Role of quercetin in modulating rat cardiomyocyte gene expression profile

Agri-Food Waste from Apple, Pear, and Sugar Beet as a Source of Protective Bioactive Molecules for Endothelial Dysfunction and Its Major Complications

Endothelial damage is recognized as the initial step that precedes several cardiovascular diseases (CVD), such as atherosclerosis, hypertension, and coronary artery disease. It has been demonstrated that the best treatment for CVD is prevention, and, in the frame of a healthy lifestyle, the consumption of vegetables, rich in bioactive molecules, appears effective at reducing the risk of CVD. In this context, the large amount of agri-food industry waste, considered a global problem due to its environmental and economic impact, represents an unexplored source of bioactive compounds. This review provides a summary regarding the possible exploitation of waste or by-products derived by the processing of three traditional Italian crops-apple, pear, and sugar beet-as a source of bioactive molecules to protect endothelial function. Particular attention has been given to the bioactive chemical profile of these pomaces and their efficacy in various pathological conditions related to endothelial dysfunction. The waste matrices of apple, pear, and sugar beet crops can represent promising starting material for producing "upcycled" products with functional applications, such as the prevention of endothelial dysfunction linked to cardiovascular diseases.

Fermentation of Vaccinium floribundum Berries with Lactiplantibacillus plantarum Reduces Oxidative Stress in Endothelial Cells and Modulates Macrophages Function

Accumulating evidence suggests that high consumption of natural antioxidants promotes health by reducing oxidative stress and, thus, the risk of developing cardiovascular diseases. Similarly, fermentation of natural compounds with lactic acid bacteria (LAB), such as Lactiplantibacillus plantarum, enhances their beneficial properties as regulators of the immune, digestive, and cardiovascular system. We investigated the effects of fermentation with Lactiplantibacillus plantarum on the antioxidant and immunomodulatory effects of Pushgay berries (Vaccinium floribundum, Ericaceae family) in human umbilical vein endothelial cells (HUVECs) and macrophage cell line RAW264.7. Polyphenol content was assayed by Folin–Ciocalteu and HPLC-MS/MS analysis. The effects of berries solutions on cell viability or proliferation were assessed by WST8 (2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium, monosodium salt and Lactate dehydrogenase (LDH) release, Trypan blue exclusion test, and Alamar blue assay. Antioxidant activity was evaluated by a cell-based chemiluminescent probe for the detection of intracellular H₂O₂ production in HUVECs. Heme oxygenase-1 (HO-1) expression levels were investigated by RT-qPCR. Glutathione reductase (GR), glutathione peroxidase (Gpx), superoxide dismutase (SOD), and catalase (CAT) activities, as markers of intracellular antioxidant defense, were evaluated by spectrophotometric analysis. The immunomodulatory activity was examined in RAW 264.7 by quantification of inducible nitric oxide synthase (iNOS) and Tumor Necrosis Factor—alpha (TNFα) by RT-qPCR. Data showed that fermentation of Pushgay berries (i) enhances the content of quercetin aglycone, and (ii) increases their intracellular antioxidant activity, as indicated by the reduction in H₂O₂-induced cell death and the decrease in H₂O₂-induced HO-1 gene expression in HUVECs treated for 24 h with fermented berries solution (10 µg/mL). Moreover, treatment with Pushgay berries for 72 h (10 µg/mL) promotes cells growth in RAW 264.7, and only fermented Pushgay berries increase the expression of iNOS in the same cell line. Taken together, our results show that LAB fermentation of Pushgay berries enhances their antioxidant and immunomodulatory properties.

Antioxidant and Anti-Inflammatory Profiles of Spent Coffee Ground Extracts for the Treatment of Neurodegeneration

Spent coffee grounds (SCGs), waste products of coffee beverage production, are rich in organic compounds such as phenols. Different studies have demonstrated phenol beneficial effects in counteracting neurodegenerative diseases. These diseases are associated with oxidative stress and neuroinflammation, which initiates the degeneration of neurons by overactivating microglia. Unfortunately, to date, there are no pharmacological therapies to treat these pathologies. The aim of this study was to evaluate the phenolic content of 4 different SCG extracts and their ability to counteract oxidative stress and neuroinflammation. Caffeine and 5-O-caffeoylquinic acid were the most abundant compounds in all extracts, followed by 3-O-caffeoylquinic acid and 3,5-O-dicaffeoylquinic acid. The four extracts demonstrated a different ability to counteract oxidative stress and neuroinflammation in vitro. In particular, the methanol extract was the most effective in protecting neuron-like SH-SY5Y cells against H₂O₂-induced oxidative stress by upregulating endogenous antioxidant enzymes such as thioredoxin reductase, heme oxygenase 1, NADPH quinone oxidoreductase, and glutathione reductase. The water extract was the most effective in counteracting lipopolysaccharide-induced neuroinflammation in microglial BV-2 cells by strongly reducing the expression of proinflammatory mediators through the modulation of the TLR4/NF-κB pathway. On these bases, SCG extracts could represent valuable nutraceutical sources for the treatment of neurodegeneration.

