Polyphenols and health: update and perspectives

Exploring beneficial effects of phytobiotics in marine shrimp farming: A review

Marine shrimp farming, mainly Penaeus monodon and Litopenaeus vannamei, is an important component of the aquaculture industry. Marine shrimp farming helps produce a protein source for humans, provides job opportunities, and generates lucrative profits for investors. Intensification farming practices can lead to poor water quality, stress, and malnutrition among the farmed marine shrimp, resulting in disease outbreaks and poor production, impeding the development of marine shrimp farming. Antibiotics are the common short-term solution to treat diseases in marine shrimp farming. Moreover, the negative impacts of using antibiotics on public health and the environment erode consumer confidence in aquaculture products. Recently, research on using phytobiotics as a prophylactic agent in aquaculture has become a hot topic. Various phytobiotics have been explored to reveal their beneficial effects on aquaculture species. In this review paper, the sources and modes of action of phytobiotics are presented. The roles of phytobiotics in improving growth performance, increasing antioxidant capacity, enhancing the immune system, stimulating disease resistance, and mitigating stress due to abiotic factors in marine shrimp culture are recapitulated and discussed.

Phytochemical Investigation of Carex praecox Schreb. and ACE-Inhibitory Activity of Oligomer Stilbenes of the Plant

Phenolic compounds are the main special metabolites of Cyperaceae species from phytochemical, pharmacological, and chemotaxonomical points of view. The present study focused on the isolation, structure determination, and pharmacological investigation of constituents from Carex praecox. Twenty-six compounds, including lignans, stilbenes, flavonoids, megastigmanes, chromenes, and phenylpropanoids, were identified from the methanol extract of the plant. Five of these compounds, namely, carexines A-E, are previously undescribed natural products. All compounds were isolated for the first time from C. praecox. The ACE-inhibitory activity of seven stilbenoid compounds was tested, and (-)-hopeaphenol proved to be the most active (IC50 7.7 ± 0.9 μM). The enzyme-kinetic studies revealed a mixed-type inhibition; therefore, domain-specific studies were also conducted. The in silico docking of (-)-hopeaphenol to the ACE affirmed some favorable interactions. In addition, the antiproliferative and antibacterial effects of some compounds were also evaluated.

Dietary (poly)phenols and cardiometabolic health: from antioxidants to modulators of the gut microbiota

(Poly)phenols are plant secondary metabolites widely abundant in plant foods and beverages comprising a very large number of compounds with diverse structure and biological activities. Accumulating evidence indicates that these compounds exert beneficial effects against cardiometabolic diseases, and this review will provide a summary of current knowledge in this area. Epidemiological and clinical data collectively suggest that intake of flavonoids reduces the risk of cardiovascular disease (CVD), with the evidence being particularly strong for the flavan-3-ol subclass. However, to provide adequate dietary recommendations, a better understanding of their estimated content in foods and intake among the general public is needed. Regarding mechanisms of action, we now know that it is unlikely that (poly)phenols act as direct antioxidants in vivo, as it was hypothesised for decades with the popularity of in vitro antioxidant capacity assays. One of the reasons is that upon ingestion, (poly)phenols are extensively metabolised into a wide array of circulating metabolites with different bioactivities than their precursors. Well-conducted in vitro and in vivo studies and human nutrigenomic analysis have revealed new molecular targets that may be underlying the health benefits of (poly)phenols, such as the nitric oxide pathway. Recently, a bi-directional relationship was established between (poly)phenols and the gut microbiota, suggesting that individual gut microbial metabolising capacity may be a key factor explaining the variability in the cardiometabolic response to (poly)phenols. Future research is needed to elucidate which are the key factors affecting such capacity, and whether it can be modulated, along with the mechanisms of action.

Purple Carrot Extract Exhibits a Neuroprotective Profile in th e Nigrostriatal Pathway in the Reserpine-induced Model of Parkinson 's Disease

BACKGROUND

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the nigrostriatal pathway. Even with scientific and technological advances, the therapeutic approaches used for the treatment of PD have shown to be largely ineffective in controlling the progression of symptoms in the long term. There is a growing demand for the development of novel therapeutic strategies for PD treatment. Different herbs and supplements have been considered as adjuvant to treat the symptoms of Parkinsonism. The carrot is one of the most consumed vegetable species worldwide, and its root is known for its content of anthocyanins, which possess antioxidant and antiinflammatory properties. This study evaluated the neuroprotective effect of purple carrot extract (CAR) in rats on the reserpine (RES)-induced progressive parkinsonism model.

METHODS

Male rats (6-month-old) received orally the CAR (400 mg/kg) or vehicle and subcutaneously RES (0.01 mg/kg) or vehicle for 28 days (Preventive Phase). From the 29th day, rats received CAR or vehicle daily and RES (0.1 mg/kg) or vehicle every other day (for 23 days, Protective phase). Behavioral tests were conducted throughout the treatment. Upon completion, the animals' brain were processed for tyrosine hydroxylase (TH) immunohistochemical assessment.

RESULTS

Our results showed that the chronic treatment of CAR protected against motor disabilities, reducing the time of catalepsy behavior and decreasing the frequency of oral movements, possibly by preserving TH levels in the Ventral Tegmental Area (VTA) and SNpc.

CONCLUSION

CAR extract is effective to attenuate motor symptoms in rats associated with increased TH+ levels in the Ventral Tegmental Area (VTA) and SNpc, indicating the potential nutraceutical benefits of CAR extract in a progressive parkinsonism model induced by RES.

Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review

Fruits, vegetables, and other food items contain phytochemicals or secondary metabolites which may be considered non-essential nutrients but have medicinal importance. These dietary phytochemicals exhibit chemopreventive and therapeutic effects against numerous diseases. Polyphenols are secondary metabolites found in vegetables, fruits, and grains. These compounds exhibit several health benefits such as immune modulators, vasodilators, and antioxidants. This review focuses on recent studies on using dietary polyphenols to treat cardiovascular disorders, atherosclerosis, and vascular endothelium deficits. We focus on exploring the safety of highly effective polyphenols to ensure their maximum impact on cardiac abnormalities and discuss recent epidemiological evidence and intervention trials related to these properties. Kaempferol, quercetin, and resveratrol prevent oxidative stress by regulating proteins that induce oxidation in heart tissues. In addition, polyphenols modulate the tone of the endothelium of vessels by releasing nitric oxide (NO) and reducing low-density lipoprotein (LDL) oxidation to prevent atherosclerosis. In cardiomyocytes, polyphenols suppress the expression of inflammatory markers and inhibit the production of inflammation markers to exert an anti-inflammatory response. Consequently, heart diseases such as strokes, hypertension, heart failure, and ischemic heart disease could be prevented by dietary polyphenols.

Variation, during Shelf Life, of Functional Properties of Biscuits Enriched with Fibers Extracted from Artichoke (Cynara scolymus L.)

