Polyphenolic grape extract inhibits platelet activation through PECAM-1: an explanation for the French paradox

Neuroprotective Potential of Flavonoids in Brain Disorders

Flavonoids are a large subgroup of polyphenols known to be sourced from over 6000 natural products, including fruits, vegetables, bark, and herbs. Due to their antioxidant properties, flavonoids have been implicated as a therapy source for many diseases and conditions, including inflammation, vasculitis, venous insufficiency, and hemorrhoids. Currently, some flavonoids are being researched for their antioxidant ability concerning neuroprotection. These flavonoids can penetrate the blood-brain barrier and, depending on the specific flavonoid, retain adequate bioavailability in certain brain regions. Further data suggest that flavonoids could have a strong anti-inflammatory effect in the brain, which not only could be a robust therapeutic source for known neuroinflammatory diseases such as Alzheimer's Disease or Parkinson's Disease but also could be a therapeutic source for ischemic or hemorrhagic conditions such as a stroke. While flavonoid toxicity exists, they are relatively safe and non-invasive drugs from natural origins. As such, exploring the known mechanisms and therapies may highlight and establish flavonoid therapy as a viable source of therapy for stroke patients. As stated, many flavonoids are already being isolated, purified, and implemented in both in vitro and in vivo experiments. As these flavonoids proceed to clinical trials, it will be important to understand how they function as a therapy, primarily as antioxidants, and by other secondary mechanisms. This review aims to elucidate those mechanisms and explore the neuroprotective role of flavonoids.

Influence of a bearing-wastewater phenolic compound (3,4-dimethylphenol, 3,4-DMP) treatment on Ca2+ homeostasis and its related cytotoxicity in human proximal renal tubular epithelial cells

A lot of phenolic compounds are widespread in industrial effluents and they are considerable environmental pollutants. Being a compound commercially available, the effect of a bearing-wastewater phenolic compound 3,4-dimethylphenol (3,4-DMP) on Ca²⁺ homeostasis and its related physiology has not been explored in cultured human kidney cell models. The aim of this study was to explore the effect of 3,4-DMP on [Ca²⁺]_i and viability in HK-2 human proximal renal tubular epithelial cells. In terms of Ca²⁺ signaling, 3,4-DMP (5-100 μM) induced [Ca²⁺]_i rises only in HK-2 cells and Ca²⁺ removal reduced the signal by 40%. In Ca²⁺-containing medium, 3,4-DMP-induced Ca²⁺ entry was inhibited by 20% by a modulator of store-operated Ca²⁺ channels (2-APB), and by a PKC activator (PMA) and inhibitor (GF109203X). Moreover, 3,4-DMP-induced Mn²⁺ influx suggesting of Ca²⁺ entry. In Ca²⁺-free medium, inhibition of PLC with U73122 abolished 3,4-DMP-induced [Ca²⁺]_i rises. Furthermore, treatment with the endoplasmic reticulum Ca²⁺ pump inhibitor thapsigargin abolished 3,4-DMP-evoked [Ca²⁺]_i rises. Conversely, treatment with 3,4-DMP abolished thapsigargin-evoked [Ca²⁺]_i rises. Regarding to cell viability, 3,4-DMP (60-140 μM) killed cells in a concentration-dependent fashion in HK-2 cells. Chelation of cytosolic Ca²⁺ with BAPTA-AM partially reversed cytotoxicity of 3,4-DMP. Collectively, our data suggest that in HK-2 cells, 3,4-DMP-induced [Ca²⁺]_i rises by evoking Ca²⁺ entry via PKC-sensitive store-operated Ca²⁺ entry and PLC-dependent Ca²⁺ release from the endoplasmic reticulum. 3,4-DMP also caused cytotoxicity that was linked to preceding [Ca²⁺]_i rises. Our findings provide new insight into the cytotoxic effects of 3,4-DMP and the possible mechanisms underlying these effects.

Going "Green" in the Prevention and Management of Atherothrombotic Diseases: The Role of Dietary Polyphenols

During the 20th century processed and ready-to-eat foods became routinely consumed resulting in a sharp rise of fat, salt, and sugar intake in people's diets. Currently, the global incidence of obesity, raised blood lipids, hypertension, and diabetes in an increasingly aged population contributes to the rise of atherothrombotic events and cardiovascular diseases (CVD) mortality. Drug-based therapies are valuable strategies to tackle and help manage the socio-economic impact of atherothrombotic disorders though not without adverse side effects. The inclusion of fresh fruits and vegetables rich in flavonoids to human diets, as recommended by WHO offers a valuable nutritional strategy, alternative to drug-based therapies, to be explored in the prevention and management of atherothrombotic diseases at early stages. Though polyphenols are mostly associated to color and taste in foods, food flavonoids are emerging as modulators of cholesterol biosynthesis, appetite and food intake, blood pressure, platelet function, clot formation, and anti-inflammatory signaling, supporting the health-promoting effects of polyphenol-rich diets in mitigating the impact of risk factors in atherothrombotic disorders and CVD events. Here we overview the current knowledge on the effect of polyphenols particularly of flavonoid intake on the atherothrombotic risk factors and discuss the caveats and challenges involved with current experimental cell-based designs.

