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Special Issue "New Trends in Polyphenols and Health"

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

Deadline for manuscript submissions: closed (28 February 2022) | Viewed by 15609

Special Issue Editors

Dr. Marisa Freitas
E-Mail Website
Guest Editor
LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
Interests: natural products; polyphenols; diabetes; inflammation; nanoparticles
Special Issues, Collections and Topics in MDPI journals
Dr. Daniela Ribeiro
E-Mail Website
Guest Editor
LAQV, REQUIMTE, Faculdade de Ciências Agrárias e do Ambiente, Universidade dos Açores, 9700-042 Angra do Heroísmo, Portugal
Interests: antioxidants; inflammation; structure-activity relationships; polyphenols
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Eduarda Fernandes
E-Mail Website
Guest Editor
LAQV, REQUIMTE, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, 4050-313 Porto, Portugal
Interests: natural products; polyphenols; diabetes; inflammation; obesity
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Polyphenols are characterized by the presence of one or more phenolic groups in a chemical structure, varying from simple phenolic molecules to complex high-molecular-weight polymers. Naturally occurring polyphenols are highly diversified and encompass various chemical groups, such as phenolic acids, stilbenes, flavonoids, and lignans, with thousands of members in each group. These compounds have been identified in edible and non-edible plants, and can be found mainly in fruits, vegetables, and cereals. Innumerous biological activities have been attributed to polyphenols, namely, antioxidant, anti-inflammatory, anticancer, antidiabetic, and antiobesity, among others.

There have been several in vitro studies covering the health benefits of polyphenols. However, the poor bioavailability and extensive metabolism of these compounds restrict their biological effects in vivo. Moreover, there is a need to study a high number of compounds in panels of structurally related polyphenols in order to allow the establishment of accurate structure-activity relationships, which will favor the choice of the most promising scaffolds regarding each specific disease.

Therefore, the main, but not exclusive, topics to be dealt with in this Special Issue are the following:

  • Biological activities of different groups of polyphenols;
  • Strategies to overcome the poor bioavailability of polyphenols;
  • Establishment of structure-activity relationships;
  • Validation of new methods to evaluate the beneficial effects of polyphenols on human health.

We would like to invite you to participate in this Special Issue on “New Trends in Polyphenols and Health” by submitting a contribution in the form of an original research paper, short communication, and/or global or specialized critical review according to your field of expertise. Papers will be published upon acceptance, regardless of the Special Issue publication date (30 September 2021).

Dr. Marisa Freitas
Dr. Daniela Ribeiro
Prof. Dr. Eduarda Fernandes
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 submissions that pass pre-check are 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 semimonthly 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 2300 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

  • Polyphenols
  • Biological activity
  • Nanoencapsulation
  • Structure-activity relationship

Published Papers (14 papers)

