Current Pharmaceutical Design - Volume 24, Issue 2, 2018

Background: Skin aging is a complex biological process influenced by a combination of intrinsic and extrinsic factors, leading to cumulative alterations of skin structure, function and appearance. Polyphenols, which are secondary plant metabolites, represent one of the largest classes of compounds used in dermatology and nutricosmetics to combat skin aging. The main objective is to provide an overview of the existing literature linking skin aging and the ability of polyphenols as regulatory elements able to maintain skin homeostasis. Methods: In this review, we discuss recent progress in understanding the molecular bases of skin aging, with specific emphasis on some well known and extensively studied polyphenols which have significant anti-aging influences and photoprotective effects. Results: Although no relevant clinical data exist and standard delivery systems have not been established, promising results have been obtained in many in vitro and animal models. A wide variety of polyphenols may minimize mechanisms underlying the functional manifestations of photoaging and chronological skin aging. Conclusion: Polyphenols exert their influence mostly through their antioxidant and anti-inflammatory effects, thereby abrogating collagen degradation and/or increasing procollagen synthesis.

Background: Naturally occurring polyphenols are the subject of increasing attention due to their potent antioxidant activity and their marked effects on the prevention of various oxidative stress-associated diseases such as cancer. Ellagic acid (EA) is an herbal polyphenol that is structurally a condensed dimer of gallic acid. Methods: This review aims to provide a comprehensive and updated overview on the biological activities of EA and potential therapeutic applications. Results: EA is found in fruits and nuts, either in the combined form with hexahydroxydiphenic acid or in the bound form (ellagitannins). EA exhibits many biological properties such as antioxidant, anti-diabetic, anticancer and apoptosis-inducing activities. These biological and pharmacological properties are relevant to the treatment of several human diseases. Conclusion: Owing to its multiple mechanisms of action, EA represents a potential therapeutic agent against human diseases particularly cancer.

Background: Histone deacetylases (HDACs) are a group of histone modification enzymes with pivotal role in disease pathogenesis especially in cancer development. Increased activity of certain types of HDACs and positive effects of HDAC inhibition has been shown in several types of cancers. Furthermore, few HDAC inhibitors have been approved by the FDA for cancer treatment, and this has generated interest in finding new HDAC inhibitors as potential anti-cancer agents. Curcumin, a natural polyphenol extracted from turmeric, is a safe and bioactive phytochemical with a wide range of molecular targets and pharmacological activities including promising anti-cancer properties. Methods: A systematic literature search using appropriate keywords was made to identify articles reporting the modulatory effect of curcumin on HDACs in different types of cancer in vitro and in vivo. Results: HDACs have emerged as novel targets of curcumin that their modulation may contribute to the putative anti-cancer effects of curcumin. Curcumin inhibits HDAC activity, and down-regulates the expression of HDAC types 1, 2, 3, 4, 5, 6, 8 and 11 in different cancer cell lines and mice, while the activity and expression of HDAC2 have been reported to be up-regulated by curcumin in COPD and heart failure models. Conclusion: Available in vitro and in vivo data are encouraging and in favor of the HDAC inhibitory activity of curcumin but clinical evidence on the efficacy of curcumin as an adjunct treatment in cancer patients is lacking.

Background: A high dietary intake of polyphenols has been associated with a reduced cardiovascular mortality, due to their antioxidant properties. However, growing evidence suggests that counteracting oxidative stress in cardiovascular disease might also reduce sympathetic nervous system overactivity. Methods: This article reviews the most commonly used techniques to measure sympathetic activity in humans; the role of sympathetic activation in the pathophysiology of cardiovascular diseases; current evidence demonstrating that oxidative stress is involved in the regulation of sympathetic activity and how antioxidants and polyphenols might counteract sympathetic overactivity, particularly focusing on preliminary data from human studies. Results: The main mechanisms by which polyphenols are cardioprotective are related to the improvement of vascular function and their anti-atherogenic effect. Furthermore, a blood pressure-lowering effect was consistently demonstrated in randomized controlled trials in humans, when the effect of flavonoid-rich foods, such as tea and chocolate, was tested. More recent studies suggest that inhibition of sympathetic overactivity might be one of the mechanisms by which these substances exert their cardioprotective effects. Indeed, an increased adrenergic traffic to the vasculature is a major mechanism of disease in a number of cardiovascular and extra-cardiac diseases, including hypertension, obesity, metabolic syndrome and heart failure. A considerable body of evidence, mostly from experimental studies, support the hypothesis that reactive oxygen species might exert sympathoexcitatory effects both at the central and at the peripheral level. Accordingly, supplementation with antioxidants might reduce adrenergic overdrive to the vasculature and blunt cardiovascular reactivity to stress. Conclusions: While supplementation with “classical” antioxidants such as ROS-scavengers has many limitations, increasing the intake of polyphenol-rich foods seems to be a promising novel therapeutic strategy to reduce the deleterious effects of increased adrenergic tone, particularly in essential hypertension.