To boost revaluation of industrial by-products of artichoke, this research tries to determine the stability throughout storage of phenolic compounds and their antioxidant activity in biscuits enriched with fiber-rich powders extracted from b y-products of artichokes (FRPA). To determine the most stable extraction method, biscuits were formulated with FRPA extracted by two different environmentally friendly extraction solvents: water (W) and a solution of 1% CaCl2∙5H2O (CA) and compared with biscuits made with pea fiber (P) and control biscuits (B) without fiber added. Initially and during storage, the biscuits enriched with FRPA (W, CA) showed a higher content of bioavailable polyphenols and antioxidant activity compared to the control biscuits (B) and the reference fiber (P, pea fiber). In conclusion, FRPA are an excellent source of bioavailable fiber with antioxidant activity, but especially the FRPA extracted with 1% CaCl2∙5H2O (CA), and they could present a good alternative to the use of pea fiber.

New Insights on Dietary Polyphenols for the Management of Oxidative Stress and Neuroinflammation in Diabetic Retinopathy

Diabetic retinopathy (DR) is a neurodegenerative and vascular pathology that is considered one of the leading causes of blindness worldwide, resulting from complications of advanced diabetes mellitus (DM). Current therapies consist of protocols aiming to alleviate the existing clinical signs associated with microvascular alterations limited to the advanced disease stages. In response to the low resolution and limitations of the DR treatment, there is an urgent need to develop more effective alternative therapies to optimize glycemic, vascular, and neuronal parameters, including the reduction in the cellular damage promoted by inflammation and oxidative stress. Recent evidence has shown that dietary polyphenols reduce oxidative and inflammatory parameters of various diseases by modulating multiple cell signaling pathways and gene expression, contributing to the improvement of several chronic diseases, including metabolic and neurodegenerative diseases. However, despite the growing evidence for the bioactivities of phenolic compounds, there is still a lack of data, especially from human studies, on the therapeutic potential of these substances. This review aims to comprehensively describe and clarify the effects of dietary phenolic compounds on the pathophysiological mechanisms involved in DR, especially those of oxidative and inflammatory nature, through evidence from experimental studies. Finally, the review highlights the potential of dietary phenolic compounds as a prophylactic and therapeutic strategy and the need for further clinical studies approaching the efficacy of these substances in DR management.

Transcriptomic Analysis on the Peel of UV-B-Exposed Peach Fruit Reveals an Upregulation of Phenolic- and UVR8-Related Pathways

UV-B treatment deeply influences plant physiology and biochemistry, especially by activating the expression of responsive genes involved in UV-B acclimation through a UV-B-specific perception mechanism. Although the UV-B-related molecular responses have been widely studied in Arabidopsis, relatively few research reports deepen the knowledge on the influence of post-harvest UV-B treatment on fruit. In this work, a transcriptomic approach is adopted to investigate the transcriptional modifications occurring in the peel of UV-B-treated peach (Prunus persica L., cv Fairtime) fruit after harvest. Our analysis reveals a higher gene regulation after 1 h from the irradiation (88% of the differentially expressed genes-DEGs), compared to 3 h recovery. The overexpression of genes encoding phenylalanine ammonia-lyase (PAL), chalcone syntase (CHS), chalcone isomerase (CHI), and flavonol synthase (FLS) revealed a strong activation of the phenylpropanoid pathway, resulting in the later increase in the concentration of specific flavonoid classes, e.g., anthocyanins, flavones, dihydroflavonols, and flavanones, 36 h after the treatment. Upregulation of UVR8-related genes (HY5, COP1, and RUP) suggests that UV-B-triggered activation of the UVR8 pathway occurs also in post-harvest peach fruit. In addition, a regulation of genes involved in the cell-wall dismantling process (PME) is observed. In conclusion, post-harvest UV-B exposure deeply affects the transcriptome of the peach peel, promoting the activation of genes implicated in the biosynthesis of phenolics, likely via UVR8. Thus, our results might pave the way to a possible use of post-harvest UV-B treatments to enhance the content of health-promoting compounds in peach fruits and extending the knowledge of the UVR8 gene network.

Cardiovascular disease protective properties of blueberry polyphenols (Vaccinium corymbosum): a concise review

Increasing epidemiological evidence suggests inverse association between consumption of diets rich in fruits and vegetables and the incidence of cardiovascular diseases (CVD), metabolic syndrome disorders, certain types of cancer, neurodegenerative disorders, and other forms of human chronic diseases. This may be due to the contents of some bioactive phytochemicals, especially polyphenols, which are abundant in fruits and vegetables and have antioxidant effects. Berry fruits are reported to have the highest total antioxidant capacity (TAC) among fruits. They may protect against CVD and hypertension either directly or in tandem with other cellular mechanisms. Blueberry anthocyanins have been reported to exhibit cardiovascular protective health effects by preventing cholesterol-induced atherosclerosis, and reduction of oxidative and inflammatory damages to the endothelium through several mechanisms. Such mechanisms may involve suppressing the release of inflammatory mediators, protection against ischemic damage of the heart as well as cardiomyocyte survival, lower systolic and mean arterial pressures and renal nitrite content in addition to multiple other beneficial effects. However, several limitations in existing studies make it difficult to draw conclusions regarding the preventive effects of blueberries and other polyphenols-rich foods, especially as data supporting a causal relationship between direct antioxidant capacity and CVD are insufficient or limited. It is also unclear, which molecules exert this effect since few studies with isolated polyphenols have been conducted in addition to a lack of proper understanding of other mechanisms that may be involved. This review is, therefore aimed at discussing some of the current literature information on the cardiovascular protective effects of blueberries with suggestions for future research directions.

Graphical Abstract

Graphical abstract demonstrating the overall mechanisms of CVD protection by blueberry and blueberry polyphenols and anthocyanins. Blueberry consumption leads to reduced CVD complications due to the modulation of several mechanisms associated with CVD.

Comparative Study on Chemical Composition of Green and Black Table Olives Brines of the Endemic ''Sigoise'' Cultivar: Recovery of high-Added Values Compounds

The effluents derived from the processing of table olives stand for a serious environmental problem. The study aims to valorize the brine water of table olives at different stages of ripening (green and black) of the Algerian variety Sigoise of Bejaia (East) and Mascara (West). The physico-chemical characterization revealed that these samples display have a high acid pH and salinity. The comparative study of phenolic levels exhibited showed very significant differences between the brine waters of green olives from Bejaia and Mascara, while the brines of black olives presented showed comparable levels. A high strong antioxidant potential was confirmed by DPPH (CI₅₀ =0.35 μg/100 ml-0.50 μg/100 ml) and FRAP (CI₅₀ =626.89 μg/100 ml-875.54 μg/100 ml) tests. Chemical screening by HPLC-DAD of the four samples identified high concentrations of hydroxytyrosol (HT) (390.4 mg/100 ml-360.8 mg/100 ml) and tyrosol (202.2 mg/100 ml-101.4 mg/100 ml). This study provided a deeper insight into the phenolic profile and the antioxidant potential of these brines.

