Constituents and Metabolites of a French Oak Wood Extract (Robuvit®) in Serum and Blood Cell Samples of Women Undergoing Hysterectomy

Impedimetric detection of gut-derived metabolites using 2D Germanene-based materials

Apart from the extensively researched graphene under the Group 14 2D materials, monolayered germanene and its derivatives have been gaining interest lately as alternative class of 2D materials owing to their facile synthesis, and attractive electronic and optical properties. Herein, three different functionalized germanene-based nanomaterials, namely Ge-H, Ge-CH3 and Ge-C3-CN were investigated on their novel incorporation in impedimetric immunosensors for the detection of gut-derived metabolites associated with neurological diseases, such as kynurenic acid (KA) and quinolinic acid (QA). The designed germanene-based immunosensor relies on an indirect competitive mechanism using disposable electrode printed chips. The competition for a fixed binding site of a primary antibody occurs between the bovine serum albumin-conjugated antigens on the electrode surface and the free antigens in the solution. Among the three materials, Ge-H displayed superior bioanalytical performance in KA and QA detection. Lower limits of detection of 5.07-11.38 ng/mL (26.79-68.11 nM) were attained for KA and QA with a faster reaction time than previously reported methods. Also, minimal cross-reactivity with interfering compounds, good reproducibility in impedimetric responses (RSD = 2.43-7.51 %) and long-term stability up to a month at 4 °C were the other attributes that the proposed Ge-H competitive impedimetric immunosensor has accomplished. The application of the developed Ge-H immunosensor to serum samples allowed an accurate KA and QA quantification at physiologically relevant levels. This work serves as a stepping-stone in the development of germanene-based nanomaterials for their implementation into cost-effective, miniaturized, portable and rapid impedimetric immunosensors, which are highly desirable for point-of-care testing in clinical settings.

Development and validation of a LC-MS/MS method for the quantification of phenolic compounds in human saliva after intake of a procyanidin-rich pine bark extract

Plant-derived phenolic compounds are regularly ingested as food compounds or as food supplements. Concentrations of individual compounds and metabolites are typically measured in serum or urine samples. This, however, allows no conclusion on the distribution into organs and tissues. An easily accessible biofluid is saliva. At this point, it was not clear yet, whether polyphenols circulating in the blood would be secreted or diffuse into saliva. The purpose of the present study was to develop and validate a method using liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for analysis of phenolic compounds in human saliva. Method validation for the quantification of taxifolin, ferulic acid, caffeic acid, gallic acid, para-coumaric acid, and protocatechuic acid and the gut microbial catechin metabolite δ-(3,4-dihydroxyphenyl)-γ-valerolactone (M1) in human saliva was performed according to current guidelines for bioanalytical method validation. The lower limit of quantification ranged from 0.82 ng/ml for M1 to 8.20 ng/ml for protocatechuic acid. The method was successfully applied to an authentic saliva sample of a volunteer after swallowing of procyanidin-rich pine bark extract capsules (dietary supplement Pycnogenol®). All polyphenols except ferulic acid were quantified at concentrations ranging from 1.20 ng/ml (M1) to 10.34 ng/ml (gallic acid). Notably, in contrast to serum samples, all phenolic compounds were present without sulfate or glucuronic acid conjugation in saliva, suggesting an enzymatic deconjugation, e.g., by a β-glucuronidase activity, during compound transfer from serum to saliva. Since M1 is only produced in the gut, its presence in saliva ruled out the possibility of sample contamination by phenolic compounds residing in the oral cavity after food intake. To the best of our knowledge, this is the first time that the gut microbiota-derived metabolite M1 has been detected in saliva. To further investigate the role of phenolic compounds in saliva, the described analytical method can be applied in clinical studies investigating the biodistribution of polyphenols and their metabolites.

Potential Use of Quercus dalechampii Ten. and Q. frainetto Ten. Barks Extracts as Antimicrobial, Enzyme Inhibitory, Antioxidant and Cytotoxic Agents

The bark resulted as a by-product after different Quercus sp. processing is a valuable alternative source of phenolic compounds (mainly tannins). Hence, the focus of the present work was to obtain eight extracts from the rhytidome of the less-studied Q. dalechampii and Q. frainetto and characterize them in terms of chemical and bioactive profiles. Ultrasound and microwave-assisted extraction methods were used for the preparation of the extracts. Total phenolic and tannin contents were assessed through classic spectrophotometric methods, while several individual phenolic compounds were identified and quantified using UPLC-PDA. Antioxidant, enzyme-inhibitory, antibacterial, and cytotoxic activities were tested using in vitro assays; additionally being evaluated was the ability of the extracts to inhibit the adherence of MRSA to suture wires. The UPLC analysis confirmed the presence of gallic acid, catechin, taxifolin, vanillic acid, epicatechin, and caffeic acid. The results showed that tested extracts were able to exert cytotoxic effects, at 6% and 3% concentrations, on confluent cells. The tested solutions inhibit α-glucosidase activity and the antibacterial potential suggested a mild to moderate effect against the Gram-positive strains. Overall, the obtained results revealed rich phenolic and tannin contents for the extracts obtained from both species through microwave-assisted extraction, probably responsible for their mild antibacterial and cytotoxic effects.

Effects of Robuvit® on the progression of non-alcoholic fatty liver disease

BACKGROUND

The aim of this study was to evaluate the effects of Robuvit^® in preventing the progression of chronic hepatitis (CH) in non-alcoholic fatty liver disease (NAFLD) which encompasses the entire spectrum of fatty liver disease, from isolated steatosis to non-alcoholic steatohepatitis (NASH).

