Proanthocyanidin (PAC) consumption has been linked to better colonic health, but PACs are poorly absorbed, making them a target for colonic metabolism. The resulting metabolites are low molecular weight and could potentially be absorbed. To understand the effects of dietary PACs it would be important to resolve the metabolic issue and link these changes to microbial population changes in a suitable model for human digestion. Here, six crossbred female pigs were fed a diet containing 1% (w/w) of MegaNatural® Gold grape seed extract (GSE) daily for 6 days. Fecal samples were analyzed by normal phase LC coupled to fluorescence detection and LC-MS/ToF. DNA was extracted from pig fecal samples and the V3/V4 region of the 16S rRNA gene was sequenced using an Illumina MiSeq. Intact parent PACs (dimer–pentamer) were observed in the feces on days 3 and 6 at similar high levels (~400 mg kg−1 total) during ingestion of GSE but were absent 48 h post-feeding. The major phenolic metabolites were 4-hydroxyphenylvaleric acid and 3-hydroxybenzoic acid which increased by ~30 and 3 mg kg−1 respectively. The GSE diet also caused an ecological shift in the microbiome, dramatically increasing Lachnospiraceae, Clostridales, Lactobacillus and Ruminococcacceae. The relationship between dietary PACs and colon health may be attributable to the altered bacterial populations or phenolic compounds in the colon.
The aim of the present study was to test grape seed extract (GSE) as a functional ingredient to lower blood pressure (BP) in individuals with pre-hypertension. A single-centre, randomised, two-arm, double-blinded, placebo-controlled, 12-week, parallel study was conducted in middle-aged adults with pre-hypertension. A total of thirty-six subjects were randomised (1:1) to Placebo (n 18) or GSE (n 18) groups; twentynine of them completed all the protocol-specified procedures (Placebo, n 17; GSE, n 12). Subjects consumed a juice (167 kJ (40 kcal)) containing 0 mg (Placebo) or 300 mg/d GSE (150 mg) twice daily for 6 weeks preceded by a 2-week Placebo run-in and followed by 4-week no-beverage follow-up. Compliance was monitored. BP was measured at screening, 0, 6 and 10 weeks of intervention and blood samples were collected at 0, 3, 6 and 10 weeks of intervention. GSE significantly reduced systolic BP (SBP) by 5·6 % (P = 0·012) and diastolic BP (DBP) by 4·7 % (P = 0·049) after 6 weeks of intervention period, which was significantly different (SBP; P = 0·03) or tended to be different (DBP; P = 0·08) from Placebo. BP returned to baseline after the 4-week discontinuation period of GSE beverage. Subjects with higher initial BP experienced greater BP reduction; nearly double the effect size. Fasting insulin and insulin sensitivity tended to improve after 6 weeks of GSE beverage supplementation (P = 0·09 and 0·07, respectively); no significant changes were observed with fasting plasma lipids, glucose, oxidised LDL, flow-mediated dilation or vascular adhesion molecules. Total plasma phenolic acid concentrations were 1·6 times higher after 6 weeks of GSE v. Placebo. GSE was found to be safe and to improve BP in people with pre-hypertension, supporting the use of GSE as a functional ingredient in a low-energy beverage for BP control.Key words: Grape seed extract: Blood pressure: Pre-hypertension: Endothelial function: Insulin sensitivity: Polyphenols Hypertension is a major risk factor for fatal and non-fatal CVD events (1)(2)(3) . Hypertension may affect >90 % of individuals during their lifetimes (4) . Current estimates indicate that hypertension costs the USA almost $70 billion annually in direct medical expenses (5) . Randomised clinical trials and meta-analyses indicate that blood pressure (BP) reductions lower the risk of myocardial infarction, stroke and other cardiovascular deaths (6,7) . Therefore, adequate control of BP in the healthy range is of enormous individual and public health importance.Pre-hypertension is a condition defined by a systolic BP (SBP) between 120 and 139 mmHg or a measured diastolic BP (DBP) between 80 and 89 mmHg (8) . The Framingham Heart Study showed that the 4-year incidence of hypertension increased between 17·6 and 37·3 % in individuals with pre-hypertension between 35 and 64 years of age (9) . Current medical practice does not treat pre-hypertension per se; however, the importance of lifestyle modifications are emphasised in the Joint National Committee (JNC)-7 and JNC-8, which re...