Dill Extract Induces Elastic Fiber Neosynthesis and Functional Improvement in the Ascending Aorta of Aged Mice with Reversal of Age-Dependent Cardiac Hypertrophy and Involvement of Lysyl Oxidase-Like-1

Elastic fibers (90% elastin, 10% fibrillin-rich microfibrils) are synthesized only in early life and adolescence mainly by the vascular smooth muscle cells through the cross-linking of its soluble precursor, tropoelastin. Elastic fibers endow the large elastic arteries with resilience and elasticity. Normal vascular aging is associated with arterial remodeling and stiffening, especially due to the end of production and degradation of elastic fibers, leading to altered cardiovascular function. Several pharmacological treatments stimulate the production of elastin and elastic fibers. In particular, dill extract (DE) has been demonstrated to stimulate elastin production in vitro in dermal equivalent models and in skin fibroblasts to increase lysyl oxidase–like-1 (LOXL-1) gene expression, an enzyme contributing to tropoelastin crosslinking and elastin formation. Here, we have investigated the effects of a chronic treatment (three months) of aged male mice with DE (5% or 10% v/v, in drinking water) on the structure and function of the ascending aorta. DE treatment, especially at 10%, of aged mice protected pre-existing elastic lamellae, reactivated tropoelastin and LOXL-1 expressions, induced elastic fiber neo-synthesis, and decreased the stiffness of the aging aortic wall, probably explaining the reversal of the age-related cardiac hypertrophy also observed following the treatment. DE could thus be considered as an anti-aging product for the cardiovascular system.

Modulation of Aquaporins by Dietary Patterns and Plant Bioactive Compounds

Healthful dietary patterns and bioactive compounds supplementation can be adopted as simple and easy intervention to prevent, attenuate or cure clinical disorders, especially when it comes to degenerative and chronic diseases. In the recent years, a growing body of evidence indicates Aquaporins (AQPs), a family of membrane channel proteins widely expressed in the human body, among the targets underlying the beneficial action played by some food nutrients and phytochemical compounds. Here, we provide an overview of what is known regarding the AQP modulation exerted by healthful dietary patterns and plant polyphenols.

A Proteomic Approach to Uncover Neuroprotective Mechanisms of Oleocanthal against Oxidative Stress

Neurodegenerative diseases represent a heterogeneous group of disorders that share common features like abnormal protein aggregation, perturbed Ca2+ homeostasis, excitotoxicity, impairment of mitochondrial functions, apoptosis, inflammation, and oxidative stress. Despite recent advances in the research of biomarkers, early diagnosis, and pharmacotherapy, there are no treatments that can halt the progression of these age-associated neurodegenerative diseases. Numerous epidemiological studies indicate that long-term intake of a Mediterranean diet, characterized by a high consumption of extra virgin olive oil, correlates with better cognition in aged populations. Olive oil phenolic compounds have been demonstrated to have different biological activities like antioxidant, antithrombotic, and anti-inflammatory activities. Oleocanthal, a phenolic component of extra virgin olive oil, is getting more and more scientific attention due to its interesting biological activities. The aim of this research was to characterize the neuroprotective effects of oleocanthal against H₂O₂-induced oxidative stress in neuron-like SH-SY5Y cells. Moreover, protein expression profiling, combined with pathways analyses, was used to investigate the molecular events related to the protective effects. Oleocanthal was demonstrated to counteract oxidative stress, increasing cell viability, reducing reactive oxygen species (ROS) production, and increasing reduced glutathione (GSH) intracellular level. Proteomic analysis revealed that oleocanthal significantly modulates 19 proteins in the presence of H₂O₂. In particular, oleocanthal up-regulated proteins related to the proteasome, the chaperone heat shock protein 90, the glycolytic enzyme pyruvate kinase, and the antioxidant enzyme peroxiredoxin 1. Moreover, oleocanthal protection seems to be mediated by Akt activation. These data offer new insights into the molecular mechanisms behind oleocanthal protection against oxidative stress.

Therapeutic potential of quercetin as a cardiovascular agent

Flavonoids are integral components of various vegetation and in foods; consequently, they represent an inevitable part of the diet. Historical and epidemiological proof recommend that diet plans consisting of flavonoids such as quercetin have positive health benefits, especially on the heart. Flavonoids have been proven to be active against hypertension, inflammation, diabetes and vascular diseases. Quercetin exhibits significant heart related benefits as inhibition of LDL oxidation, endothelium-independent vasodilator effects, reduction of adhesion molecules and other inflammatory markers, the protective effect on nitric oxide and endothelial function under conditions of oxidative stress, prevention of neuronal oxidative and inflammatory damage and platelet antiaggregant effects. Searching for experimental evidence to validate the cardioprotective effects of quercetin, we review here the recent detailed in vivo studies. Quercetin and its derivatives lead to an enhancement in heart features, indicating the prospective for quercetin to be used therapeutically in the treatment of cardiac diseases. Several evidence-based studies suggest mechanisms to observe cardiovascular diseases such as aging effects, hypertension, angiotensin-converting enzyme activity and endothelial-dependent and independent functions. Different animal models including human are also used to elucidate the in vivo role of quercetin in cardiovascular diseases. The role of quercetin and its derivatives may go beyond their existence in food and has potential as a lead molecule in drug development programs.

