Endothelial function and cardiovascular disease: Effects of quercetin and wine polyphenols

A Comprehensive Polyphenolic Characterization of Five Montmorency Tart Cherry (Prunus cerasus L.) Product Formulations

The Montmorency tart cherry (Prunus cerasus L., MTC) polyphenols may contribute to reduced inflammation and oxidative stress biomarkers in the body. However, a comprehensive polyphenolic profile of MTC products is lacking. This study provides a comparative analysis of the polyphenolic distribution of individual anthocyanins, flavonols, flavanols, hydroxycinnamic acids, and hydroxybenzoic acids in five MTC products (frozen raw fruit, freeze-dried powder, sweet dried fruit, unsweetened dried fruit, juice concentrate). Twenty-three polyphenols were detected, and 21 were positively identified. Results from three replicates indicate that frozen raw MTC has the most total polyphenolics. Juice concentrate, unsweetened dried MTC, freeze-dried MTC powder, and sweet dried MTC contained 26%, 40%, 60%, and 77% fewer total polyphenolics than frozen raw MTC. Hydroxycinnamic acids, flavonols, and anthocyanins predominated, accounting for 87-99% of total polyphenols in MTC products. Chlorogenic acid, rutin, cyanidin-3-sophoroside, feruloquinic acid, ferulic acid, and coumaric acid isomers were noteworthy polyphenolics. Hydroxycinnamic acids predominated in sweet dried (82%), unsweetened dried (74%), juice concentrate (66%), and frozen-raw (54%) MTC. Flavonols predominated in freeze-dried MTC powder (52%). Anthocyanins, particularly cyanidin glycosides, were important polyphenolics in frozen-raw cherries (18%) but less so in other MTC products. These findings highlight the variability in polyphenols in MTC products and emphasize the importance of selecting appropriate MTC products for specific health benefits.

Cadmium-Induced Hepatotoxicity in Mice - Prophylactic Supplementation of Quercetin Exerts Hepatoprotective Effect by Modulating PI3K/Akt/NF-kappaB Signaling Pathway

This current study seeks to examine the pre-protective function of Quercetin in Cadmium (Cd)-induced liver damage, along with its modulation of the PI3K/Akt/NF-kappaB signaling pathway. A total of 60 male C57BL/6J mice were randomly assigned to four groups: control (C), quercetin (Q, 100 mg/kg/day), Cd (Cd, 2.5 mg/kg/day), and quercetin and Cd (Q+Cd). Before receiving Cd treatment, quercetin was administered intragastrically for 4 weeks. In the present study, liver markers, oxidative stress parameters, pro-inflammatory cytokines, liver histopathology, apoptotic markers and PI3K/Akt/NF-kappaB signaling molecules were examined. We observed that the body weight of the Cd-treated mice dramatically rise after 4 weeks of quercetin pre-administration, and the Cd concentration was significantly decreased. Liver function markers like alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were significantly reduced in quercetin treatment in Cd-induced mice. Additionally, we observed that quercetin reduced Cd-mediated liver injury in mice by assessing the level of malondialdehyde (MDA), and the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) concentrations and the histological alterations. By monitoring tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and interleukin-1beta (IL-1beta), quercetin successfully reduced the inflammatory cytokines that the Cd metal caused in the liver. Additionally, in the liver tissues of Cd-mediated, quercetin could enhance the expression of Bcl-2 and decrease the expression of p-Akt, p-PI3K, Bax, Caspase-9, Caspase-3, NF-kappaB. In conclusion, quercetin protects against Cd induced liver injury via several pathways, including oxidative stress, inflammation and apoptosis, and its protective effect correlates with antioxidant activity.

Antihypertensive effect of patulitrin and other constituents from Tagetes patula L. (French marigold) in acute L-NAME induced hypertensive rats

The work is aimed to evaluate the blood pressure reducing effect of constituents from methanol extract and associated constituents of Tagetes patula flowers in normotensive and L-NAME induced hypertensive rats. The HPLC analysis of methanol extract of Tagetes patula flowers (JFM) resulted in the quantitative identification and percent comparison of four phenolic constituents, protocatechuic acid (PA), methyl protocatechuate (MPA), patulitrin (TRIN) and patuletin (PAT). All the extracts, fractions and compounds examined showed significant blood pressure lowering activity. Patulitrin (TRIN) which has emerged as the major constituent (15.33%) of T. patula flowers showed significant 30% and 68% fall in blood pressure in normotensive and L-NAME induced hypertensive rats respectively. The patuletin (PAT), which is an aglycone of TRIN displayed high percentage (84%) of antihypertensive activity. Further, comprehensive and advanced studies on these constituents may result in preparation of an effective blood pressure lowering medicine with active precious rare flavonoids, patuletin and patulitrin.

Highly selective and sensitive molecularly imprinted sensors for the electrochemical assay of quercetin in methanol extracts of Rubus sanctus and Fragaria vesca

Quercetin (QUE) is a powerful antioxidant and one of the common phenolic compounds found in plants, vegetables, and fruits, which has shown many pharmacological activities. The complex nature of the matrix in which QUE is found and its importance and potential uses in diverse applications force the researchers to develop selective and sensitive sensors. In the present work, a novel molecularly imprinted polymer (MIP)-based electrochemical sensor was fabricated for the selective and sensitive determination of the QUE in plant extracts and food supplements. Tryptophan methacrylate (TrpMA) was chosen as the functional monomer, whereas the photopolymerization (PP) method was applied using a glassy carbon electrode (GCE). Electrochemical and morphological characterizations of the developed sensor (TrpMA@QUE/MIP-GCE) were performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). The linear range of the developed sensor was determined to be in the range of 1.0-25 pM, while the limit of detection (LOD) was calculated to be 0.235 pM. In conclusion, The TrpMA@QUE/MIP-GCE sensor might be classified as a promising platform for selective and sensitive determination of QUE not only in plant extracts but also in commercial food supplements because of its reliability, reproducibility, repeatability, stability, and fast response time.

Bioactive compounds from Actinidia arguta fruit as a new strategy to fight glioblastoma

In recent years, there has been a significant demand for natural products as a mean of disease prevention or as an alternative to conventional medications. The driving force for this change is the growing recognition of the abundant presence of valuable bioactive compounds in natural products. On recent years Actinia arguta fruit, also known as kiwiberry, has attracted a lot of attention from scientific community due to its richness in bioactive compounds, including phenolic compounds, organic acids, vitamins, carotenoids and fiber. These bioactive compounds contribute to the fruit's diverse outstanding biological activities such as antioxidant, anti-inflammatory, neuroprotective, immunomodulatory, and anti-cancer properties. Due to these properties, the fruit may have the potential to be used in the treatment/prevention of various types of cancer, including glioblastoma. Glioblastoma is the most aggressive form of brain cancer, displaying 90 % of recurrence rate within a span of 2 years. Despite the employment of an aggressive approach, the prognosis remains unfavorable, emphasizing the urgent requirement for the development of new effective treatments. The preclinical evidence suggests that kiwiberry has potential impact on glioblastoma by reducing the cancer self-renewal, modulating the signaling pathways involved in the regulation of the cell phenotype and metabolism, and influencing the consolidation of the tumor microenvironment. Even though, challenges such as the imprecise composition and concentration of bioactive compounds, and its low bioavailability after oral administration may be drawbacks to the development of kiwiberry-based treatments, being urgent to ensure the safety and efficacy of kiwiberry for the prevention and treatment of glioblastoma. This review aims to highlight the potential impact of A. arguta bioactive compounds on glioblastoma, providing novel insights into their applicability as complementary or alternative therapies.

