E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Special Issue "New Frontiers on the Metabolism, Bioavailability and Health Effects of Phenolic Compounds"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Natural Products".

Deadline for manuscript submissions: closed (30 June 2016)

Special Issue Editors

Guest Editor
Dr. Rafael Llorach

Asunción Biomarkers & Nutrimetabolomic Lab, Nutrition and Food Science Department, XaRTA, INSA, Campus Torribera, Pharmacy Faculty, University of Barcelona, Spain
Website | E-Mail
Guest Editor
Dr. Pedro Mena

Laboratory of Phytochemicals in Physiology, Department of Food Science, University of Parma, Parma, Italy
Website | E-Mail
Interests: nutrition, phytochemicals, phenolic compounds, bioavailability, metabolism, metabolites, disease prevention, liquid chromatography-mass spectrometry

Special Issue Information

Dear Colleagues,

The Special Issue “New Frontiers on the Metabolism, Bioavailability and Health Effects of Phenolic Compounds” should, with a set of fresh eyes, shed light on how (poly)phenolic substances are: (1) metabolized and turned into bioavailable molecules and (2) able to impact different biological processes related to human health. Phenolic compounds, and in particular, plant‑-derived secondary metabolites, have shown promising health promotion features in epidemiological and human intervention studies concerning the prevention of non-communicable diseases. The elucidation of the metabolic fate of (poly)phenolic constituents and their bioavailability is a tipping point for fully unraveling the bioactive(s) responsible for phenolic compounds' demonstrated preventative effects on cardiovascular diseases, metabolic syndrome, neurodegenerative disorders, and certain kinds of cancer. There is a need for addressing: (1) the colonic microbiota catabolism of phenolic compounds and (2) the inter-individual differences in bioavailability and bioefficacy due to the diversity of microbiota composition. Moreover, future research should be focused on: (1) understanding the dose/phenolic intake–response relationship via pharmacokinetic studies and (2) evaluating proper biomarkers of intake. The design of nutritionally‑ matched control/test foodstuffs is also required for conducting well-‑controlled intervention studies with both animals and human subjects. In vitro investigations using physiologically achievable concentrations of (poly)phenol phase II metabolites with appropriate model test systems are also encouraged to give adequate mechanistic insights. On the other hand, foodomics technologies (metabolomics, nutrigenomics, and proteomics) should be used to assess the role of phenolic bioactives from a comprehensive perspective. Likewise, any novel food-processing approach trying to enhance the bioavailability of (poly)phenols or sticking to what really happens after phenolic consumption should be taken into consideration. Finally, new communication channels and educational programs that are able to bring to the general public the well-defined biological properties of phenolics should be implemented. In conclusion, this Special Issue should review all the aspects concerning the metabolism, bioavailability, and biological properties of (poly)phenolic compounds and discuss attempts to solve current critical gaps. Novel methodologies or out of the box approaches can also complement current knowledge and assist in the study of plant bioactives.

Dr. Rafael Llorach
Dr. Pedro Mena
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

 

Keywords

Phenolic compounds Dietary plant bioactives Colonic catabolism Phase II metabolites Gut microbiota Bioavailability Bioactivity Human intervention trials Metabolomics

Published Papers (19 papers)

View options order results:
result details:
Displaying articles 1-19
Export citation of selected articles as:

Editorial

Jump to: Research, Review

Open AccessEditorial New Frontiers on the Metabolism, Bioavailability and Health Effects of Phenolic Compounds
Molecules 2017, 22(1), 151; doi:10.3390/molecules22010151
Received: 11 January 2017 / Revised: 13 January 2017 / Accepted: 13 January 2017 / Published: 17 January 2017
Cited by 1 | PDF Full-text (152 KB) | HTML Full-text | XML Full-text

Research

Jump to: Editorial, Review

Open AccessArticle Relationship between the Ingestion of a Polyphenol-Rich Drink, Hepcidin Hormone, and Long-Term Training
Molecules 2016, 21(10), 1333; doi:10.3390/molecules21101333
Received: 29 June 2016 / Revised: 28 September 2016 / Accepted: 1 October 2016 / Published: 8 October 2016
Cited by 3 | PDF Full-text (842 KB) | HTML Full-text | XML Full-text
Abstract
The effects of polyphenol-rich foods on the iron status of athletes, as well as the effect of physical training on the hormone hepcidin, implicated in iron metabolism, are not clear. We investigated the influence on iron metabolism of a long-term training intervention of
[...] Read more.
The effects of polyphenol-rich foods on the iron status of athletes, as well as the effect of physical training on the hormone hepcidin, implicated in iron metabolism, are not clear. We investigated the influence on iron metabolism of a long-term training intervention of 120 days, measuring the hepcidin concentration in the plasma of 16 elite triathletes, and the effect of the ingestion of 200 mL of either aronia-citrus juice or a placebo drink for 45 days, in a crossover design. The highest plasma hepcidin concentrations were observed at the beginning of the study (116 ± 63 nM) and levels steadily decreased until the end of the intervention (final value 10 ± 7.5 nM). Long-term training might reduce inflammation and, hence, could be responsible for the decrease in hepcidin in triathletes. Polyphenols from aronia-citrus juice did not interfere in iron absorption, as we did not observe significant differences between the intake of the placebo drink or juice with regard to hepcidin levels. Further studies are required to ascertain the time and conditions necessary to restore hepcidin levels, which reflect the iron status of triathletes. Full article
Figures