Hybridization of Aminoadamantanes with Cinnamic Acid Analogues and Elucidation of Their Antioxidant Profile

A series of seventeen cinnamic acid hybrids (4ai–ci) were obtained through an amidation of aminoadamantanes (amantadine, rimantadine, and memantine) with mixed anhydride generated from different substituted cinnamic acid and ethyl chloroformate. 1H NMR, 13C NMR, IR, and HRMS were used for the confirmation of the structures of the synthesized hybrids. Moreover, the antioxidant profiles of amides were estimated as per five different in vitro methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid cation radical (ABTS⁺), ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC) assay, and inhibition of Fe(III)/asc induced lipid peroxidation (LP) in brain homogenate. For comparison, caffeic acid (CaffA), known as a potent naturally occurring antioxidant, was used as a reference compound in our study. The results revealed that the most prominent antioxidant activity was demonstrated by compound 4b2, with excellent CUPRAC, FRAP, scavenging ABTS+˙ potential, and inhibition of Fe/asc–induced LP, followed by 4c6 > 4a6 > CaffA > 4c5 and 4a5 > 4a7. Overall, the results suggest that the hybrids (4b2, 4c6, and 4a6) consisting of a caffeoyl moiety and lipophilic adamantane core endow the molecules with the higher antioxidant activity than their parent compound (caffeic acid), especially against LP. Thus, these promising antioxidants could have beneficial effects in various pathological conditions, where oxidative stress is implicated.

The Flavonol Quercitrin Hinders GSK3 Activity and Potentiates the Wnt/β-Catenin Signaling Pathway

The Wnt/β-catenin signaling pathway dictates cell proliferation and differentiation during embryonic development and tissue homeostasis. Its deregulation is associated with many pathological conditions, including neurodegenerative disease, frequently downregulated. The lack of efficient treatment for these diseases, including Alzheimer’s disease (AD), makes Wnt signaling an attractive target for therapies. Interestingly, novel Wnt signaling activating compounds are less frequently described than inhibitors, turning the quest for novel positive modulators even more appealing. In that sense, natural compounds are an outstanding source of potential drug leads. Here, we combine different experimental models, cell-based approaches, neuronal culture assays, and rodent behavior tests with Xenopus laevis phenotypic analysis to characterize quercitrin, a natural compound, as a novel Wnt signaling potentiator. We find that quercitrin potentiates the signaling in a concentration-dependent manner and increases the occurrence of the Xenopus secondary axis phenotype mediated by Xwnt8 injection. Using a GSK3 biosensor, we describe that quercitrin impairs GSK3 activity and increases phosphorylated GSK3β S9 levels. Treatment with XAV939, an inhibitor downstream of GSK3, impairs the quercitrin-mediated effect. Next, we show that quercitrin potentiates the Wnt3a-synaptogenic effect in hippocampal neurons in culture, which is blocked by XAV939. Quercitrin treatment also rescues the hippocampal synapse loss induced by intracerebroventricular injection of amyloid-β oligomers (AβO) in mice. Finally, quercitrin rescues AβO-mediated memory impairment, which is prevented by XAV939. Thus, our study uncovers a novel function for quercitrin as a Wnt/β-catenin signaling potentiator, describes its mechanism of action, and opens new avenues for AD treatments.

Resorcinol Derivatives as Novel Aldose Reductase Inhibitors: In Silico and In Vitro Evaluation

Background:

The polyol pathway, an alternative way of carbohydrate metabolism, is activated by hyperglycemia. Aldose reductase (AR), the first and rate-limiting enzyme of the polyol pathway, is responsible for the reduction of glucose to sorbitol. Inhibiting the aldose reductase enzyme and reducing the polyol pathway is considered an effective method to prevent and postpone the onset of diabetic complications.

Objective:

Therefore, in this work, we investigate the inhibition effects of certain resorcinol derivatives and the positive control compound quercetin on the AR enzyme in vitro and in silico. These phenolic compounds, whose inhibitory effects on the AR enzyme were investigated, were also compared with known drugs in terms of their drug-like characteristics.

Methods:

Three methods were used to determine the inhibitory effects of resorcinol derivatives on recombinant human AR enzyme. After the in vitro inhibition effects were determined spectrophotometrically, the binding energy and binding modes were determined by molecular docking method. Finally, the MM-GBSA method was used to determine the free binding energies of the inhibitors for the AR enzyme.

Results:

5-pentylresorcinol compound showed the strongest inhibition effect on recombinant human AR enzyme with an IC50 value of 9.90 μM. The IC50 values of resorcinol, 5-methylresorcinol, 4- ethylresorcinol, 4-hexylresorcinol, 2-methylresorcinol, and 2,5-dimethylresorcinol compounds were determined as 49.50 μM, 43.31 μM, 19.25 μM, 17.32 μM, 28.87 μM, 57.75 μM, respectively.

Conclusion:

The results of this research showed that resorcinol compounds are effective AR inhibitors. These findings are supported by molecular docking, molecular mechanics, and ADME investigations undertaken to corroborate the experimental in vitro results.

In Vitro Antioxidant and Prooxidant Activities of Red Raspberry (Rubus idaeus L.) Stem Extracts

Leaves and stems of red raspberry (Rubus idaeus) are used in Lithuanian folk medicine. Healing properties of raspberry are related to the content of bioactive compounds, mainly polyphenols. Extracts of raspberry leaves contained higher total phenolic content (TPC) (1290 mg/L, expressed in gallic acid equivalent) compared to that in extracts of stems or peeled bark (up to 420 mg/L and 598 mg/L, respectively). To find out whether the collection time of herbal material was critical for the properties of the extracts, the stems were collected at different times of the year. TPC in the extracts depended more on extraction conditions rather than on the sampling time. Antioxidant activity of raspberry stem and bark extracts tested by spectrophotometric (DPPH● scavenging) and electrochemical (cyclic and differential pulse voltammetry) assays correlated with TPC. DPPH radical scavenging activity values for stem, leaf, and bark extracts were as follows: ≤1.18 ± 0.07, 1.63 ± 0.10, and ≤1.90 ± 0.04 (mmol/L, TROLOX equivalent), respectively. Assessed electrochemically, hydrogen peroxide-scavenging activity of extracts was independent on TPC. The latter activity was related to the presence of some protein in the extract as revealed by gel electrophoresis. Prooxidant activity of raspberry stem extracts was dependent on solution pH and temperature.

Cisplatin Chemotherapy and Cochlear Damage: Otoprotective and Chemosensitization Properties of Polyphenols

Significance: Cisplatin is an important component of treatment regimens for different cancers. Notwithstanding that therapeutic success often results from partial efficacy or stabilizing the disease, chemotherapy failure is driven by resistance to drug treatment and occurrence of side effects, such as progressive irreversible ototoxicity. Cisplatin's side effects, including ototoxicity, are often dose limiting. Recent Advances: Cisplatin ototoxicity results from several mechanisms, including redox imbalance caused by reactive oxygen species production and lipid peroxidation, activation of inflammation, and p53 and its downstream pathways that culminate in apoptosis. Considerable efforts in research have targeted development of molecular interventions that can be concurrently administered with cisplatin or other chemotherapies to reduce side effect toxicities while preserving or enhancing the antineoplastic effects. Evidence from studies has indicated some polyphenols, such as curcumin, can help to regulate redox signaling and inflammatory effects. Furthermore, polyphenols can exert opposing effects in different types of tissues, that is, normal cells undergoing stressful conditions versus cancer cells. Critical Issues: This review article summarizes evidence of curcumin antioxidant effect against cisplatin-induced ototoxicity that is converted to a pro-oxidant activity in cisplatin-treated cancer cells, thus providing an ideal chemosensitivity combined with otoprotection. Polyphenols can modulate the adaptive responses to stress in the cisplatin-exposed cochlea. These adaptive effects can result from the interaction/cross talk between the cell's defenses, inflammatory molecules, and the key signaling molecules of signal transducers and activators of transcription 3 (STAT-3), nuclear factor κ-B (NF-κB), p53, and nuclear factor erythroid 2-related factor 2 (Nrf-2). Future Directions: We provide molecular evidence for alternative strategies for chemotherapy with cisplatin addressing the otoprotection and chemosensitization properties of polyphenols. Antioxid. Redox Signal. 36, 1229-1245.