Nano Drug Delivery Strategies for an Oral Bioenhanced Quercetin Formulation

Quercetin, a naturally occurring flavonoid, has been credited with a wide spectrum of therapeutic properties. However, the oral use of quercetin is limited due to its poor water solubility, low bioavailability, rapid metabolism, and rapid plasma clearance. Quercetin has been studied extensively when used with various nanodelivery systems for enhancing quercetin bioavailability. To enhance its oral bioavailability and efficacy, various quercetin-loaded nanosystems such as nanosuspensions, polymer nanoparticles, metal nanoparticles, emulsions, liposomes or phytosomes, micelles, solid lipid nanoparticles, and other lipid-based nanoparticles have been investigated in in-vitro cells, in-vivo animal models, and humans. Among the aforementioned nanosystems, quercetin phytosomes are attracting more interest and are available on the market. The present review covers insights into the possibilities of harnessing quercetin for several therapeutic applications and a special focus on anticancer applications and the clinical benefits of nanoquercetin formulations.

Natural flavonols: actions, mechanisms, and potential therapeutic utility for various diseases

Background

Flavonols are phytoconstituents of biological and medicinal importance. In addition to functioning as antioxidants, flavonols may play a role in antagonizing diabetes, cancer, cardiovascular disease, and viral and bacterial diseases. Quercetin, myricetin, kaempferol, and fisetin are the major dietary flavonols. Quercetin is a potent scavenger of free radicals, providing protection from free radical damage and oxidation-associated diseases.

Main body of the abstract

An extensive literature review of specific databases (e.g., Pubmed, google scholar, science direct) were conducted using the keywords "flavonol," "quercetin," "antidiabetic," "antiviral," "anticancer," and "myricetin." Some studies concluded that quercetin is a promising antioxidant agent while kaempferol could be effective against human gastric cancer. In addition, kaempferol prevents apoptosis of pancreatic beta-cells via boosting the function and survival rate of the beta-cells, leading to increased insulin secretion. Flavonols also show potential as alternatives to conventional antibiotics, restricting viral infection by antagonizing the envelope proteins to block viral entry.

Short conclusion

There is substantial scientific evidence that high consumption of flavonols is associated with reduced risk of cancer and coronary diseases, free radical damage alleviation, tumor growth prevention, and insulin secretion improvement, among other diverse health benefits. Nevertheless, more studies are required to determine the appropriate dietary concentration, dose, and type of flavonol for a particular condition to prevent any adverse side effects.

Protective Effect of Quercetin 3-O-Glucuronide against Cisplatin Cytotoxicity in Renal Tubular Cells

Quercetin, a flavonoid with promising therapeutic potential, has been shown to protect from cisplatin nephrotoxicity in rats following intraperitoneal injection, but its low bioavailability curtails its prospective clinical utility in oral therapy. We recently developed a micellar formulation (P-quercetin) with enhanced solubility and bioavailability, and identical nephroprotective properties. As a first aim, we herein evaluated the oral treatment with P-quercetin in rats, which displayed no nephroprotection. In order to unravel this discrepancy, quercetin and its main metabolites were measured by HPLC in the blood and urine after intraperitoneal and oral administrations. Whilst quercetin was absorbed similarly, the profile of its metabolites was different, which led us to hypothesize that nephroprotection might be exerted in vivo by a metabolic derivate. Consequently, we then aimed to evaluate the cytoprotective capacity of quercetin and its main metabolites (quercetin 3-O-glucoside, rutin, tamarixetin, isorhamnetin and quercetin 3-O-glucuronide) against cisplatin toxicity, in HK-2 and NRK-52E tubular cell lines. Cells were incubated for 6 h with quercetin, its metabolites or vehicle (pretreatment), and subsequently 18 h in cotreatment with 10-300 μM cisplatin. Immediately after treatment, cell cultures were subject to the MTT technique as an index of cytotoxicity and photographed under light microscopy for phenotypic assessment. Quercetin afforded no direct cytoprotection and quercetin-3-O-glucuronide was the only metabolite partially preventing the effect of cisplatin in cultured tubule cells. Our results identify a metabolic derivative of quercetin contributing to its nephroprotection and prompt to further explore exogenous quercetin-3-O-glucuronide in the prophylaxis of tubular nephrotoxicity.

Chrysin attenuates high-fat-diet-induced myocardial oxidative stress via upregulating eNOS and Nrf2 target genes in rats

Hypercholesterolemia is one of the risk factors associated with increased morbidity and mortality in cardiovascular disorders. Chrysin (Chy) is reported to exhibit anti-inflammatory, anti-cancerous, anti-oxidative, anti-aging, and anti-atherogenic properties. In the present study, we aimed to investigate whether Chy would mediate the cardioprotective effect against hypercholesterolemia-triggered myocardial oxidative stress. Male Sprague Dawley rats were divided into different groups as control and fed with high-fat diet (HFD) followed by oral administration of Chy (100 mg/kg b.wt), atorvastatin (Atv) (10 mg/kg b.wt), and L-NAME (10 mg/kg b.wt) for 30 days. At the end of the experimental period, the rats were sacrificed and tissues were harvested. Biochemical results showed a significant increase of cardiac disease marker enzymes (ALT, AST, and CKMB), lipid peroxidation, and lipid profile (TC, TG, LDL, and VLDL) in HFD-fed rat tissues when compared to control, whereas oral administration of Chy significantly reduced the activities of these marker enzymes and controlled the lipid profile. qRT-PCR studies revealed that Chy administration significantly increased the expression of endothelial nitric oxide synthase (eNOS), and Nrf2 target genes such as SOD, catalase, and GCL3 in left ventricular heart tissue of HFD-challenged rats. Immunohistochemistry results also showed that Chy treatment increased myocardial protein expression of eNOS and Nrf2 in HFD-challenged rats. Concluding the results of the present study, the Chy could mediate the cardioprotective effect through the activation of eNOS and Nrf2 signaling against hypercholesterolemia-induced oxidative stress. Thus, the administration of Chy would provide a promising therapeutic strategy for the prevention of HFD-induced oxidative stress-mediated myocardial complications.