The in vitro bioavailability of anti-platelet peptides in collagen hydrolysate from silver carp (Hypophthalmichthys molitrix) skin

Previous animal experiments indicated collagen hydrolysates (CHs) intake decreased platelet release indicators in plasma and highlight potential applications as healthcare supplements to combat cardiovascular disease. The oligopeptides (GPR, GPRG, and GPRGP) have anti-platelet activities. However, it is still unclear whether they are bioactive compounds in CHs from silver carp skin. We investigated the bioavailability of oligopeptides using simulated gastrointestinal digestion and Caco-2 model. Anti-thrombotic activities, in vitro platelet aggregation and formation of platelet thrombus, were evaluated. They resisted gastrointestinal digestion and could be absorbed by Caco-2. Oligopeptides inhibited platelet aggregation induced by adenosine diphosphate and thrombin with IC₅₀ of 0.160, 0.283, 0.251 mg/ml and 0.714, 1.008, 0.917 mg/ml for GPR, GPRG, and GPRGP, respectively. Oligopeptides prolonged the time of platelet thrombus and inhibited coagulation cascades, but CHs performed no bleeding side effect. These results confirmed that oligopeptides could be used as bioactive compounds of dietary supplements for pre-thrombotic to prevent thrombosis. PRACTICAL APPLICATIONS: Oligopeptides, GPR, GPRG, and GPRGP, derived from silver carp (Hypophthalmichthys molitrix) skin collagen, performed anti-thrombotic activities from their anti-platelet aggregation and anticoagulation activities. But the collagen hydrolysates containing these peptides had no side effect of bleeding in the mice model. Furthermore, this study investigated the bioavailability of these three bioactive peptides by the Caco-2 cells model. Thus, oligopeptides GPR, GPRG, and GPRGP are a potential index of bioactive compounds in the preparation of anti-thrombotic functional foods or healthcare supplements for people at the pre-thrombotic state.

Effects of Grape Seed Proanthocyanidin Extract on Vascular Endothelial Function in Participants with Prehypertension: A Randomized, Double-Blind, Placebo-Controlled Study

This study aimed to investigate the effects of grape seed proanthocyanidin extract (GSPE) on blood pressure and vascular endothelial function in middle-aged Japanese adults with prehypertension. We conducted a randomized, double-blind, placebo-controlled study on 6 men and 24 women aged 40-64 years old. The participants were randomized to receive tablets containing either low-dose (200 mg/day) or high-dose (400 mg/day) GSPE, or placebo, for 12 weeks. Systolic and diastolic blood pressures (SBP and DBP, respectively), brachial flow-mediated dilation (FMD), and other cardiovascular parameters were measured before and after 4, 8, and 12 weeks of treatment. The mean SBP in the high-dose group significantly decreased by 13 mmHg after 12 weeks (P = 0.028), although FMD did not change. In an ad hoc analysis of non-smoking participants (n = 21), the mean SBP, DBP, stiffness parameter β, distensibility, incremental elastic modulus (Einc), and pulse wave velocity (PWV) also significantly improved in the high-dose group after 12 weeks. Changes in Einc and PWV from baseline to 12 weeks were significantly greater in the high-dose group than in the placebo group (Einc, P = 0.023; PWV, P = 0.03). GSPE consumption could help maintain vascular elasticity and normal blood pressure in this population.

Combined Osmotic and Membrane Distillation for Concentration of Anthocyanin from Muscadine Pomace

Bioactive anthocyanins from aqueous extracts of muscadine grape pomace were concentrated using osmotic distillation (OD) and direct contact membrane distillation (DCMD) using polypropylene (PP) and poly(ethylene chlorotrifluoroethylene) (ECTFE) membranes. The driving force for OD is created by using a high concentration brine solution while the driving force for DCMD is generated by elevating the feed temperature relative to the permeate temperature. The brine concentration used was 4 M. The lowest fluxes were obtained for OD. Given the temperature sensitive nature of anthocyanins, the maximum temperature difference during DCMD was limited to 30 °C. The feed temperature was 40 °C and the permeate at 10 °C. Consequently, the maximum flux during DCMD was also limited. A combination of OD and DCMD was found to give the highest fluxes. High-performance liquid chromatography (HPLC) and HPLC-electrospray mass spectrometry were used to identify and quantify anthocyanins, cyanidin-3,5-O-diglucoside, delphinidin-3,5-O-diglucoside, petunidin-3,5-O-diglucoside, peonidin-3,5-O-diglucoside, and malvidin-3,5-O-diglucoside. The results obtained here suggest that, though water fluxes for DI water feed streams for PP and ECTFE membrane were similar, the fluxes obtained for the two membranes when using muscadine pomace extracts were different. Concentration factors of close to 3 was obtained for anthocyanins. Membranes also showed slightly different performance in the concentration process. Membrane surfaces were analyzed using scanning electron microscopy and Fourier-transformed infrared spectroscopy. The results suggest that adsorption of these anthocyanins on the membrane surface lead to performance differences. In an actual operation, selection of an appropriate membrane and regeneration of the membrane will be important for optimized performance. PRACTICAL APPLICATIONS: Anthocyanins are valuable therapeutic compounds, which are found in the solid residue left following fruit juice pressing. However, recovery and concentration of these therapeutic compounds remains challenging due to their stability. Here, a novel membrane-based unit operation has been investigated in order to concentrate the anthocyanins that have been extracted into aqueous solutions. The unit operation investigated here use mild processing conditions. Insights into the factors that need to be considered when optimizing of the unit operation for commercialization are discussed.