Current evidence shows that monomeric flavonoids are known to be only slightly absorbed in the small intestine, but the metabolism of oligomeric and polymeric proanthocyanidins (PAC) in the colon is poorly understood. The objective of this study was to optimize the analysis of grape seed extract (GSE) in feces and use that method to assess the presence of PAC in the colon after ingestion of GSE. Rats were fed a diet ad libitum containing 0.25% (w/w) GSE for 10 days. Feces were collected daily and colonic contents at sacrifice on day 10, respectively. The recovery of fecal PAC using a solid-phase extraction (SPE) method was >70%. PAC were separated by normal-phase HPLC with fluorescence detection, and subsequent peak confirmation was done by MS-ion trap. The concentration of colonic contents at day 10 was 13.9 mg/kg for monomer, and those for oligomers (dimers-hexamers) were 33.4, 84.6, 87.2, 57.3, and 35.7 mg/kg, respectively. The concentration of monomeric and oligomeric PAC in daily feces was similar among days. In the mass balance analysis, approximately 11% of ingested PAC was recovered in the feces. These findings indicate that ingested PAC were present in the colon as the intact parent compounds and thus may contribute to the health of the gastrointestinal tract.
Anthocyanins are a class of polyphenols abundant in the skins of red grapes, and have been shown to have anti-cancer effects in models of colon cancer [Cooke et al. Int J Cancer 2006;119:2213-2220; Jing et al. J Agric Food Chem 2008;56:9391-9398]. Gut microflora metabolize anthocyanins to phenolic acids and aldehydes. These metabolites may explain the relationship between anthocyanin consumption and reduced incidence of colorectal cancer (CRC). Previously, gallic acid (Gal), 3-O-methylgallic acid (Megal), and 2,4,6-trihydroxybenzaldehyde (THBA) were found to decrease Caco-2 cell viability to a larger extent than other anthocyanin metabolites. To better understand the potential anti-CRC action of these compounds, this paper investigated their capacity to modulate the cell cycle, and induce apoptotic cell death. Dividing Caco-2 cells were incubated for 24-72 h in the presence of 10-100 µM Gal, Megal, THBA, and malvidin-3-glucoside (M3g). THBA reduced cell viability only at 100 µM, while Gal and Megal (10-100 µM) caused a time- and dose-dependent decrease in cell viability. After 72 h incubation, the metabolites caused cell cycle arrest at G0 /G1 . The activation of the apoptotic pathway by Megal, Gal, and THBA was evidenced by the activation of caspase-3. However, only Megal and Gal caused DNA fragmentation and nuclear condensation. Megal, Gal, and THBA inhibited transcription factors NF-κB, AP-1, STAT-1, and OCT-1 which are known to be activated in CRC. In conclusion, the anti-cancer effects of Megal and Gal occurs as a consequence of both the inhibition of cell proliferation and induction of apoptosis. The inhibition of transcription factors that promote cell proliferation and survival can in part underlie the observed effects.
Mouse knockouts facilitate the study ofgene functions. Often, multiple abnormal phenotypes are induced when a gene is inactivated. The International Mouse Phenotyping Consortium (IMPC) has generated thousands of mouse knockouts and catalogued their phenotype data. We have acquired metabolomics data from 220 plasma samples from 30 unique mouse gene knockouts and corresponding wildtype mice from the IMPC. To acquire comprehensive metabolomics data, we have used liquid chromatography (LC) combined with mass spectrometry (MS) for detecting polar and lipophilic compounds in an untargeted approach. We have also used targeted methods to measure bile acids, steroids and oxylipins. In addition, we have used gas chromatography GC-TOFMS for measuring primary metabolites. The metabolomics dataset reports 832 unique structurally identified metabolites from 124 chemical classes as determined by ChemRICH software. The GCMS and LCMS raw data files, intermediate and finalized data matrices, R-Scripts, annotation databases, and extracted ion chromatograms are provided in this data descriptor. The dataset can be used for subsequent studies to link genetic variants with molecular mechanisms and phenotypes.
