Effect of the French oak wood extract Robuvit on markers of oxidative stress and activity of antioxidant enzymes in healthy volunteers: a pilot study

Added-Value Compounds in Cork By-Products: Methods for Extraction, Identification, and Quantification of Compounds with Pharmaceutical and Cosmetic Interest

The growing threat of climatic crisis and fossil fuel extinction has caused a boom in sustainability trends. Consumer demand for so-called eco-friendly products has been steadily increasing, built upon the foundation of environmental protection and safeguarding for future generations. A natural product that has been used for centuries is cork, resulting from the outer bark of Quercus suber L. Currently, its major application is the production of cork stoppers for the wine industry, a process that, although considered sustainable, generates by-products in the form of cork powder, cork granulates, or waste such as black condensate, among others. These residues possess constituents of interest for the cosmetic and pharmaceutical industries, as they exhibit relevant bioactivities, such as anti-inflammatory, antimicrobial, and antioxidant. This interesting potential brings forth the need to develop methods for their extraction, isolation, identification, and quantification. The aim of this work is to describe the potential of cork by-products for the cosmetic and pharmaceutical industry and to assemble the available extraction, isolation, and analytical methods applied to cork by-products, as well the biological assays. To our knowledge, this compilation has never been done, and it opens new avenues for the development of new applications for cork by-products.

Tannin in Ruminant Nutrition: Review

Tannins are polyphenols characterized by different molecular weights that plants are able to synthetize during their secondary metabolism. Macromolecules (proteins, structural carbohydrates and starch) can link tannins and their digestion can decrease. Tannins can be classified into two groups: hydrolysable tannins and condensed tannins. Tannins are polyphenols, which can directly or indirectly affect intake and digestion. Their ability to bind molecules and form complexes depends on the structure of polyphenols and on the macromolecule involved. Tannins have long been known to be an "anti-nutritional agent" in monogastric and poultry animals. Using good tannins' proper application protocols helped the researchers observe positive effects on the intestinal microbial ecosystem, gut health, and animal production. Plant tannins are used as an alternative to in-feed antibiotics, and many factors have been described by researchers which contribute to the variability in their efficiencies. The objective of this study was to review the literature about tannins, their effects and use in ruminant nutrition.

Nephrotonic and Nephroprotective medicinal herbs in traditional Persian Medicine: Review and assessment of scientific evidence

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The tendency to use herbal and complementary therapies has been increased dramatically in last decades. The aim of this study is reviewing nephrotonic and nephroprotective medicinal herbs in traditional Persian Medicine (TPM) historical books, and assessment of relevant scientific evidence and possible mechanisms of action. In this study, seven major references among pharmaceutical books of PM from the 11th to 19th centuries were selected and were searched with key words equivalent to “nephroprotection”. To find new studies, the scientific name of medicinal herbs which were repeated twice or more were searched using data bases including PubMed, and Google scholar with keywords of nephroprotective, renal disorder, renal failure and kidney. Also, probable effective mechanisms were explored with key words including oxidative stress, antioxidant, inflammation, anti-inflammatory and angiotensin-converting-enzyme inhibitor. 210 herbal remedies were found with kidney strengthening, nephroprotective, and atrophy prevention effects in reviewed books. The most repeated herbs were 41 Results of scientific evidence showed that the possible functional mechanisms of these plants include anti-inflammatory, anti-oxidative, blood pressure/glucose-lowering effect as well as improvement of glomerular filtration, prevention of tissue damage, and enhancing the reconstructive power of cells. The list of medicinal herbs in this study can be used as a base of future studies on production of new medicines for prevention or treatment of renal failure and for the enhancement of renal performance.

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.