Aronia melanocarpa Fruit Juice Modulates ACE2 Immunoexpression and Diminishes Age-Related Remodeling of Coronary Arteries in Rats

The aim of the study is to evaluate the effect of Aronia melanocarpa fruit juice (AMJ) supplementation on age-related coronary arteries remodeled in aged rat hearts. Male Wistar rats (n = 24) were divided into three groups: (1) young controls (CY), aged 2 months, without AMJ supplementation; (2) old controls (CO), aged 27 months, without AMJ supplementation; and (3) the AMJ group (A), which used 27-month old animals, supplemented orally with AMJ for 105 days. AMJ supplementation did not influence the wall-to-diameter parameter (Kernohan index) of the coronary arteries of test animals. Aged rats supplemented with AMJ showed a significant decrease in the amount of collagen fibers in their coronary tunica media, as compared with the old controls. The intensity of the immunoreaction for alpha smooth muscle actin (αSMA) in the coronary tunica media was significantly lower in the supplemented group than in the old controls. The intensity of the angiotensin-converting enzyme 2 (ACE2) immunoreaction in the coronary tunica media of the supplemented group was significantly higher than the one observed in the old controls. These results indicate the positive effects of AMJ supplementation on the age-dependent remodeling of coronary arteries and support for the preventive potential of antioxidant-rich functional food supplementation in age-related diseases.

Hybrid Classification/Regression Approach to QSAR Modeling of Stoichiometric Antiradical Capacity Assays' Endpoints

Quantitative structure-activity relationships (QSAR) are a widely used methodology allowing not only a better understanding of the mechanisms of chemical reactions, including radical scavenging, but also to predict the relevant properties of chemical compounds without their synthesis, isolation and experimental testing. Unlike the QSAR modeling of the kinetic antioxidant assays, modeling of the assays with stoichiometric endpoints depends strongly on the number of hydroxyl groups in the antioxidant molecule, as well as on some integral molecular descriptors characterizing the proportion of OH-groups able to enter and complete the radical scavenging reaction. In this work, we tested the feasibility of a "hybrid" classification/regression approach, consisting of explicit classification of individual OH-groups as involved in radical scavenging reactions, and using further the number of these OH-groups as a descriptor in simple-regression QSAR models of antiradical capacity assays with stoichiometric endpoints. A simple threshold classification based on the sum of trolox-equivalent antiradical capacity values was used, selecting OH-groups with specific radical stability- and reactivity-related electronic parameters or their combination as "active" or "inactive". We showed that this classification/regression modeling approach provides a substantial improvement of the simple-regression QSAR models over those built on the number of total phenolic OH-groups only, and yields a statistical performance similar to that of the best reported multiple-regression QSARs for antiradical capacity assays with stoichiometric endpoints.

Polydatin combats methotrexate-induced pulmonary fibrosis in rats: Involvement of biochemical and histopathological assessment

Polydatin (PD) is a polyphenolic compound found naturally in many fruits such as grapes. It has anti-oxidant and anti-inflammatory activities that are of paramount importance for its pharmacological actions. This study aimed to explore possible protective effects of PD against methotrexate (MTX)-induced pulmonary fibrosis in rats. A single oral dose of MTX (14 mg/kg) per week for 2 weeks caused a significant decrease in glutathione (GSH) content with a marked increase in transforming growth factor-beta (TGF-β), alpha-smooth muscle actin (α-SMA), pulmonary content of malondialdehyde (MDA), interleukin-1β (IL-1β), Hydroxyproline, tumor necrosis factor-alpha (TNF-α), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) as compared with the control group. Contrarily, daily administration of PD (25, 50, and 100 mg/kg, p.o.) for 14 days concomitantly with MTX ameliorated MTX-induced pulmonary fibrosis as indicated by mitigation of the previously mentioned biochemical parameters and histopathological changes in a dose-dependent manner. In conclusion, the protective effect of PD against pulmonary fibrosis induced by MTX in rats might be attributed to its anti-oxidant, anti-inflammatory as well as anti-fibrotic effects.

Endothelium-Independent Relaxation of Vascular Smooth Muscle Induced by Persimmon-Derived Polyphenol Phytocomplex in Rats

The vasorelaxant effect of polyphenols is well known, and the mortality rate due to coronary artery disease is low in people who consume polyphenol-containing foods. We aimed to elucidate the mechanism by which polyphenols derived from persimmon juice (PJ) and persimmon leaves (PLs) induce vasorelaxation and suppress vasocontraction in the superior mesenteric arteries isolated from male Sprague Dawley rats. Vasocontraction was induced with 1 µM phenylephrine, and polyphenol-induced vasorelaxation was expressed as a percentage of the previous tone induced by phenylephrine. PJ powder (100 mg/L) induced higher levels of vasorelaxation (mean ± standard error of the mean, 88.6% ± 4.4%) than PLs powder (1 g/L; 72.0% ± 10.8%). Nitric oxide pathway inhibitors (NG-nitro-L-arginine methyl ester + carboxy-PTIO) did not affect persimmon-derived polyphenol-induced vasorelaxation, whereas potassium chloride, tetraethylammonium, and potassium-channel inhibitors did. Vasorelaxation was endothelium independent with both extracts. Phenylephrine-induced vasocontraction was suppressed by pretreatment with PJ and PLs powder, even when inositol triphosphate-mediated Ca²⁺ release and extracellular Ca²⁺ influx were inhibited. These results suggest that persimmon-derived polyphenol phytocomplex cause vasorelaxation and inhibit vasocontraction through hyperpolarization of smooth muscle cells. Persimmon-derived polyphenols may be able to prevent cardiovascular diseases caused by abnormal contraction of blood vessels.

Biocatalytic Approaches for an Efficient and Sustainable Preparation of Polyphenols and Their Derivatives

Many sectors of industry, such as food, cosmetics, nutraceuticals, and pharmaceuticals, have increased their interest in polyphenols due to their beneficial properties. These molecules are widely found in Nature (plants) and can be obtained through direct extraction from vegetable matrices. Polyphenols introduced through the diet may be metabolized in the human body via different biotransformations leading to compounds having different bioactivities. In this context, enzyme-catalyzed reactions are the most suitable approach to produce modified polyphenols that not only can be studied for their bioactivity but also can be labeled as green, natural products. This review aims to give an overview of the potential of biocatalysis as a powerful tool for the modification of polyphenols to enhance their bioaccessibility, bioavailability, biological activity or modification of their physicochemical properties. The main polyphenol transformations occurring during their metabolism in the human body have been also presented.

