the scavenging activety of green tea extract ,but heating or treating with diaomite had less effect on the scavenging activity of black tea extract. Ascorbic acid, for having synergic effect with tea extracts, could enhance the scavenging activity of tea extracts markedly, and the contrary was cupric ion. Reducing sugars such as fructose and glucose also had some syncrgic effect to tea extracts.

Efficacy of green tea extract on PC3 prostate cancer cells through upregulation of miR-195 expression and suppression of epithelial to mesenchymal transition

OBJECTIVE: To evaluate anticancer efficacy of green tea extract(GTE) on PC3 prostate cancer cells. METHODS: By using quantitative real-time polymerase chain reaction(qRT-PCR) and Western blot methods, the expression of miR-195 and the epithelial to mesenchymal transition(EMT) markers such as E-cadherin and vimentin was analyzed. RESULTS: Based on the results of 2D and 3D cell culture models, the inhibition of EMT and up regulation of miR-195 expression were detected. CONCLUSIONS: Our findings will be helpful to design anti-tumor regimens with natural product original, and more studies will be required to identify the related mechanisms involving anticancer activities of green tea via miRNAs.

Caffeine is responsible for the bloodglucose-lowering effects of green tea and Puer tea extractsin BALB/c mice

The present study was designed to determine the effects of Puer tea and green tea on blood glucose level. Male BALB/c mice were administered green tea extract(GTE) or Puer tea extract(PTE), either intragastrically or in their drinking water. The major components of these teas are epigallocatechin gallate(EGCG) and caffeine, respectively. Blood glucose measurement results showed that mice fed intragastrically or mice that drank GTE, PTE or caffeine showed significantly lower blood glucose levels compared to the control group. However, EGCG exhibited no influence on the blood glucose levels. When caffeine was eliminated from the GTE and PTE, the effect on the blood glucose levels was abolished, but the effect was recovered when caffeine was re-introduced into the extracts. Evaluation of hematological and biochemical indices at the time of the greatest caffeine-induced decrease in blood glucose levels showed that the effect of caffeine was specific. Microarray analyses were performed in 3T3-L1 preadipocytes and mature adipocytes treated with 0.1 mg·m L-1 caffeine to identify factors that might be involved in the mechanisms underlying these effects. The results showed that few genes were changed after caffeine treatment in adipocytes, and of them only phospholipid transfer protein(PLTP) may be ralated to blood glucose. In conclusion, this study indicates that caffeine may be the key constituent of tea that decreases blood glucose levels, and it may be used to treat type 2 diabetes.

Study on Extraction Technology of Theabrownine from Liubao Tea and Its Antioxidant Activity

[ Objective] This study aimed to provide theoretical reference for the extraction of theabrownine from Liubao tea, determination of the biological activity, and development and utilization of theabrownine. [Method] Orthogonal experimental design was adopted to investigate the effects of solid-liquid ratio, extraction temperature, extraction duration, and extraction frequency on the yield of theabrownine extracted from Liubao tea. The extraction technology was optimized, and the antioxidant activity of theabrownine was analyzed. [ Result] The results showed that extraction frequency and extraction temperature had significant effects on the yield of theabrownine extracted from Liubao tea, while solid-liquid ratio and extraction duration had no significant effect. The optimal conditions for extracting theabrownine from Liubao tea were determined as follows ： solid-liquid ratio was 1 ： 30, extraction temperature was 100℃, extraction duration was 80 min, and extraction frequency was 4 times. Under these conditions, the yield of theabrownine reached 22.92%. Results of antioxidant activity determination showed that hydroxyl radical-scavenging activity of theabrownine was as high as 74%, and the scavenging effects was significantly higher than that of Vitamin C under low concentrations; nitroso-scavenging activity of theabrownine reached 73%, with no significant difference from that of Vitamin C; superoxide anion free radical-scavenging activity of theabrownine could be above 60%, which was lower than that of Vitamin C. [Condusion] Liubao tea contains abundant theabrownine that has relatively high antioxidant activity with good prospects in antioxidant application, which lays solid foundation for in-depth development of Liubao tea.