Colorectal cancer (CRC) has the third highest incidence worldwide. Epidemiological studies showed that the consumption of fruit and vegetables containing procyanidins (PCA), polymers of flavan‐3‐ols, is associated with lower CRC risk. However, the molecular mechanisms supporting this positive association are unclear. This study investigated the capacity of PCA with different degrees of polymerization to reduce CRC cell growth, characterizing the underlying mechanisms. Compared to the monomer ((−)‐epicatechin) and the trimer, the hexamer (Hex) was the most active at reducing CRC cell viability. Hex caused a concentration‐ (2.5–50 μM) and time‐ (24–72 h) dependent decrease in the viability of six human CRC cell lines in culture. Hex caused CRC apoptotic Caco‐2 cell death within 24 h, as evidenced by caspase 3 and caspase 9 activation, DNA fragmentation, and changes in nuclear morphology/staining. Hex‐induced apoptosis occurs through the mitochondrial pathway, as evidenced by an increased Bad mitochondrial translocation, and cytochrome c release from the mitochondria to the cytosol. Hex also arrested the Caco‐2 cell cycle at G2/M phase and upregulated genes involved in autophagy. Mechanistically, in Caco‐2 cells Hex inhibited the PI3K/Akt signaling pathway, causing the downstream downregulation of proteins involved in the regulation of cell survival (Bad, GSK‐3β). Accordingly, the Akt inhibitor MKK‐2206 decreased Bad and GSK‐3β phosphorylation. MKK‐2206 decreased cell growth, having an additive effect with Hex. In conclusion, our results show that large PCA can inhibit CRC cell growth via the Akt kinase pathway, demonstrating a mechanism to explain the epidemiological evidence linking PCA‐rich diets with lower CRC risk. © 2016 Wiley Periodicals, Inc.
There is emerging evidence suggesting that consumption of beverage and food rich in polyphenol may offer protective effects against various neurodegenerative, cardiovascular diseases and cancers. Proanthocyanidins (PACs) are one of the most abundant polyphenol in human diets, but also one of the least absorbed polyphenol mostly due to their size and structure complexity. PACs or condensed tannins are oligomers and polymers of monomeric unit flavan-3-ol (+)-catechin or (−)-epicatechin. To date, the absorption and metabolism of PACs are still remains largely unknown. The aim of this mini review was to highlight the absorption and metabolism of PACs, their effect in the gut and sample preparation for analysis. Ultimately, the potential bioactivities derived from the interaction between PACs metabolites and the gut microbiota warrants further investigation.
Alcohol-related liver disease is a major public health burden, and the gut microbiota is an important contributor to disease pathogenesis. The aim of the present study is to characterize functional alterations of the gut microbiota and test their performance for short-term mortality prediction in patients with alcoholic hepatitis. We integrated shotgun metagenomics with untargeted metabolomics to investigate functional alterations of the gut microbiota and host cometabolism in a multicenter cohort of patients with alcoholic hepatitis. Profound changes were found in the gut microbial composition, functional metagenome, serum, and fecal metabolomes in patients with alcoholic hepatitis compared with nonalcoholic controls. We demonstrate that in comparison with single omics alone, the performance to predict 30-day mortality was improved when combining microbial pathways with respective serum metabolites in patients with alcoholic hepatitis. The area under the receiver operating curve was higher than 0.85 for the tryptophan, isoleucine, and methionine pathways as predictors for 30-day mortality, but achieved 0.989 for using the urea cycle pathway in combination with serum urea, with a bias-corrected prediction error of 0.083 when using leave-one-out cross validation. Conclusion: Our study reveals changes in key microbial metabolic pathways associated with disease severity that predict short-term mortality in our cohort of patients with alcoholic hepatitis. (Hepatology Communications 2020;4:1168-1182). A lcohol-related liver disease is a major health care burden and a leading cause of morbidity and mortality worldwide. (1) The individual susceptibility of patients with alcohol use disorder to liver disease is highly variable. Some patients develop alcoholic hepatitis, a severe manifestation of alcoholrelated liver disease with a short-term mortality of about 40%-50% (2) Pharmacologic treatment options Abbreviations: AUC, area under the curve; AUROC, area under the receiver operating characteristic curve; AH_c, patients with alcoholic hepatitis with cirrhosis; AUD_nc, patients with alcohol use disorder without cirrhosis; AUD_c, patients with alcohol use disorder with cirrhosis; Ctrl, control; FIB-4, Fibrosis-4 index; G1, controls; G2, patients with alcohol use disorder without cirrhosis; G3, patients with alcohol use disorder with cirrhosis; G4, patients with alcoholic hepatitis without cirrhosis; G5, patients with alcoholic hepatitis with cirrhosis;
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