Background: Accumulating evidence suggests potential preventive effects of chocolate/cocoa on the risk of cardio vascular disease (CVD). However, cocoa products also contain high levels of sugar and fat, which increase CVD risk factors. Even, the identity of the substance in chocolate/cocoa that has a favorable effect on CVD and CVD risk factors remains unclear, growing evidence from experimental studies suggests that cocoa polyphenols might be a major contributor to cardiovascular-protective effects. However, epidemiological studies, which are necessary to evaluate an association between the risk of CVD and cocoa polyphenol, remain sparse. Methods: We will discuss recent evidence regarding the association between cocoa polyphenol consumption and the risks of CVD and its risk factors by reviewing recent epidemiological studies. We shall also provide some guidance for patient counseling and will discuss the public health implications for recommending cocoa polyphenol consumption to prevent CVD. Results: Epidemiological studies evaluating the association between cocoa polyphenol itself and the risk of CVD are sparse. However, evidence from limited epidemiological studies suggests that cocoa polyphenol consumption may lower the risk of CVD. Conclusion: Given the potential adverse effects of the consumption of cocoa products with high fat and sugar and the fact that the most appropriate dose of cocoa polyphenol for cardio-protective effects has not yet been established, health care providers should remain cautious about recommending cocoa/cocoa polyphenol consumption to their patients to reduce the risk of CVD, taking the characteristics of individual patients into careful consideration.

Background: Coronary artery disease (CAD) is a disease progressing over many years. Genetic factors, as well as the exposure to risk factors, are continuously leading to endothelial dysfunction, vascular alterations and, eventually, organ damage, major cardiovascular events and deaths. Oxidative stress, platelet hyperactivity and low-grade inflammation are important modulators in this context, contributing to plaque formation. Since platelet activation plays a critical role in the development and progression of atherothrombotic events, the inhibition of platelet hyperactivity may contribute to decreased atherothrombotic risk. The consumption of bioactive foods, and plant-derived polyphenols in particular, might impart anti-thrombotic and cardiovascular protective effects. Methods: Aim of this work is to focus on the potential of dietary derived polyphenols to reduce platelet hyperactivity or hypercoagulability in addition to discussing their possible complementary anti-platelet therapeutic potential. All the relevant publications on this topic were systematically reviewed. Results: Various studies demonstrated that polyphenol supplementation affects platelet aggregation and function in vitro and in vivo, mainly neutralizing free radicals, inhibiting platelet activation and related signal transduction pathways, blocking thromboxane A2 receptors and enhancing nitric oxide production. Experimental data concerning the effect of dietary polyphenols on platelet aggregation in vivo are poor, and results are often conflicting. Only flavanols clearly mirrored in vivo showed the efficacy in vitro in modulating platelet function. Conclusion: Dietary polyphenols, and above all flavanols contained in cocoa and berries, reduce platelet activation and aggregation via multiple pathways. However, more controlled interventional studies are required to establish which doses are required as well as what circulating concentrations are sufficient to induce functional antiplatelet effects.