Open AccessArticle Red Grape Skin Polyphenols Blunt Matrix Metalloproteinase-2 and -9 Activity and Expression in Cell Models of Vascular Inflammation: Protective Role in Degenerative and Inflammatory Diseases
Molecules 2016, 21(9), 1147; doi:10.3390/molecules21091147
Received: 30 June 2016 / Revised: 17 August 2016 / Accepted: 25 August 2016 / Published: 29 August 2016
Cited by 5 | PDF Full-text (3242 KB) | HTML Full-text | XML Full-text
Abstract
Matrix metalloproteinases (MMPs) are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases’ activity and expression are regulated by oxidative stress, we sought to
[...] Read more.
Matrix metalloproteinases (MMPs) are endopeptidases responsible for the hydrolysis of various components of extracellular matrix. MMPs, namely gelatinases MMP-2 and MMP-9, contribute to the progression of chronic and degenerative diseases. Since gelatinases’ activity and expression are regulated by oxidative stress, we sought to evaluate whether supplementation with polyphenol-rich red grape skin extracts modulated the matrix-degrading capacity in cell models of vascular inflammation. Human endothelial and monocytic cells were incubated with increasing concentrations (0.5–25 μg/mL) of Negroamaro and Primitivo red grape skin polyphenolic extracts (NSPE and PSPE, respectively) or their specific components (0.5–25 μmol/L), before stimulation with inflammatory challenge. NSPE and PSPE inhibited, in a concentration-dependent manner, endothelial invasion as well as the MMP-9 and MMP-2 release in stimulated endothelial cells, and MMP-9 production in inflamed monocytes, without affecting tissue inhibitor of metalloproteinases (TIMP)-1 and TIMP-2. The matrix degrading inhibitory capacity was the same for both NSPE and PSPE, despite their different polyphenolic profiles. Among the main polyphenols of grape skin extracts, trans-resveratrol, trans-piceid, kaempferol and quercetin exhibited the most significant inhibitory effects on matrix-degrading enzyme activities. Our findings appreciate the grape skins as rich source of polyphenols able to prevent the dysregulation of vascular remodelling affecting degenerative and inflammatory diseases. Full article
Figures

Open AccessArticle Plasma and Urinary Phenolic Profiles after Acute and Repetitive Intake of Wild Blueberry
Molecules 2016, 21(9), 1120; doi:10.3390/molecules21091120
Received: 29 July 2016 / Revised: 17 August 2016 / Accepted: 17 August 2016 / Published: 25 August 2016
Cited by 5 | PDF Full-text (741 KB) | HTML Full-text | XML Full-text
Abstract
Recent studies have shown that blueberries may have cardiovascular and cognitive health benefits. In this work, we investigated the profile of plasma and urine (poly)phenol metabolites after acute and daily consumption of wild blueberries for 30 days in 18 healthy men. The inter-individual
[...] Read more.
Recent studies have shown that blueberries may have cardiovascular and cognitive health benefits. In this work, we investigated the profile of plasma and urine (poly)phenol metabolites after acute and daily consumption of wild blueberries for 30 days in 18 healthy men. The inter-individual variability in plasma and urinary polyphenol levels was also investigated. Blood samples were collected at baseline and 2 h post-consumption on day 1 and day 30. Twenty-four-hour urine was also collected on both days. A total of 61 phenolic metabolites were quantified in plasma at baseline, of which 43 increased after acute or chronic consumption of blueberries over one month. Benzoic and catechol derivatives represented more than 80% of the changes in phenolic profile after 2 h consumption on day 1, whereas hippuric and benzoic derivatives were the major compounds that increased at 0 and 2 h on day 30, respectively. The total (poly)phenol urinary excretion remained unchanged after 30 days of wild blueberry intake. The inter-individual variability ranged between 40%–48% in plasma and 47%–54% in urine. Taken together, our results illustrate that blueberry (poly)phenols are absorbed and extensively metabolized by phase II enzymes and by the gut microbiota, leading to a whole array of metabolites that may be responsible for the beneficial effects observed after blueberry consumption. Full article
Figures