Traditional Applications of Tannin Rich Extracts Supported by Scientific Data: Chemical Composition, Bioavailability and Bioaccessibility

Tannins are polyphenolic compounds historically utilized in textile and adhesive industries, but also in traditional human and animal medicines or foodstuffs. Since 20th-century, advances in analytical chemistry have allowed disclosure of the chemical nature of these molecules. The chemical profile of extracts obtained from previously selected species was investigated to try to establish a bridge between traditional background and scientific data. The study of the chemical composition of these extracts has permitted us to correlate the presence of tannins and other related molecules with the effectiveness of their apparent uses. The revision of traditional knowledge paired with scientific evidence may provide a supporting background on their use and the basis for developing innovative pharmacology and food applications based on formulations using natural sources of tannins. This traditional-scientific approach can result useful due to the raising consumers' demand for natural products in markets, to which tannin-rich extracts may pose an attractive alternative. Therefore, it is of interest to back traditional applications with accurate data while meeting consumer's acceptance. In this review, several species known to contain high amounts of tannins have been selected as a starting point to establish a correlation between their alleged traditional use, tannins content and composition and potential bioaccessibility.

By-Products of Agri-Food Industry as Tannin-Rich Sources: A Review of Tannins' Biological Activities and Their Potential for Valorization

During recent decades, consumers have been continuously moving towards the substitution of synthetic ingredients of the food industry by natural products, obtained from vegetal, animal or microbial sources. Additionally, a circular economy has been proposed as the most efficient production system since it allows for reducing and reutilizing different wastes. Current agriculture is responsible for producing high quantities of organic agricultural waste (e.g., discarded fruits and vegetables, peels, leaves, seeds or forestall residues), that usually ends up underutilized and accumulated, causing environmental problems. Interestingly, these agri-food by-products are potential sources of valuable bioactive molecules such as tannins. Tannins are phenolic compounds, secondary metabolites of plants widespread in terrestrial and aquatic natural environments. As they can be found in plenty of plants and herbs, they have been traditionally used for medicinal and other purposes, such as the leather industry. This fact is explained by the fact that they exert plenty of different biological activities and, thus, they entail a great potential to be used in the food, nutraceutical and pharmaceutical industry. Consequently, this review article is directed towards the description of the biological activities exerted by tannins as they could be further extracted from by-products of the agri-food industry to produce high-added-value products.

A Comprehensive Review of Phytochemistry and Biological Activities of Quercus Species

The Quercus genus provides a large amount of biomaterial with many applications in fields like pharmaceutics, cosmetics, and foodstuff areas. Due to the worldwide dissemination of the genus, many species were used for centuries in traditional healing methods or in the wine maturing process. This review aims to bring together the results about phytoconstituents from oak extracts and their biological applicability as antioxidants, antimicrobial, anticancer, etc. The literature data used in this paper were collected via PubMed, Scopus, and Science Direct (2010–June 2020). The inclusion criteria were papers published in English, with information about phytoconstituents from Quercus species (leaves, bark and seeds/acorns) and biological activities such as antioxidant, antibacterial, antiobesity, anti-acne vulgaris, antifungal, anticancer, antiviral, antileishmanial, antidiabetic, anti-inflammatory. The exclusion criteria were the research of other parts of the Quercus species (e.g., galls, wood, and twigs); lack of information about phytochemistry and biological activities; non-existent Quercus species reported by the authors. The most studied Quercus species, in terms of identified biomolecules and biological activity, are Q. brantii, Q. infectoria and Q. robur. The Quercus species have been reported to contain several phytoconstituents. The main bioactive phytochemicals are phenolic compounds, volatile organic compounds, sterols, aliphatic alcohols and fatty acids. The, Quercus species are intensely studied due to their antioxidant, anti-inflammatory, antimicrobial, and anticancer activities, provided by their phytochemical composition. The general conclusion is that oak extracts can be exploited for their biological activity and can be used in research fields, such as pharmaceutical, nutraceutical and medical.

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).