Background: Cardiovascular disease (CVD) is currently the leading cause of death globally. The metabolic syndrome (MetS), a clustering of risk factors including hypertension, hyperglycemia, elevated low-density lipoprotein (LDL) cholesterol, reduced high-density lipoprotein (HDL) cholesterol and increased visceral adiposity, is a significant risk factor for the development of CVD. Non-alcoholic fatty liver disease (NAFLD), often referred to as the hepatic manifestation of MetS, is a constellation of progressive liver disorders closely linked to obesity, diabetes, and insulin resistance. NAFLD initially presents as relatively benign, non-progressive hepatic steatosis, but it may, in certain individuals, progress to nonalcoholic steatohepatitis, fibrosis, cirrhosis, or hepatocellular carcinoma. Currently, there are no validated treatments for NAFLD. Polyphenols are important bioactive dietary compounds and may represent a natural complementary and integrative therapy for the treatment of CVDassociated risk factors, including elevated serum cholesterol and triglyceride levels, as well as NAFLD. Understanding their molecular mechanisms of action is important in the design of future human intervention studies. Methods: Several studies utilizing in vitro and in vivo models have helped to identify underlying molecular mechanisms of action of polyphenols. Results: This review will highlight recent advances regarding the molecular actions of dietary procyanidins, with a special focus on those originating from procyanidin-rich grape seed extracts, with a focus on the signaling pathways utilized to exert beneficial metabolic effects. Conclusion: Modulation of nuclear receptor activity and histone deacetylase inhibition has been identified as underlying mechanisms contributing to procyanidin-mediated amelioration of dyslipidemia and steatosis.

Background: Pathogenesis of breast cancer is paralleled by distinct alterations in the expression profile of several microRNAs (miRNAs). Recent studies have shown that miRNAs can serve as diagnostic and prognostic markers, and also as therapeutic targets in breast cancer. Curcumin is a biologically active dietary polyphenol that has emerged with strong anti-tumor properties that are also documented in breast cancer. Methods: A multi-database electronic search was performed to provide an overview of curcumin as an adjunct therapy and miRNA modulator in breast cancer and highlight the significance of observations for the treatment of cancer therapies. Results: The putative anti-tumor properties of curcumin are mediated by diverse mechanisms including inhibition of cell proliferation, metastasis, migration, invasion and angiogenesis, and induction of G2/M cell cycle arrest, apoptosis and paraptosis. Recent evidence implies that curcumin can interact with several oncogenic and tumorsuppressive miRNAs involved in different stages of breast cancer. In this context, up-regulation of miR181b, miR-34a, miR-16, miR-15a and miR-146b-5p, and down-regulation of miR-19a and miR-19b have been shown following the treatment of several breast cancer cell lines with curcumin. These effects lead to the suppression of tumorigenesis and metastasis, and induction of apoptosis. Conclusion: Curcumin appears as an important miRNA modulator in breast cancer. However, further investigations are warranted to elucidate the impact of curcumin on miRNA transcriptome profile of breast cancer and the resulting impact of experimental models.

Background: Polyphenols are a family of natural antioxidants that in recent years have been studied and tested for their potential benefits towards cardiovascular diseases. Objective: The aim of this review is to focus the attention on the presumed lipid-lowering and atheroprotective effects of polyphenols, administered either as individual molecules (nutritional supplements) and as functional foods, on the basis of the evidence coming from randomized controlled trials (RCTs) and their meta-analyses. Method: A search strategy was conducted to identify studies in PubMed (January 1980 to September 2016); in particular, we have included human clinical trials, reviews and meta-analyses when they offered suitable insights and elucidations regarding the action of polyphenols on lipid profile and cardiovascular disease risk. Results: Literature data on polyphenols suggest that they potentially could exert an effect on lipid profile, especially by reducing the oxidation of LDL-C. Polyphenols from cocoa, grape, green tea, berries and soy are the ones that have shown more clinically relevant effect. However, quantitative data on cholesterol reduction are still unclear and often conflicting. Conclusion: Polyphenols, if taken in adequate dosages, can exert in some cases a positive effect on the prevention of cardiovascular risk and lipid oxidation, despite an unclear effect on lipid levels.