Enhanced nutraceutical potential of gamma irradiated black soybean extracts

Radiation processing of soybean, varying in seed coat colour, was carried out at dose levels of 0.25, 0.5 and 1 kGy to evaluate their potential anti-proliferative and cytoprotective effects in an in vitro cell culture system. Irradiated and control black (Kalitur) and yellow (DS9712) soybean extracts were characterized in terms of total phenolics, flavonoids and anthocyanins, especially cyanidin-3-glucoside (C3G). Using an epithelial cell line, BEAS-2B the potential cytoprotective effects of soybean extracts were evaluated in terms of intracellular ROS levels and cell viability. The most relevant scavenging effect was found in Kalitur, with 78% decrease in ROS, which well correlated with a 33% increase in C3G after a 1 kGy dose. Results evidenced a correspondence between in vitro antioxidant activity and a potential health property of black soybean extracts, exemplifying the nutraceutical role of C3G. To our knowledge this study is the first report validating the cytoprotective effects of irradiated black soybean extracts.

Luteolin, quercetin, genistein and quercetagetin inhibit the effects of lipopolysaccharide obtained from Porphyromonas gingivalis in H9c2 cardiomyoblasts

Background

One of the microorganisms from dental plaque associated with severe inflammatory responses in infectious endocarditis is Porphyromonas gingivalis. It is a Gram-negative bacteria harvested from chronic periodontitis patients. Lipopolysaccharide (LPS) obtained from P. gingivalis promotes the expressions of interleukin-1 (IL-1), IL-6 and tumor necrosis factor alpha (TNF-α). Flavonoids are thought to participate in processes that control inflammation, such as the expression of cyclooxygenase-2 (COX-2).

Methods

We investigated the effects of luteolin, quercetin, genistein and quercetagetin on cardiomyoblasts treated with LPS alone or in combination with following inhibitors p38 (SB203580), ERK (PD98059), JNK (SP600125) and PKC (Calphostin C) for 1 h. The kinase activation and COX-2 expression levels were determined at the gene and protein levels.

Results

These flavonoids are considered to inhibit the activation of mitogen-activated protein kinase (MAPK) and the degradation of inhibitor of kappa B-alpha (IκB-α). They also play a role in COX-2 expression.

Conclusion

We conclude that the tested flavonoids inhibit inflammatory responses induced by LPS in H9c2 cells.

Effects of Polyphenols on Oxidative Stress-Mediated Injury in Cardiomyocytes

Cardiovascular diseases are the main cause of mortality and morbidity in the world. Hypertension, ischemia/reperfusion, diabetes and anti-cancer drugs contribute to heart failure through oxidative and nitrosative stresses which cause cardiomyocytes nuclear and mitochondrial DNA damage, denaturation of intracellular proteins, lipid peroxidation and inflammation. Oxidative or nitrosative stress-mediated injury lead to cardiomyocytes apoptosis or necrosis. The reactive oxygen (ROS) and nitrogen species (RNS) concentration is dependent on their production and on the expression and activity of anti-oxidant enzymes. Polyphenols are a large group of natural compounds ubiquitously expressed in plants, and epidemiological studies have shown associations between a diet rich in polyphenols and the prevention of various ROS-mediated human diseases. Polyphenols reduce cardiomyocytes damage, necrosis, apoptosis, infarct size and improve cardiac function by decreasing oxidative stress-induced production of ROS or RNS. These effects are achieved by the ability of polyphenols to modulate the expression and activity of anti-oxidant enzymes and several signaling pathways involved in cells survival. This report reviews current knowledge on the potential anti-oxidative effects of polyphenols to control the cardiotoxicity induced by ROS and RNS stress.

Lifelong quercetin enrichment and cardioprotection in Mdx/Utrn+/− mice

Duchenne Muscular Dystrophy (DMD) is associated with progressive cardiac pathology; however, the SIRT1/PGC1-α activator quercetin may cardioprotect dystrophic hearts. We tested the extent to which long-term 0.2% dietary quercetin enrichment attenuates dystrophic cardiopathology in Mdx/Utrn+/− mice. At 2 mo, Mdx/Utrn+/− mice were fed quercetin-enriched (Mdx/Utrn+/−-Q) or control diet (Mdx/Utrn+/−) for 8 mo. Control C57BL/10 (C57) animals were fed a control diet for 10 mo. Cardiac function was quantified by MRI at 2 and 10 mo. Spontaneous physical activity was quantified during the last week of treatment. At 10 mo hearts were excised for histological and biochemical analysis. Quercetin feeding improved various physiological indexes of cardiac function in diseased animals. Mdx/Utrn+/−-Q also engaged in more high-intensity physical activity than controls. Histological analyses of heart tissues revealed higher expression and colocalization of utrophin and α-sarcoglycan. Lower abundance of fibronectin, cardiac damage (Hematoxylin Eosin-Y), and MMP9 were observed in quercetin-fed vs. control Mdx/Utrn+/− mice. Quercetin evoked higher protein abundance of PGC-1α, cytochrome c, ETC complexes I–V, citrate synthase, SOD2, and GPX compared with control-fed Mdx/Utrn+/−. Quercetin decreased abundance of inflammatory markers including NFκB, TGF-β1, and F4/80 compared with Mdx/Utrn+/−; however, P-NFκB, P-IKBα, IKBα, CD64, and COX2 were similar between groups. Dietary quercetin enrichment improves cardiac function in aged Mdx/Utrn+/− mice and increases mitochondrial protein content and dystrophin glycoprotein complex formation. Histological analyses indicate a marked attenuation in pathological cardiac remodeling and indicate that long-term quercetin consumption benefits the dystrophic heart.