Polyphenol Extracts from Red Wine and Grapevine: Potential Effects on Cancers

Wine has been popular worldwide for many centuries and currently remains an important component of our diet. Scientific interest in wine and its health effects has grown considerably since the 1990s with the emergence of the “French Paradox” concept, correlating moderate wine consumption, a characteristic of the Mediterranean diet, and low incidence of coronary heart diseases. Since then, the positive effects on health, health promotion, disease prevention, and disease prognosis of moderate wine consumption, in particular red wine, have been attributed to its polyphenolic compounds such as resveratrol, quercetin, and other flavonoids acting as antioxidants. Several epidemiological, in vivo and in vitro, studies have reported that moderate red wine or red wine polyphenolic extract consumption may be active in the prevention and treatment of chronic diseases such as cardiovascular disease, metabolic syndrome, degenerative pathologies, and cancer. The aim of this review is to summarize the current findings about the effects of red wine polyphenols on cancer and to discuss how the polyphenolic composition of red wine may influence its chemopreventive properties.

Polyphenol Extracts from Red Wine and Grapevine: Potential Effects on Cancers

Wine has been popular worldwide for many centuries and currently remains an important component of our diet. Scientific interest in wine and its health effects has grown considerably since the 1990s with the emergence of the "French Paradox" concept, correlating moderate wine consumption, a characteristic of the Mediterranean diet, and low incidence of coronary heart diseases. Since then, the positive effects on health, health promotion, disease prevention, and disease prognosis of moderate wine consumption, in particular red wine, have been attributed to its polyphenolic compounds such as resveratrol, quercetin, and other flavonoids acting as antioxidants. Several epidemiological, in vivo and in vitro, studies have reported that moderate red wine or red wine polyphenolic extract consumption may be active in the prevention and treatment of chronic diseases such as cardiovascular disease, metabolic syndrome, degenerative pathologies, and cancer. The aim of this review is to summarize the current findings about the effects of red wine polyphenols on cancer and to discuss how the polyphenolic composition of red wine may influence its chemopreventive properties.

Therapeutic potential of flavonoids in inflammatory bowel disease: A comprehensive review

The inflammatory process plays a central role in the development and progression of numerous pathological situations, such as inflammatory bowel disease (IBD), autoimmune and neurodegenerative diseases, metabolic syndrome, and cardiovascular disorders. IBDs involve inflammation of the gastrointestinal area and mainly comprise Crohn’s disease (CD) and ulcerative colitis (UC). Both pathological situations usually involve recurring or bloody diarrhea, pain, fatigue and weight loss. There is at present no pharmacological cure for CD or UC. However, surgery may be curative for UC patients. The prescribed treatment aims to ameliorate the symptoms and prevent and/or delay new painful episodes. Flavonoid compounds are a large family of hydroxylated polyphenolic molecules abundant in plants, including vegetables and fruits which are the major dietary sources of these compounds for humans, together with wine and tea. Flavonoids are becoming very popular because they have many health-promoting and disease-preventive effects. Most interest has been directed towards the antioxidant activity of flavonoids, evidencing a remarkable free-radical scavenging capacity. However, accumulating evidence suggests that flavonoids have many other biological properties, including anti-inflammatory, antiviral, anticancer, and neuroprotective activities through different mechanisms of action. The present review analyzes the available data about the different types of flavonoids and their potential effectiveness as adjuvant therapy of IBDs.

The impact of dietary flavonoid supplementation on smoking-induced inflammatory process and fibrinolytic impairment

BACKGROUND AND AIMS

Smoking is associated with increased inflammatory process and impairment of fibrinolytic status. Concord grape juice (CGJ), a rich source of flavonoids, can modify cardiovascular risk factors. We aimed to evaluate the impact of CGJ on smoking-induced impairment of inflammatory and fibrinolytic status in healthy smokers.