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Research

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Article
Dry Dosage Forms of Add-Value Bioactive Phenolic Compounds by Supercritical CO2-Assisted Spray-Drying
Molecules 2022, 27(6), 2001; https://doi.org/10.3390/molecules27062001 - 20 Mar 2022
Viewed by 637
Abstract
Every year, grapevine pruning produces huge amounts of residue, 90% of which are from vine shoots. These are a rich source of natural antioxidants, mostly phenolic compounds, which, when properly extracted, can give rise to added-value products. However, their lack of solubility in [...] Read more.
Every year, grapevine pruning produces huge amounts of residue, 90% of which are from vine shoots. These are a rich source of natural antioxidants, mostly phenolic compounds, which, when properly extracted, can give rise to added-value products. However, their lack of solubility in aqueous media and high susceptibility to thermal and oxidative degradation highly limit their bioavailability. Encapsulation in suitable carriers may have a positive impact on their bioavailability and bioactivity. Previous data on vine-shoot extraction have identified gallic acid (GA) and resveratrol (RSV) as the main phenolic compounds. In this work, model dry powder formulations (DPFs) of GA and RSV using hydroxypropyl cellulose (HPC) as carriers were developed using Supercritical CO2-Assisted Spray Drying (SASD). A 32 full factorial Design of Experiments investigated the solid and ethanol contents to ascertain process yield, particle size, span, and encapsulation efficiency. Amorphous powder yields above 60%, and encapsulation efficiencies up to 100% were achieved, representing excellent performances. SASD has proven to be an efficient encapsulation technique for these phenolic compounds, preserving their antioxidation potential after three months in storage with average EC50 values of 30.6 µg/mL for GA–DPFs and 149.4 µg/mL for RSV–DPF as assessed by the scavenging capacity of the DPPH radical. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Resveratrol Promotes Angiogenesis in a FoxO1-Dependent Manner in Hind Limb Ischemia in Mice
Molecules 2021, 26(24), 7528; https://doi.org/10.3390/molecules26247528 - 12 Dec 2021
Cited by 1 | Viewed by 1114
Abstract
Critical limb ischemia (CLI) is a severe form of peripheral artery diseases (PAD) and seriously endangers the health of people. Therapeutic angiogenesis represents an important treatment strategy for CLI; various methods have been applied to enhance collateral circulation. However, the current development drug [...] Read more.
Critical limb ischemia (CLI) is a severe form of peripheral artery diseases (PAD) and seriously endangers the health of people. Therapeutic angiogenesis represents an important treatment strategy for CLI; various methods have been applied to enhance collateral circulation. However, the current development drug therapy to promote angiogenesis is limited. Resveratrol (RSV), a polyphenol compound extracted from plants, has various properties such as anti-oxidative, anti-inflammatory and anti-cancer effects. Whether RSV exerts protective effects on CLI remains elusive. In the current study, we demonstrated that oral intake of RSV significantly improved hind limb ischemia in mice, and increased the expression of phosphorylated Forkhead box class-O1 (FoxO1). RSV treatment in human umbilical vein endothelial cells (HUVECs) could increase the phosphorylation of FoxO1 and its cytoplasmic re-localization to promote angiogenesis. Then we manipulated FoxO1 in HUVECs to further verify that the effect of RSV on angiogenesis is in a FoxO1-dependent manner. Furthermore, we performed metabolomics to screen the metabolic pathways altered upon RSV intervention. We found that the pathways of pyrimidine metabolism, purine metabolism, as well as alanine, aspartate and glutamate metabolism, were highly correlated with the beneficial effects of RSV on the ischemic muscle. This study provides a novel direction for the medical therapy to CLI. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Polyphenols as Potential Inhibitors of SARS-CoV-2 RNA Dependent RNA Polymerase (RdRp)
Molecules 2021, 26(24), 7438; https://doi.org/10.3390/molecules26247438 - 08 Dec 2021
Cited by 5 | Viewed by 1221
Abstract
An increasing number of studies have demonstrated the antiviral nature of polyphenols, and many polyphenols have been proposed to inhibit SARS-CoV or SARS-CoV-2. Our previous study revealed the inhibitory mechanisms of polyphenols against DNA polymerase α and HIV reverse transcriptase to show that [...] Read more.
An increasing number of studies have demonstrated the antiviral nature of polyphenols, and many polyphenols have been proposed to inhibit SARS-CoV or SARS-CoV-2. Our previous study revealed the inhibitory mechanisms of polyphenols against DNA polymerase α and HIV reverse transcriptase to show that polyphenols can block DNA elongation by competing with the incoming NTPs. Here we applied computational approaches to examine if some polyphenols can also inhibit RNA polymerase (RdRp) in SARS-CoV-2, and we identified some better candidates than remdesivir, the FDA-approved drug against RdRp, in terms of estimated binding affinities. The proposed compounds will be further examined to develop new treatments for COVID-19. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Protective Role of Flavonoids against Intestinal Pro-Inflammatory Effects of Silver Nanoparticles