Apple Supplementation Improves Hemodynamic Parameter and Attenuates Atherosclerosis in High-Fat Diet-Fed Apolipoprotein E-Knockout Mice

Epidemiological studies describe the association between apple consumption and improved cardiovascular and metabolic dysfunction. Our recent multiparametric screening on cellular model studies has shown that apples exhibit vascular tropism including Granny Smith (GS) variety independently of the storage condition. The present study aimed to evaluate the cardiovascular and metabolic protection of supplementation of GS variety after storage in classic cold (GSCC) and extreme ultra-low oxygen conditions (GSXO) in the apolipoprotein E-deficient 8-week-old mice fed with high fat diet for 14 weeks. Supplementation with GSCC and GXO decreases circulating triglycerides, the expression of genes involved in lipogenesis, without change in cholesterol and glucose concentrations and HOMA-IR. Only GSXO supplementation ameliorates body weight gain, insulin level, and HDL/LDL ratio. GSXO supplementation does not modify cardiac parameters; while supplementation with GSCC decreases heart rate and improves cardiac output. Interestingly, GSCC and GSXO reduce systolic and diastolic blood pressure with a differential time course of action. These effects are associated with substantial decrease of atherosclerotic lesions. These data reinforce the knowledge about the vascular tropism of apple supplementation and underscore their ability to improve both cardiovascular and metabolic alterations in a mouse model of atherosclerosis.

Is Drinking Alcohol Really Linked to Cardiovascular Health? Evidence from the Kardiovize 2030 Project

Existing data have described benefits and drawbacks of alcohol consumption on cardiovascular diseases (CVD), but no research has evaluated its association with the cardiovascular health (CVH) score proposed by the American Heart Association. Here, we conducted a cross-sectional analysis on the Kardiovize cohort (Brno, Czech Republic), to investigate the relationship between alcohol consumption and CVH. We included 1773 subjects (aged 25–64 years; 44.2% men) with no history of CVD. We compared CVD risk factors, CVH metrics (i.e., BMI, healthy diet, physical activity level, smoking status, blood pressure, fasting glucose, and total cholesterol) and CVH score between and within several drinking categories. We found that the relationship between drinking habits and CVH was related to the amount of alcohol consumed, drinking patterns, and beverage choices. Heavy drinkers were more likely to smoke tobacco, and to report diastolic blood pressure, fasting glucose, triglycerides, and low-density lipoprotein (LDL)-cholesterol at higher level than non-drinkers. Among drinkers, however, people who exclusively drank wine exhibited better CVH than those who exclusively drank beer. Although our findings supported the hypothesis that drinking alcohol was related to the CVH in general, further prospective research is needed to understand whether the assessment of CVH should incorporate information on alcohol consumption.

Protective effect of quercetin against myocardial ischemia as a Ca2+ channel inhibitor: involvement of inhibiting contractility and Ca2+ influx via L-type Ca2+ channels

Many studies describe the stimulating effect of quercetin on Ca²⁺ channels and the treatment of cardiovascular diseases such as myocardial ischemia and hypertension. However, these studies are scattered and contradictory. The aim of this study is to elucidate the protective effects of quercetin against isoproterenol (ISO)-induced myocardial ischemia and verify the cellular mechanisms based on the L-type Ca²⁺ channel (LTCC), Ca²⁺ transients, and myocardial contractility. An animal model of myocardial ischemia was established by subcutaneous injection of ISO for 2 days. Quercetin significantly reduced J-point elevation, heart rate, reactive oxygen species, serum levels of myocardial enzymes, superoxide dismutase, catalase, glutathione, glutathione peroxidase, glutathione S-transferase and improved heart pathologic morphology. L-type Ca²⁺ current (I_Ca-L) was tested in an experiment with isolated rat myocardial cells by using the whole-cell patch-clamp recording technique and IonOptix Myocam detection system. Quercetin reduced I_Ca-L in a concentration-dependent fashion with a half-maximal inhibitory concentration of 4.67 × 10^-4 M. Quercetin also shifted the current-voltage curve upwards, moved the activation and inactivation curves to the left and inhibited the amplitude of the cell shortening and Ca²⁺ transients. The results showed that quercetin acts as a LTCC inhibitor and exerts a cardioprotective effect by inhibiting Ca²⁺ influx and contractility in rats.

Relation between redox homeostasis blood parameters in cirrhotic patients and endothelial dysfunction development

BACKGROUND

Liver is one of the first organs to be exposed to reactive oxygen species (ROS). But the data about the levels of redox homeostasis parameters in the patients with liver cirrhosis (LC) are contradictory. We hypothesized that the levels of malondialdehyde and catalase should change in accordance with the LC severity causing the endothelial dysfunction.

METHODS

In a randomized way with the preliminary stratification by the presence of LC 81 patients and 20 healthy volunteers were examined. To determine the contents of catalase, malondialdehyde, cyclic guanosine monophosphate, endothelin-1, renin, aldosterone, natriuretic peptide, the routine standardized methods were used.

RESULTS

Patients with LC revealed the statistically significant increase of malondialdehyde and decrease of catalase levels in parallel with the increase of cyclic guanosine monophosphate, endothelin-1, renin, aldosterone, natriuretic peptide contents and disease course worsening according to the Child-Pugh criteria. It testifies the huge oxidative stress impact on the organism. Initially, at the stage of LC compensation, it slightly stimulates the activation of antioxidant system, followed by its gradual suppression at the stages of sub- and decompensation. Disorders of redox homeostasis lead to the endothelial dysfunction that becomes the background of extrahepatic comorbid disorders.

CONCLUSIONS

Cirrhotic patients have significant abnormalities in the redox homeostasis, which become the background of the endothelial dysfunction - common trigger mechanism for the syntrophic comorbid diseases and early pathophysiologic symptom of the unfavorable prognosis for such patients.

The Effects of Quercetin Supplementation on Blood Pressures and Endothelial Function Among Patients with Metabolic Syndrome and Related Disorders: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

This systematic review and meta-analysis of randomized controlled trials (RCTs) were performed to determine the effect of quercetin administration on blood pressures and endothelial function among patients with metabolic syndrome (MetS) and related disorders.

METHODS

We searched systematically online databases including Cochrane Library, EMBASE, MEDLINE, and Web of Science to identify the relevant RCTs until December 2018. Q-test and I2 statistics were applied to assess heterogeneity among the included studies. Data were pooled using a random-effects model and weighted mean difference (WMD) was considered as the overall effect size.

RESULTS

Out of 284 citations, 8 RCTs were included in the meta-analysis. We found a significant reduction in systolic blood pressure (SBP) (WMD: -1.69; 95% CI: -3.22, -0.17) following the intake of quercetin supplements. However, quercetin supplementation did not significantly affect diastolic blood pressure (DBP) (WMD: -3.14; 95% CI: -8.24, 1.95), vascular cell adhesion molecule 1 (VCAM-1) (WMD: -24.49; 95% CI: -53.74, 4.77) and intercellular adhesion molecule 1 (ICAM-1) (WMD: -5.78; 95% CI: -12.93, 1.38).

CONCLUSION

In summary, the current meta-analysis demonstrated that quercetin supplementation significantly reduced SBP, yet did not affect DBP, VCAM-1 and ICAM-1 among patients with MetS and related disorders.