Figure 1

Open AccessArticle Phytoestrogen Metabolism by Adult Human Gut Microbiota
Molecules 2016, 21(8), 1034; doi:10.3390/molecules21081034
Received: 3 March 2016 / Revised: 22 July 2016 / Accepted: 4 August 2016 / Published: 9 August 2016
Cited by 10 | PDF Full-text (1110 KB) | HTML Full-text | XML Full-text
Abstract
Phytoestrogens are plant-derived polyphenols with a structure similar to human estrogens. The three main groups of phytoestrogens, isoflavones, ellagitannins, and lignans, are transformed into equol, urolithins, and enterolignans, respectively, by bacteria. These metabolites have more estrogenic/antiestrogenic and antioxidant activities than their precursors, and
[...] Read more.
Phytoestrogens are plant-derived polyphenols with a structure similar to human estrogens. The three main groups of phytoestrogens, isoflavones, ellagitannins, and lignans, are transformed into equol, urolithins, and enterolignans, respectively, by bacteria. These metabolites have more estrogenic/antiestrogenic and antioxidant activities than their precursors, and they are more bioavailable. The aim of this study was to analyze the metabolism of isoflavones, lignans and ellagitannins by gut microbiota, and to study the possible correlation in the metabolism of these three groups of phytoestrogens. In vitro fermentation experiments were performed with feces samples from 14 healthy adult volunteers, and metabolite formation was measured by HPLC-PAD and HPLC-ESI/MS. Only the microbiota of one subject produced equol, while most of them showed production of O-desmethylangolensin (O-DMA). Significant inter-subject differences were observed in the metabolism of dihydrodaidzein and dihydrogenistein, while the glucoside isoflavones and their aglycones showed less variability, except for glycitin. Most subjects produced urolithins M-5 and E. Urolithin D was not detected, while uroltithin B was found in half of the individuals analyzed, and urolithins A and C were detected in two and four subjects, respectively. Enterolactone was found in all subjects, while enterodiol only appeared in five. Isoflavone metabolism could be correlated with the metabolism of lignans and ellagitannins. However, the metabolism of ellagitannins and lignans could not be correlated. This the first study where the metabolism of the three groups together of phytoestrogen, isoflavones, lignans, and ellagitannins by gut microbiota is analyzed. Full article
Figures

Figure 1

Open AccessArticle Phenolic and Volatile Composition of a Dry Spearmint (Mentha spicata L.) Extract
Molecules 2016, 21(8), 1007; doi:10.3390/molecules21081007
Received: 6 June 2016 / Revised: 25 July 2016 / Accepted: 27 July 2016 / Published: 3 August 2016
Cited by 6 | PDF Full-text (744 KB) | HTML Full-text | XML Full-text
Abstract
The present paper reports a complete mass spectrometric characterization of both the phenolic and volatile fractions of a dried spearmint extract. Phenolic compounds were analysed by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MSn) and a total of 66 compounds were tentatively
[...] Read more.
The present paper reports a complete mass spectrometric characterization of both the phenolic and volatile fractions of a dried spearmint extract. Phenolic compounds were analysed by ultra-high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MSn) and a total of 66 compounds were tentatively identified, being the widest phenolic characterisation of spearmint to date. The analysis suggests that the extract is composed of rosmarinic acid and its derivatives (230.5 ± 13.5 mg/g) with smaller amounts of salvianolic acids, caffeoylquinic acids, hydroxybenzoic acids, hydroxycinnamic acids, flavones, and flavanones. Head space solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) technique, that was applied to characterize the volatile fraction of spearmint, identified molecules belonging to different chemical classes, such as p-cymene, isopiperitone, and piperitone, dihydroedulan II, menthone, p-cymen-8-ol, and β-linalool. This comprehensive phytochemical analysis can be useful to test the authenticity of this product rich in rosmarinic acid and other phenolics, and when assessing its biological properties. It may also be applied to other plant-derived food extracts and beverages containing a broad range of phytochemical compounds. Full article
Figures