METHODS

We studied the effect of a 2-week oral treatment with CGJ in 26 healthy smokers on three occasions (day 0: baseline, day 7 and day 14) in a randomized, placebo-controlled, double-blind, cross-over design. Measurements were carried out before (pSm) and 20 min after (Sm20) cigarette smoking. Serum levels of intercellular adhesion molecule-1 (sICAM-1) and plasminogen activator inhibitor 1 (PAI-1) were measured as markers of inflammatory and fibrinolytic status, respectively.

RESULTS

Treatment with CGJ reduced pSm sICAM-1 levels (p < 0.001), while placebo had no impact on ICAM-1 levels (p = 0.31). Moreover, treatment with CGJ decreased pSm values of PAI-1 (p < 0.001) while placebo had no impact on PAI-1 levels (p = 0.89). Smoking induced an elevation in PAI-1 levels after smoking compared to pro-smoking levels in all study days and in both arms (CGJ and placebo) of the study (p < 0.001 for all). Interestingly, CGJ compared to placebo, attenuated the acute smoking increase in sICAM-1 and PAI-1 levels (p < 0.001 and p = 0.005 respectively).

CONCLUSIONS

CGJ consumption improved inflammatory and fibrinolytic status in healthy smokers and attenuated acute smoking induced increase in ICAM-1 and PAI-1 levels. These findings shed further light on the favorable effects of flavonoids in cardiovascular health.

Flavonoids as Potent Scavengers of Hydroxyl Radicals

Oxidative stress is a fundamental principle in the pathophysiology of many diseases. It occurs when the production of reactive oxygen species exceeds the capacity of the cell defense system. The hydroxyl radical is a reactive oxygen species that is commonly formed in vivo and can cause serious damage to biomolecules, such as lipids, proteins, and nucleic acids. It plays a role in inflammation-related diseases, like chronic inflammation, neurodegeneration, and cancer. To overcome excessive oxidative stress and thus to prevent or stop the progression of diseases connected to it, scientists try to combat oxidative stress and to find antioxidant molecules, including those that scavenge hydroxyl radical or diminish its production in inflamed tissues. This article reviews various methods of hydroxyl radical production and scavenging. Further, flavonoids, as natural plant antioxidants and essential component of the human diet, are reviewed as compounds interacting with the production of hydroxyl radicals. The relationship between hydroxyl radical scavenging and the structure of the flavonoids is discussed. The structural elements of the flavonoid molecule most important for hydroxyl radical scavenging are hydroxylation of ring B and a C2-C3 double bond connected with a C-3 hydroxyl group and a C-4 carbonyl group. Hydroxylation of ring A also enhances the activity, as does the presence of gallate and galactouronate moieties as substituents on the flavonoid skeleton.

Chronocoulometry of wine on multi-walled carbon nanotube modified electrode: Antioxidant capacity assay

Phenolic antioxidants of wine were electrochemically oxidized on multi-walled carbon nanotubes modified glassy carbon electrode (MWNT/GCE) in phosphate buffer solution. Three oxidation peaks were observed at 0.39, 0.61 and 0.83V for red dry wine and 0.39, 0.80 and 1.18 V for white dry wine, respectively, using differential pulse voltammetry at pH 4.0. The oxidation potentials for individual phenolic antioxidants confirmed the integral nature of the analytical signals for the wines examined. A one-step chronocoulometric method at 0.83 and 1.18 V for red and white wines, respectively, has been developed for the evaluation of wine antioxidant capacity (AOC). The AOC is expressed in gallic acid equivalents per 1L of wine. The AOC of white wine was significantly less than red wine (386 ± 112 vs. 1224 ± 184, p<0.0001), as might be expected. Positive correlations were observed between gallic acid equivalent AOC of wine and total antioxidant capacity, based on coulometric titration with electrogenerated bromine (r=0.8957 at n=5 and r=0.8986 at n=4 for red and white wines, respectively).

Effect of traditional Uyghur medicine abnormal Savda Munziq extract on rabbit platelet aggregation in vitro and rat arteriovenous shunt thrombosis in vivo

OBJECTIVE

Abnormal Savda Munziq (ASMq) is a standard herbal preparation used in Uyghur traditional medicine to fight chronic diseases including cardiovascular, but its specific effects on thrombosis and platelet aggregation are unknown.

METHODS

Rabbit platelets were incubated with ASMq extract (10, 20, 40 µg/ml) for 15, 30, or 60 min, and aggregation was induced with ADP and collagen. In vivo, ASMq extract 2.97 g/kg, 5.94g/kg, 11.88 g/kg per os daily for 15 days were tested on thrombus wet weight in a rat model of arterio-venous bypass thrombosis. Plasma thromboxane B2 (TXB2) and 6-keto-PGF1a (6PG) were measured by radioimmunoassay. Aspirin (12 µg/ml and 5mg/kg) and saline were used as control in both experiments.