Background: Polyphenols widely distributed in plants, fruits and vegetables have received considerable attention on account of their physiological functions, including their antioxidant and anti-inflammatory properties. Some antioxidant components of cacao liquor prepared from fermented and roasted cacao beans, which is a major ingredient of cocoa and chocolate products, have been characterized as flavan-3-ols and procyanidin oligomers. Methods: This review focuses on a specific group of (-)-epicatechins and their oligomers, the procyanidins, in cacao products. Dietary polyphenols in cacao products have been shown to reduce hypertension, reduce platelet aggregation, improve serum lipids, and lower the incidence of atherosclerosis in animal studies and clinical trials. Conclusion: The intake of cacao products reduces hypertension and atherosclerosis on account of their physiological functions as antioxidants and anti-inflammation agents, indicating the mechanisms of prevention of hypertension and atherosclerosis by polyphenols.

Background: Polyphenol-rich dietary sources are acknowledged to have potential cardiovascular health benefits, particularly in reducing cardiovascular disease risk. Methods: This systematic review sought to determine the effect of polyphenol-rich foods and beverages upon microvascular function, which is of considerable importance in its contribution towards the pathophysiology of microvascular-related complications but also in the future development of (macro-vessel) cardiovascular disease. Results: Overall, consumption of polyphenol-rich foods and beverages demonstrate improved microvascular function, although this is dependent upon the polyphenol source, the dose of the product, the duration of consumption and the population group studied. Most subgroups reviewed suggest an overall beneficial effect on microvascular function, particularly grape-derived products, cocoa, tea, pine bark and Rutaceae aurantiae. Other groups remain equivocal and require further study due to the limited research performed to date. Conclusion: Polyphenols are abundant in the human diet and this systematic review demonstrates that they are an inexpensive, non-pharmacological approach for improving cardiovascular health in currently healthy individuals and in populations with microvascular dysfunction.

Background: The aging of western societies is leading to a dramatic increase in the prevalence of chronic conditions, threatening the health status and then the sustainability of our healthcare systems. In particular, dementia is being increasingly recognized as a public health priority, given its enormous socioeconomic burdens further amplified by the absence of treatments really effective in improving the clinical course of the disease. Methods: The question of whether some degree of cognitive deterioration is an inevitable part of aging or should be considered as a pathological pre-stage of dementia is currently debated. This is a field in need of research because accelerated brain aging as well as further decline in cognition might be preventable in the early stages of cognitive impairment. Herein, we discuss evidence from clinical and experimental studies on the role of polyphenols in preserving cognitive performance across life. Results: In recent years, the possibility of favorably influencing the cognitive trajectory through promotion of lifestyle modifications has been increasingly investigated. In particular, the relationship between nutritional habits and brain health has attracted special attention. Dietary polyphenols exhibit a strong potential to promote brain due to their efficacy in protecting neurons against oxidative stress-induced injury, suppressing neuroinflammation and in ameliorating cardiovascular risk factor control and cardiovascular function thus counteracting neurotoxicity and neurodegeneration. Conclusion: Emerging evidence suggest that dietary polyphenols, in particular flavonoids, may exert beneficial effects on the central nervous system thus representing a potential tool to preserve cognitive performance throught senescence.

Background: Polyphenols are bioactive compounds that can be found mostly in foods like fruits, cereals, vegetables, dry legumes, chocolate and beverages such as coffee, tea and wine. They are extensively used in the prevention and treatment of cardiovascular disease (CVD) providing protection against many chronic illnesses. Their effects on human health depend on the amount consumed and on their bioavailability. Many studies have demonstrated that polyphenols have also good effects on the vascular system by lowering blood pressure, improving endothelial function, increasing antioxidant defences, inhibiting platelet aggregation and low-density lipoprotein oxidation, and reducing inflammatory responses. Methods: This review is focused on some groups of polyphenols and their effects on several cardiovascular risk factors such as hypertension, oxidative stress, atherogenesis, endothelial dysfunction, carotid artery intima-media thickness, diabetes and lipid disorders. Results: It is proved that these compounds have many cardio protective functions: they alter hepatic cholesterol absorption, triglyceride biosynthesis and lipoprotein secretion, the processing of lipoproteins in plasma, and inflammation. In some cases, human long-term studies did not show conclusive results because they lacked in appropriate controls and in an undefined polyphenol dosing regimen. Conclusion: Rigorous evidence is necessary to demonstrate whether or not polyphenols beneficially impact CVD prevention and treatment.