Oral and Intra-nasal Administration of Nanoparticles in the Cerebral Ischemia Treatment in Animal Experiments: Considering its Advantages and Disadvantages

BACKGROUND

Over the past few decades, nanotechnology has dramatically advanced; from the precise strategies of synthesizing modern nanostructures to methods of entry into the body. Using nanotechnology in diagnosis, drug delivery, determining signaling pathways, and tissue engineering is great hope for the treatment of stroke. The drug-carrying nanoparticles are a way to increase drug absorption through the mouth or nose in treating the stroke.

OBJECTIVE

In this article, in addition to explaining pros and cons of oral and intra-nasal administration of nanoparticles in the brain ischemia treatment of animal models, the researchers introduce some articles in this field and briefly mentioned their work outcomes.

METHODS

A number of relevant published articles 183 were initially collected from three popular databases including PubMed, Google Scholar, and Scopus. The articles not closely related to the main purpose of the present work were removed from the study process. The present data set finally included 125 published articles.

RESULTS

Direct delivery of the drug to the animal brain through the mouth and nose has more therapeutic effects than systemic delivery of drugs. The strategy of adding drugs to the nanoparticles complex can potentially improve the direct delivery of drugs to the CNS.

CONCLUSION

Despite the limitations of oral and intra-nasal routes, the therapeutic potential of oral and intra-nasal administration of nano-medicines is high in cerebral ischemia treatment.

Flavonoids sensitize tumor cells to radiation: molecular mechanisms and relevance to cancer radiotherapy

Purpose: Radiobiological research continues to focus on finding newer strategies for enhanced killing of tumor cells by ionizing radiation. In recent years, chemotherapeutic drugs have been found to possess the capabilities to sensitize tumor cells without affecting the normal cells. There have been increasing research efforts to identify novel and nontoxic compounds which cause minimal or no harm to normal cells but maximize tumor toxicity response to radiation exposure. Extensive researches on flavonoids that are compounds derived from plants have shown that these have promising abilities as radioprotectors and radiosensitizers.Conclusions: In this review, we examine the role of flavonoids as potential radiosensitizers, review the underlying molecular mechanisms and discuss their potential usefulness in improving cancer radiotherapy. It is emphasized that obtaining a deeper insight into the molecular mechanisms underlying the combined action of flavonoids and ionizing radiation may provide new directions for radiobiological research applicable to the much needed enhanced selective tumor cytotoxicity to treatment agents.

Lipoic acid antagonizes paraquat-induced vascular endothelial dysfunction by suppressing mitochondrial reactive oxidative stress

Paraquat (PQ) is a widely used herbicide in the agricultural field. The lack of an effective antidote is the significant cause of high mortality in PQ poisoning. Here, we investigate the antagonistic effects of alpha lipoic acid (α-LA), a naturally existing antioxidant, on PQ toxicity in human microvascular endothelial cells (HMEC-1). All the doses of 250, 500 and 1000 μM α-LA significantly inhibited 1000 μM PQ-induced cytotoxicity in HMEC-1 cells. α-LA pretreatment remarkably diminished the damage to cell migration ability, recovered the declined levels of the vasodilator factor nitric oxide (NO), elevated the expression level of endothelial nitric oxide synthases (eNOS), and inhibited the upregulated expression of vasoconstrictor factor endothelin-1 (ET-1). Moreover, α-LA pretreatment inhibited reactive oxygen species (ROS) generation, suppressed the damage to the mitochondrial membrane potential (ΔΨ _m) and mitigated the inhibition of adenosine triphosphate (ATP) production in HMEC-1 cells. These results suggested that α-LA could alleviate PQ-induced endothelial dysfunction by suppressing oxidative stress. In summary, our present study provides novel insight into the protective effects and pharmacological potential of α-LA against PQ toxicity in microvascular endothelial cells.

Casein nanoparticles in combination with 2-hydroxypropyl-β-cyclodextrin improves the oral bioavailability of quercetin

The aim of this work was to optimize the preparative process of quercetin loaded casein nanoparticles as well as to evaluate the pharmacokinetics of this flavonoid when administered orally in Wistar rats. Nanoparticles were obtained by coacervation after the incubation of casein, 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and quercetin in an aqueous environment. Then, nanoparticles were purified and dried. The resulting nanoparticles displayed a size of 200 nm with a negative zeta potential and a payload of about 32 μg/mg. Release studies showed a zero-order kinetic, suggesting a mechanism based on erosion of the nanoparticle matrix. For the pharmacokinetic study, quercetin was orally administered to rats as a single dose of 25 mg/kg. Animals treated with quercetin-loaded casein nanoparticles displayed higher plasma levels than those observed in animals receiving the solution of the flavonoid (control). Thus, the relative oral bioavailability of quercetin when administered as casein nanoparticles (close to 37%) was found to be about 9-times higher than the oral solution of the flavonoid in a mixture of PEG 400 and water. In summary, the combination of casein and 2-hydroxypropyl-β-cyclodextrin produces nanoparticles that may be a good option to load quercetin for both nutraceutical and pharmaceutical purposes.

Cardiovascular Effects of Flavonoids

:

Cardiovascular Disease (CVD) is the major cause of death worldwide, especially in Western society. Flavonoids are a large group of polyphenolic compounds widely distributed in plants, present in a considerable amount in fruit and vegetable. Several epidemiological studies found an inverse association between flavonoids intake and mortality by CVD. The antioxidant effect of flavonoids was considered the main mechanism of action of flavonoids and other polyphenols. In recent years, the role of modulation of signaling pathways by direct interaction of flavonoids with multiple protein targets, namely kinases, has been increasingly recognized and involved in their cardiovascular protective effect. There are strong evidence, in in vitro and animal experimental models, that some flavonoids induce vasodilator effects, improve endothelial dysfunction and insulin resistance, exert platelet antiaggregant and atheroprotective effects, and reduce blood pressure. Despite interacting with multiple targets, flavonoids are surprisingly safe. This article reviews the recent evidence about cardiovascular effects that support a beneficial role of flavonoids on CVD and the potential molecular targets involved.

The Action of Polyphenols in Diabetes Mellitus and Alzheimer's Disease: A Common Agent for Overlapping Pathologies

Diabetes Mellitus (DM) and Alzheimer's disease (AD) are two prevalent diseases in modern societies, which are caused mainly by current lifestyle, aging and genetic alterations. It has already been demonstrated that these two diseases are associated, since individuals suffering from DM are prone to develop AD. Conversely, it is also known that individuals with AD are more susceptible to DM, namely type 2 diabetes (T2DM). Therefore, these two pathologies, although completely different in terms of symptomatology, end up sharing several mechanisms at the molecular level, with the most obvious being the increase of oxidative stress and inflammation. Polyphenols are natural compounds widely spread in fruits and vegetables whose dietary intake has been considered inversely proportional to the incidence of DM and AD. So, it is believed that this group of phytochemicals may have preventive and therapeutic potential, not only by reducing the risk and delaying the development of these pathologies, but also by improving brain's metabolic profile and cognitive function. The aim of this review is to understand the extent to which DM and AD are related pathologies, the degree of similarity and the relationship between them, to detail the molecular mechanisms by which polyphenols may exert a protective effect, such as antioxidant and anti-inflammatory effects, and highlight possible advantages of their use as common preventive and therapeutic alternatives.

