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.

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.

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.

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.

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.