Molecules 2021, 26(21), 6610; https://doi.org/10.3390/molecules26216610 - 31 Oct 2021
Cited by 1 | Viewed by 885
Abstract
Silver nanoparticles (AgNP) have been increasingly incorporated into food-related and hygiene products for their unique antimicrobial and preservative properties. The consequent oral exposure may then result in unpredicted harmful effects in the gastrointestinal tract (GIT), which should be considered in the risk assessment [...] Read more.
Silver nanoparticles (AgNP) have been increasingly incorporated into food-related and hygiene products for their unique antimicrobial and preservative properties. The consequent oral exposure may then result in unpredicted harmful effects in the gastrointestinal tract (GIT), which should be considered in the risk assessment and risk management of these materials. In the present study, the toxic effects of polyethyleneimine (PEI)-coated AgNP (4 and 19 nm) were evaluated in GIT-relevant cells (Caco-2 cell line as a model of human intestinal cells, and neutrophils as a model of the intestinal inflammatory response). This study also evaluated the putative protective action of dietary flavonoids against such harmful effects. The obtained results showed that AgNP of 4 and 19 nm effectively induced Caco-2 cell death by apoptosis with concomitant production of nitric oxide, irrespective of the size. It was also observed that AgNP induced human neutrophil oxidative burst. Interestingly, some flavonoids, namely quercetin and quercetagetin, prevented the deleterious effects of AgNP in both cell types. Overall, the data of the present study provide a first insight into the promising protective role of flavonoids against the potentially toxic effects of AgNP at the intestinal level. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Alpha-Glucosidase Inhibitory Assay-Screened Isolation and Molecular Docking Model from Bauhinia pulla Active Compounds
Molecules 2021, 26(19), 5970; https://doi.org/10.3390/molecules26195970 - 01 Oct 2021
Cited by 1 | Viewed by 825
Abstract
The aim of this research was to establish the constituents of Bauhinia pulla as anti-diabetic agents. A phytochemistry analysis was conducted by chromatographic and spectroscopic techniques. The alpha-glucosidase inhibitory assay screening resulted in the isolation of eight known compounds of quercetin, quercitrin, luteolin, [...] Read more.
The aim of this research was to establish the constituents of Bauhinia pulla as anti-diabetic agents. A phytochemistry analysis was conducted by chromatographic and spectroscopic techniques. The alpha-glucosidase inhibitory assay screening resulted in the isolation of eight known compounds of quercetin, quercitrin, luteolin, 5-deoxyluteolin, 4-methyl ether isoliquiritigenin, 3,2′,4′-trihydroxy-4-methoxychalcone, stigmasterol and β-sitosterol. Ethanol leaf extracts showed potential effects, which led to a strong inhibitory activity of isolated quercetin at 138.95 µg/mL and 5.41 µg/mL of IC50, respectively. The docking confirmed that flavonoids and chalcones had the same potential binding sites and responsibilities for their activity. This study was the first report of Bauhinia pulla chemical constituents and its alpha-glucosidase inhibition. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Comparative Analysis of the Antitumor Activity of Cis- and Trans-Resveratrol in Human Cancer Cells with Different p53 Status
Molecules 2021, 26(18), 5586; https://doi.org/10.3390/molecules26185586 - 14 Sep 2021
Cited by 1 | Viewed by 873
Abstract
Resveratrol, a natural plant phytoalexin, is produced in response to fungal infection or− UV irradiation. It exists as an isomeric pair with cis- and trans-conformation. Whereas multiple physiological effects of the trans-form, including a pronounced anti-tumoral activity, are nowadays elucidated, much less knowledge [...] Read more.
Resveratrol, a natural plant phytoalexin, is produced in response to fungal infection or− UV irradiation. It exists as an isomeric pair with cis- and trans-conformation. Whereas multiple physiological effects of the trans-form, including a pronounced anti-tumoral activity, are nowadays elucidated, much less knowledge exists concerning the cis-isomer. In our work, we analyzed the antiproliferative and cytotoxic properties of cis-resveratrol in four different human tumor entities in direct comparison to trans-resveratrol. We used human cell lines as tumor models for hepatocellular carcinoma (HCC; HepG2, Hep3B), colon carcinoma (HCT-116, HCT-116/p53(−/−)), pancreatic carcinoma (Capan-2, MiaPaCa-2), and renal cell carcinoma (A498, SN12C). Increased cytotoxicity in all investigated tumor cells was observed for the trans-isomer. To verify possible effects of the tumor suppressor p53 on resveratrol-induced cell death, we used wild type and p53-deleted or -mutated cell lines for every tested tumor entity. Applying viability and cytotoxicity assays, we demonstrated a differential, dose-dependent sensitivity towards cis- or trans-resveratrol among the respective tumor types. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Antioxidant Effects of Anthocyanin-Rich Riceberry™ Rice Flour Prepared Using Dielectric Barrier Discharge Plasma Technology on Iron-Induced Oxidative Stress in Mice
Molecules 2021, 26(16), 4978; https://doi.org/10.3390/molecules26164978 - 17 Aug 2021