What's in wine? A clinician's perspective<sup/>

Alcoholic beverages, specifically wine, have been consumed for many years. Wine is postulated to play an important role in the improvement of cardiovascular risk factors. Most epidemiological studies have found sustained consumption at light-to-moderate amounts to increase HDL cholesterol, reduce platelet aggregation, and promote fibrinolysis. Wine consumption has been inversely associated with ischemic heart disease, and the alcohol-blood pressure association, in most studies, follows a J-shaped curve. These outcomes have been attributed to the molecular constituents of wine, namely ethanol and polyphenols. Due to the continued interest in wine as a biological beverage, we review the chemistry of wine as clinicians, including its chemical composition, viticulture and enological practices, and other chemical factors that influence the bioactive components of wine. We also outline the biological effects of wine components and directions for future research.

Quercetin induces the selective uptake of HDL-cholesterol via promoting SR-BI expression and the activation of the PPARγ/LXRα pathway

Reverse cholesterol transport (RCT) is the process to deliver cholesterol to the liver for further excretion and involves scavenger receptor class B type I (SR-BI)-mediated selective lipid uptake (SLU) from high-density lipoprotein cholesterol (HDL-C). The up-regulation of hepatic SR-BI expression accelerates HDL-C clearance in circulation and impedes the development of atherosclerosis (AS). In the present study, we explored the modulation of hepatic SR-BI expression and SR-BI-mediated SLU by quercetin, a natural flavonoid compound in the diet with a favorable role in cardiovascular disorders. We found that quercetin significantly increased the expression level of SR-BI in HepG2 cells in a concentration- and time-dependent manner. Besides, quercetin had stimulatory effects on the binding of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil)-labeled HDL to hepatocytes and ¹²⁵I/³H-CE-HDL association. Treatment with small interfering RNA (siRNA) or SR-BI specific inhibitor, BLT-1, inhibited quercetin-induced Dil-HDL binding and selective HDL-C uptake. Treatment with quercetin increased both proliferator-activated receptor γ (PPARγ) and liver X receptor α (LXRα) levels. Additionally, the quercetin-induced expression of SR-BI, Dil-HDL binding and the selective uptake of HDL-C were significantly attenuated by treatment with PPARγ siRNA, LXRα siRNA, and their antagonists, respectively. In C57BL/6 mice, quercetin administration potently increased SR-BI, PPARγ and LXRα levels and lipid accumulation in the liver. Altogether, our results suggest that quercetin-induced up-regulation of SR-BI and subsequent lipid uptake in hepatocytes might contribute to its beneficial effects on cholesterol homeostasis and atherogenesis.

Natural products: a hope for glioblastoma patients

Glioblastoma (GBM) is one of the most aggressive malignant tumors with an overall dismal survival averaging one year despite multimodality therapeutic interventions including surgery, radiotherapy and concomitant and adjuvant chemotherapy. Few drugs are FDA approved for GBM, and the addition of temozolomide (TMZ) to standard therapy increases the median survival by only 2.5 months. Targeted therapy appeared promising in in vitro monolayer cultures, but disappointed in preclinical and clinical trials, partly due to the poor penetration of drugs through the blood brain barrier (BBB). Cancer stem cells (CSCs) have intrinsic resistance to initial chemoradiation therapy (CRT) and acquire further resistance via deregulation of many signaling pathways. Due to the failure of classical chemotherapies and targeted drugs, research efforts focusing on the use of less toxic agents have increased. Interestingly, multiple natural compounds have shown antitumor and apoptotic effects in TMZ resistant and p53 mutant GBM cell lines and also displayed synergistic effects with TMZ. In this review, we have summarized the current literature on natural products or product analogs used to modulate the BBB permeability, induce cell death, eradicate CSCs and sensitize GBM to CRT.

Prediction of GPCR-Ligand Binding Using Machine Learning Algorithms

We propose a novel method that predicts binding of G-protein coupled receptors (GPCRs) and ligands. The proposed method uses hub and cycle structures of ligands and amino acid motif sequences of GPCRs, rather than the 3D structure of a receptor or similarity of receptors or ligands. The experimental results show that these new features can be effective in predicting GPCR-ligand binding (average area under the curve [AUC] of 0.944), because they are thought to include hidden properties of good ligand-receptor binding. Using the proposed method, we were able to identify novel ligand-GPCR bindings, some of which are supported by several studies.

Dietary Polyphenols in the Prevention of Stroke

Polyphenols have an important protective role against a number of diseases, such as atherosclerosis, brain dysfunction, stroke, cardiovascular diseases, and cancer. Cardiovascular diseases are the number one cause of death worldwide: more people die annually from cardiovascular diseases than from any other cause. The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use, and excess alcohol intake. The dietary consumption of polyphenols has shown to be inversely associated with morbidity and mortality by cardio- and cerebrovascular diseases. It is well-known that the protective effects of polyphenols in vivo depend on the grade how they are extracted from food and on their intestinal absorption, metabolism, and biological action with target tissues. The aim of this review was to summarise the relation between polyphenols of different plant sources and stroke in human intervention studies, animal models, and in vitro studies.

Wine and Cardiovascular Health: A Comprehensive Review

Alcoholic beverages have been consumed for thousands of years, attracting great human interest for social, personal, and religious occasions. In addition, they have long been debated to confer cardioprotective benefits. The French Paradox is an observation of a low prevalence of ischemic heart disease, with high intakes of saturated fat, a phenomenon accredited to the consumption of red wine. Although many epidemiological investigations have supported this view, others have attributed it to beer or spirits, with many suggesting that the drink type is not important. Although excessive consumption of alcoholic beverages is commonly regarded to be detrimental to cardiovascular health, there is a debate as to whether light-to-moderate intake is cardioprotective. Although there is extensive epidemiological support for this drinking pattern, a consensus has not been reached. On the basis of published work, we describe the composition of wine and the effects of constituent polyphenols on chronic cardiovascular diseases.

The anti-inflammatory effects of Morin hydrate in atherosclerosis is associated with autophagy induction through cAMP signaling

SCOPE

Although the previous trials of inflammation have indicated that morin hydrate (MO) hold considerable promise, understanding the distinct mechanism of MO against inflammation remains a challenge.