RESULTS

ASMq inhibited ADP and collagen-induced aggregation in vitro in a dose-dependent manner that increased over time, to a maximum of 6.4 ± 1.3% and 21.6 ± 4.0% for ADP and collagen, respectively, at one hour׳s incubation with the highest concentration, whereas the effects of aspirin (34.5 ± 2.2% and 41.9 ± 2.5%, respectively) were stable over time. In vivo, ASMq inhibited thrombus formation dose-dependently, by 70% at the highest dose, compared to 67% with aspirin. ASMq essentially did not change prostaglandin production, compared to the clear inhibition by aspirin.

CONCLUSION

Abnormal Savda Munziq extract inhibits dose-dependent platelet aggregation with ADP or collagen in vitro and thrombosis in vivo to values similar to those of aspirin, though unlike aspirin this effect does not seem mediated by an inhibition of cyclo-oxygenase.

Bioaccessibility of polyphenols associated with dietary fiber and in vitro kinetics release of polyphenols in Mexican ‘Ataulfo’ mango (Mangifera indica L.) by-products

The biological properties of polyphenol (PP) depend on its bioaccessibility and bioavailability.

Black tea polyphenols: a mechanistic treatise

Dietary interventions are among the emerging trends to curtail physiological malfunctioning like cancer, diabetes, cardiac complications, etc. The essence of phytonutrients has developed the concept of nutraceuticals at the junction of diet health linkages. In this context, theaflavin & thearubigins are the oxidized derivatives of black tea catechins during fermentation having nutraceutical potential owing to esterification of hydroxyl ring with digallate esters. Theaflavin may influence activation of transcription factors such as NFnB or AP-1 that ultimately hinder the formation of nitric oxide expression gene. Likewise, black tea contains a unique amino acid theanine acts as neurotransmitter owing to its ability to cross the blood-brain barrier. Moreover, it boasts immunity by enhancing the disease-fighting ability of gamma delta T cells. Theaflavin & thearubigins act as safeguard against oxidative stress thereby effective in the cardiac functioning. The mechanistic approach of these antioxidants is likely to be associated with inhibition of redox sensitive transcription factors & pro-oxidant enzymes such as xanthine oxidase or nitric oxide synthase. However, their involvement in antioxidative enzyme induction as in glutathione-S-transferases is also well documented. They act as curative agent against numerous pathological disorders by disrupting the electron chain thus inhibiting the progression of certain ailments. Black tea polyphenols established themselves as strong antioxidants due to their standard one-electron potential, and their vitality is dependent on the concentration of polyphenols and pH for their inclusive execution. Present review is an attempt to enrich the readers regarding the health promoting aspects of black tea polyphenols. Concomitantly, it needs core attention of researchers for the exploitations of black tea flavanols as an important dietary constituent for the vulnerable segment.

Protective effects of neohesperidin dihydrochalcone against carbon tetrachloride-induced oxidative damage in vivo and in vitro

The purpose of this study was to investigate the possible hepatoprotective effects of neohesperidin dihydrochalcone (NHDC) on carbon tetrachloride (CCl4)-induced acute oxidative injury in vivo and in vitro. In a mouse model, intraperitoneal injection of CCl4 resulted in a significant increase in serum aspartate transaminase (AST) and alanine transaminase (ALT) activities. Histopathological examination revealed severe hepatocyte necrosis and destruction of architecture in liver lesions, and immunohistochemical staining illustrated a remarkable enhancement of COX-2 and iNOS expression. The levels of hepatic antioxidant, such as, catalase (CAT), total superoxide dismutase (T-SOD), glutathione peroxidase (GP-X) and glutathione (GSH) were decreased, compared to the control group. However, pretreatment of NHDC for six consecutive days significantly ameliorated these changes. Moreover, Western blotting assay indicated pretreatment with NHDC also down-regulated CCl4-induced protein expressions of NF-κB, IL-6, caspase 3 and caspase 8. In HepG2 cell model, CCl4-treatment caused significant decrease in cell viability, antioxidant activities and GSH level, increase in intracellular reactive oxygen species (ROS) and thiobarbituric acid reactive substances (TBARS) level. Interestingly, pretreatment of NHDC effectively relieved CCl4-induced oxidative damage in a dose-dependent manner. In conclusion, NHDC appeared to possess promising anti-oxidative and anti-inflammatory capacities, it is possible to be used as a hepatoprotective agent.