Open AccessArticle Effects on Nitric Oxide Production of Urolithins, Gut-Derived Ellagitannin Metabolites, in Human Aortic Endothelial Cells
Molecules 2016, 21(8), 1009; doi:10.3390/molecules21081009
Received: 13 June 2016 / Revised: 19 July 2016 / Accepted: 29 July 2016 / Published: 2 August 2016
Cited by 7 | PDF Full-text (1625 KB) | HTML Full-text | XML Full-text
Abstract
The consumption of foodstuffs yielding circulating compounds able to maintain endothelial function by improving nitric oxide (NO) bioavailability can be considered as an effective strategy for cardiovascular disease prevention. This work assessed the in vitro effects of urolithin A, urolithin B, and urolithin
[...] Read more.
The consumption of foodstuffs yielding circulating compounds able to maintain endothelial function by improving nitric oxide (NO) bioavailability can be considered as an effective strategy for cardiovascular disease prevention. This work assessed the in vitro effects of urolithin A, urolithin B, and urolithin B-glucuronide, ellagitannin-derived metabolites of colonic origin, on NO release and endothelial NO synthase (eNOS) activation in primary human aortic endothelial cells (HAECs). Urolithins were tested both individually at 15 μM and as a mixture of 5 μM each, at different time points. The biotransformation of these molecules in cell media due to cell metabolism was also evaluated by UHPLC-MSn. The mix of urolithins at 5 μM significantly increased nitrite/nitrate levels following 24 h of incubation, while single urolithins at 15 μM did not modify NO bioavailability. Both the mix of urolithins at 5 μM and urolithin B-glucuronide at 15 μM activated eNOS expression. All urolithins underwent metabolic reactions, but these were limited to conjugation with sulfate moieties. This study represents a step forward in the understanding of cardiovascular health benefits of ellagitannin-rich foodstuffs and backs the idea that peripheral cells may contribute to urolithin metabolism. Full article
Figures

Figure 1

Open AccessArticle In Vivo Release Kinetics and Antibacterial Activity of Novel Polyphenols-Enriched Chewing Gums
Molecules 2016, 21(8), 1008; doi:10.3390/molecules21081008
Received: 8 June 2016 / Revised: 27 July 2016 / Accepted: 29 July 2016 / Published: 2 August 2016
Cited by 2 | PDF Full-text (1303 KB) | HTML Full-text | XML Full-text
Abstract
Chewing gums may be particularly effective means for delivering and maintaining bioactive molecules, included in the gum formulation, able to have an anti-cariogenic effect. The purposes of this study were: to develop novel chewing gums containing quercetin (Qt); to evaluate their release using
[...] Read more.
Chewing gums may be particularly effective means for delivering and maintaining bioactive molecules, included in the gum formulation, able to have an anti-cariogenic effect. The purposes of this study were: to develop novel chewing gums containing quercetin (Qt); to evaluate their release using in vivo trial; finally, to test their in vivo antibacterial effect against oral Streptococcus mutans strains. A preliminary study was performed to produce new gums, enriched with the polyphenol quercetin. Then, a first in vivo experimental study was assessed to test the percentages of Qt released in the saliva of young volunteers. Moreover, a second clinical trial was performed to analyze the antibacterial capability of these enriched chewing gums against S. mutans strains after 14 days of daily consumption. The release analysis showed that a more effective release of Qt occurs in the first minutes of chewing, and it does not change saliva pH values. Moreover, Qt included in gums demonstrates an effective antibacterial activity, showing a reduction of the concentration of S. mutans strains in saliva samples, especially after 7 days. Qt included in experimental chewing gums could be efficiently released into the oral cavity and could promote an effective anti-caries concentration in volunteer’s saliva, without changing salivary pH values. Full article
Figures