NEW & NOTEWORTHY The current investigation provides first-time evidence that quercetin provides physiological cardioprotection against dystrophic pathology and is associated with improved spontaneous physical activity. Secondary findings suggest that quercetin-dependent outcomes are in part due to PGC-1α pathway activation.

Molecular Properties of Red Wine Compounds and Cardiometabolic Benefits

Wine has been used since the dawn of human civilization. Despite many health benefits, there is still a lot of discussion about the real properties of its components and its actions on cells and molecular interactions. A large part of these issues permeate the fine line between the amount of alcohol that causes problems to organic systems and the amount that could be beneficial for the health. However, even after the process of fermentation, wine conserves different organic compounds from grapes, such as polysaccharides, acids, and phenolic compounds, such as flavonoids and nonflavonoids. These substances have known anti-inflammatory and antioxidant capacities, and are considered as regulatory agents in cardiometabolic process. In this study, the main chemical components present in the wine, its interaction with molecules and biological mechanisms, and their interference with intra- and extracellular signaling are reviewed. Finally, the properties of wine that may benefit cardiovascular system are also revised.

Nutraceutical Bioactive Compounds Promote Healthspan Counteracting Cardiovascular Diseases

Cardiovascular diseases (CVDs) are the leading cause of mortality in the Western world. Multiple factors are involved in CVD, including genetic factors and modifiable factors such as diet, physical activity, and smoking. CVD incidence and prevalence increase progressively with age, and it is estimated that over 80% of men and women older than 75 years have clinically manifest CVD. To reduce the gap between life expectancy (LE) and healthy life expectancy is one of the main challenges of the 21st century. Lifestyle improvement appears to be the only sustainable approach to face the dramatic chronic-degenerative disease burden of an aging population. A healthy lifestyle, represented by avoiding smoking, following a healthy diet, and practicing physical activity, protects from chronic-degenerative disease onset and progression. A healthy dietetic approach specifically formulated for elderly people, with a defined pattern of nutraceutical bioactive compounds, may represent a key strategy to improve the aging process and increase the life span. This short review summarizes the biochemical mechanisms underpinning the cardiovascular protective effects of some nutraceutical compounds such as quercetin and sulforaphane.

Polyphenols as Modulators of Aquaporin Family in Health and Disease

Polyphenols are bioactive molecules widely distributed in fruits, vegetables, cereals, and beverages. Polyphenols in food sources are extensively studied for their role in the maintenance of human health and in the protection against development of chronic/degenerative diseases. Polyphenols act mainly as antioxidant molecules, protecting cell constituents against oxidative damage. The enormous number of polyphenolic compounds leads to huge different mechanisms of action not fully understood. Recently, some evidence is emerging about the role of polyphenols, such as curcumin, pinocembrin, resveratrol, and quercetin, in modulating the activity of some aquaporin (AQP) isoforms. AQPs are integral, small hydrophobic water channel proteins, extensively expressed in many organs and tissues, whose major function is to facilitate the transport of water or glycerol over cell plasma membranes. Here we summarize AQP physiological functions and report emerging evidence on the implication of these proteins in a number of pathophysiological processes. In particular, this review offers an overview about the role of AQPs in brain, eye, skin diseases, and metabolic syndrome, focusing on the ability of polyphenols to modulate AQP expression. This original analysis can contribute to elucidating some peculiar effects exerted by polyphenols and can lead to the development of an innovative potential preventive/therapeutic strategy.

Cardiac and Vascular Synergic Protective Effect of Olea europea L. Leaves and Hibiscus sabdariffa L. Flower Extracts

This study was aimed at investigating the cardiovascular effects of an Olea europea L. leaf extract (OEE), of a Hibiscus sabdariffa L. flower extract (HSE), and of their 13 : 2 w/w mixture in order to assess their cardiac and vascular activity. Both extracts were fully characterized in their bioactive compounds by HPLC-MS/MS analysis. The study was performed using primary vascular endothelial cells (HUVECs) to investigate the antioxidant and cytoprotective effect of the extracts and their mixture and isolated guinea-pig left and right atria and aorta to evaluate the inotropic and chronotropic activities and vasorelaxant properties. In cultured HUVECs, OEE and HSE reduced intracellular reactive oxygen species formation and improved cell viability, following oxidative stress in dose-dependent manner. OEE and HSE exerted negative inotropic and vasorelaxant effects without any chronotropic property. Interestingly, the mixture exerted higher cytoprotective effects and antioxidant activities. Moreover, the mixture exerted an inotropic effect similar to each single extract, while it revealed an intrinsic negative chronotropic activity different from the single extract; its relaxant activity was higher than that of each single extract. In conclusion OEE and HSE mixture has a good potential for pharmaceutical and nutraceutical application, thanks to the synergistic effects of the single phytochemicals.