Optimization of Extraction Process of Yingshan Cloud Tea Polysaccharides by Response Surface Methodology

[Objectives] This study was conducted to explore the optimal process conditions for hot water extraction of polysaccharides from Yingshan cloud tea. [Methods] Based on single factor experiments, with the extraction rate of polysaccharides as the response value and liquid-to-solid ratio, extraction temperature and extraction time as investigation factors, the optimum extraction process for tea polysaccharides from Yingshan cloud tea was determined by Box-Behnken central componse design and response surface analysis method. [Results] Under the conditions of the liquid-to-solid ratio of 50∶1(ml/g), the extraction temperature at 94 ℃ and the extraction time of 210 min, the extraction rate of polysaccharides from Yingshan cloud tea reached 2.16%. [Conclusions] This study will provide theoretical basis and reference for subsequent related research.

Extraction and Quantification of Total Polyphenol Content in Different Parts of Selected Tea Cultivars

Tea (Cammelia sinensis) is the most widely consumed beverage in the world and has been reported to have unlimited health benefits due to its antioxidant properties. There is a high correlation between polyphenol compounds with antioxidant properties. Tea leaves are a major source of polyphenols. The aim of the present investigation was to determine the approximate level of polyphenols in different other parts of the tea plant to give comparative data on obtaining extracts that can be used to design products through value addition to assist in the prevention of diseases associated with oxidative stress. Twenty-one selected region specific tea varieties were used to obtain roots, flowers, leaves and barks. Leaves were prepared by microwaving and the remaining portions processed as green non-aerated teas and black aerated tea. Roots, barks, flowers were sun-dried and milled. Total polyphenol content was determined by calorimetric method using Folin-Ciocalteu reagent. The obtained results suggest that different parts of tea plant have varying numbers of total polyphenols with microwaved leaves having mean levels at 23.1%, steamed leaves (non-aerated green tea) at 22.37%, aerated leaves at 15.51%, barks at 14.92%, flowers at 10.62% and roots at 1.48%.

Comparative Study on the Effect of Extractant on the Detection of Imidaclothiz Residue in Tea

Imidaclothiz residue in tea was determined by high performance liquid chromatography（ HPLC）,using different extractants including hexane,acetonitrile,acetone,hexane-acetonitrile（ 1∶ 1）,acetonitrile-acetone（ 1∶ 1） and hexane-ethyl acetate（ 1∶ 1）. The results indicated that all the extractants displayed excellent extraction capacities of imidaclothiz residue in tea and insignificant interference on the accuracy. Under the optimized extraction volume（ 20 ml）,the recovery values were in the ranges of 82. 3%-100. 7%,85. 8%-101. 1%,85. 9%-95. 2%,82. 3%-101. 3%,82. 4%-100. 5% and 88. 6%-102. 3%,respectively,with the relative standard deviations smaller than 10%. Moreover,mixed solvent showed improved extraction capacity,and the highest extraction capacity and promoted stability were approached by using hexane-ethyl acetate（ 1∶ 1） as coextractants.

Optimization of Supercritical Fluid Extraction of Tea Flower Polysaccharides by Using Response Surface Method

Polysaccharide production from tea flower(TFPS) was carried out using supercritical fluid extraction(SFE).Response surface methodology(RSM),based on a five level,four variable small central composite design,was employed to obtain the best possible combination of extraction time,pressure,temperature and ethanol content of modifier for maximum production.The optimum conditions were as follows:extraction time of 170 min,pressure of45 MPa,temperature of 75 ℃,and 50% aqueous ethanol solution as modifier.Under these conditions,the experimental yield was 6.56 ± 0.37%,which was similar to the value predicted by the model.Monosaccharide composition of TFPS was fucose,rhamnose,arabinose,xylose,galactose,glucose,mannose,fructose,ribose,galacturonic acid and glucuronic acid in a molar percent of 31.69,0.21,0.49,1.29,35.82,0.97,1.63,18.34,7.88,1.06 and 0.63.Compared to other extraction methods,SFE could achieve higher yield and gain more types of monosaccharide.