Figure 1

Open AccessArticle Gallic Acid Promotes Wound Healing in Normal and Hyperglucidic Conditions
Molecules 2016, 21(7), 899; doi:10.3390/molecules21070899
Received: 19 March 2016 / Revised: 28 June 2016 / Accepted: 1 July 2016 / Published: 8 July 2016
Cited by 7 | PDF Full-text (6165 KB) | HTML Full-text | XML Full-text
Abstract
Skin is the outermost layer of the human body that is constantly exposed to environmental stressors, such as UV radiation and toxic chemicals, and is susceptible to mechanical wounding and injury. The ability of the skin to repair injuries is paramount for survival
[...] Read more.
Skin is the outermost layer of the human body that is constantly exposed to environmental stressors, such as UV radiation and toxic chemicals, and is susceptible to mechanical wounding and injury. The ability of the skin to repair injuries is paramount for survival and it is disrupted in a spectrum of disorders leading to skin pathologies. Diabetic patients often suffer from chronic, impaired wound healing, which facilitate bacterial infections and necessitate amputation. Here, we studied the effects of gallic acid (GA, 3,4,5-trihydroxybenzoic acid; a plant-derived polyphenolic compound) on would healing in normal and hyperglucidic conditions, to mimic diabetes, in human keratinocytes and fibroblasts. Our study reveals that GA is a potential antioxidant that directly upregulates the expression of antioxidant genes. In addition, GA accelerated cell migration of keratinocytes and fibroblasts in both normal and hyperglucidic conditions. Further, GA treatment activated factors known to be hallmarks of wound healing, such as focal adhesion kinases (FAK), c-Jun N-terminal kinases (JNK), and extracellular signal-regulated kinases (Erk), underpinning the beneficial role of GA in wound repair. Therefore, our results demonstrate that GA might be a viable wound healing agent and a potential intervention to treat wounds resulting from metabolic complications. Full article
Open AccessArticle Coffee Silverskin Extract Protects against Accelerated Aging Caused by Oxidative Agents
Molecules 2016, 21(6), 721; doi:10.3390/molecules21060721
Received: 14 April 2016 / Revised: 20 May 2016 / Accepted: 20 May 2016 / Published: 1 June 2016
Cited by 6 | PDF Full-text (2356 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful
[...] Read more.
Nowadays, coffee beans are almost exclusively used for the preparation of the beverage. The sustainability of coffee production can be achieved introducing new applications for the valorization of coffee by-products. Coffee silverskin is the by-product generated during roasting, and because of its powerful antioxidant capacity, coffee silverskin aqueous extract (CSE) may be used for other applications, such as antiaging cosmetics and dermaceutics. This study aims to contribute to the coffee sector’s sustainability through the application of CSE to preserve skin health. Preclinical data regarding the antiaging properties of CSE employing human keratinocytes and Caenorhabditis elegans are collected during the present study. Accelerated aging was induced by tert-butyl hydroperoxide (t-BOOH) in HaCaT cells and by ultraviolet radiation C (UVC) in C. elegans. Results suggest that the tested concentrations of coffee extracts were not cytotoxic, and CSE 1 mg/mL gave resistance to skin cells when oxidative damage was induced by t-BOOH. On the other hand, nematodes treated with CSE (1 mg/mL) showed a significant increased longevity compared to those cultured on a standard diet. In conclusion, our results support the antiaging properties of the CSE and its great potential for improving skin health due to its antioxidant character associated with phenols among other bioactive compounds present in the botanical material. Full article
Figures

Open AccessArticle Methyl Jasmonate: An Alternative for Improving the Quality and Health Properties of Fresh Fruits
Molecules 2016, 21(6), 567; doi:10.3390/molecules21060567
Received: 14 March 2016 / Revised: 19 April 2016 / Accepted: 21 April 2016 / Published: 31 May 2016
Cited by 3 | PDF Full-text (1177 KB) | HTML Full-text | XML Full-text
Abstract
Methyl jasmonate (MeJA) is a plant growth regulator belonging to the jasmonate family. It plays an important role as a possible airborne signaling molecule mediating intra- and inter-plant communications and modulating plant defense responses, including antioxidant systems. Most assessments of this compound have
[...] Read more.
Methyl jasmonate (MeJA) is a plant growth regulator belonging to the jasmonate family. It plays an important role as a possible airborne signaling molecule mediating intra- and inter-plant communications and modulating plant defense responses, including antioxidant systems. Most assessments of this compound have dealt with post-harvest fruit applications, demonstrating induced plant resistance against the detrimental impacts of storage (chilling injuries and pathogen attacks), enhancing secondary metabolites and antioxidant activity. On the other hand, the interactions between MeJA and other compounds or technological tools for enhancing antioxidant capacity and quality of fruits were also reviewed. The pleiotropic effects of MeJA have raisen numerous as-yet unanswered questions about its mode of action. The aim of this review was endeavored to clarify the role of MeJA on improving pre- and post-harvest fresh fruit quality and health properties. Interestingly, the influence of MeJA on human health will be also discussed. Full article
Open AccessFeature PaperArticle Encapsulation of Beetroot Pomace Extract: RSM Optimization, Storage and Gastrointestinal Stability
Molecules 2016, 21(5), 584; doi:10.3390/molecules21050584
Received: 29 February 2016 / Revised: 23 April 2016 / Accepted: 27 April 2016 / Published: 30 April 2016
Cited by 4 | PDF Full-text (967 KB) | HTML Full-text | XML Full-text
Abstract
One of the great problems in food production are surplus by-products, usually utilized for feeding animals and for preparation of dietary fibre or biofuel. These products represent potential sources of bioactive antioxidants and colour-giving compounds which could be used in the pharmaceutical industry
[...] Read more.
One of the great problems in food production are surplus by-products, usually utilized for feeding animals and for preparation of dietary fibre or biofuel. These products represent potential sources of bioactive antioxidants and colour-giving compounds which could be used in the pharmaceutical industry and as food additives. In the present study beetroot pomace extract was encapsulated in soy protein by a freeze drying method. Process parameters (core: wall ratio, extract concentration and mixing time) were optimized using response surface methodology (RSM) in order to obtain the optimum encapsulate (OE) with the highest polyphenol encapsulation efficiency (EE) and radical scavenging activity on DPPH radicals (SA). Using the calculated optimum conditions, the EE (86.14%) and SA (1668.37 μmol Trolox equivalents/100 g) of OE did not differ significantly (p < 0.05) from the predicted ones. The contents of total polyphenols (326.51 mg GAE/100 g), flavonoids (10.23 mg RE/100 g), and betalains (60.52 mg betanin/100 g and 61.33 mg vulgaxanthin-I/100 g), individual content of phenolic compounds and betalains by HPLC, and the ability to reduce Fe3+ ions, i.e., reducing power (394.95 μmol Trolox equivalents/100 g) of OE were determined as well. During three months of storage at room temperature, polyphenol retention was much higher (76.67%) than for betalain pigments, betacyanins (17.77%) and betaxanthins (17.72%). In vitro digestion and release of phenolics from OE showed higher release rate in simulated intestinal fluid than in gastric fluid. These results suggest encapsulation as a contemporary method for valorisation of sensitive bioactive compounds from food industry by-products. Full article
Figures

