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.

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.

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.

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.

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.

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.

Effects of green tea-and amla extracts on quality and melanosis of Indian white prawn(Fenneropenaeus indicus,Milne Edwards,1837)during chilled storage

Effect of ethanol extracts of green tea(Camellia sinensis L.)and amla(Phyllanthus emblica Linn)were investigated on quality and melanosis of chilled stored Indian white prawn(Fenneropenaeus indicus)during 28 days.Extracts were subjected to antioxidant assays viz.1,1-diphenyl-2-picryl hydrazyl radical reducing power methods(DPPH),total antioxidant capacity(TAC),total phenolic content(TPC)and ferric reducing antioxidant power(FRAP)to evaluate antioxidant potentiality and fourier-transform infrared spectroscopy(FT-IR)to identify organic constituents.Polyphenol oxidase(PPO)inhibition was assessed to check the efficacy of the extracts as anti-melanogenic agents.Biochemical(total volatile nitrogen,free fatty acid and peroxide values),bacteriological(aerobic counts),melanosis inhibition and sensory quality of chilled stored shrimp were addressed to investigate the efficacy of extracts as preservative and anti-melanogenic remedy.Free reducing power of green tea-and amla extracts were in a range of 28.72-65.67%and 17.38-66.95%,respectively.Phenolic content level was almost same for green tea and amla extract(2.46±0.002 and 2.51±0.036 mg GAE/gram).Total antioxidant capacity of green tea(210.33±4.63 mg EqAsc/g)was slightly higher than that of amla extracts(145.56±1.98 mg EqAsc/g).FRAP value revealed that green tea(477.49±3.25 mgE Fe(II)/g)had more ferric reducing power than amla(324.39±5.85 mgE Fe(II)/g).FT-IR analysis revealed the presence of essential organic bioactive compounds,which play an important role in reducing lipid oxidation and quality loss,and both extracts possess an encouraging PPO inhibition ability.Treatment by green tea-and amla extracts on chilled stored shrimp showed promising effects on biochemical and microbiological parameters followed by melanosis inhibition and enhanced sensory attributes.Treated Indian white prawn with green tea-and amla extract revealed significantly(P<0.05)lower value of biochemical indices and microbial load during chilled storage compared to untreated sample.

Effects of mango and partridge tea extracts on microbial,physical,and chemical properties of tilapia fillets treated with in-package cold plasma during refrigerator storage

Objectives:The effect of natural extracts on the oxidative quality of cold plasma(CP)-treated tilapia fillets during 9 d refrigerator storage was explored by adding mango and partridge tea extracts as natural antioxidants.Materials and Methods:The effects of mango and partridge tea extracts on the fish during storage were evaluated using the total viable count(TVC),total volatile basic nitrogen(TVB-N),thiobarbituric acid reactive substance(TBARS),carbonyl values,and color.Results:The results showed that on the ninth day,the TVC of the mango extract(ME)-CP group was 3.52±0.08 log colony-forming units/g,which was significantly(P<0.05)lower than that of the other groups,while the TBARS of ME-CP and partridge tea extract(MOE)-CP was similar.The TVB-N values in the ME-CP and MOE-CP groups were 10.21±0.7 mg/100 g and 14.27±0.31 mg/100 g,respectively,which were within the acceptable values.The sulfhydryl and carbonyl contents in ME-CP were lower than those in MOE-CP;however,no significant variation was de­tected in texture.No significant changes were observed in the L*values among the treatment groups,while the b*values in the MOE-CP group were significantly increased(P<0.05).Conclusions:Therefore,the addition of ME combined with CP treatment can inhibit microbial growth,lipid oxidation,and protein oxidation in tilapia fillets without significantly impacting their color.