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.

Polyphenols in exercise performance and prevention of exercise-induced muscle damage

Although moderate physical exercise is considered an essential component of a healthy lifestyle that leads the organism to adapt itself to different stresses, exercise, especially when exhaustive, is also known to induce oxidative stress, inflammation, and muscle damage. Many efforts have been carried out to identify dietary strategies or micronutrients able to prevent or at least attenuate the exercise-induced muscle damage and stress. Unfortunately most studies have failed to show protection, and at the present time data supporting the protective effect of micronutrients, as antioxidant vitamins, are weak and trivial. This review focuses on those polyphenols, present in the plant kingdom, that have been recently suggested to exert some positive effects on exercise-induced muscle damage and oxidative stress. In the last decade flavonoids as quercetin, catechins, and other polyphenols as resveratrol have caught the scientists attention. However, at the present time drawing a clear and definitive conclusion seems to be untimely.

Sweet chestnut (Castanea sativa Mill.) bark extract: cardiovascular activity and myocyte protection against oxidative damage

This work was aimed at evaluating the cardioprotective effects of Castanea sativa Mill. (CSM) bark extract characterized in its phenolic composition by HPLC-DAD-MS analysis. The study was performed using primary cultures of neonatal rat cardiomyocytes to investigate the antioxidant and cytoprotective effects of CSM bark extract and isolated guinea pig left and right atria, left papillary muscle, and aorta to evaluate its direct effect on cholinergic and adrenergic response. In cultured cardiomyocytes the CSM bark extract reduced intracellular reactive oxygen species formation and improved cell viability following oxidative stress in dose-dependent manner. Moreover, the extract decreased the contraction induced by noradrenaline (1  μ M) in guinea pig aortic strips and induced transient negative chronotropic and positive inotropic effects without involvement of cholinergic or adrenergic receptors in the guinea pig atria. Our results indicate that CSM bark extract exhibits antioxidant activity and might induce cardioprotective effect.

Phytochemical profile and nutraceutical value of old and modern common wheat cultivars

Among health-promoting phytochemicals in whole grains, phenolic compounds have gained attention as they have strong antioxidant properties and can protect against many degenerative diseases. Aim of this study was to profile grain phenolic extracts of one modern and five old common wheat (Triticum aestivum L.) varieties and to evaluate their potential antiproliferative or cytoprotective effect in different cell culture systems.Wheat extracts were characterized in terms of antioxidant activity and phenolic composition (HPLC/ESI-TOF-MS profile, polyphenol and flavonoid contents). Results showed that antioxidant activity (FRAP and DPPH) is mostly influenced by flavonoid (both bound and free) content and by the ratio flavonoids/polyphenols. Using a leukemic cell line, HL60, and primary cultures of neonatal rat cardiomyocytes, the potential antiproliferative or cytoprotective effects of different wheat genotypes were evaluated in terms of intracellular reactive oxygen species levels and cell viability. All tested wheat phenolic extracts exerted dose-dependent cytoprotective and antiproliferative effects on cardiomyocytes and HL60 cells, respectively. Due to the peculiar phenolic pattern of each wheat variety, a significant genotype effect was highlighted. On the whole, the most relevant scavenging effect was found for the old variety Verna. No significant differences in terms of anti-proliferative activities among wheat genotypes was observed.Results reported in this study evidenced a correspondence between the in vitro antioxidant activity and potential healthy properties of different extracts. This suggests that an increased intake of wheat grain derived products could represent an effective strategy to achieve both chemoprevention and protection against oxidative stress related diseases.

Quercetin reduces inflammatory responses in LPS-stimulated cardiomyoblasts

Flavonoids possess several biological and pharmacological activities. Quercetin (Q), a naturally occurring flavonoid, has been shown to downregulate inflammatory responses and provide cardioprotection. However, the mechanisms behind the anti-inflammatory properties of Q in cardiac cells are poorly understood. In inflammation, nitric oxide (NO) acts as a proinflammatory mediator and is synthesized by inducible nitric oxide synthase (iNOS) in response to pro-inflammatory agents such as lipopolysaccharide (LPS), a causative agent in myocardial depression during sepsis. In the present study, we evaluated the protective effect of Q on rat cardiac dysfunction during sepsis induced by LPS. Pretreatment of H9c2 cardiomyoblasts with Q inhibited LPS-induced iNOS expression and NO production and counteracted oxidative stress caused by the unregulated NO production that leads to the generation of peroxynitrite and other reactive nitrogen species. In addition, Q pretreatment significantly counteracted apoptosis cell death as measured by immunoblotting of the cleaved caspase 3 and caspase 3 activity. Q also inhibited the LPS-induced phosphorylation of the stress-activated protein kinases (JNK/SAPK) and p38 MAP kinase that are involved in the inhibition of cell growth as well as the induction of apoptosis. In conclusion, these results suggest that Q might serve as a valuable protective agent in cardiovascular inflammatory diseases.