Plant extracts inhibit ADP-induced platelet activation in humans: their potential therapeutic role as ADP antagonists

Adenosine diphosphate (ADP) plays a pivotal role in platelet activation. Platelet hyperactivity is associated with vascular disease and also has a key role in haemostasis and thrombosis. ADP activates platelets through three purinoceptor subtypes, the G(q)-coupled P2Y(1) receptor, G(i)-coupled P2Y(12) receptor and P2X(1) ligand-gated cation channel. Platelet ADP purinergic receptors are therefore suitable targets for antiplatelet drugs. Thienopyridines such as clopidogrel and ticlopidine, as well as other ADP receptor antagonists like prasugrel, ticagrelor, cangrelor and elinogrel have demonstrated clinical benefits via the inhibition of the selective purinergic ADP receptor, P2Y(12). However, they still have limitations in their mode of action and efficacy, like increased risk of bleeding. Thus, the ongoing pursuit to develop newer and more effective antiplatelet agents continues. There is a growing interest in the purinergic antiplatelet properties exhibited by plant extracts. This article considers the following: pomolic acid isolated from Licania pittieri, brazilin isolated from the heartwood of Caesalpinia sappan L, phylligenin isolated from the twigs of Muraltia vulpina, bark oil of Gonystylus velutinus, seed and bark extracts from Aesculus hippocastanum L. and red wine phenolics and catechins isolated from green tea. Moreover, the method used to investigate platelet purinergic receptors should be considered, since using a more sensitive, high-resolution platelet sizer can sometimes detect platelet variations when the light transmission method was not able to do so. The exact mechanisms by which these plant extracts work need further investigation. They all however inhibit ADP-induced activation in human platelets. This could explain, at least in part, the protective effect of plant extracts as antiplatelet agents.

Red grape berry-cultured cells reduce blood pressure in rats with metabolic-like syndrome

PURPOSE

Cumulative evidence suggests that moderate red wine consumption protects the cardiovascular system. The effect of cultured cells derived from red grape berry (RGC) on blood pressure (BP) has not been investigated. We therefore studied the antihypertensive effects of oral consumption of RGC in experimental rat model of metabolic-like syndrome and assessed its effect on human umbilical vein endothelial cells (HUVECs).

METHODS

Forty male Sprague-Dawley rats were fed for 5 weeks with either a high fructose diet (HFD) (n = 10) or HFD supplemented, during the last 2 weeks, with different doses (200, 400 and 800 mg/kg/day) of RGC suspended in their food (n = 30). BP, plasma triglycerides, insulin and adiponectin levels were measured at the beginning and after 3 and 5 weeks of diet. RGC effect on vasodilatation was evaluated by its ability to affect endothelin-1 (ET-1) production and endothelial nitric oxide synthase (eNOS) expression in HUVECs.

RESULTS

BP, plasma triglycerides, insulin and adiponectin increased significantly in rats fed with a HFD. The increase in BP, plasma triglycerides and insulin was attenuated by RGC supplementation. Incubation of HUVECs with RGC demonstrated a concentration-dependent inhibition of ET-1 secretion and increase in the level of eNOS, signaling a positive effect of RGC on vasodilatation.

CONCLUSION

In rats with metabolic-like syndrome, RGC decreased BP and improved metabolic parameters. These beneficial effects may be mediated by the cell constituents, highly rich with polyphenols and resveratrol, reside in their natural state.

Polyphenols: benefits to the cardiovascular system in health and in aging

Numerous studies have demonstrated the importance of naturally occurring dietary polyphenols in promoting cardiovascular health and emphasized the significant role these compounds play in limiting the effects of cellular aging. Polyphenols such as resveratrol, epigallocatechin gallate (EGCG), and curcumin have been acknowledged for having beneficial effects on cardiovascular health, while some have also been shown to be protective in aging. This review highlights the literature surrounding this topic on the prominently studied and documented polyphenols as pertaining to cardiovascular health and aging.

Oxidative stress and cardiovascular health: therapeutic potential of polyphenols

Reactive oxygen species (ROS) are important in normal cellular function and physiology. However, oxidative stress resulting from an accumulation of ROS has a detrimental impact on cellular function, and ROS has been implicated in the pathogenesis of a number of diseases, including cardiovascular diseases. This review provides a summary of the impact of ROS on cardiovascular health and diseases, highlighting the therapeutic use of antioxidants. In addition, this review summarizes the health benefits of polyphenols, and the recent progress on understanding the cellular and physiological actions by which polyphenols may impart their beneficial properties on cardiovascular health.

Inhibition and induction of glutathione S-transferases by flavonoids: possible pharmacological and toxicological consequences

Many studies reviewed herein demonstrated the potency of some flavonoids to modulate the activity and/or expression of glutathione S-transferases (GSTs). Because GSTs play a crucial role in the detoxification of xenobiotics, their inhibition or induction may significantly affect metabolism and biological effects of many drugs, industrials, and environmental contaminants. The effect of flavonoids on GSTs strongly depends on flavonoid structure, concentration, period of administration, as well as on GST isoform and origin. Moreover, the results obtained in vitro are often contrary to the vivo results. Based on these facts, the revelation of important flavonoid-drug or flavonoid-pollutant interaction has been complicated. However, it should be borne in mind that ingestion of certain flavonoids in combination with drugs or pollutants (e.g., acetaminophen, simvastatin, cyclophosphamide, cisplatine, polycyclic aromatic hydrocarbons, chlorpyrifos, acrylamide, and isocyanates), which are GST substrates, could have significant pharmacological and toxicological consequences. Although reasonable consumptions of a flavonoids-rich diet (that may lead to GST induction) are mostly beneficial, the uncontrolled intake of high concentrations of certain flavonoids (e.g., quercetin and catechins) in dietary supplements (that may cause GST inhibition) may threaten human health.

