Green tea is consumed worldwide, especially in East Asia. The main components of green tea are caffeine and polyphenolic compounds known as catechins. Of the catechins, - -epigallocatechingallate EGCG is the most abundant in green tea. EGCG has been reported to be responsible for many of the potential health benefits of green tea, including decreased weight gain and alleviated insulin resistance Richard et al. Bose et al. Lee et al. EGCG significantly reduced the body weight and mass of various adipose tissues, and considerably reduced levels of plasma triglycerides TAGs and liver lipids Lee et al.
Chen et al. Ortsater et al. Several epidemiological studies revealed the beneficial effects of tea and EGCG on obesity in humans; however, the results were not always positive in human participant studies Suzuki et al.
For example, Baladia et al. Therefore, loss of body fat may require a higher intake of EGCG or other catechins, or the addition of metabolic stimulants Yang et al. Yang et al. They proposed two major mechanisms involving EGCG: 1 decreased absorption of lipids and proteins in the intestine, thus reducing calorie intake and 2 activation of AMPK in liver, skeletal muscle, and white adipose tissue.
However, only one study has reported activation of AMPK by EGCG in cultured cells and in liver tissues of mice, suggesting that the effects of catechins, including their anti-obesity and anti-cancer effects, are at least partially mediated by activation of AMPK Murase et al.
We also aimed to explore 1 whether EGCG-activated AMPK phosphorylation played a central part in reducing the accumulation of fats in adipose tissues and 2 whether EGCG had similar effects on the regulation of lipid accumulation in different adipose depots. The mice were divided into four groups at around 8 weeks old; each group included eight male mice. Mice in the control group were fed a control diet DJ, Research Diets.
After 20 weeks of feeding, changes in body weight, food intake, water intake, and blood glucose were recorded. The animal experiments in this study were approved by the animal ethics committee of Yunnan Agricultural University No , March 18, The primer sequences are provided in Table 1. After three washes with TBST buffer, the blots were incubated with appropriately diluted horseradish peroxidase-conjugated secondary antibodies for 1 h at room temperature.
The immunoblots were visualized with an enhanced chemiluminescence detection kit Tiangen Biotech, Beijing, China. Protein levels were normalized to tubulin as a loading control. Blood was taken from the inside canthus and collected in micro-centrifuge tubes with heparin sodium.
All blood sample analysis took place at the Second Affiliated Hospital in Kunming. Statistical analysis of the experimental data was performed using SPSS These results indicated that administration of EGCG could reduce obesity and the accumulation of epididymal fat in mice. EGCG reduced obesity and the adipose weight in mice. A The body weights of mice after 20 weeks feeding; B Lee index; C ratio of subcutaneous fat weight to body weight; and D epididymal fat weight to body weight. EGCG has previously been shown to increase fecal lipid content, suggesting decreased digestion and absorption of lipids Bose et al.
Effect of EGCG on lipid excretion. To explore the mechanisms by which EGCG reduced adipose indices in HFD mice, we separately determined the mRNA expression levels of genes associated with lipid metabolism in subcutaneous adipose tissue and epididymal adipose tissue.
In subcutaneous adipose tissues, the expression of several genes for lipid synthesis, such as acc1 and fas , decreased significantly in the HFD group; however, EGCG administration increased their expression significantly by comparison Figures 4A,B , 6A. Effect of EGCG on the expression of genes involved in lipogenesis, oxidation, and transportation in subcutaneous adipose tissues of mice. The relative mRNA expression of the hsl gene, which is involved in lipolysis, was decreased significantly in HFD and EGCG mice Figure 5G ; however, the expression level of another gene associated with lipolysis, atgl , was similar among all the groups Figure 5H.
Effect of EGCG on the expression of genes involved in lipogenesis, oxidation, and transportation in epididymal adipose tissues of mice. Therefore, we determined the activity of AMPK. The objective of the present study was to determine whether the fat-loss functions of EGCG involved similar effects on regulation of lipid accumulation in different adipose depots, as well as to explore the underlying mechanisms.
These results seemed contradictory in this study. The reason might be that our experiment had lasted for 20 weeks, some mice had higher body lengths along with higher body weights but not obese, which might have some effects on data analysis. Then we calculate the fat index of mice, and found that EGCG significantly reduced fat accumulation in epididymal fat tissues, but not in subcutaneous fat tissues. These results indicate that EGCG reduce obesity might mainly via reducing lipid accumulation in epididymal fat tissue.
Our results were partially consistent to previous studies of Lee et al. The reason might be that the doses of EGCG were different between our study and previous studies.
A combined transcriptomics and lipidomics analysis on different adipose tissues demonstrated that gene regulation in response to HFD and fatty acid patterns differed markedly between adipose depots Caesar et al. The evidence for any health boost is lacking, and there are potential risks. Sign In. Become a Member. Remember Me. Forgot username or password? Not a member? Need further assistance? Please call Member Services at Does it work, and is it safe?
By Consumer Reports. Last updated: June 05, Sharing is Nice Yes, send me a copy of this email. Send We respect your privacy. Oops, we messed up. Try again later. When you shop through retailer links on our site, we may earn affiliate commissions.
Learn more. Shop Smarter for Supplements. Epigallocatechin gallate, or EGCG, is a polyphenol found in green tea along with catechin, epicatechin, proathocyanidins and others. A typical cup of tea brewed from dried leaves yields about to mg of polyphenols, but only a small portion of that is EGCG, which is considered the most beneficial compound of the group.
Numerous health effects have been attributed to EGCG, including weight loss -- but the research was conducted with such high concentrations of EGCG that you are unlikely to get enough from drinking green tea alone. Research has shown that EGCG may help increase calorie burn and help the body use stored fat for energy, although the exact mechanism is unclear. A study at the University of Chicago showed that rats reduced their calorie intake by 60 percent after seven daily EGCG injections, allowing them to lose 21 percent of their body weight.
Researchers believe that the EGCG may alter the levels of "hunger hormones," thus reducing the appetite. It is unclear whether the body may not absorb EGCG fully from the digestive tract, but if an oral extract didn't work, that leaves little hope for the lower concentrations provided by oral tea consumption.
There is no established dose for EGCG, partly because the research has been all over the map. Ronald Hoffman mentions a French study that found results using 90 mg of EGCG three times daily, while a study in the "Journal of the American College of Nutrition" found that twice-daily doses of mg reduced resting heart rate and blood glucose levels, but did not affect weight loss.
0コメント