Quercetin offers cardioprotection against progression of experimental autoimmune myocarditis by suppression of oxidative and endoplasmic reticulum stress via endothelin-1/MAPK signalling

In order to test the hypothesis that treatment with quercetin at a dose of 10 mg/kg protects from the progression of experimental autoimmune myocarditis (EAM) to dilated cardiomyopathy (DCM), we have used the rat model of EAM induced by porcine cardiac myosin. Our results identified that the post-myocarditis rats suffered from elevated endoplasmic reticulum (ER) stress and adverse cardiac remodelling in the form of myocardial fibrosis, whereas the rats treated with quercetin have been protected from these changes as evidenced by the decreased myocardial levels of ER stress and fibrosis markers when compared with the vehicle-treated DCM rats. In addition, the myocardial dimensions and cardiac function were preserved significantly in the quercetin-treated rats in comparison with the DCM rats treated with vehicle alone. Interestingly, the rats treated with quercetin showed significant suppression of the myocardial endothelin-1 and also the mitogen activated protein kinases (MAPK) suggesting that the protection offered by quercetin treatment against progression of EAM involves the modulation of MAPK signalling cascade. Collectively, the present study provides data to support the role of quercetin in protecting the hearts of the rats with post myocarditis DCM.

Cystamine-tacrine dimer: a new multi-target-directed ligand as potential therapeutic agent for Alzheimer's disease treatment

Alzheimer's disease (AD) is the most common cause of dementia, clinically characterized by loss of memory and progressive deficits in different cognitive domains. An emerging disease-modifying approach to face the multifactorial nature of AD may be represented by the development of Multi-Target Directed Ligands (MTDLs), i.e., single compounds which may simultaneously modulate different targets involved in the neurodegenerative AD cascade. The structure of tacrine, an acetylcholinesterase (AChE) inhibitor (AChEI), has been widely used as scaffold to provide new MTDLs. In particular, its homodimer bis(7)tacrine represents an interesting lead compound to design novel MTDLs. Thus, in the search of new rationally designed MTDLs against AD, we replaced the heptamethylene linker of bis(7)tacrine with the structure of cystamine, leading to cystamine-tacrine dimer. In this study we demonstrated that the cystamine-tacrine dimer is endowed with a lower toxicity in comparison to bis(7)tacrine, it is able to inhibit AChE, butyrylcholinesterase (BChE), self- and AChE-induced beta-amyloid aggregation in the same range of the reference compound and exerts a neuroprotective action on SH-SY5Y cell line against H(2)O(2)-induced oxidative injury. The investigation of the mechanism of neuroprotection showed that the cystamine-tacrine dimer acts by activating kinase 1 and 2 (ERK1/2) and Akt/protein kinase B (PKB) pathways. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Quercetin accumulates in nuclear structures and triggers specific gene expression in epithelial cells

Quercetin is a flavonol modifying a number of cell processes in different cell lines. Here, we present evidence that nonconjugated quercetin enters cells possibly via organic anion transporter polypeptides and quickly accumulates in the nucleus where it concentrates at distinct foci. Furthermore, it induces major transcriptional events with a high number of transcripts being modified over time and about 2200 transcripts being continuously influenced by the agent. The latter transcripts are related to cell cycle and adhesion, xenobiotic metabolism, immune-related factors and transcription. In addition, quercetin up-regulates the expression of estrogen receptors α and β. The overall outcome on cell fate is reflected by an inhibition of cell proliferation, cell cycle arrest in the G1 phase and reduction of the cells' migratory potential due to actin cytoskeleton disorganization. Finally, we report that the flavonol modifies the transcription and/or activity of numerous transcription factors. In conclusion, our data support the idea that quercetin may actively accumulate in discrete cell structures and exert more than just antioxidant actions on epithelial cells by regulating mechanisms related to gene transcription.

Mitochondria-targeted cardioprotection in aldosteronism

Chronic aldosterone/salt treatment (ALDOST) is accompanied by an adverse structural remodeling of myocardium that includes multiple foci of microscopic scarring representing morphologic footprints of cardiomyocyte necrosis. Our previous studies suggested that signal-transducer-effector pathway leading to necrotic cell death during ALDOST includes intramitochondrial Ca overloading, together with an induction of oxidative stress and opening of the mitochondrial permeability transition pore (mPTP). To further validate this concept, we hypothesized that mitochondria-targeted interventions will prove to be cardioprotective. Accordingly, 8-week-old male Sprague-Dawley rats receiving 4 weeks ALDOST were cotreated with either quercetin, a flavonoid with mitochondrial antioxidant properties, or cyclosporine A (CsA), an mPTP inhibitor, and compared with ALDOST alone or untreated, age/sex-matched controls. We monitored mitochondrial free Ca and biomarkers of oxidative stress, including 8-isoprostane and H2O2 production; mPTP opening; total Ca in cardiac tissue; and collagen volume fraction to quantify replacement fibrosis, a biomarker of cardiomyocyte necrosis, and employed terminal deoxynucleotidyl transferase dUTP nick end labeling assay to address apoptosis in coronal sections of ventricular myocardium. Compared with controls, at 4 weeks ALDOST we found a marked increase in mitochondrial H2O2 production and 8-isoprostane levels, an increased propensity for mPTP opening, and greater concentrations of mitochondrial free [Ca]m and total tissue Ca, coupled with a 5-fold rise in collagen volume fraction without any terminal deoxynucleotidyl transferase dUTP nick end labeling-based evidence of cardiomyocyte apoptosis. Each of these pathophysiologic responses to ALDOST was prevented by quercetin or cyclosporine A cotreatment. Thus, mitochondria play a central role in initiating the cellular-subcellular mechanisms that lead to necrotic cell death and myocardial scarring. This destructive cycle can be interrupted and myocardium salvaged with its structure preserved by mitochondria-targeted cardioprotective strategies.