Anything New under the Sun? An Update on Modulation of Bioactive Compounds by Different Wavelengths in Agricultural Plants

Plants continuously rely on light as an energy source and as the driver of many processes in their lifetimes. The ability to perceive different light radiations involves several photoreceptors, which in turn activate complex signalling cascades that ultimately lead to a rearrangement in plant metabolism as an adaptation strategy towards specific light conditions. This review, after a brief summary of the structure and mode of action of the different photoreceptors, introduces the main classes of secondary metabolites and specifically focuses on the influence played by the different wavelengths on the content of these compounds in agricultural plants, because of their recognised roles as nutraceuticals.

Polyphenols and Visual Health: Potential Effects on Degenerative Retinal Diseases

Dietary polyphenols are a group of natural compounds that have been proposed to have beneficial effects on human health. They were first known for their antioxidant properties, but several studies over the years have shown that these compounds can exert protective effects against chronic diseases. Nonetheless, the mechanisms underlying these potential benefits are still uncertain and contradictory effects have been reported. In this review, we analyze the potential effects of polyphenol compounds on some visual diseases, with a special focus on retinal degenerative diseases. Current effective therapies for the treatment of such retinal diseases are lacking and new strategies need to be developed. For this reason, there is currently a renewed interest in finding novel ligands (or known ligands with previously unexpected features) that could bind to retinal photoreceptors and modulate their molecular properties. Some polyphenols, especially flavonoids (e.g., quercetin and tannic acid), could attenuate light-induced receptor damage and promote visual health benefits. Recent evidence suggests that certain flavonoids could help stabilize the correctly folded conformation of the visual photoreceptor protein rhodopsin and offset the deleterious effect of retinitis pigmentosa mutations. In this regard, certain polyphenols, like the flavonoids mentioned before, have been shown to improve the stability, expression, regeneration and folding of rhodopsin mutants in experimental in vitro studies. Moreover, these compounds appear to improve the integration of the receptor into the cell membrane while acting against oxidative stress at the same time. We anticipate that polyphenol compounds can be used to target visual photoreceptor proteins, such as rhodopsin, in a way that has only been recently proposed and that these can be used in novel approaches for the treatment of retinal degenerative diseases like retinitis pigmentosa; however, studies in this field are limited and further research is needed in order to properly characterize the effects of these compounds on retinal degenerative diseases through the proposed mechanisms.

Effects of grape products on inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials

This systematic review and meta-analysis of randomized controlled trials (RCTs) were conducted to determine the effects of grapes and grape products on inflammation and oxidative stress among adults. PubMed, Scopus, ISI Web of Science, and Cochrane Library databases were searched up to July 2020 to identify RCTs investigating the effects of grape and grape products on inflammatory and oxidative stress markers. Weighted mean differences (WMD) were pooled using a random-effects model. Of the 8,962 identified studies, 24 RCTs (27 arms) were included in the statistical analysis. Grape products significantly reduced serum C-reactive protein (CRP) levels (WMD: -0.35 mg/L; 95% CI: -0.62, -0.09, p = .008), but they had no significant effect on serum tumor necrosis factor-alpha (TNF-α) (WMD = -1.08 pg/ml; 95% CI: -2.29, 0.11, p = .07), interleukin-6 (IL-6) (WMD = 0.13 pg/ml; 95% CI: -0.35, 0.60, p = .60), total antioxidant capacity (TAC) (WMD = 0.15; 95% CI: -0.35, 0.65, p = .54), or malondialdehyde (MDA) (WMD = 0.14; 95% CI: -0.64, 0.92, p = .72). The analysis indicated possible decreasing effects of grapes and grape products on CRP, but they might not be able to change IL-6, TNF-α, TAC, and MDA concentrations. Nonetheless, further studies are warranted before definitive conclusions may be reached.

Assessment of In Vitro Bioaccessibility of Polyphenols from Annurca, Limoncella, Red Delicious, and Golden Delicious Apples Using a Sequential Enzymatic Digestion Model

Four different varieties of apples have been considered (Limoncella, Annurca, Red Delicious, and Golden Delicious) to estimate the extent of colon polyphenolics release after in vitro sequential enzyme digestion. Since several studies report a positive effect of apple polyphenols in colonic damage, we found of interest to investigate the colon release of polyphenols in different varieties of apples in order to assess their prevention of colonic damage. UHPLC-HRMS analysis and antioxidant activity (ABTS, DPPH, and FRAP assays) were carried out on the apple extracts (peel, flesh, and whole fruit) obtained from not digested samples and on bioaccessible fractions (duodenal and colon bioaccessible fractions) after in vitro digestion. Polyphenolic content and antioxidant activities were found to vary significantly among the tested cultivars with Limoncella showing the highest polyphenol content accompanied by an excellent antioxidant activity in both flesh and whole fruit. The overall trend of soluble antioxidant capacity from the soluble duodenal phase (SDP) and soluble colonic phase (SCP) followed the concentrations of flavanols, procyandinis, and hydroxycinnamic acids under the same digestive steps. Our results highlighted that on average 64.2% of the total soluble antioxidant activity was released in the SCP with Limoncella exhibiting the highest values (82.31, 70.05, and 65.5%, respectively for whole fruit, flesh, and peel). This result suggested that enzymatic treatment with pronase E and viscozyme L, to reproduce biochemical conditions occurring in the colon, is effective for breaking the dietary fiber-polyphenols interactions and for the release of polyphenols which can exercise their beneficial effects in the colon. The beneficial effects related to the Limoncella consumption could thus be of potential great relevance to counteract the adverse effects of pro-oxidant and inflammatory processes on intestinal cells.

Electroactive Phenolic Contributors and Antioxidant Capacity of Flesh and Peel of 11 Apple Cultivars Measured by Cyclic Voltammetry and HPLC-DAD-MS/MS

In this study, 11 apple cultivars were characterized by their total phenolic content (TPC) and total flavonoid content (TFC) and antioxidant, reducing, and chelating capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) test, cyclic voltammetry (CV), and ferric reducing antioxidant power (FRAP) assays; and ferrous ion chelating capacity. The phenolic compounds in flesh and peel were determined by liquid chromatography coupled to mass spectrometry and diode array detector (HPLC-DAD-MS/MS) and their electroactivity by CV. The results showed higher TPC, TFC, and antioxidant capacity by DPPH test in the peels of all apple cultivars as compared to the respective flesh. The peel extracts also showed two-fold higher FRAP values as compared to the flesh extracts. The reducing capacity of the peel and flesh determined by CV measurements confirmed the results achieved by spectrophotometric methods of evaluating antioxidant capacity. There was no significant difference in chelating capacity in the peel and flesh. The HPLC-DAD-MS/MS analysis showed the presence of 11 phenolic compounds in the peel and flesh which varied in antioxidant, reducing, and chelating activity. The order of the phenolic compound content in flesh and peel in Quinte cultivar, which showed the highest antioxidant capacity, was as follows: epicatechin > chlorogenic acid > quercetin 3-arabinoside > quercetin 3-glucoside > cyanidin 3-galactoside > quercetin 3-rhamnoside > catechin > phloridzin > rutin > phloretin = quercetin. CV results were highly correlated with those obtained by spectrophotometry and HPLC-DAD-MS/MS, providing evidence to support the use of cyclic voltammetry as a rapid method to determine the phenolic profile and reducing the power of apple flesh and peel. The association between antioxidant assays and phenolic compound content showed that the highest contribution to the antioxidant capacity of apple peel and flesh was provided by catechin, epicatechin, and cyadinin-3-galactoside, while phloretin, phloridzin, and chlorogenic acid were the main contributors to chelating activity. Results from this study clearly indicate that removing the peel from apples may induce a significant loss of antioxidants.