Open AccessArticle The Powdering Process with a Set of Ceramic Mills for Green Tea Promoted Catechin Extraction and the ROS Inhibition Effect
Molecules 2016, 21(4), 474; doi:10.3390/molecules21040474
Received: 3 February 2016 / Revised: 22 March 2016 / Accepted: 1 April 2016 / Published: 11 April 2016
Cited by 1 | PDF Full-text (2429 KB) | HTML Full-text | XML Full-text
Abstract
For serving green tea, there are two prominent methods: steeping the leaf or the powdered leaf (matcha style) in hot water. The purpose of the present study was to reveal chemical and functional differences before and after the powdering process of green tea
[...] Read more.
For serving green tea, there are two prominent methods: steeping the leaf or the powdered leaf (matcha style) in hot water. The purpose of the present study was to reveal chemical and functional differences before and after the powdering process of green tea leaf, since powdered green tea may contribute to expanding the functionality because of the different ingesting style. In this study, we revealed that the powdering process with a ceramic mill and stirring in hot water increased the average extracted concentration of epigallocatechin gallate (EGCG) by more than three times compared with that in leaf tea using high-performance liquid chromatography (HPLC) and liquid chromatography–tandem mass Spectrometry (LC-MS/MS) analyses. Moreover, powdered green tea has a higher inhibition effect of reactive oxygen species (ROS) production in vitro compared with the same amount of leaf tea. Our data suggest that powdered green tea might have a different function from leaf tea due to the higher catechin contents and particles. Full article
Figures

Open AccessArticle The Tissue Distribution and Urinary Excretion Study of Gallic Acid and Protocatechuic Acid after Oral Administration of Polygonum Capitatum Extract in Rats
Molecules 2016, 21(4), 399; doi:10.3390/molecules21040399
Received: 20 January 2016 / Revised: 13 March 2016 / Accepted: 19 March 2016 / Published: 24 March 2016
Cited by 1 | PDF Full-text (2158 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In the present study, we investigated the tissue distribution and urinary excretion of gallic acid (GA) and protocatechuic acid (PCA) after rat oral administration of aqueous extract of Polygonum capitatum (P. capitatum, named Herba Polygoni Capitati in China). An UHPLC-MS/MS analytical
[...] Read more.
In the present study, we investigated the tissue distribution and urinary excretion of gallic acid (GA) and protocatechuic acid (PCA) after rat oral administration of aqueous extract of Polygonum capitatum (P. capitatum, named Herba Polygoni Capitati in China). An UHPLC-MS/MS analytical method was developed and adopted for quantification of GA and PCA in different tissue homogenate and urine samples. Interestingly, we found that GA and PCA showed a relatively targeted distribution in kidney tissue after dosing 60 mg/kg P. capitatum extract (equivalent to 12 mg/kg of GA and 0.9 mg/kg of PCA). The concentrations of GA and PCA in the kidney tissue reached 1218.62 ng/g and 43.98 ng/g, respectively, at one hour after oral administration. The results helped explain the empirical use of P. capitatum for kidney diseases in folk medicine. Further studies on urinary excretion of P. capitatum extract indicated that GA and PCA followed a concentrated elimination over a 4-h period. The predominant metabolites were putatively identified to be 4-methylgallic acid (4-OMeGA) and 4-methylprotocatechuic acid (4-OMePCA) by analyzing their precursor ions and characteristic fragment ions using tandem mass spectrometry. However, the amount of unchanged GA and PCA that survived the metabolism were about 14.60% and 15.72% of the total intake, respectively, which is reported for the first time in this study. Full article
Figures