METHODS AND RESULTS

This study investigated the effect of MO in atherosclerosis in ApoE^-/- mice and underlying cell signaling of MO effect in inflammation in human umbilical vein endothelial cells (HUVECs). Administration of MO significantly reduced serum lipid level, inflammatory cytokines (TNF-α and ICAM-1), and atherosclerotic plaque formation in vivo. MO presence attenuated the expression of TNF-α-induced inflammatory cytokines (ICAM-1, COX-2, and MMP-9), and remarkably enhanced microtubule associated protein 1 light chain 3 beta 2 (MAP1LC3B2) expression and sequestosome 1 (SQSTM1/p62) degradation in HUVECs. These MO effects were significantly prevented by the presence of autophagic inhibitors, 3-methyladenine (3-MA), or chloroquine (CQ), as well as siRNA suppression of ATG5 and BECN1. MO increased intracellular cAMP levels and activated cAMP-PKA-AMPK-SIRT1 signaling in vivo and in vitro. These changes resulted in increased expression of autophagy-related protein MAP1LC3B2 and decreased secretion of inflammatory cytokines (ICAM-1, COX-2, and MMP-9).

CONCLUSION

Our results suggest that anti-AS and anti-inflammatory effects of MO are largely associated with its induction of autophagy through stimulation of cAMP-PKA-AMPK-SIRT1 signaling pathway.

Factors modulating bioavailability of quercetin-related flavonoids and the consequences of their vascular function

Nowadays dietary flavonoids attract much attention in the prevention of chronic diseases. Epidemiological and intervention studies strongly suggest that flavonoid intake has beneficial effects on vascular health. It is unlikely that flavonoids act as direct antioxidants, although oxidative stress profoundly contributes to vascular impairment leading to cardiovascular diseases. Instead, flavonoids may exert their function by tuning the cellular redox state to an adaptive response or tolerable stress. However, the optimum intake of flavonoids from supplements or diet has not been clarified yet, because a number of exogenous and endogenous factors modulating their bioavailability affect their vascular function. This review will focus on the current knowledge of the bioavailability and vascular function of quercetin as a representative of antioxidative flavonoids. Current intervention studies imply that intake of quercetin-rich onion improves vascular health. Onion may be superior to quercetin supplement from the viewpoint of quercetin bioavailability, probably because the food matrix enhances the intestinal absorption of quercetin. α-Glucosylation increases its bioavailability by elevating the accessibility to the absorptive cells. Prenylation may enhance bioaccumulation at the target site by increasing the cellular uptake. However, these chemical modifications do not guarantee health benefits to the vascular system. Dietary quercetin is exclusively present as their conjugated form in the blood stream. Quercetin may exert its vascular function as an aglycone within macrophage cells after inflammation-induced deconjugation and as conjugated metabolites by targeting endothelial cells. The relationship between the bioavailability and bio-efficacy should be clarified, to evaluate the vascular function of a wide variety of dietary flavonoids.

Resveratrol protects against oxidized low‑density lipoprotein‑induced human umbilical vein endothelial cell apoptosis via inhibition of mitochondrial‑derived oxidative stress

Resveratrol, a natural phytochemical found in grapes and red wine, has been found to possess protective effects against endothelial cell apoptosis and oxidative damage. Oxidized-low density lipoprotein (ox-LDL) can induce apoptosis of endothelial cells, which is an important initial event in several cardiovascular diseases. However, the effect of resveratrol on ox-LDL-induced apoptosis and oxidative damage, and the possible associated mechanisms remain to be elucidated. In the present study, following exposure to ox-LDL, human umbilical vein endothelial cells (HUVECs) were treated with or without resveratrol. Cell viability was examined using Cell Counting Kit-8 and 5-bromo-2′-deoxyuridine uptake assays, respectively. Cell apoptosis was determined by flow cytometry. Apoptosis-associated markers were detected using western blot analysis. Oxidative stress was analyzed using molecular and biochemical approaches. Resveratrol restored ox-LDL-induced HUVEC injury and apoptosis in a dose-dependent manner. In addition, compared with the control group, ox-LDL treatment decreased the B cell lymphoma-2 (Bcl-2)/Bcl-2-associated X protein ratio, mitochondrial membrane potential and activation of superoxide dismutase, and enhanced the release of mitochondrial cytochrome c into the cytoplasm, the activation of caspase and lipid peroxidation. All these alterations were significantly inhibited following treatment with resveratrol. The results demonstrated that resveratrol prevented HUVEC apoptosis through inhibiting mitochondria-derived oxidative damage. These findings may provide a novel mechanism by which resveratrol prevents against endothelial cell apoptosis.

Aspalatone Prevents VEGF-Induced Lipid Peroxidation, Migration, Tube Formation, and Dysfunction of Human Aortic Endothelial Cells

Although aspalatone (acetylsalicylic acid maltol ester) is recognized as an antithrombotic agent with antioxidative and antiplatelet potential; its efficacy in preventing endothelial dysfunction is not known. In this study, we examined the antiangiogenic, antioxidative, and anti-inflammatory effect of aspalatone in human aortic endothelial cells (HAECs). Specifically, the effect of aspalatone on VEGF-induced HAECs growth, migration, tube formation, and levels of lipid peroxidation-derived malondialdehyde (MDA) was examined. Our results indicate that the treatment of HAECs with aspalatone decreased VEGF-induced cell migration, tube formation, and levels of MDA. Aspalatone also inhibited VEGF-induced decrease in the expression of eNOS and increase in the expression of iNOS, ICAM-1, and VCAM-1. Aspalatone also prevented the VEGF-induced adhesion of monocytes to endothelial cells. Furthermore, aspalatone also prevented VEGF-induced release of inflammatory markers such as Angiopoietin-2, Leptin, EGF, G-CSF, HB-EGF, and HGF in HAECs. Thus, our results suggest that aspalatone could be used to prevent endothelial dysfunction, an important process in the pathophysiology of cardiovascular diseases.

Antihypertensive effects of Tartary buckwheat flavonoids by improvement of vascular insulin sensitivity in spontaneously hypertensive rats

Tartary buckwheat flavonoids alleviate hypertension through attenuating vascular insulin resistance and oxidative stress.

Quercetin and derivatives: useful tools in inflammation and pain management

Inflammation represents a very frequent condition in humans; it is often underestimated, making the problem an increasingly alarming phenomenon. For these reasons, conventional therapies are losing their effectiveness, leaving room for innovative therapies. In this field, natural products showed their efficacy in various diseases; and flavonoids, in particular quercetin, is known for its broad range of activities. In this review, we have highlighted its efficacy in various models of inflammation, focusing also on the activity of its semisynthetic derivatives, and those naturally present in plant extracts. Finally, the analgesic property of quercetin, intrinsically linked to its anti-inflammatory action, has been also evaluated, to investigate about an innovative approach to this interesting natural compound, such as analgesic remedial.