Effect of resveratrol and quercetin on the susceptibility of Escherichia coli to antibiotics

Activities of plant polyphenols (PPs), resveratrol and quercetin, alone or in combination with four conventional antibiotics against Escherichia coli have been investigated. In medium without antibiotics, both polyphenols caused a dose-dependent growth inhibition. However, pretreatment with resveratrol (40 and 100 μg ml^-1) and quercetin (40 μg ml^-1) reduced the bacteriostatic effect of kanamycin, streptomycin, cefotaxime and partially of ciprofloxacin. With few exceptions, both PPs also reduced the bactericidal effect of tested antibiotics. Paradoxically, low doses of PPs enhanced the bactericidal effect of kanamycin and partially ciprofloxacin. Compared to quercetin, resveratrol showed a weaker effect on the induction of antioxidant genes and the resistance of E. coli to the oxidative stress generated by hydrogen peroxide treatment. Both polyphenols at high doses reduced membrane potential. Altogether, these findings suggest that the decrease in the bactericidal effect of antibiotics by high doses of polyphenols is mostly due to bacteriostatic action of the latter. In the case of quercetin, the contribution of its antioxidant activity for antibiotic protection may be significant. There is a growing interest in the use of plant-derived compounds to enhance the toxicity of traditional antibiotics. This and other studies show that, under certain conditions, the use of polyphenols as adjuvants may not exert the expected therapeutic effect, but rather to decrease antimicrobial activity of antibiotics.

Wine's Phenolic Compounds and Health: A Pythagorean View

In support of the J curve that describes the association between wine consumption and all-cause mortality, researchers and the lay press often advocate the health benefits of (poly)phenol consumption via red wine intake and cite the vast amount of in vitro literature that would corroborate the hypothesis. Other researchers dismiss such evidence and call for total abstention. In this review, we take a skeptical, Pythagorean stance and we critically try to move the debate forward by pointing the readers to the many pitfalls of red wine (poly)phenol research, which we arbitrarily treat as if they were pharmacological agents. We conclude that, after 30 years of dedicated research and despite the considerable expenditure, we still lack solid, "pharmacological", human evidence to confirm wine (poly)phenols' biological actions. Future research will eventually clarify their activities and will back the current recommendations of responsibly drinking moderate amounts of wine with meals.

Activation of Nrf2 by Natural Bioactive Compounds: A Promising Approach for Stroke?

Stroke represents one of the main causes of disability and death worldwide. The pathological subtypes of stroke are ischemic stroke, the most frequent, and hemorrhagic stroke. Nrf2 is a transcription factor that regulates redox homeostasis. In stress conditions, Nrf2 translocates inside the nucleus and induces the transcription of enzymes involved in counteracting oxidative stress, endobiotic and xenobiotic metabolism, regulators of inflammation, and others. Different natural compounds, including food and plant-derived components, were shown to be able to activate Nrf2, mediating an antioxidant response. Some of these compounds were tested in stroke experimental models showing several beneficial actions. In this review, we focused on the studies that evidenced the positive effects of natural bioactive compounds in stroke experimental models through the activation of Nrf2 pathway. Interestingly, different natural compounds can activate Nrf2 through multiple pathways, inducing a strong antioxidant response associated with the beneficial effects against stroke. According to several studies, the combination of different bioactive compounds can lead to a better neuroprotection. In conclusion, natural bioactive compounds may represent new therapeutic strategies against stroke.

Altering salivary protein profile can decrease aversive oromotor responding to quinine in rats

Bitter taste is often associated with toxins, but accepting some bitter foods, such as green vegetables, can be an important part of maintaining a healthy diet. It has previously been shown that animals exposed to quinine upregulate a set of salivary proteins (SPs), and those with upregulated SPs have increased rates of feeding on a quinine diet as well as increased brief-access licking to and higher detection thresholds for quinine. These studies suggest that SPs alter orosensory feedback; however, they rely on SPs upregulated by diet exposure and cannot control for the role of learning. Here, we use taste reactivity to determine if SPs can alter bitter taste in animals with no previous bitter diet experience. First, saliva with proteins stimulated by injections of isoproterenol and pilocarpine was collected from anesthetized rats; this "donor saliva" was analyzed for protein concentration and profile. Bitter-naïve rats were implanted with oral catheters and infused with taste stimuli dissolved in saliva that contained all of the SPs from the donors, saliva that was filtered of SPs, water, or artificial saliva. Their orofacial movements were recorded and quantified. We found that presence of quinine increased movements associated with aversive stimuli, but adding SPs to the infusion was sufficient to reduce aversive oromotor responding to quinine. The effect was dependent on the total protein concentration of the saliva, as protein concentration increased aversive responses decreased. Additionally, infusions of whole saliva altered aversive responding to quinine, but not other stimuli (citric acid, NaCl, sucrose). Our work suggests that effect of these SPs is specific and the presence of SPs is sufficient to decrease aversive orosensory feedback to bitter stimuli.

Caffeates and Caffeamides: Synthetic Methodologies and Their Antioxidant Properties

Polyphenols are secondary metabolites of plants and include a variety of chemical structures, from simple molecules such as phenolic acids to condensed tannins and highly polymerized compounds. Caffeic acid (3,4-dihydroxycinnamic acid) is one of the hydroxycinnamate metabolites more widely distributed in plant tissues. It is present in many food sources, including coffee drinks, blueberries, apples, and cider, and also in several medications of popular use, mainly those based on propolis. Its derivatives are also known to possess anti-inflammatory, antioxidant, antitumor, and antibacterial activities, and can contribute to the prevention of atherosclerosis and other cardiovascular diseases. This review is an overview of the available information about the chemical synthesis and antioxidant activity of caffeic acid derivatives. Considering the relevance of these compounds in human health, many of them have been the focus of reviews, taking as a center their obtaining from the plants. There are few revisions that compile the chemical synthesis methods, in this way, we consider that this review does an important contribution.