Associations between flavonoids and cardiovascular disease incidence or mortality in European and US populations

Twenty publications from twelve prospective cohorts have evaluated associations between flavonoid intakes and incidence or mortality from cardiovascular disease (CVD) among adults in Europe and the United States. The most common outcome was coronary heart disease mortality, and four of eight cohort studies reported significant inverse associations for at least one flavonoid class (multivariate adjusted p(trend) < 0.05). Three of seven cohorts reported that greater flavonoid intake was associated with lower risk of incident stroke. Comparisons among the studies were difficult because of variability in the flavonoid classes included, demographic characteristics of the populations, outcomes assessed, and length of follow-up. The most commonly examined flavonoid classes were flavonols and flavones combined (11 studies). Only one study examined all seven flavonoid classes. The flavonol and flavone classes were most strongly associated with lower coronary heart disease mortality. Evidence for protection from other flavonoid classes and CVD outcomes was more limited. The hypothesis that flavonoid intakes are associated with lower CVD incidence and mortality requires further study.

Resveratrol: French paradox revisited

Resveratrol is a polyphenol that plays a potentially important role in many disorders and has been studied in different diseases. The research on this chemical started through the “French paradox,” which describes improved cardiovascular outcomes despite a high-fat diet in French people. Since then, resveratrol has been broadly studied and shown to have antioxidant, anti-inflammatory, anti-proliferative, and anti-angiogenic effects, with those on oxidative stress possibly being most important and underlying some of the others, but many signaling pathways are among the molecular targets of resveratrol. In concert they may be beneficial in many disorders, particularly in diseases where oxidative stress plays an important role. The main focus of this review will be the pathways affected by resveratrol. Based on these mechanistic considerations, the involvement of resveratrol especially in cardiovascular diseases, cancer, neurodegenerative diseases, and possibly in longevity will be is addressed.

Natural product extract of Dicksonia sellowiana induces endothelium-dependent relaxations by a redox-sensitive Src- and Akt-dependent activation of eNOS in porcine coronary arteries

BACKGROUND/AIMS

The consumption of polyphenol-rich food is associated with a decreased mortality from coronary diseases. This study examined whether a standardized hydroalcoholic extract of Dicksonia sellowiana (HEDS) triggered endothelium-dependent relaxations in porcine coronary artery rings and characterized the underlying mechanism.

METHODS

The phosphorylation level of Src, Akt and eNOS was assessed by Western blot analysis, the formation of reactive oxygen species by dihydroethidine staining and the level of eNOS Ser1177 phosphorylation by immunohistochemical staining in sections of coronary arteries.

RESULTS

HEDS-induced endothelium-dependent relaxations were strongly reduced by Nω-nitro-L-arginine, an eNOS inhibitor, and by its combination with charybdotoxin plus apamin, inhibitors of endothelium-derived hyperpolarizing factor-mediated responses. These relaxations were markedly reduced by MnTMPyP (a membrane-permeant mimetic of superoxide dismutase), polyethylene glycol catalase (PEG-catalase; a membrane-permeant analog of catalase), and by wortmannin (an inhibitor of PI3-kinase). HEDS-induced sustained phosphorylation of Akt and eNOS in endothelial cells was abolished by MnTMPyP, PEG-catalase and wortmannin. Oral administration of HEDS induced a significant decrease of mean arterial pressure in spontaneously hypertensive rats.

CONCLUSION

These findings indicate that HEDS caused endothelium-dependent relaxations of coronary artery rings through the redox-sensitive activation of the endothelial PI3-kinase/Akt pathway leading to the subsequent activation of eNOS by phosphorylation. HEDS also has antihypertensive properties.

Evaluation of antiaggregatory activity of flavonoid aglycone series

BACKGROUND

Among natural compounds, present in every day diet, flavonoids have shown beneficial effect in prevention of cardiovascular diseases that can be attributed, at least partially to the described antiaggregatory activity i.e. antiplatelet effects of flavonoids. Due to the ever increasing pharmacological interest in antiplatelet agents a systematic experimental evaluation of large flavonoid series is needed.

METHODS

A set of thirty flavonoid aglycones has been selected for the evaluation. All measurements of aggregation were done under standardized and firmly controlled in vitro conditions. The whole blood samples, multiple platelet functional analyzer and adenosine diphosphate (ADP) as a weak agonist of aggregation were selected for this purpose.