Viewed by 832
Abstract
Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) [...] Read more.
Redox-active iron generates reactive oxygen species that can cause oxidative organ dysfunction. Thus, the anti-oxidative systems in the body and certain dietary antioxidants, such as anthocyanins, are needed to control oxidative stress. We aimed to investigate the effects of dielectric barrier discharge (DBD) plasma technology in the preparation of Riceberry™ rice flour (PRBF) on iron-induced oxidative stress in mice. PRBF using plasma technology was rich in anthocyanins, mainly cyanidine-3-glucoside and peonidine-3-glucoside. PRBF (5 mg AE/mg) lowered WBC numbers in iron dextran (FeDex)-loaded mice and served as evidence of the reversal of erythrocyte superoxide dismutase activity, plasma total antioxidant capacity, and plasma and liver thiobarbituric acid-reactive substances in the loading mice. Consequently, the PRBF treatment was observed to be more effective than NAC treatment. PRBF would be a powerful supplementary and therapeutic antioxidant product that is understood to be more potent than NAC in ameliorating the effects of iron-induced oxidative stress. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Optimization and Validation of an In Vitro Standardized Glycogen Phosphorylase Activity Assay
Molecules 2021, 26(15), 4635; https://doi.org/10.3390/molecules26154635 - 30 Jul 2021
Cited by 2 | Viewed by 752
Abstract
Glycogen phosphorylase (GP) is a key enzyme in the glycogenolysis pathway and a potential therapeutic target in the management of type 2 diabetes. It catalyzes a reversible reaction: the release of the terminal glucosyl residue from glycogen as glucose 1-phosphate; or the transfer [...] Read more.
Glycogen phosphorylase (GP) is a key enzyme in the glycogenolysis pathway and a potential therapeutic target in the management of type 2 diabetes. It catalyzes a reversible reaction: the release of the terminal glucosyl residue from glycogen as glucose 1-phosphate; or the transfer of glucose from glucose 1-phosphate to glycogen. A colorimetric method to follow in vitro the activity of GP with usefulness in structure-activity relationship studies and high-throughput screening capability is herein described. The obtained results allowed the choice of the optimal concentration of enzyme of 0.38 U/mL, 0.25 mM glucose 1-phosphate, 0.25 mg/mL glycogen, and temperature of 37 °C. Three known GP inhibitors, CP-91149, a synthetic inhibitor, caffeine, an alkaloid, and ellagic acid, a polyphenol, were used to validate the method, CP-91149 being the most active inhibitor. The effect of glucose on the IC50 value of CP-91149 was also investigated, which decreased when the concentration of glucose increased. The assay parameters for a high-throughput screening method for discovery of new potential GP inhibitors were optimized and standardized, which is desirable for the reproducibility and comparison of results in the literature. The optimized method can be applied to the study of a panel of synthetic and/or natural compounds, such as polyphenols. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Efficacy of Caffeic Acid on Diabetes and Its Complications in the Mouse
Molecules 2021, 26(11), 3262; https://doi.org/10.3390/molecules26113262 - 28 May 2021
Cited by 8 | Viewed by 1462
Abstract
Diabetic dyslipidemia and hyperglycemia contribute to excessive reactive oxygen species (ROS) production, leading to deleterious complications, such as nephropathy, atherosclerosis and cardiac dysfunction, and target major organs in the body. The aim of this study was to investigate the effect of caffeic acid [...] Read more.
Diabetic dyslipidemia and hyperglycemia contribute to excessive reactive oxygen species (ROS) production, leading to deleterious complications, such as nephropathy, atherosclerosis and cardiac dysfunction, and target major organs in the body. The aim of this study was to investigate the effect of caffeic acid (CA) on mouse weight and survival, serum level of fasting blood glucose (FBG), serum lipid parameters and atherogenic indices, oxidative damage in blood, liver and kidney tissue, pathophysiological changes and their function markers in healthy and alloxan-induced type 1 diabetic mice. Diabetes was induced in mice with a single intravenous injection of alloxan (75 mg kg−1). Two days later, CA (50 mg kg−1) was given intraperitoneally for seven days in diabetic mice. Diabetes affected glucose level, lipid profile, hematological and biochemical parameters, induced DNA damage and apoptotic/necrotic death in whole blood cells, liver and kidney, leading to weight loss and a decreased lifespan. CA treatment of diabetic mice revealed a protective effect on the liver and kidney, hypoglycemic and hypolipidemic properties and high protection against atherogenic outcomes. The obtained results suggest that CA is a safe and potent agent against diabetes that acts as an effective antioxidant in reducing serum glucose, lipid profile and atherogenic indices, leading to increased lifespan in mice. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Novel Semi-Synthetic Cu (II)–Cardamonin Complex Exerts Potent Anticancer Activity against Triple-Negative Breast and Pancreatic Cancer Cells via Inhibition of the Akt Signaling Pathway
Molecules 2021, 26(8), 2166; https://doi.org/10.3390/molecules26082166 - 09 Apr 2021