Urinary excretion rate and bioavailability of chlorogenic acid, caffeic acid, p-coumaric acid, and ferulic acid in non-fasted rats maintained under physiological conditions

Hydroxycinnamic acids (HAs) are one of the major classes of phenolic compounds and epidemiological studies have suggested that they have beneficial health effects. This study aimed to determine the urinary excretion rate of chlorogenic acid, caffeic acid, p-coumaric acid, and ferulic acid in non-fasted rats and to estimate their bioavailability under physiological conditions. Previous studies have primarily used fasted animals, which exhibit severe changes in various physiological processes. Furthermore, the food matrix can affect HA bioavailability. Thus, our studies using non-fasted rats under physiological conditions may allow for a more accurate determination of both the HA urinary excretion rate and the bioavailability of HAs. HAs were successively gavaged to rats at a dose of 40 mg/kg body weight (BW) with a wash-out period of one week. The rats were fed the AIN-93M diet throughout the experiment. The urine was collected at time intervals of 0–6 h, 6–24 h, and 24–48 h after HA administration. Ingested HAs, except chlorogenic acid, were primarily excreted in the urine within 0–6 h as free forms or conjugated (glucuronidated and/or sulfated) forms. The majority of the ingested chlorogenic acid was detected in the urine at 6–24 h or 24–48 h as caffeic acid, p-coumaric acid, ferulic acid, and their conjugates. The total urinary excretion rate (% of the dose) at 48 h was ferulic acid (73.2%) > caffeic acid (61.6%) > p-coumaric acid (54.1%) >> chlorogenic acid (4.9%). The percentages of the conjugates in the urine differed amongst the rats gavaged with the individual HAs (74% for chlorogenic acid, 83% for caffeic acid, 68% for p-coumaric acid, and 96% for ferulic acid), which may be explained by their distinct bioactivities. These data reveal that caffeic acid, p-coumaric acid, and ferulic acid are much more bioavailable than chlorogenic acid, even though they are excreted more rapidly than chlorogenic acid. Our findings may provide additional insight into the health benefits of HAs and how they function in the body.

Role of Apple Phytochemicals, Phloretin and Phloridzin, in Modulating Processes Related to Intestinal Inflammation

Plant-derived food consumption has gained attention as potential intervention for the improvement of intestinal inflammatory diseases. Apple consumption has been shown to be effective at ameliorating intestinal inflammation symptoms. These beneficial effects have been related to (poly)phenols, including phloretin (Phlor) and its glycoside named phloridzin (Phldz). To deepen the modulatory effects of these molecules we studied: i) their influence on the synthesis of proinflammatory molecules (PGE2, IL-8, IL-6, MCP-1, and ICAM-1) in IL-1β-treated myofibroblasts of the colon CCD-18Co cell line, and ii) the inhibitory potential of the formation of advanced glycation end products (AGEs). The results showed that Phlor (10-50 μM) decreased the synthesis of PGE2 and IL-8 and the formation of AGEs by different mechanisms. It is concluded that Phlor and Phldz, compounds found exclusively in apples, are positively associated with potential beneficial effects of apple consumption.

Investigation of antioxidant activity of selenium compounds and their mixtures with tea polyphenols

The antioxidant interactions between selenium species and tea polyphenols were investigated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, cupric reducing antioxidant capacity (CUPRAC) and Folin-Ciocalteu (FC) assay. Se(IV) exhibited the lowest antioxidant properties in comparison to other selenium compounds in all assays. The highest reducing power was obtained for SeMet, while the highest ability to scavenging DPPH radicals for MeSeCys. The results obtained experimentally for the mixtures containing selenium species and green or black tea infusion were compared with theoretical values calculated by adding up the effects of both individual components analyzed separately. The results obtained from each assay clearly show that observed effect is not additive. In almost every case the theoretical value of antioxidant capacity was significantly higher from that obtained from the activity of the binary mixture of black tea infusion with selenium compound decreased in the order: SeMet > Se(IV) > Se(VI) > MeSeCys, while for similar mixtures with green tea infusion: MeSeCys > Se(VI) > SeMet ~ Se(IV).

Bioactivity of dietary polyphenols: The role of metabolites

A polyphenol-rich diet protects against chronic pathologies by modulating numerous physiological processes, such as cellular redox potential, enzymatic activity, cell proliferation and signaling transduction pathways. However, polyphenols have a low oral bioavailability mainly due to an extensive biotransformation mediated by phase I and phase II reactions in enterocytes and liver but also by gut microbiota. Despite low oral bioavailability, most polyphenols proved significant biological effects which brought into attention the low bioavailability/high bioactivity paradox. In recent years, polyphenol metabolites have attracted great interest as many of them showed similar or higher intrinsic biological effects in comparison to the parent compounds. There is a huge body of literature reporting on the biological functions of polyphenol metabolites generated by phase I and phase II metabolic reactions and gut microbiota-mediated biotransformation. In this respect, the review highlights the pharmacokinetic fate of the major dietary polyphenols (resveratrol, curcumin, quercetin, rutin, genistein, daidzein, ellagitannins, proanthocyanidins) in order to further address the efficacy of biometabolites as compared to parent molecules. The present work strongly supports the contribution of metabolites to the health benefits of polyphenols, thus offering a better perspective in understanding the role played by dietary polyphenols in human health.

Dietary Flavanols: A Review of Select Effects on Vascular Function, Blood Pressure, and Exercise Performance

An individual's diet affects numerous physiological functions and can play an important role in reducing the risk of cardiovascular disease. Epidemiological and clinical studies suggest that dietary flavanols can be an important modulator of vascular risk. Diets and plant extracts rich in flavanols have been reported to lower blood pressure, especially in prehypertensive and hypertensive individuals. Flavanols may act in part through signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxing and constricting factors. During exercise, flavanols have been reported to modulate metabolism and respiration (e.g., maximal oxygen uptake, O₂ cost of exercise, and energy expenditure), and reduce oxidative stress and inflammation, resulting in increased skeletal muscle efficiency and endurance capacity. Flavanol-induced reductions in blood pressure during exercise may decrease the work of the heart. Collectively, these effects suggest that flavanols can act as an ergogenic aid to help delay the onset of fatigue. More research is needed to better clarify the effects of flavanols on vascular function, blood pressure regulation, and exercise performance and establish safe and effective levels of intake. Flavanol-rich foods and food products can be useful components of a healthy diet and lifestyle program for those seeking to better control their blood pressure or to enhance their physical activity. Key teaching points • Epidemiological and clinical studies indicate that dietary flavanols can reduce the risk of vascular disease. • Diets and plant extracts rich in flavanols have been reported to lower blood pressure and improve exercise performance in humans. • Mechanisms by which flavanols may reduce blood pressure function include alterations in signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxation and constriction factors. • Mechanisms by which flavanols may enhance exercise performance include modulation of metabolism and respiration (e.g., maximal oxygen uptake, O₂ cost of exercise, and energy expenditure) and reduction of oxidative stress and inflammation. These effects can result in increased skeletal muscle efficiency and endurance capacity. • Further research is needed to clarify the amount, timing, and frequency of flavanol intake for blood pressure regulation and exercise performance.