Dietary quercetin supplementation increases serum antioxidant capacity and alters hepatic gene expression profile in rats

The aim of this study was to determine the effect of quercetin on hepatic gene expression profile in rats. Twenty male Wistar rats were divided into the control group and the quercetin-treated group, in which a diet containing 0.5% quercetin was provided. After two weeks of feeding, serum and liver samples were collected. Biomarkers of oxidative stress, including serum ferric reducing antioxidant power (FRAP) values and levels of ascorbic acid, vitamin E (VE), glutathione (GSH) and malondialdehyde (MDA) were measured. The hepatic gene expression profile was examined using a microarray technique. The results showed that serum FRAP value, levels of ascorbic acid and VE were increased significantly, whereas serum levels of GSH and MDA were not changed significantly after quercetin supplementation. The microarray analysis revealed that some hepatic genes involved in phase 2 reaction, metabolism of cholesterol and homocysteine, and energy production were expressed differentially in response to quercetin administration. These findings provide a molecular basis for the elucidation of the actions played by quercetin in vivo.

H2O2 preconditioning modulates phase II enzymes through p38 MAPK and PI3K/Akt activation

Ischemic preconditioning is a complex cardioprotective phenomenon that involves adaptive changes in cells and molecules and occurs in a biphasic pattern: an early phase after 1-2 h and a late phase after 12-24 h. While it is widely accepted that reactive oxygen species are strongly involved in triggering ischemic preconditiong, it is not clear if they play a major role in the early or late phase of preconditioning and which are the mechanisms involved. The present study was designed to investigate the mechanisms behind H(2)O(2)-induced cardioprotection in rat neonatal cardiomyocytes. We focused on antioxidant and phase II enzymes and their modulation by protein kinase signaling pathways and nuclear-factor-E(2)-related factor-1 (Nrf1) and Nrf2. H(2)O(2) preconditioning was able to counteract oxidative stress more effectively in the late than in the early phase of adaptation. In particular, H(2)O(2) preconditioning counteracted oxidative stress-induced apoptosis by decreasing caspase-3 activity, increasing Bcl2 expression and selectively increasing the expression and activity of antioxidant and phase II enzymes through Nrf1 and Nrf2 translocation to the nucleus. The downregulation of Nrf1 and Nrf2 by small interfering RNA reduced the expression level of phase II enzymes. Specific inhibitors of phosphatidylinositol 3-kinase/Akt and p38 MAPK activation partially reduced the cardioprotection elicited by H(2)O(2) preconditioning and the induction and activity of phase II enzymes. These findings demonstrate, for the first time, a key role for Nrf1, and not only for Nrf2, in the induction of phase II enzymes triggered by H(2)O(2) preconditioning.

Cholesterol metabolism is modulated by quercetin in rats

Quercetin has attracted much attention recently because of its antioxidant capacity and potential in the prevention of chronic degenerative diseases. However, its actions and the mechanisms involved are not completely understood. In this study, male Wistar rats were fed a diet containing 0.5% quercetin for 14 days. Serum samples were collected at the end of the experiment, and the overall serum metabolic profile was investigated by (1)H nuclear magnetic resonance (NMR)-based metabolomic analysis. Remarkable changes in the serum metabolic profile were manifested with the relative increase in the levels of lactate and low-density lipoprotein/very low-density lipoprotein (LDL/VLDL) and reduction in glucose, high-density lipoprotein (HDL), and some amino acids after quercetin exposure. Biochemical measurements confirmed that the serum low-density lipoprotein cholesterol (LDL-C) level was increased significantly after quercetin treatment. Our current findings indicate that quercetin can induce a remarkable change in cholesterol metabolism. Further studies are needed to investigate the molecular mechanisms and the possible links to the health effects or toxic actions of quercetin.