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

Ellagitannins are signature constituents of oak wood and their consumption has been associated with various health benefits. In vivo, they undergo metabolic degradation including gut microbial metabolism yielding urolithins. Only limited data is available about compounds being present in blood after intake of an extract from French oak wood, Robuvit®. In the course of a randomized, double-blind, controlled clinical investigation, 66 patients undergoing hysterectomy received placebo or 300 mg Robuvit® per day before and over 8 weeks after surgery. Serum and blood cell samples were analyzed by liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). The number of urolithin producers and the urolithin levels increased after intake of Robuvit®. In serum samples, the median concentration of urolithin A was 14.0 ng/ml [interquartile range (IQR) 57.4] after 8 weeks. Urolithin B was determined at 22.3 ng/ml (IQR 12.6), urolithin C at 2.66 ng/ml (IQR 2.08). In blood cells, lower concentrations and only urolithins A and B were detected. A statistically significant association of lower post-surgical pain scores with metabotype A was detected (p < 0.05). To conclude, supplementation with French oak wood extract raised urolithin generation in patients and suggested health advantages for urolithin-producers.

Proanthocyanidins and hydrolysable tannins: occurrence, dietary intake and pharmacological effects

Tannins are a heterogeneous group of high MW, water-soluble, polyphenolic compounds, naturally present in cereals, leguminous seeds and, predominantly, in many fruits and vegetables, where they provide protection against a wide range of biotic and abiotic stressors. Tannins exert several pharmacological effects, including antioxidant and free radical scavenging activity as well as antimicrobial, anti-cancer, anti-nutritional and cardio-protective properties. They also seem to exert beneficial effects on metabolic disorders and prevent the onset of several oxidative stress-related diseases. Although the bioavailability and pharmacokinetic data for these phytochemicals are still sparse, gut absorption of these compounds seems to be inversely correlated with the degree of polymerization. Further studies are mandatory to better clarify how these molecules and their metabolites are able to cross the intestinal barrier in order to exert their biological properties. This review summarizes the current literature on tannins, focusing on the main, recently proposed mechanisms of action that underlie their pharmacological and disease-prevention properties, as well as their bioavailability, safety and toxicology.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Psychiatric Disorders and Polyphenols: Can They Be Helpful in Therapy?

The prevalence of psychiatric disorders permanently increases. Polyphenolic compounds can be involved in modulation of mental health including brain plasticity, behaviour, mood, depression, and cognition. In addition to their antioxidant ability other biomodulating properties have been observed. In the pathogenesis of depression disturbance in neurotransmitters, increased inflammatory processes, defects in neurogenesis and synaptic plasticity, mitochondrial dysfunction, and redox imbalance are observed. Ginkgo biloba, green tea, and Quercus robur extracts and curcumin can affect neuronal system in depressive patients. ADHD patients treated with antipsychotic drugs, especially stimulants, report significant adverse effects; therefore, an alternative treatment is searched for. An extract from Ginkgo biloba and from Pinus pinaster bark, Pycnogenol, could become promising complementary supplements in ADHD treatment. Schizophrenia is a devastating mental disorder, with oxidative stress involved in its pathophysiology. The direct interference of polyphenols with schizophrenia pathophysiology has not been reported yet. However, increased oxidative stress caused by haloperidol was inhibited ex vivo by different polyphenols. Curcumin, extract from green tea and from Ginkgo biloba, may have benefits on serious side effects associated with administration of neuroleptics to patients suffering from schizophrenia. Polyphenols in the diet have the potential to become medicaments in the field of mental health after a thorough study of their mechanism of action.

An Effect of Oak-Wood Extract (Robuvit®) on Energy State of Healthy Adults-A Pilot Study

The purpose of our study was to examine the psychological benefits of the treatment with Robuvit® (Horphag Research Ltd.) – polyphenolic extract obtained from the wood of oak Quercus robur – on the healthy elderly individuals using energy subscale scores of the Activation – Deactivation Adjective Check List. Analysis was focused on the comparison of pre-post treatment effect of Robuvit on symptoms of fatigue. In the total group of volunteers, significant increase of average question scores was found in three of four subscales of feelings (energy, tiredness, and tension) after 4 weeks of Robuvit administration. Effects of extract were observed mainly after stratification of total group of volunteers according to the level of feeling at the pre-treatment questionnaire. Our results demonstrate positive effect of Robuvit on mental and energy level in healthy human without any unwanted side effects. © 2015 The Authors Phytotherapy Research Published by John Wiley & Sons Ltd.