Cited by 2 | Viewed by 1176
Abstract
Cardamonin is a polyphenolic natural product that has been shown to possess cytotoxic activity against a variety of cancer cell lines. We previously reported the semi-synthesis of a novel Cu (II)–cardamonin complex (19) that demonstrated potent antitumour activity. In this study, [...] Read more.
Cardamonin is a polyphenolic natural product that has been shown to possess cytotoxic activity against a variety of cancer cell lines. We previously reported the semi-synthesis of a novel Cu (II)–cardamonin complex (19) that demonstrated potent antitumour activity. In this study, we further investigated the bioactivity of 19 against MDA-MB-468 and PANC-1 cancer cells in an attempt to discover an effective treatment for triple-negative breast cancer (TNBC) and pancreatic cancer, respectively. Results revealed that 19 abolished the formation of MDA-MB-468 and PANC-1 colonies, exerted growth-inhibitory activity, and inhibited cancer cell migration. Further mechanistic studies showed that 19 induced DNA damage resulting in gap 2 (G2)/mitosis (M) phase arrest and microtubule network disruption. Moreover, 19 generated reactive oxygen species (ROS) that may contribute to induction of apoptosis, corroborated by activation of caspase-3/7, PARP cleavage, and downregulation of Mcl-1. Complex 19 also decreased the expression levels of p-Akt and p-4EBP1, which indicates that the compound exerts its activity, at least in part, via inhibition of Akt signalling. Furthermore, 19 decreased the expression of c-Myc in PANC-1 cells only, which suggests that it may exert its bioactivity via multiple mechanisms of action. These results demonstrate the potential of 19 as a therapeutic agent for TNBC and pancreatic cancer. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
The Potential of Parsley Polyphenols and Their Antioxidant Capacity to Help in the Treatment of Depression and Anxiety: An In Vivo Subacute Study
Molecules 2021, 26(7), 2009; https://doi.org/10.3390/molecules26072009 - 01 Apr 2021
Cited by 11 | Viewed by 1515
Abstract
Depression and anxiety are major mental health problems in all parts of the world. These illnesses are associated with a number of risk factors, including oxidative stress. Psychotropic drugs of a chemical nature have demonstrated several side effects that elevated the impact of [...] Read more.
Depression and anxiety are major mental health problems in all parts of the world. These illnesses are associated with a number of risk factors, including oxidative stress. Psychotropic drugs of a chemical nature have demonstrated several side effects that elevated the impact of those illnesses. Faced with this situation, natural products appear to be a promising alternative. The aim of this study was to evaluate the anxiolytic and antidepressant effects of the Petroselinum sativum polyphenols in vivo, as well as its correlated antioxidant properties in vitro. Anxiolytic activity of the extract (50 and 100 mg/kg) was evaluated using the open field and the light-dark chamber tests, while the antidepressant activity was evaluated using the forced swimming test. The antioxidant activity of the extract was evaluated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical test and the FRAP (iron-reducing capacity) test. The phenolic extract showed very powerful anxiolytic and antidepressant-like effects, especially at a dose of 100 mg/kg, decreasing the depressive behavior in mice (decreased immobility time) and also the anxiolytic behavior (tendency for discovery in the center and illuminated areas) better even than those of paroxetine and bromazepam (classic drugs) concomitant with those results the extract also showed an important antioxidant capacity. These preliminary results suggest that Petroselinum sativum exhibits anxiolytic and antidepressant potential for use as a complement or independent phytomedicine to treat depression and anxiety. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Article
Synthesis of Rottlerone Analogues and Evaluation of Their α-Glucosidase and DPP-4 Dual Inhibitory and Glucose Consumption-Promoting Activity
Molecules 2021, 26(4), 1024; https://doi.org/10.3390/molecules26041024 - 15 Feb 2021
Viewed by 963
Abstract
Our previous study found that desmethylxanthohumol (1) inhibited α-glucosidase in vitro. Recently, further investigations revealed that dehydrocyclodesmethylxanthohumol (2) and its dimer analogue rottlerone (3) exhibited more potent α-glucosidase inhibitory activity than 1. The aim of this [...] Read more.
Our previous study found that desmethylxanthohumol (1) inhibited α-glucosidase in vitro. Recently, further investigations revealed that dehydrocyclodesmethylxanthohumol (2) and its dimer analogue rottlerone (3) exhibited more potent α-glucosidase inhibitory activity than 1. The aim of this study was to synthesize a series of rottlerone analogues and evaluate their α-glucosidase and DPP-4 dual inhibitory activity. The results showed that compounds 4d and 5d irreversibly and potently inhibited α-glucosidase (IC50 = 0.22 and 0.12 μM) and moderately inhibited DPP-4 (IC50 = 23.59 and 26.19 μM), respectively. In addition, compounds 4d and 5d significantly promoted glucose consumption, with the activity of 5d at 0.2 μM being comparable to that of metformin at a concentration of 1 mM. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Review