Open AccessArticle In Vivo Effects of Quercetin in Association with Moderate Exercise Training in Improving Streptozotocin-Induced Aortic Tissue Injuries
Molecules 2015, 20(12), 21770-21786; doi:10.3390/molecules201219802
Received: 24 October 2015 / Revised: 26 November 2015 / Accepted: 30 November 2015 / Published: 4 December 2015
Cited by 2 | PDF Full-text (1883 KB) | HTML Full-text | XML Full-text
Abstract
Background: Diabetes mellitus (DM) is a chronic endocrine-metabolic disorder associated with endothelial dysfunction. Hyperglycemia, dyslipidemia and abnormal nitric oxide-mediated vasodilatation are the major causal factors in the development of endothelial dysfunction in DM. The prevention of endothelial dysfunction may be a first target
[...] Read more.
Background: Diabetes mellitus (DM) is a chronic endocrine-metabolic disorder associated with endothelial dysfunction. Hyperglycemia, dyslipidemia and abnormal nitric oxide-mediated vasodilatation are the major causal factors in the development of endothelial dysfunction in DM. The prevention of endothelial dysfunction may be a first target against the appearance of atherosclerosis and cardiovascular diseases. We have investigated the synergistic protective effects of quercetin administration and moderate exercise training on thoracic aorta injuries induced by diabetes. Methods: Diabetic rats that performed exercise training were subjected to a swimming training program (1 h/day, 5 days/week, 4 weeks). The diabetic rats received quercetin (30 mg/kg body weight/day) for 4 weeks. At the end of the study, the thoracic aorta was isolated and divided into two parts; one part was immersed in 10% formalin for histopathological evaluations and the other was frozen for the assessment of oxidative stress markers (malondialdehyde, MDA and protein carbonyls groups, PC), the activity of antioxidant enzymes (superoxide dismutase, SOD and catalase, CAT), nitrite plus nitrate (NOx) production and inducible nitric oxide synthase (iNOS) protein expression. Results: Diabetic rats showed significantly increased MDA and PC levels, NOx production and iNOS expression and a reduction of SOD and CAT activity in aortic tissues. A decrease in the levels of oxidative stress markers, NOx production and iNOS expression associated with elevated activity of antioxidant enzymes in the aortic tissue were observed in quercetin-treated diabetic trained rats. Conclusions: These findings suggest that quercetin administration in association with moderate exercise training reduces vascular complications and tissue injuries induced by diabetes in rat aorta by decreasing oxidative stress and restoring NO bioavailability. Full article

Review

Jump to: Editorial, Research

Open AccessReview The Health Benefiting Mechanisms of Virgin Olive Oil Phenolic Compounds
Molecules 2016, 21(12), 1734; doi:10.3390/molecules21121734
Received: 14 September 2016 / Revised: 2 December 2016 / Accepted: 12 December 2016 / Published: 16 December 2016
Cited by 8 | PDF Full-text (222 KB) | HTML Full-text | XML Full-text
Abstract
Virgin olive oil (VOO) is credited as being one of the many healthful components associated with the Mediterranean diet. Mediterranean populations experience reduced incidence of chronic inflammatory disease states and VOO is readily consumed as part of an everyday Mediterranean dietary pattern. VOO
[...] Read more.
Virgin olive oil (VOO) is credited as being one of the many healthful components associated with the Mediterranean diet. Mediterranean populations experience reduced incidence of chronic inflammatory disease states and VOO is readily consumed as part of an everyday Mediterranean dietary pattern. VOO is rich in phenolic compounds and the health promoting benefits of these phenolics are now established. Recent studies have highlighted the biological properties of VOO phenolic compounds elucidating their anti-inflammatory activities. This paper will review current knowledge on the anti-inflammatory and nutrigenomic, chemoprotective and anti-atherosclerotic activities of VOO phenolics. In addition the concentration, metabolism and bioavailability of specific phenolic compounds will be discussed. The evidence presented in the review concludes that oleurepein, hydroxytyrosol and oleocanthal have potent pharmacological activities in vitro and in vivo; however, intervention studies with biologically relevant concentrations of these phenolic compounds are required. Full article
Open AccessReview The Role of Natural Polyphenols in the Prevention and Treatment of Cervical Cancer—An Overview
Molecules 2016, 21(8), 1055; doi:10.3390/molecules21081055
Received: 30 June 2016 / Revised: 6 August 2016 / Accepted: 8 August 2016 / Published: 17 August 2016
Cited by 5 | PDF Full-text (4323 KB) | HTML Full-text | XML Full-text
Abstract
Cervical cancer represents the second leading cause of death for women worldwide. The importance of the diet and its impact on specific types of neoplasia has been highlighted, focusing again interest in the analysis of dietary phytochemicals. Polyphenols have shown a wide range
[...] Read more.
Cervical cancer represents the second leading cause of death for women worldwide. The importance of the diet and its impact on specific types of neoplasia has been highlighted, focusing again interest in the analysis of dietary phytochemicals. Polyphenols have shown a wide range of cellular effects: they may prevent carcinogens from reaching the targeted sites, support detoxification of reactive molecules, improve the elimination of transformed cells, increase the immune surveillance and the most important factor is that they can influence tumor suppressors and inhibit cellular proliferation, interfering in this way with the steps of carcinogenesis. From the studies reviewed in this paper, it is clear that certain dietary polyphenols hold great potential in the prevention and therapy of cervical cancer, because they interfere in carcinogenesis (in the initiation, development and progression) by modulating the critical processes of cellular proliferation, differentiation, apoptosis, angiogenesis and metastasis. Specifically, polyphenols inhibit the proliferation of HPV cells, through induction of apoptosis, growth arrest, inhibition of DNA synthesis and modulation of signal transduction pathways. The effects of combinations of polyphenols with chemotherapy and radiotherapy used in the treatment of cervical cancer showed results in the resistance of cervical tumor cells to chemo- and radiotherapy, one of the main problems in the treatment of cervical neoplasia that can lead to failure of the treatment because of the decreased efficiency of the therapy. Full article
Figures