Using chemiluminescence to determine whole blood antioxidant capacity in rheumatoid arthritis and Parkinson's disease patients

The consequences of oxidative stress and inflammation are implicated in a wide range of diseases, including rheumatoid arthritis and Parkinson's disease. The status of antioxidant capacity in rheumatoid arthritis and Parkinson's disease remains unclear, in part due to common practice of assaying erythrocytes separately to plasma. This method removes any synergistic interactions between plasma and erythrocyte-based antioxidants. The experiments in this report tested antioxidant capacity in whole blood, erythrocytes and plasma by group and disease stage. Medically diagnosed patients were recruited along with appropriate control group participants. Fasting venous blood was assayed using chemiluminescence methods for: time to maximum light emitted, maximum light emitted, and plasma antioxidant capacity in vitamin E analogue units. Here we demonstrate that whole blood exhibits higher antioxidant capacity than either plasma or erythrocytes assayed separately. We report increased oxidative stress in the blood of rheumatoid arthritis patients by group (p = 0.018, p = 0.049). We show increased antioxidant capacity in Parkinson's disease patients by group (p < 0.001). For later stage Parkinson's disease patients, we report reduced oxidative stress (p = 0.025), and increased antioxidant capacity and for erythrocytes (p < 0.001, p = 0.004) and whole blood (p < 0.001, p = 0.003). Early stage Parkinson's disease showed higher antioxidant capacity on only one measure (p = 0.008). Whole blood chemiluminescence is a useful technique for determining redox status in disease and might help clarify the role of oxidative stress in rheumatoid arthritis and Parkinson's disease.

Insights on Localized and Systemic Delivery of Redox-Based Therapeutics

Reactive oxygen and nitrogen species are indispensable in cellular physiology and signaling. Overproduction of these reactive species or failure to maintain their levels within the physiological range results in cellular redox dysfunction, often termed cellular oxidative stress. Redox dysfunction in turn is at the molecular basis of disease etiology and progression. Accordingly, antioxidant intervention to restore redox homeostasis has been pursued as a therapeutic strategy for cardiovascular disease, cancer, and neurodegenerative disorders among many others. Despite preliminary success in cellular and animal models, redox-based interventions have virtually been ineffective in clinical trials. We propose the fundamental reason for their failure is a flawed delivery approach. Namely, systemic delivery for a geographically local disease limits the effectiveness of the antioxidant. We take a critical look at the literature and evaluate successful and unsuccessful approaches to translation of redox intervention to the clinical arena, including dose, patient selection, and delivery approach. We argue that when interpreting a failed antioxidant-based clinical trial, it is crucial to take into account these variables and importantly, whether the drug had an effect on the redox status. Finally, we propose that local and targeted delivery hold promise to translate redox-based therapies from the bench to the bedside.

Effect of different home-cooking methods on textural and nutritional properties of sweet potato genotypes grown in temperate climate conditions

BACKGROUND

The European Union (EU) market for sweet potato is small but is growing considerably and and has increased by 100% over the last 5 years. The cultivation of sweet potato in temperate climate conditions has not considered extensively and could be a new opportunity for the EU market. Healthy and qualitative traits of different sweet potato cultivars grown in temperate climate conditions were evaluated in accordance with four cooking methods.

RESULTS

Traditional cultivars showed high hardness and adhesiveness values. The highest concentrations of sugars (especially maltose) and phenolic acids (caffeic and chlorogenic) were found in samples treated by boiling and steaming. High antioxidant activity was found in fried potatoes. Qualitative traits of sweet potatoes treated by microwaves did not report any significant variation compared to the control.

CONCLUSION

Traditional and new sweet potato cultivars can be cultivated in temperate climate conditions and show interesting qualitative properties, especially as a result of the presence of antioxidant compounds. Concerning global quality, colored varieties expressed a better profile than traditional Italian ones and they are suitable for the European market, giving new opportunities for consumers and producers. © 2017 Society of Chemical Industry.

Antibacterial Activity of Polyphenols: Structure-Activity Relationship and Influence of Hyperglycemic Condition

Polyphenols are plant-derived natural products with well-documented health benefits to human beings, such as antibacterial activities. However, the antibacterial activities of polyphenols under hyperglycemic conditions have been rarely studied, which could be relevant to their antibacterial efficacy in disease conditions, such as in diabetic patients. Herein, the antibacterial activities of 38 polyphenols under mimicked hyperglycemic conditions were evaluated. The structure-antibacterial activity relationships of polyphenols were also tested and analyzed. The presence of glucose apparently promoted the growth of the bacterial strains tested in this study. The OD600 values of tested bacteria strains increased from 1.09-fold to 1.49-fold by adding 800 mg/dL glucose. The polyphenols showed structurally dependent antibacterial activities, which were significantly impaired under the hyperglycemic conditions. The results from this study indicated that high blood glucose might promote bacterial infection, and the hyperglycemic conditions resulting from diabetes were likely to suppress the antibacterial benefits of polyphenols.

Polyphenol intake and cardiovascular risk factors in a population with type 2 diabetes: The TOSCA.IT study

BACKGROUND

The role of polyphenol intake on cardiovascular risk factors is little explored, particularly in people with diabetes.

AIM

To evaluate the association between the intake of total polyphenols and polyphenol classes with the major cardiovascular risk factors in a population with type 2 diabetes.

METHODS

Dietary habits were investigated in 2573 males and females participants of the TOSCA.IT study. The European Prospective Investigation on Cancer and Nutrition (EPIC) questionnaire was used to assess dietary habits. In all participants, among others, we assessed anthropometry, plasma lipids, blood pressure, C-reactive protein and HbA1c following a standard protocol. The USDA and Phenol-Explorer databases were used to estimate the polyphenol content of the habitual diet.

RESULTS

Average intake of polyphenols was 683.3 ± 5.8 mg/day. Flavonoids and phenolic acids were the predominant classes (47.5% and 47.4%, respectively). After adjusting for potential confounders, people with the highest intake of energy-adjusted polyphenols (upper tertile) had a more favorable cardiovascular risk factors profile as compared to people with the lowest intake (lower tertile) (BMI was 30.7 vs 29.9 kg/m², HDL-cholesterol was 45.1 vs 46.9 mg/dl, LDL-cholesterol was 103.2 vs 102.1 mg/dl, triglycerides were 153.4 vs 148.0 mg/dl, systolic and diastolic blood pressure were respectively 135.3 vs 134.3 and 80.5 vs 79.6 mm/Hg, HbA1c was 7.70 vs 7.67%, and C-reactive Protein was 1.29 vs 1.25 mg/dl, p < .001 for all). The findings were very similar when the analysis was conducted separately for flavonoids or phenolic acids, the two main classes of polyphenols consumed in this population.

CONCLUSIONS

Polyphenol intake is associated with a more favorable cardiovascular risk factors profile, independent of major confounders. These findings support the consumption of foods and beverages rich in different classes of polyphenols particularly in people with diabetes.

CLINICAL TRIAL

http://www.clinicaltrials.gov; Study ID number: NCT00700856.

The Oxygen Paradox, oxidative stress, and ageing

Professor Helmut Sies is being lauded in this special issue of Archives of Biochemistry & Biophysics, on the occasion of his retirement as Editor-in-Chief. There is no doubt that Helmut has exerted an enormously positive influence on this journal, the fields of Biochemistry & Biophysics in general, and the areas of free radical and redox biology & medicine in particular. Helmut Sies' many discoveries about peroxide metabolism, glutathione, glutathione peroxidases, singlet oxygen, carotenoids in general and lycopene in particular, and flavonoids, fill the pages of his more than 600 publications. In addition, he will forever be remembered for coining the term 'oxidative stress' that is so widely used (and sometimes abused) by most of his colleagues.