1H-NMR Metabolomics Analysis of the Effect of Rubusoside on Serum Metabolites of Golden Hamsters on a High-Fat Diet.

Rubusoside is a natural sweetener and the active component of Rubus suavissimus. The preventive and therapeutic effect of rubusoside on high-fat diet-induced (HFD) serum metabolite changes in golden hamsters was analyzed by 1H-NMR metabolomics to explore the underlying mechanism of lipid metabolism regulation. 1H-NMR serum metabolomics analyses revealed a disturbed amino acid-, sugar-, fat-, and energy metabolism in HFD animals. Animals supplemented with rubusoside can partly reverse the metabolism disorders induced by high-fat diet and exerted good anti-hypertriglyceridemia effect by intervening in some major metabolic pathways, involving amino acid metabolism, synthesis of ketone bodies, as well as choline and 4-hydroxyphenylacetate metabolism. This study indicates that rubusoside can interfere with and normalize high-fat diet-induced metabolic changes in serum and could provide a theoretical basis to establish rubusoside as a potentially therapeutic tool able to revert or prevent lipid metabolism disorders.

Pharmacokinetics of glycerol phenylbutyrate in pediatric patients 2 months to 2 years of age with urea cycle disorders.

INTRODUCTION: Glycerol phenylbutyrate (GPB) is approved in the US and EU for the chronic management of patients ≥2 months of age with urea cycle disorders (UCDs) who cannot be managed by dietary protein restriction and/or amino acid supplementation alone. GPB is a pre-prodrug, hydrolyzed by lipases to phenylbutyric acid (PBA) that upon absorption is beta-oxidized to the active nitrogen scavenger phenylacetic acid (PAA), which is conjugated to glutamine (PAGN) and excreted as urinary PAGN (UPAGN). Pharmacokinetics (PK) of GPB were examined to see if hydrolysis is impaired in very young patients who may lack lipase activity. METHODS: Patients 2 months to <2 years of age with UCDs from two open label studies (n = 17, median age 10 months) predominantly on stable doses of nitrogen scavengers (n = 14) were switched to GPB. Primary assessments included traditional plasma PK analyses of PBA, PAA, and PAGN, using noncompartmental methods with WinNonlin™. UPAGN was collected periodically throughout the study up to 12 months. RESULTS: PBA, PAA and PAGN rapidly appeared in plasma after GPB dosing, demonstrating evidence of GPB cleavage with subsequent PBA absorption. Median concentrations of PBA, PAA and PAGN did not increase over time and were similar to or lower than the values observed in older UCD patients. The median PAA/PAGN ratio was well below one over time, demonstrating that conjugation of PAA with glutamine to form PAGN did not reach saturation. Covariate analyses indicated that age did not influence the PK parameters, with body surface area (BSA) being the most significant covariate, reinforcing current BSA based dosing recommendations as seen in older patients. CONCLUSION: These observations demonstrate that UCD patients aged 2 months to <2 years have sufficient lipase activity to adequately convert the pre-prodrug GPB to PBA. PBA is then converted to its active moiety (PAA) providing successful nitrogen scavenging even in very young children.

Comparative analysis of fecal phenolic content between normal and obese rats after oral administration of tea polyphenols.

Tea polyphenols (TP) have many health benefits, but most are metabolized into low molecular-weight phenolic acids after oral administration. In the present study, the absorption, metabolism, and excretion of catechins in rats fed a normal chow diet and in obese rats fed a high-fat and high-sugar (HFHS) diet were compared. After a ten-day oral administration of TP (500 mg per kg bw), the plasma levels of (-)-epigallocatechin gallate (EGCG) and (-)-gallocatechin gallate (GCG) in obese rats were significantly lower than those in the normal group. In obese rats, the fecal levels of EGCG, (-)-epicatechin gallate (ECG) and GCG were significantly enhanced. Ten phenolic metabolites of TP were quantitatively analyzed, and the results showed that 4-hydroxyphenylacetic acid was the primary metabolite in feces and plasma. The plasma and fecal concentrations of 4-hydroxyphenylacetic acid in the obese group were significantly lower than those in normal rats, but the levels of 4-hydroxyphenylpropionic acid in plasma and feces were increased. The content of other phenolic acids was also dramatically changed. These results suggested that a HFHS diet might influence the excretion of tea catechins, leading to insufficient metabolism of catechins by the gut microflora.

Dose-Dependent Increase in Unconjugated Cinnamic Acid Concentration in Plasma Following Acute Consumption of Polyphenol Rich Curry in the Polyspice Study.

Spices that are rich in polyphenols are metabolized to a convergent group of phenolic/aromatic acids. We conducted a dose-exposure nutrikinetic study to investigate associations between mixed spices intake and plasma concentrations of selected, unconjugated phenolic/aromatic acids. In a randomized crossover study, 17 Chinese males consumed a curry meal containing 0 g, 6 g, and 12 g of mixed spices. Postprandial blood was drawn up to 7 h at regular intervals and plasma phenolic/aromatic acids were quantified via liquid chromatography tandem mass spectrometry (LC-MS/MS). Cinnamic acid (CNA, p < 0.0001) and phenylacetic acid (PAA, p < 0.0005) concentrations were significantly increased with mixed spices consumption, although none of the other measured phenolic/aromatic acids differ significantly between treatments. CNA displayed a high dose-exposure association (R² > 0.8, p < 0.0001). The adjusted mean area under the plasma concentration-time curve until 7 h (AUC0⁻7 h) for CNA during the 3 increasing doses were 8.4 ± 3.4, 376.1 ± 104.7 and 875.7 ± 291.9 nM.h respectively. Plasma CNA concentration may be used as a biomarker of spice intake.