Figure 1

Open AccessReview Coffee Consumption and Oxidative Stress: A Review of Human Intervention Studies
Molecules 2016, 21(8), 979; doi:10.3390/molecules21080979
Received: 28 June 2016 / Revised: 19 July 2016 / Accepted: 21 July 2016 / Published: 28 July 2016
Cited by 9 | PDF Full-text (986 KB) | HTML Full-text | XML Full-text
Abstract
Research on the potential protective effects of coffee and its bioactives (caffeine, chlorogenic acids and diterpenes) against oxidative stress and related chronic disease risk has been increasing in the last years. The present review summarizes the main findings on the effect of coffee
[...] Read more.
Research on the potential protective effects of coffee and its bioactives (caffeine, chlorogenic acids and diterpenes) against oxidative stress and related chronic disease risk has been increasing in the last years. The present review summarizes the main findings on the effect of coffee consumption on protection against lipid, protein and DNA damage, as well as on the modulation of antioxidant capacity and antioxidant enzymes in human studies. Twenty-six dietary intervention studies (involving acute and chronic coffee intake) have been considered. Overall, the results suggest that coffee consumption can increase glutathione levels and improve protection against DNA damage, especially following regular/repeated intake. On the contrary, the effects of coffee on plasma antioxidant capacity and antioxidant enzymes, as well as on protein and lipid damage, are unclear following both acute and chronic exposure. The high heterogeneity in terms of type of coffee, doses and duration of the studies, the lack of information on coffee and/or brew bioactive composition, as well as the choice of biomarkers and the methods used for their evaluation, may partially explain the variability observed among findings. More robust and well-controlled intervention studies are necessary for a thorough understanding of the effect of coffee on oxidative stress markers in humans. Full article
Figures

Open AccessReview Polyphenols: Extraction Methods, Antioxidative Action, Bioavailability and Anticarcinogenic Effects
Molecules 2016, 21(7), 901; doi:10.3390/molecules21070901
Received: 31 May 2016 / Revised: 28 June 2016 / Accepted: 5 July 2016 / Published: 11 July 2016
Cited by 26 | PDF Full-text (1411 KB) | HTML Full-text | XML Full-text
Abstract
Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given,
[...] Read more.
Being secondary plant metabolites, polyphenols represent a large and diverse group of substances abundantly present in a majority of fruits, herbs and vegetables. The current contribution is focused on their bioavailability, antioxidative and anticarcinogenic properties. An overview of extraction methods is also given, with supercritical fluid extraction highlighted as a promising eco-friendly alternative providing exceptional separation and protection from degradation of unstable polyphenols. The protective role of polyphenols against reactive oxygen and nitrogen species, UV light, plant pathogens, parasites and predators results in several beneficial biological activities giving rise to prophylaxis or possibly even to a cure for several prevailing human diseases, especially various cancer types. Omnipresence, specificity of the response and the absence of or low toxicity are crucial advantages of polyphenols as anticancer agents. The main problem represents their low bioavailability and rapid metabolism. One of the promising solutions lies in nanoformulation of polyphenols that prevents their degradation and thus enables significantly higher concentrations to reach the target cells. Another, more practiced, solution is the use of mixtures of various polyphenols that bring synergistic effects, resulting in lowering of the required therapeutic dose and in multitargeted action. The combination of polyphenols with existing drugs and therapies also shows promising results and significantly reduces their toxicity. Full article
Figures

Back to Top