Systems pharmacology exploration of botanic drug pairs reveals the mechanism for treating different diseases

Multi-herb therapy has been widely used in Traditional Chinese medicine and tailored to meet the specific needs of each individual. However, the potential molecular or systems mechanisms of them to treat various diseases have not been fully elucidated. To address this question, a systems pharmacology approach, integrating pharmacokinetics, pharmacology and systems biology, is used to comprehensively identify the drug-target and drug-disease networks, exemplified by three representative Radix Salviae Miltiorrhizae herb pairs for treating various diseases (coronary heart disease, dysmenorrheal and nephrotic syndrome). First, the compounds evaluation and the multiple targeting technology screen the active ingredients and identify the specific targets for each herb of three pairs. Second, the herb feature mapping reveals the differences in chemistry and pharmacological synergy between pairs. Third, the constructed compound-target-disease network explains the mechanisms of treatment for various diseases from a systematic level. Finally, experimental verification is taken to confirm our strategy. Our work provides an integrated strategy for revealing the mechanism of synergistic herb pairs, and also a rational way for developing novel drug combinations for treatments of complex diseases.

Oxidative stress and abdominal aortic aneurysm: potential treatment targets

Abdominal aortic aneurysm (AAA) is a significant cause of mortality in older adults. A key mechanism implicated in AAA pathogenesis is inflammation and the associated production of reactive oxygen species (ROS) and oxidative stress. These have been suggested to promote degradation of the extracellular matrix (ECM) and vascular smooth muscle apoptosis. Experimental and human association studies suggest that ROS can be favourably modified to limit AAA formation and progression. In the present review, we discuss mechanisms potentially linking ROS to AAA pathogenesis and highlight potential treatment strategies targeting ROS. Currently, none of these strategies has been shown to be effective in clinical practice.

Estimation of Apple Intake for the Exposure Assessment of Residual Chemicals Using Korea National Health and Nutrition Examination Survey Database

The aims of this study were to develop strategies and algorithms of calculating food commodity intake suitable for exposure assessment of residual chemicals by using the food intake database of Korea National Health and Nutrition Examination Survey (KNHANES). In this study, apples and their processed food products were chosen as a model food for accurate calculation of food commodity intakes uthrough the recently developed Korea food commodity intake calculation (KFCIC) software. The average daily intakes of total apples in Korea Health Statistics were 29.60 g in 2008, 32.40 g in 2009, 34.30 g in 2010, 28.10 g in 2011, and 24.60 g in 2012. The average daily intakes of apples by KFCIC software was 2.65 g higher than that by Korea Health Statistics. The food intake data in Korea Health Statistics might have less reflected the intake of apples from mixed and processed foods than KFCIC software has. These results can affect outcome of risk assessment for residual chemicals in foods. Therefore, the accurate estimation of the average daily intake of food commodities is very important, and more data for food intakes and recipes have to be applied to improve the quality of data. Nevertheless, this study can contribute to the predictive estimation of exposure to possible residual chemicals and subsequent analysis for their potential risks.

Quercetin solubilisation in bile salts: A comparison with sodium dodecyl sulphate

•

Quercetin partitions into bile salt and SDS micelles.

•

Quercetin’s UV–visible spectra reflect its environment and micelle formation.

•

Quercetin’s binding site is more hydrophobic in bile salt micelles.

•

Pyrene fluorescence confirms quercetin’s spectral data.

•

The results contribute to understanding quercetin’s low bioavailability.

To understand the bioaccessibility of the flavonoid quercetin we studied its interaction with bile salt micelles. The environmental sensitivity of quercetin’s UV–visible absorption spectrum gave information about quercetin partitioning. Two quercetin absorption peaks gave complementary information: Peak A (240–280 nm) on the intermicellar phase and Peak B (340–440 nm) on the micellar phase. Thus, by altering pH, we showed that only non-ionised quercetin partitions into micelles. We validated our interpretation by studying quercetin’s interaction with SDS micelles. Pyrene fluorescence and the quercetin UV–visible spectra show that the adsorption site for pyrene and quercetin in bile salt micelles is more hydrophobic than that for SDS micelles. Also, both quercetin and pyrene reported a higher critical micelle concentration for bile salts than for SDS. Our method of using a flavonoid as an intrinsic probe, is generally applicable to other lipophilic bioactives, whenever they have observable environmental dependent properties.

Effect of a high fat, high sucrose diet on the promotion of non-alcoholic fatty liver disease in male rats: the ameliorative role of three natural compounds

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease with a complex pathophysiology. The clinical features of NAFLD include obesity, insulin resistance (IR) and dyslipidemia. Consumption of a diet high in saturated fats and sucrose is an important factor in the increasing occurrence of these metabolic disorders, primarily NAFLD and IR. We sought to assess the role of a high-fat, high-sucrose (HFS) diet in the promotion of NAFLD and to evaluate the effects of quercetin (Q), berberine (BB) and o-coumaric acid (CA) on modulation of these disorders.

METHODS

Fifty male rats were divided into 2 main groups as follows: group 1 comprised 10 rats fed a standard diet (SD), and group 2 comprised 40 rats fed an HFS diet for 6 weeks and then subdivided equally into 4 groups; one of these groups served as the HFS diet and each of the other three groups received daily supplementation with either Q, CA or BB for 6 weeks.

RESULTS

In the present study, several metabolic disorders were induced in our laboratory animal model, as evidenced by histological and biochemical changes. These alterations included serum and hepatic dyslipidemia (i.e., increased triglyceride, total cholesterol and low-density lipoprotein levels and decreased high-density lipoprotein levels), alterations in metabolic enzyme activities (lipase, glycerol-3-phosphate dehydrogenase, and glucose-6-phosphate dehydrogenase), histological changes in the liver (micro- and macrovesicular steatosis) and the downregulation of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissue and the liver. Daily oral supplementation with Q, CA or BB for 6 weeks after NAFLD induction had a hypolipidemic action and modulated metabolic markers.

CONCLUSION

We showed that an HFS diet is able to promote NAFLD, and our results suggest that CA and BB are promising complementary supplements that can ameliorate the metabolic disorders associated with an HFS diet; however, Q requires further investigation.

Apple Peel Supplemented Diet Reduces Parameters of Metabolic Syndrome and Atherogenic Progression in ApoE-/- Mice

Cardiovascular Diseases (CVD) represent about 30% of all causes of death worldwide. The development of CVD is related in many cases with the previous existence of metabolic syndrome (MS). It is known that apple consumption has a cardiovascular protecting effect, containing phenolic compounds with antioxidant effect, which are concentrated in the fruit peel. The objective of this study was to test the effect of apple peel consumption in a murine model of MS and apoE−/− mice. Apple supplemented diets reduced the biochemical parameters (glycaemia, total cholesterol, HDL-cholesterol, LDL-cholesterol, ureic nitrogen, triglycerides, insulin, and asymmetric dimethylarginine (ADMA)) of MS model in CF1 mice significantly. The model apoE−/− mouse was used to evaluate the capacity of the apple peel to revert the progression of the atherogenesis. FD with HAP reverts cholesterol significantly and slows down the progression of the plate diminishing the cholesterol accumulation area. With these results, it can be concluded that the consumption of apple peel reduces several MS parameters and the atherogenic progression in mice.

