Polyphenols from Fu Brick Tea Reduce Obesity via Modulation of Gut Microbiota and Gut Microbiota-Related Intestinal Oxidative Stress and Barrier Function.

Fu brick tea (FBT) is a microbial-fermented tea, which is produced by the solid-state fermentation of tea leaves. Previous studies have proved that FBT aqueous extracts could attenuate obesity and gut microbiota dysbiosis. However, the bioactive components in FBT that contribute to these activities remain unclear. In this study, we aimed to investigate the effects of FBT polyphenols (FBTPs) on obesity, gut microbiota, and gut microbiota-related intestinal oxidative stress and barrier function and to further investigate whether the antiobesity effect of FBTPs was dependent on the alteration of gut microbiota. The results showed that FBTP supplementation effectively attenuated obesity in high-fat diet (HFD)-fed rats. FBTP supplementation improved the intestinal oxidative stress and intestinal barrier function, including intestinal inflammation and the integrity of the intestinal barrier. Furthermore, FBTP intervention significantly attenuated HFD-induced gut microbiota dysbiosis, characterized by increased phylogenetic diversity and decreased Firmicutes/Bacteroidetes ratio. Certain core microbes, including Akkermansia muciniphila, Alloprevotella, Bacteroides, and Faecalibaculum, were also found to be improved by FBTPs. Moreover, the antiobesity effect of FBTPs was gut microbiota-dependent, as demonstrated by a fecal microbiota transplantation experiment. Collectively, we concluded that FBTPs reduced obesity by modulating the gut microbiota and gut microbiota-related intestinal oxidative stress and barrier function. Therefore, FBTPs may be used as prebiotic agents to treat obesity and gut microbiota dysbiosis in obese individuals.

Combined use of epigallocatechin-3-gallate (EGCG) and caffeine in low doses exhibits marked anti-obesity synergy through regulation of gut microbiota and bile acid metabolism.

Epigallocatechin-3-gallate (EGCG) and caffeine constitute the most effective ingredients of weight loss in tea. However, whether combination of EGCG and caffeine exhibits anti-obesity synergy remains unclear. Here, we showed low-doses of EGCG and caffeine used in combination led to synergistic anti-obesity effects equivalent to those of high-dose EGCG. Furthermore, combination treatment exhibited a synergistic effect on altering gut microbiota, including decreased Firmicutes level and increased Bifidobacterium level. Other notable effects of combination treatment included synergistic effects on: increasing fecal acetic acid, propionic acid, and total SCFAs; decreasing expression of GPR43; and increasing microbial bile salt hydrolase gene copies in the gut, facilitating generation of unconjugated BAs and enhancing fecal BA loss. Additionally, combination treatment demonstrated synergistic effects toward increasing the expression of hepatic TGR5 and decreasing the expression of intestinal FXR-FGF15, resulting in increased expression of hepatic CYP7A1. Thus, the synergistic effect may be attributed to regulation of gut microbiota and BA metabolism.

Dark tea extracts: Chemical constituents and modulatory effect on gastrointestinal function.

Processing of dark tea varieties, such as Fu brick tea, Liupao tea, Qianliang tea, and Qing brick tea, includes solid-state fermentation involving microorganisms. In this study, we analyzed the major chemical constituents of dark tea extracts and evaluated their modulatory effect on the gastrointestinal function in normal mice, including the improvement of gastrointestinal transit and intestinal microbial, as well as the attenuation of intestinal microbial dysbiosis and intestinal pathological damage, and the adjustment of immune function in antibiotic-treated mice. Substantial differences in major chemical constituents, including total polyphenols, total organic acids, water extract content, 18 free amino acids, gallic acid, and six tea catechins, were observed among Fu brick tea, Qianliang tea, Qing brick tea, and Liupao tea extracts. Extracts from the four dark tea varieties significantly promoted gastrointestinal transit and colonization of beneficial Bifidobacterium and Lactobacillus, and inhibited the growth of harmful Escherichia coli and Enterococcus in normal mice. In addition, Qianliang tea, Qing brick tea, and Liupao tea extracts significantly accelerated the reversal of the ampicillin sodium-induced pathological damage in the ileum, intestinal bacterial dysbiosis (Bifidobacterium, Lactobacillus, E. coli, and Enterococcus), and low immunity.

Tea consumption and colorectal cancer risk: a meta-analysis of prospective cohort studies.

PURPOSE: Data from in vitro and animal studies support the preventive effect of tea (Camellia sinensis) against colorectal cancer. Further, many epidemiologic studies evaluated the association between tea consumption and colorectal cancer risk, but the results were inconsistent. We conducted a meta-analysis of prospective cohort studies to systematically assess the association between tea consumption and colorectal cancer risk. METHODS: A comprehensive literature review was conducted to identify the related articles by searching PubMed and Embase up to June, 2019. Summary relative risks (RRs) and 95% confidence intervals (CIs) were calculated using a fixed effect model. RESULTS: Twenty cohort articles were included in the present meta-analysis involving 2,068,137 participants and 21,437 cases. The combined RR of colorectal cancer for the highest vs. lowest tea consumption was determined to 0.97 (95% CI 0.94-1.01) with marginal heterogeneity (I2 = 24.0%, P = 0.093) among all studies. This indicated that tea consumption had no significant association with colorectal cancer risk. Stratified analysis showed that no significant differences were found in all subgroups. We further conducted the gender-specific meta-analysis for deriving a more precise estimation. No significant association was observed between tea consumption and colorectal cancer risk in male (combined RR = 0.97; 95% CI 0.90-1.04). However, tea consumption had a marginal significant inverse impact on colorectal cancer risk in female (combined RR = 0.93; 95% CI 0.86-1.00). Further, we found a stronger inverse association between tea consumption and risk of colorectal cancer among the female studies with no adjustment of coffee intake (RR: 0.90; 95% CI 0.82-1.00, P < 0.05) compared to the female studies that adjusted for coffee intake (RR = 0.97; 95% CI 0.87-1.09, P > 0.05). CONCLUSIONS: Our finding indicates that tea consumption has no significant impact on the colorectal cancer risk in both genders combined, but gender-specific meta-analysis shows that tea consumption has a marginal significant inverse impact on colorectal cancer risk in female.

[Effect of jiangu granule on levels of urinary deoxypyridinoline and osseous intigrin beta1 mRNA expression in Ovariectomized osteoporosis model rats].

OBJECTIVE: To investigate the regulatory effect of Jiangu Granule (JGG) on osteoblast and its effect on bone absorption on the molecular level and from aspect of bone metabolism. METHODS: Osteoporosis model SD rats established by ovariectomy were interfered by drug. Levels of urinary deoxypyridinoline (D-Pyr) and osseous integrin beta1 (Itgbeta1) mRNA expression were detected by ELISA and in situ hybridization, respectively. RESULTS: Level of urinary D-Pyr increased (P < 0.01) and osseous Itgbeta1 mRNA expression decreased significantly in the model rats. After treatment with JGG for 12 weeks, the D-Pyr levels in them decreased significantly (P < 0.05), while the quantity of osteoblasts and the expression of Itgbeta1 mRNA in bone tissue increased obviously. Conclusion JGG can not only decrease the catabolism of collagen fiber type I in bone matrix, but also promote the osteogenic activity of osteoblast. So, it can improve or reverse the pathological tendency of osteogenesis shortage caused by E2 reduction to play its action in strengthening bone.