Prospective randomized trial evaluating blood and prostate tissue concentrations of green tea polyphenols and quercetin in men with prostate cancer.

We evaluated if chronic consumption of quercetin (Q) with green tea extract (GTE) enhances the bioavailability of GT polyphenols (GTPs) and reduces methylation activity as previously observed in mouse xenograft tumors. In this prospective, randomized, parallel design, placebo controlled study, thirty-one men with prostate cancer consumed daily 1 gram of GTE (830 mg of GTP) with 800 mg of Q (GT + Q) or placebo (GT + PL) for four weeks before prostatectomy. First morning voided urine was collected at baseline, 3 weeks and the day of surgery, and prostate tissue on the day of surgery. In week 3, plasma concentration of GTPs and Q was measured in blood collected before and 2 hours after the morning dose. Prostate tissue epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) were detected in 67 and 93% of participants in the GT + Q group and 75 and 94% of participants in the GT + PL group. Q was increased 14-fold, 12-fold and 4.5-fold in plasma, urine, and prostate tissue, respectively, in the GT + Q compared to the GT + PL-group. There was a trend for decreased EGC levels in urine collected prior to prostatectomy in the GT + Q compared to GT + PL-group (p = 0.053). Plasma epigallocatechin (EGC) showed a trend to increase (p = 0.066) two hours after capsule intake in the GT + Q vs. the GT + PL-group. There was no significant difference between the groups in GTP content or methylation activity in prostate tissue or RBCs. No liver toxicity was observed. Although our findings are suggestive, further studies are warranted evaluating if Q alters GTP metabolism.

Decaffeinated green and black tea polyphenols decrease weight gain and alter microbiome populations and function in diet-induced obese mice.

PURPOSE: Decaffeinated green tea (GT) and black tea (BT) polyphenols inhibit weight gain in mice fed an obesogenic diet. Since the intestinal microflora is an important contributor to obesity, it was the objective of this study to determine whether the intestinal microflora plays a role in the anti-obesogenic effect of GT and BT. METHODS: C57BL/6J mice were fed a high-fat/high-sucrose diet (HF/HS, 32% energy from fat; 25% energy from sucrose) or the same diet supplemented with 0.25% GTP or BTP or a low-fat/high-sucrose (LF/HS, 10.6% energy from fat, 25% energy from sucrose) diet for 4 weeks. Bacterial composition was assessed by MiSeq sequencing of the 16S rRNA gene. RESULTS: GTP and BTP diets resulted in a decrease of cecum Firmicutes and increase in Bacteroidetes. The relative proportions of Blautia, Bryantella, Collinsella, Lactobacillus, Marvinbryantia, Turicibacter, Barnesiella, and Parabacteroides were significantly correlated with weight loss induced by tea extracts. BTP increased the relative proportion of Pseudobutyrivibrio and intestinal formation of short-chain fatty acids (SCFA) analyzed by gas chromatography. Cecum propionic acid content was significantly correlated with the relative proportion of Pseudobutyrivibrio. GTP and BTP induced a significant increase in hepatic 5'adenosylmonophosphate-activated protein kinase (AMPK) phosphorylation by 70 and 289%, respectively (P < 0.05) determined by Western blot. CONCLUSION: In summary, both BTP and GTP induced weight loss in association with alteration of the microbiota and increased hepatic AMPK phosphorylation. We hypothesize that BTP increased pAMPK through increased intestinal SCFA production, while GTPs increased hepatic AMPK through GTP present in the liver.

Cholesterol-lowering effects of dietary pomegranate extract and inulin in mice fed an obesogenic diet.

BACKGROUND: It has been demonstrated in animal studies that both polyphenol-rich pomegranate extract (PomX) and the polysaccharide inulin, ameliorate metabolic changes induced by a high-fat diet, but little is known about the specific mechanisms. OBJECTIVE: This study evaluated the effect of PomX (0.25%) and inulin (9%) alone or in combination on cholesterol and lipid metabolism in mice. METHODS: Male C57BL/6 J mice were fed high-fat/high-sucrose [HF/HS (32% energy from fat, 25% energy from sucrose)] diets supplemented with PomX (0.25%) and inulin (9%) alone or in combination for 4 weeks. At the end of intervention, serum and hepatic cholesterol, triglyceride levels, hepatic gene expression of key regulators of cholesterol and lipid metabolism as well as fecal cholesterol and bile acid excretion were determined. RESULTS: Dietary supplementation of the HF/HS diet with PomX and inulin decreased hepatic and serum total cholesterol. Supplementation with PomX and inulin together resulted in lower hepatic and serum total cholesterol compared to individual treatments. Compared to HF/HS control, PomX increased gene expression of Cyp7a1 and Cyp7b1, key regulators of bile acid synthesis pathways. Inulin decreased gene expression of key regulators of cholesterol de novo synthesis Srebf2 and Hmgcr and significantly increased fecal elimination of total bile acids and neutral sterols. Only PomX in combination with inulin reduced liver and lipid weight significantly compared to the HF/HS control group. PomX showed a trend to decrease liver triglyceride (TG) levels, while inulin or PomX-inulin combination had no effect on either serum or liver TG levels. CONCLUSION: Dietary PomX and inulin supplementation decreased hepatic and serum total cholesterol by different mechanisms and the combination leading to a significant enhancement of the cholesterol-lowering effect.

Dietary pomegranate extract and inulin affect gut microbiome differentially in mice fed an obesogenic diet.

Growing evidence suggests that dysbiosis of gut microbiota is associated with pathogenesis of a variety of human diseases. Using dietary intervention to shape the composition and metabolism of the gut microbiota is increasingly recognized. In the present study, we investigated the effects of polysaccharide inulin and polyphenol-rich pomegranate extract (PomX) alone or in combination on the cecal microbiota composition and function in a diet induced obesity mouse model. Male C57BL/6 mice were randomly divided into four experimental groups and consumed either high-fat/high-sucrose [HF/HS (32% energy from fat, 25% energy from sucrose, 17% energy from protein)] diet, HF/HS diet supplemented with PomX (0.25%), or inulin (9%) or PomX and inulin in combination for 4 weeks. In mice fed the PomX-diet the proportion of Turicibacteraceae and Ruminococcaceae was significantly increased compared to the control HF/HS diet. Supplementation with inulin alone and inulin + PomX combination significantly increased the proportion of Verrucomicrobiaceae (A. muciniphila) and decreased Clostridiaceae. Only mice fed the inulin diet experienced an increase in serum lipopolysaccharide (LPS) and monocyte chemoattractant protein 1 (MCP-1), which was reversed when feeding the inulin + PomX diet. Feeding the inulin + PomX diet was associated with a significant increase in Bifidobacteriaceae and Rikenellaceae, which may have contributed to the reduction of endotoxemia markers. Inulin supplementation showed lower species richness of gut microbiota compared to mice fed with HF/HS or HF/HS/PomX, and the reduction was reversed by the addition of PomX. Inulin alone and in combination with PomX had distinct microbial clusters determined by both weighted and unweighted UniFrac Beta-Diversity principle coordinate analysis. A total of 19 KEGG biological pathways were significantly regulated in the gut microbiota with PomX and inulin alone or combined treatment. Inulin significantly enhanced KEGG infectious disease-related pathway associated with increase of serum LPS and MCP-1. No changes in gene expression of ileal proinflammatory cytokine and tight junction genes were observed in mice treated with PomX and inulin. Our results demonstrated that the gut microbiota and their biological pathways were differentially effected by dietary PomX and inulin fed combined or alone. It is therefore very important to consider the interaction among bioactive components of food when evaluating potential prebiotic effects.