Flavonoid intake and all-cause mortality

BACKGROUND

Flavonoids are bioactive compounds found in foods such as tea, chocolate, red wine, fruit, and vegetables. Higher intakes of specific flavonoids and flavonoid-rich foods have been linked to reduced mortality from specific vascular diseases and cancers. However, the importance of flavonoids in preventing all-cause mortality remains uncertain.

OBJECTIVE

The objective was to explore the association between flavonoid intake and risk of 5-y mortality from all causes by using 2 comprehensive food composition databases to assess flavonoid intake.

DESIGN

The study population included 1063 randomly selected women aged >75 y. All-cause, cancer, and cardiovascular mortalities were assessed over 5 y of follow-up through the Western Australia Data Linkage System. Two estimates of flavonoid intake (total flavonoidUSDA and total flavonoidPE) were determined by using food composition data from the USDA and the Phenol-Explorer (PE) databases, respectively.

RESULTS

During the 5-y follow-up period, 129 (12%) deaths were documented. Participants with high total flavonoid intake were at lower risk [multivariate-adjusted HR (95% CI)] of 5-y all-cause mortality than those with low total flavonoid consumption [total flavonoidUSDA: 0.37 (0.22, 0.58); total flavonoidPE: 0.36 (0.22, 0.60)]. Similar beneficial relations were observed for both cardiovascular disease mortality [total flavonoidUSDA: 0.34 (0.17, 0.69); flavonoidPE: 0.32 (0.16, 0.61)] and cancer mortality [total flavonoidUSDA: 0.25 (0.10, 0.62); flavonoidPE: 0.26 (0.11, 0.62)].

CONCLUSIONS

Using the most comprehensive flavonoid databases, we provide evidence that high consumption of flavonoids is associated with reduced risk of mortality in older women. The benefits of flavonoids may extend to the etiology of cancer and cardiovascular disease.

Modulation of nitric oxide by flavonoids

One of the main mechanisms by which dietary flavonoids are thought to influence cardiovascular disease is via protection of the bioactivity of the endothelium-derived nitric oxide (NO). Additionally, flavonoids may also interfere with the signalling cascades of inflammation and prevent overproduction of NO and its deleterious consequences in shock and ischemia-reperfusion injury. In the present paper we review the evidence of the effects of flavonoids on NO. Flavonoids exert complex actions on the synthesis and bioavailability of NO which may result both in enhanced or decreased NO levels: (1) in cell free systems, several flavonoids may scavenge NO via its pro-oxidant properties by increasing superoxide. However, under conditions of oxidative stress, flavonoids may also protect NO from superoxide-driven inactivation. (2) In intact healthy tissues, some flavonoids increase eNOS activity in endothelial cells. Paradoxically this effect involves a pro-oxidant effect which results in Ca(2+)-dependent activation of eNOS. As inhibitors of PI3K, flavonoids may potentially inhibit the PI3K/Akt-dependent activation of eNOS. (3) Under conditions of inflammation and oxidative stress, flavonoids may prevent the inflammatory signalling cascades via inhibition of NFκB and thereby downregulate iNOS. On the other hand, they also prevent the overexpression of ROS generating enzymes, reducing superoxide and peroxynitrite levels, and hence preventing superoxide-induced NO inactivation and eNOS uncoupling. Therefore, the final effect of flavonoids on NO levels will depend on the flavonoid structure and the concentrations used, on the cell type under study and particularly on the presence of inflammatory/oxidative conditions.

The flavonoid quercetin reverses pulmonary hypertension in rats

Quercetin is a dietary flavonoid which exerts vasodilator, antiplatelet and antiproliferative effects and reduces blood pressure, oxidative status and end-organ damage in humans and animal models of systemic hypertension. We hypothesized that oral quercetin treatment might be protective in a rat model of pulmonary arterial hypertension. Three weeks after injection of monocrotaline, quercetin (10 mg/kg/d per os) or vehicle was administered for 10 days to adult Wistar rats. Quercetin significantly reduced mortality. In surviving animals, quercetin decreased pulmonary arterial pressure, right ventricular hypertrophy and muscularization of small pulmonary arteries. Classic biomarkers of pulmonary arterial hypertension such as the downregulated expression of lung BMPR2, Kv1.5, Kv2.1, upregulated survivin, endothelial dysfunction and hyperresponsiveness to 5-HT were unaffected by quercetin. Quercetin significantly restored the decrease in Kv currents, the upregulation of 5-HT2A receptors and reduced the Akt and S6 phosphorylation. In vitro, quercetin induced pulmonary artery vasodilator effects, inhibited pulmonary artery smooth muscle cell proliferation and induced apoptosis. In conclusion, quercetin is partially protective in this rat model of PAH. It delayed mortality by lowering PAP, RVH and vascular remodeling. Quercetin exerted effective vasodilator effects in isolated PA, inhibited cell proliferation and induced apoptosis in PASMCs. These effects were associated with decreased 5-HT2A receptor expression and Akt and S6 phosphorylation and partially restored Kv currents. Therefore, quercetin could be useful in the treatment of PAH.

In vivo interactions between procyanidins and human saliva proteins: effect of repeated exposures to procyanidins solution

The general accepted mechanism for astringency arises from the interaction between tannins and salivary proteins (SP) resulting in (in)soluble aggregates. By HPLC analysis, it was observed that repeated sips of procyanidins (PC) solution practically depleted aPRPs (∼14%) and statherin (∼2%), and significantly reduced the amount of gPRPs. On the other hand, bPRPs were not significantly affected. In the analysis performed after the last exposure to PC solution, it was seen a significant recovering of the chromatographic peaks corresponding especially to aPRPs (∼74%) and statherin (∼80%). In vitro interaction between SP and PC results in the decrease of the chromatographic peaks of aPRPs and statherin, suggesting that these proteins were involved in the formation of a significant quantity of insoluble complexes. In general, the results suggest that the different families of SP can be involved in different stages of the development of astringency sensation.

Vanillic acid: a potential inhibitor of cardiac and aortic wall remodeling in l-NAME induced hypertension through upregulation of endothelial nitric oxide synthase

The objective of the present study is to investigate the effects of vanillic acid on blood pressure, cardiac marker enzymes, left ventricular function and endothelial nitric oxide synthase (eNOS) expression in N(ω)-nitro-l-arginine methyl ester hydrochloride (l-NAME) induced hypertension in male albino Wistar rats. In hypertensive rats, mean arterial pressure (MAP), heart rate, cardiac marker enzymes and organ weight were increased. Impaired left ventricular function and decreased aortic eNOS expression was also observed in hypertensive rats. Moreover, treatment with vanillic acid exhibited beneficial effect on blood pressure, left ventricular function and cardiac marker enzymes. In addition, treatment with vanillic acid on hypertensive rats had upregulated eNOS expression and showed beneficial effects evidenced by histopathology and ultrastructural observations of aorta. In conclusion, vanillic acid has enough potential to normalize hypertension and left ventricular function in l-NAME induced hypertensive rats. With additional studies, vanillic acid might be used as a functional drug or as an adjuvant in the management of hypertension.