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Review
Phenolics as GABAA Receptor Ligands: An Updated Review
Molecules 2022, 27(6), 1770; https://doi.org/10.3390/molecules27061770 - 08 Mar 2022
Viewed by 721
Abstract
Natural products can act as potential GABA modulators, avoiding the undesirable effects of traditional pharmacology used for the inhibition of the central nervous system such as benzodiazepines (BZD). Phenolics, especially flavonoids and phlorotannins, have been considered as modulators of the BZD-site of GABA [...] Read more.
Natural products can act as potential GABA modulators, avoiding the undesirable effects of traditional pharmacology used for the inhibition of the central nervous system such as benzodiazepines (BZD). Phenolics, especially flavonoids and phlorotannins, have been considered as modulators of the BZD-site of GABAA receptors (GABAARs), with sedative, anxiolytic or anticonvulsant effects. However, the wide chemical structural variability of flavonoids shows their potential action at more than one additional binding site on GABAARs, which may act either negatively, positively, by neutralizing GABAARs, or directly as allosteric agonists. Therefore, the aim of the present review is to compile and discuss an update of the role of phenolics, namely as pharmacological targets involving dysfunctions of the GABA system, analyzing both their different compounds and their mechanism as GABAergic modulators. We focus this review on articles written in English since the year 2010 until the present. Of course, although more research would be necessary to fully establish the type specificity of phenolics and their pharmacological activity, the evidence supports their potential as GABAAR modulators, thereby favoring their inclusion in the development of new therapeutic targets based on natural products. Specifically, the data compiled in this review allows for the directing of future research towards ortho-dihydroxy diterpene galdosol, the flavonoids isoliquiritigenin (chalcone), rhusflavone and agathisflavone (biflavonoids), as well as the phlorotannins, dieckol and triphlorethol A. Clinically, flavonoids are the most interesting phenolics due to their potential as anticonvulsant and anxiolytic drugs, and phlorotannins are also of interest as sedative agents. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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Review
Increasing the Power of Polyphenols through Nanoencapsulation for Adjuvant Therapy against Cardiovascular Diseases
Molecules 2021, 26(15), 4621; https://doi.org/10.3390/molecules26154621 - 30 Jul 2021
Viewed by 1152
Abstract
Polyphenols play a therapeutic role in vascular diseases, acting in inherent illness-associate conditions such as inflammation, diabetes, dyslipidemia, hypertension, and oxidative stress, as demonstrated by clinical trials and epidemiological surveys. The main polyphenol cardioprotective mechanisms rely on increased nitric oxide, decreased asymmetric dimethylarginine [...] Read more.
Polyphenols play a therapeutic role in vascular diseases, acting in inherent illness-associate conditions such as inflammation, diabetes, dyslipidemia, hypertension, and oxidative stress, as demonstrated by clinical trials and epidemiological surveys. The main polyphenol cardioprotective mechanisms rely on increased nitric oxide, decreased asymmetric dimethylarginine levels, upregulation of genes encoding antioxidant enzymes via the Nrf2-ARE pathway and anti-inflammatory action through the redox-sensitive transcription factor NF-κB and PPAR-γ receptor. However, poor polyphenol bioavailability and extensive metabolization restrict their applicability. Polyphenols carried by nanoparticles circumvent these limitations providing controlled release and better solubility, chemical protection, and target achievement. Nano-encapsulate polyphenols loaded in food grade polymers and lipids appear to be safe, gaining resistance in the enteric route for intestinal absorption, in which the mucoadhesiveness ensures their increased uptake, achieving high systemic levels in non-metabolized forms. Nano-capsules confer a gradual release to these compounds, as well as longer half-lives and cell and whole organism permanence, reinforcing their effectiveness, as demonstrated in pre-clinical trials, enabling their application as an adjuvant therapy against cardiovascular diseases. Polyphenol entrapment in nanoparticles should be encouraged in nutraceutical manufacturing for the fortification of foods and beverages. This study discusses pre-clinical trials evaluating how nano-encapsulate polyphenols following oral administration can aid in cardiovascular performance. Full article
(This article belongs to the Special Issue New Trends in Polyphenols and Health)
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