Rheology study of supercritically extracted tea-oil

The rheological analysis on dynamic shear rate-viscosity relationship of tea-oil extracted from tea-oil tree seeds by supercritical extraction method was carried out at gradient temperatures and constant shear rate,respectively.The results show that at 20,40,60 and 80 ℃,once the shear rate increases gradually,the torque enlarges correspondingly,while the viscosity shows little difference.However,at the constant shear rate,the rising temperature results in a steady downtrend on tea-oil viscosity.This results reveal that tea-oil viscosity is not closely correlated with shear rate at constant temperature,yet negatively correlated with temperature at constant shear rate.

Comparative assessment of total polyphenols, antioxidant and antimicrobial activity of different tea varieties of Bangladesh

Objective: To determine the total polyphenol content, antioxidant activity and antibacterial properties of the extracts of different Bangladeshi tea varieties such as flowery broken orange pekoe, broken orange pekoe, red dust and green tea.Methods: Total phenolic and flavonoid contents were determined by Folin–Ciocalteu and aluminum chloride colorimetric assay, respectively.The antioxidant capacity was determined by ferric ion reducing antioxidant power and phosphomolybdenum method.Antibacterial activity was evaluated by disc diffusion method in agar plate and subsequently, the minimum inhibitory concentration was determined by broth dilution method.Results: Total phenolic and flavonoid contents were significantly higher(P < 0.05) in green tea compared to other three black tea varieties.The green tea also showed a higher free radical scavenging and antioxidant activities than all the other tea varieties tested(P < 0.05).In addition, the extracts of all four tea varieties showed inhibitory activity against several pathogenic bacteria and also the same trend of higher antimicrobial activity of green tea than other tea varieties was observed.Conclusions: Taken together, the results of this study demonstrated that Bangladeshi tea,especially the green tea, may act as a substitute for natural antioxidants and as a promising antibacterial agent for beneficial influence in human health.

Antifi brotic effects of green tea on in vitro and in vivo models of liver fibrosis

AIM: To examine the protective effect of green tea extract (GT) on hepatic fi brosis in vitro and in vivo in dimethylnitrosamine (DMN)-induced rats.METHODS: HSC-T6, a rat hepatic stellate cell line, was used as an in vitro assay system. Cell proliferation, collagen content, and type 1 collagen expression were examined in activated HSC-T6 cells. Collagen was determined by estimating the hydroxyproline content. In rats with DMN-induced hepatic fi brosis, serum aspartate aminotransferase and alanine aminotransferase concentrations, liver hydroxyproline and lipid peroxides were determined. Pathologic changes were examined by hematoxylin & eosin staining.RESULTS: GT administration prevented the development of hepatic fibrosis in the rat model of DMN-induced liver fi brosis. These results were confi rmed both by liver histology and by quantitative measurement of hepatic hydroxyproline content, a marker of liver collagen deposition. Accordingly, inhibition of proliferation, reduced collagen deposition, and type 1 collagen expression were observed in activated HSC-T6 cells following GT treatment. These results imply that GT reduced the proliferation of activated HSC and down regulated the collagen content and expression of collagen type 1, thereby ameliorating hepatic fibrosis.CONCLUSION: This study demonstrates that greentea administration can effectively improve liver fibrosis caused by DMN, and may be used as a therapeutic option and preventive measure against hepatic f ibrosis.

铁铝氧化物对BaCl_2-TEA法测定土壤交换性酸的影响

【目的】本文探讨了铁铝氧化物对BaCl_2-TEA提取法测定土壤交换性酸结果准确性的影响。【方法】采用BaCl_2-TEA法测定了添加6种不同铁铝氧化物(无定型铁、α-Fe_2O_3、针铁矿、无定型铝、γ-Al_2O_3和三水铝石)后酸性紫色土的交换性酸含量。【结果】相比于α-Fe_2O_3、三水铝石、γ-Al_2O_3和针铁矿,化学活性较高的无定型铁和无定型铝具有较低的pH值和存在大量的Fe3+或Al3+溶出,酸性环境和Fe3+或Al3+的存在会消耗更多的TEA,造成计算得到的土壤交换性酸含量偏高。【结论】由于Al3+是致酸离子而Fe3+是干扰离子,因此不宜采用BaCl_2-TEA法测定无定型铁或Fe3+含量较高的酸性土壤的交换性酸含量。此外,对无定型铝存在的潜在酸化风险也应引起重视。