Pharmacokinetics of dietary kaempferol and its metabolite 4-hydroxyphenylacetic acid in rats.

SCOPE: Kaempferol is a major flavonoid in the human diet and in medicinal plants. The compound exerts anxiolytic activity when administered orally in mice, while no behavioural changes were observed upon intraperitoneal administration, or upon oral administration in gut sterilized animals. 4-Hydroxyphenylacetic acid (4-HPAA), which possesses anxiolytic effects when administered intraperitoneally, is a major intestinal metabolite of kaempferol. Pharmacokinetic properties of the compounds are currently not clear. METHODS AND RESULTS: UHPLC-MS/MS methods were validated to support pharmacokinetic studies of kaempferol and 4-HPAA in rats. Non-compartmental and compartmental analyses were performed. After intravenous administration, kaempferol followed a one-compartment model, with a rapid clearance (4.40-6.44l/h/kg) and an extremely short half-life of 2.93-3.79min. After oral gavage it was not possible to obtain full plasma concentration-time profiles of kaempferol. Pharmacokinetics of 4-HPAA was characterized by a two-compartment model, consisting of a quick distribution phase (half-life 3.04-6.20min) followed by a fast elimination phase (half-life 19.3-21.1min). CONCLUSION: Plasma exposure of kaempferol is limited by poor oral bioavailability and extensive metabolism. Both compounds are rapidly eliminated, so that effective concentrations at the site of action do not appear to be reached. At present, it is not clear how the anxiolytic-like effects reported for the compounds can be explained.

Phenolic acid concentrations in plasma and urine from men consuming green or black tea and potential chemopreventive properties for colon cancer.

SCOPE: Tea polyphenols are metabolized by the colonic microflora yielding phenolic metabolites, which may contribute to the health benefits of tea. We determined the serum and urine concentrations of phenolic acids, hippuric acid, and polyhydroxyphenyl-γ-valerolactones during green tea (GT) and black tea (BT) administration. The effects of (-)-epigallocatechin gallate (EGCG) and 3,4-dihydroxyphenylacetic acid (3,4-DHPAA) alone and in combination on bioavailability, intracellular metabolism, and antiproliferative activity were determined in HCT-116 colon cancer cells. METHODS AND RESULTS: The concentration of phenolic metabolites was quantified by HPLC with electrochemical detection and MS. Urine concentrations of 4-hydroxyphenylacetic acid (4-HPAA), 3-hydroxyphenylacetic acid (3-HPAA), and polyhydroxy-γ-valerolactones were increased significantly in men drinking GT compared to control. Urine concentration of 3-O-methylgallic acid (3OMGA) was significantly increased in men drinking BT compared to control. Serum 3,4-DHPAA was significantly increased after consumption of GT and BT and 4-HPAA after GT consumption. In vitro treatment of HCT-116 colon cancer cells with 3,4-DHPAA and EGCG exhibited an additive antiproliferative effect, while methylation of 3,4-DHPAA was significantly decreased. 3OMGA exhibited the strongest antiproliferative activity among the phenolic acids. CONCLUSION: The consumption of both, GT and BT, was associated with a significant increase in urinary and serum phenolic acids.

Phenylacetic acids were detected in the plasma and urine of rats administered with low-dose mulberry leaf extract.

The use of a high quercetin dose to demonstrate its absorption and bioavailability does not reflect the real dietary situation because quercetin glycosides are usually present in small amounts in the human diet. This study aimed to demonstrate the absorption and bioavailability of quercetin in mulberry leaves that represents a more physiologic dietary situation. Mulberry leaf ethanol extract was prepared similar to tea infusion, which is the way the tea leaves are generally prepared for consumption. Accordingly, rats were fed by oral intubation the mulberry leaf ethanol extract (15 g%/rat per day) or pure rutin (135 microg/rat per day) for 2 weeks. The control group received a similar volume of the vehicle, 10% ethanol. There was a significant increase in total antioxidant activity (TAA) in the urine and feces of the antioxidants-fed rats. Phenylacetic acid, a microbial metabolite of quercetin, was detected in the urine of the test animals, and quercetin was present in the fecal samples. By using an in situ intestinal preparation, 3-hydroxyphenylacetic acid, another microbial metabolite of quercetin, was detected in the plasma when the duodenal segment was instilled with 2 mg of rutin. This microbial metabolite retained 50% of the TAA of quercetin. The results of this study indicate that in a more realistic dietary situation, an increase in TAA in the body after consumption of quercetin-containing foods is contributed mainly by the microbial metabolites.

Clinical studies on the phenylethylamine hypothesis of affective disorder: urine and blood phenylacetic acid and phenylalanine dietary supplements.

To test the hypothesis that 2-phenylethylamine (PEA) modulates affect, plasma levels and urinary excretion of its main metabolite, phenylacetic acid (PAA), were studied in depressed and manic subjects, and the mood-elevating effects of its precursor, L-phenylalanine, were studied in depressed subjects. Mean total plasma PAA concentrations were 491.83 +/- 232.84 ng/ml in 12 healthy volunteers and 300.33 +/- 197.44 ng/ml in 23 drug-free patients with major depression. The 24-hour urinary PAA excretion was also measured in 48 healthy volunteers (141.1 +/- 10.2 mg PAA/24 hr) and in 144 patients with major depression (78.2 +/- 41.0 mg PAA/24 hr). The results suggest that low plasma and urinary PAA may be state markers for depression and are compatible with the PEA hypothesis. In further support, phenylalanine elevated mood in 31 of 40 depressives.