Single and concerted effects of benzo[a]pyrene and flavonoids on the AhR and Nrf2-pathway in the human colon carcinoma cell line Caco-2

As phytochemicals have the potential to counteract adverse effects of carcinogens we investigated the influence of the flavonoids quercetin and kaempferol on benzo[a]pyrene (BaP) mediated effects on human colon cancer cells, Caco-2. We focused on concerted effects on the expression of AhR and Nrf2 pathway components. In contrast to kaempferol, BaP and quercetin efficiently induced CYP1A1, CYP1A2 and CYP1B1-mRNA in Caco-2 cells. BaP not only acted via AhR activation but sustainably also by increasing AhR and by down-regulating AhRR mRNA. The flavonoids did not affect AhR expression but counteracted the BaP mediated AhRR repression. Only quercetin was found to induce AhRR mRNA. ARNT mRNA appeared to be slightly but significantly down-regulated by BaP as well as by flavonoids while expression of AIP was not or only slightly modulated. The Nrf2 pathway was activated by BaP and by the flavonoids shown by induction of Nrf2 and several of its target genes such as NQO1, GSTP1, GSTA1 and GCLC. Induction effects of 10 μm BaP on Nrf2, GSTP1 and NQO1 were abolished by the flavonoids. In summary, we show that quercetin supports AhR mediated effects. Both flavonoids, however, may counteract the effects of BaP on expression of AhR, AhRR, Nrf2, GSTP1 and NQO1. In conclusion, quercetin appears to have two faces, a flavonoid-like one and a PAH-like one which supports Ahr-mediated effects while kaempferol acts "just like a flavonoid". Thus, flavonoids have to be treated individually with respect to their anti-adverse activity.

Curculigoside attenuates human umbilical vein endothelial cell injury induced by H2O2

AIM OF THE STUDY

Vessel endothelium injury caused by reactive oxygen species (ROS) including H(2)O(2) plays a critical role in the pathogenesis of cardiovascular disorders. Therefore, agents or antioxidants that can inhibit production of ROS has highly clinical values in cardiovascular therapy. Curculigoside is the major bioactive compounds present in Curculigo orchioides, and possess potent antioxidant properties against oxidative stress insults through undefined mechanism(s). The present study was designed to test the hypothesis that curculigoside can inhibit H(2)O(2)-induced injury in human umbilical vein endothelial cells.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were treated with curculigoside in the presence/absence of hydrogen peroxide (H(2)O(2)). The protective effects of curculigoside OP-D against H(2)O(2) were evaluated.

RESULTS

HUVECs incubated with 400 μM H(2)O(2) had significantly decreased the viability of endothelial cells, which was accompanied with apparent cells apoptosis, the activation of caspase-3 and the upregulation of p53 mRNA expression. In addition, H(2)O(2) treatment induced a marked increase of MDA, LDH content and in intracellular ROS, decreased the content of nitric oxide (NO) and GSH-Px activities in endothelial cells. However, pretreatment with 0.5.5,10 μM curculigoside resulted in a significant recovery from H(2)O(2)-induced cell apoptosis. Also, it decreased other H(2)O(2)-induced damages in a concentration-dependent manner. Furthermore, pretreatment with curculigoside decreased the activity of caspase-3 and p53 mRNA expression, which was known to play a key role in H(2)O(2)-induced cell apoptosis.

CONCLUSION

The present study shows that curculigoside can protect endothelial cells against oxidative injury induced by H(2)O(2), suggesting that this compound may constitute a promising intervention against cardiovascular disorders.

Modulation of phase II enzymes by sulforaphane: implications for its cardioprotective potential

Oxidative stress plays a major role in the pathophysiology of cardiac disorders, but the experimental data on the protective effects of exogenous antioxidants are controversial. A promising cardioprotective strategy may be through the induction of the endogenous antioxidants and phase II enzymes by chemical inducers. Sulforaphane is an isothiocyanate derived from cruciferous vegetables, and it has gained attention mainly as a potential chemopreventive agent in part through the induction of detoxifying enzymes. Accordingly, this study was undertaken to investigate the time-dependent induction of gene transcription, protein expression, and enzyme activity of antioxidant and phase II enzymes [glutathione reductase, glutathione-S-transferase, glutathione peroxidase, NAD(P)H:quinone oxidoreductase-1, thioredoxin reductase] by sulforaphane in cultured rat neonatal cardiomyocytes. The potential cardioprotective action of sulforaphane was confirmed by the decrease in intracellular reactive oxygen species production, the increase in cell viability, and the decrease in DNA fragmentation after long-term treatment accompanied by the induction of antioxidants and phase II enzymes in cardiomyocytes.

Effects of nutritional antioxidants on AAPH- or AGEs-induced oxidative stress in human SW872 liposarcoma cells

High levels of oxidative stress were reported in obesity-linked type 2 diabetes and were associated with elevated formation of advanced glycation end products (AGEs). Many studies have focused on the effect of antioxidants on vascular and circulating cells such as macrophages. However, despite the major role of adipocytes in the etiology of diabetes, little is known about the effect of natural antioxidants on adipocyte response to oxidative stress. The present study reports the differential protective effects of plant nutrients toward adipose cells subjected to oxidative stress. Caffeic acid, quercetin, L: -ascorbic acid, and alpha-tocopherol were tested on SW872 liposarcoma cells subjected to a free radical generator or to AGEs. Proliferation, viability, free radical formation, and superoxide dismutase expression were assessed in treated cells. Caffeic acid and quercetin appeared as the most potent antioxidant nutrients. Our findings clearly show a novel antioxidant role for caffeic acid and quercetin at the adipose tissue level. These new data confirm the beneficial role of phytotherapy as an interesting alternative mean for the development of novel therapeutical and nutritional strategy to prevent metabolic disorders inherent to obesity-linked diabetes.