RESULTS

The results were expressed as minimal concentration of flavonoid that can significantly lower the platelet aggregation compared to the corresponding untreated sample (minimal antiaggregatory concentration--MINaAC). All analyzed flavonoids exhibited antiaggregatory activity MINaAC ranging from 0.119 μM to 122 μM, while the most potent representatives were 3,6-dihydroxyflavone (0.119 μM) and syringetin (0.119 μM).

CONCLUSIONS

Measurable antiplatelet activity established at submicromolar flavonoid concentrations suggests that even a dietary consumption of some flavonoids can make an impact on in vivo aggregation of platelets. These findings also point out a therapeutical potential of some flavonoids.

Antioxidant and prooxidant properties of flavonoids

The interest in possible health benefits of flavonoids has increased owing to their potent antioxidant and free radical scavenging activities observed in vitro. Nevertheless, the antioxidant efficacy of flavonoids in vivo is less documented and their prooxidant properties have been actually described in vivo. Due to their prooxidant properties, they are able to cause oxidative damage by reacting with various biomolecules, such as lipids, proteins and DNA. Hence, the aim of this review is to discuss both the antioxidant and prooxidant effects of flavonoids.

Ellagitannins, ellagic acid and vascular health

Hydrolysable tannins are phenolic phytochemicals that show high antioxidant and free-radical scavenging activities. For this reason their potential effects preventing oxidative related diseases, such as cardiovascular diseases, have been largely studied. In vitro studies show that ellagitannins, at concentrations in the range 10-100 μM, show some relevant anti-atherogenic, anti-thrombotic, anti-inflammatory and anti-angiogenic effects, supporting the molecular mechanisms for the vascular health benefits. While there is good evidence supporting the vascular effects in vitro, the evidence on animal models or humans is much scarcer. The in vitro results often do not match the findings in the in vivo studies. This could be explained by the low bioavailability of the antioxidant ellagitannins and ellagic acid. The main ellagitannin metabolites circulating in plasma are ellagic acid microbiota metabolites known as urolithins, and they have lost their free-radical scavenging activity. They are present in plasma as glucuronide or sulphate conjugates, at concentrations in the nM range. Future studies should focus in the bioavailable metabolites, urolithins, and in the form (conjugated with glucuronic acid or sulphate) and concentrations (nM range) in which they are found in plasma. In this review we critically discuss the role of ellagitannins and ellagic acid on vascular health.

Cardioprotective actions of grape polyphenols

The aim of this review is to discuss the accumulating evidence that suggests that grape extracts and purified grape polyphenols possess a diverse array of biological actions and may be beneficial in the prevention of some inflammatory-mediated diseases including cardiovascular disease. The active components from grape extracts, which include the grape seed, grape skin, and grape juice, that have been identified thus far include polyphenols such as resveratrol, phenolic acids, anthocyanins, and flavonoids. All possess potent antioxidant properties and have been shown to decrease low-density lipoprotein-cholesterol oxidation and platelet aggregation. These compounds also possess a range of additional cardioprotective and vasoprotective properties including antiatherosclerotic, antiarrhythmic, and vasorelaxation actions. Although not exclusive, antioxidant properties of grape polyphenols are likely to be central to their mechanism(s) of action, which also include cellular signaling mechanisms and interactions at the genomic level. This review discusses some of the evidence favoring the consumption of grape extracts rich in polyphenols in the prevention of cardiovascular disease. Consumption of grape and grape extracts and/or grape products such as red wine may be beneficial in preventing the development of chronic degenerative diseases such as cardiovascular disease.

Resveratrol blunts tumor necrosis factor-alpha-induced monocyte adhesion and transmigration

The leukocyte recruitment and transmigration across the endothelial barrier into the vessel wall are crucial steps in atherosclerosis. Leukocyte trafficking on the endothelium is elicited by induction of endothelial adhesion molecules, and its transmigration is mediated by degradation of basement membrane proteins through enzymatic activity of matrix metalloproteinases (MMP). The current study investigated whether resveratrol, a polyphenol present in grapes and red wine, was capable of inhibiting leukocyte adhesion to tumor necrosis factor (TNF)-alpha-activated endothelium. It was found that resveratrol inhibited the TNF-alpha-activated endothelial expression of vascular cell adhesion molecule-1 in a dose-dependent manner. In addition, resveratrol hampered THP-1 monocyte adhesion to activated endothelial cells. This study further examined whether resveratrol interfered with transendothelial migration of leukocytes. The MMP-2 gelatinolytic activity of endothelial cells was enhanced by TNF-alpha, which was attenuated by an addition of >/=25 microM resveratrol. In addition, 25 microM resveratrol mitigated the MMP-9 activity of THP-1 cells, followed by a marked inhibition of transendothelial migration. These results demonstrated that resveratrol suppressed monocyte adhesion and migration induced by TNF-alpha through modulating expression of adhesion molecules and gelatinolytic activity of MMP. These findings suggest that dietary resveratrol may be therapeutic agent for inhibiting leukocyte recruitment into the subendothelium during inflammatory atherosclerosis.