METHODS

One group of patients followed the Standard management (SM) and were assigned as controls while the supplementation group followed the SM and additionally took 2 Robuvit® capsules daily for 3 months (200 mg/day).

RESULTS

34 subjects with NAFLD were included in the study. The two groups completing 90 days were comparable at baseline with 18 being supplemented with Robuvit^® and 16 in the control group. The tolerability was very good, and no side effects were observed with the supplement. Fasting glucose levels were significantly lower after 3 months with Robuvit^® (P<0.05) compared to controls. The increased serum aspartate aminotransferase levels (AST), considered the key metabolic value in these patients, decreased significantly with Robuvit® (P<0.05) compared to controls. Serum alanine aminotransferase levels (ALT) also decreased significantly with the supplement compared to controls (P<0.05). Platelet count and albumin levels improved significantly with Robuvit® (P<0.05) in comparison to standard management. No other significant changes were observed. The APRI score (the AST/platelet ratio index) was also decreased with the supplementation compared to controls (P<0.05). A high APRI score provides an estimate of the possibility of the liver to develop fibrosis and eventually cirrhosis. After Robuvit® supplementation, the ultrasound characterization showed a significant decrease in the size of the liver in association with a lower echogenicity, which represents less fibrotic changes due to collagen accumulation.

CONCLUSIONS

Robuvit® improved liver function in NAFLD and prevented progression to liver fibrosis by improving hepatic metabolism in a relatively short period of time. Numerous people are affected by NAFLD, many of them with subclinical symptoms. But to date, there are no specific, definite treatment options. Prolonged evaluations of Robuvit® in a larger group of subjects is suggested.

Urolithins: a Comprehensive Update on their Metabolism, Bioactivity, and Associated Gut Microbiota

Urolithins, metabolites produced by the gut microbiota from the polyphenols ellagitannins and ellagic acid, are discovered by the research group in humans almost 20 years ago. Pioneering research suggests urolithins as pleiotropic bioactive contributors to explain the health benefits after consuming ellagitannin-rich sources (pomegranates, walnuts, strawberries, etc.). Here, this study comprehensively updates the knowledge on urolithins, emphasizing the review of the literature published during the last 5 years. To date, 13 urolithins and their corresponding conjugated metabolites (glucuronides, sulfates, etc.) have been described and, depending on the urolithin, detected in different human fluids and tissues (urine, blood, feces, breastmilk, prostate, colon, and breast tissues). There has been a substantial advance in the research on microorganisms involved in urolithin production, along with the compositional and functional characterization of the gut microbiota associated with urolithins metabolism that gives rise to the so-called urolithin metabotypes (UM-A, UM-B, and UM-0), relevant in human health. The design of in vitro studies using physiologically relevant assay conditions (molecular forms and concentrations) is still a pending subject, making some reported urolithin activities questionable. In contrast, remarkable progress has been made in the research on the safety, bioactivity, and associated mechanisms of urolithin A, including the first human interventions.

Review of Clinical Effects and Presumed Mechanism of Action of the French Oak Wood Extract Robuvit

Since ancient times, oak wood polyphenols are consumed concomitantly with beverages that are stored and aged in oak wood barrels. Among these polyphenols are roburins, which belong to the class of ellagitannins and only occur in oak. To date, water-extracted standardized French Quercus robur wood extract, commercially known as Robuvit®, has been investigated in 1172 subjects in over 20 published clinical trials. The results of the clinical studies are consistent with reported effects of urolithins regarding increased mitophagy, pointing to enhanced energy capacity. The Robuvit metabolite urolithin A, B, and C levels and the number of urolithin producers were found to be increased after intake of the extract. Mitophagy is a process, which assigns energy inefficient mitochondria to disassembly, followed by reconstruction to new and more efficient replacements. This effect of Robuvit was observed in different study groups. Supplementation of Robuvit is ascribed to aid chronically fatigued or burnt-out individuals to regain higher energy and activity levels. Robuvit has been further shown to improve conditions such as renal insufficiency, liver insufficiency, mild heart failure, posttraumatic stress disorder and fatigue after surgery and facilitate recovery from mild health impairments such as flu or hangover. There are also indications that Robuvit helps improve erectile function and general loss of vigor in elderly men. Ex vivo gene expression experiments using metabolites collected from Robuvit consumers point to increased ribosomal biogenesis in endothelial, neuronal, and keratinocyte cells. Higher ribosome density accelerates the peptide production to meet protein demand, making Robuvit a potential enhancer of physical endurance and performance. A study with recreational athletes, supplemented with Robuvit daily, reported significantly increased performance in triathlon.

The Oak-wood Extract Robuvit® Improves Recovery and Oxidative Stress after Hysterectomy: A Randomized, Double-blind, Placebo-controlled Pilot Study

Hysterectomy has a variety of medical indications and improves pre-operative symptoms but might compromise the quality of life during recovery due to symptoms such as fatigue, headache, nausea, depression, or pain. The aim of the present study was to determine the effect of a standardized extract from French oak wood (Quercus robur) containing at least 40% polyphenols of the ellagitannins class, Robuvit^®, on convalescence and oxidative stress of women after hysterectomy. Recovery status was monitored with the SF-36 questionnaire. The supplementation with Robuvit^® (300 mg/day) during 4 weeks significantly improved general and mental health, while under placebo some items significantly deteriorated. Oxidative stress and enhancement of MMP–9 activity was significantly reduced by Robuvit^® versus placebo. After 8 weeks of intervention, the patients’ condition improved independently of the intervention. Our results suggest that the use of Robuvit^® as a natural supplement relieves post-operative symptoms of patients after hysterectomy and reduces oxidative stress. The study was registered with ID ISRCTN 11457040 (13/09/2019).