Unique Properties of Polyphenol Stilbenes in the Brain: More than Direct Antioxidant Actions; Gene/Protein Regulatory Activity

Ageing, Metabolic Dysfunction, and the Therapeutic Role of Antioxidants

The gradual ageing of the world population has been accompanied by a dramatic increase in the prevalence of obesity and metabolic diseases, especially type 2 diabetes. The adipose tissue dysfunction associated with ageing and obesity shares many common physiological features, including increased oxidative stress and inflammation. Understanding the mechanisms responsible for adipose tissue dysfunction in obesity may help elucidate the processes that contribute to the metabolic disturbances that occur with ageing. This, in turn, may help identify therapeutic targets for the treatment of obesity and age-related metabolic disorders. Because oxidative stress plays a critical role in these pathological processes, antioxidant dietary interventions could be of therapeutic value for the prevention and/or treatment of age-related diseases and obesity and their complications. In this chapter, we review the molecular and cellular mechanisms by which obesity predisposes individuals to accelerated ageing. Additionally, we critically review the potential of antioxidant dietary interventions to counteract obesity and ageing.

Resveratrol promotes liver cell survival in mice liver-induced ischemia-reperfusion through unfolded protein response: a possible approach in liver transplantation

Background

Ischemia-reperfusion (I/R) of the liver is a multifactorial condition that happens during transplantation and surgery. The deleterious effects of I/R result from the acute production of reactive oxygen species (ROS), which can trigger immediate tissue damage and induce a series of destructive cellular responses, including apoptosis organ failure and inflammation. The production of ROS in the I/R process can damage the antioxidant system and cause liver damage. Resveratrol has been shown to have antioxidant properties in several investigations. Here, we address the therapeutic effect of resveratrol on I/R-induced liver injury by focusing on unfolded protein response (UPR) signaling pathway.

Methods

Five minutes before reperfusion, resveratrol was injected into the tail vein of mice. They were ischemic for 1 h and then re-perfused for 3 h before being slaughtered (I/R). The activity of liver enzymes and the expression levels of genes involved in the unfolded protein response pathway were used to measure the hepatic damage.

Results

Our results revealed that the low dose of resveratrol (0.02 and 0.2 mg/kg) post-ischemic treatment significantly reduced the ALT and AST levels. In addition, compared with the control group, the expression of UPR pathway genes GRP78, PERK, IRE1α, CHOP, and XBP1 was significantly reduced in the resveratrol group. In the mice that received lower doses of resveratrol (0.02 and 0.2 mg/kg), the histopathological changes induced by I/R were significantly improved; however, the highest dose (2 mg/kg) of resveratrol could not significantly protect and solve the I/R damage.

Conclusion

The findings of this study suggest that hepatic ischemia occurs after liver transplantation and that receiving low-dose resveratrol treatment before reperfusion may promote graft survival through inhibition of UPR arms, especially PERK and IRE1α.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-022-00611-4.

Targeting autophagy and neuroinflammation pathways with plant-derived natural compounds as potential antidepressant agents

Major depressive disorder (MDD) is a life-threatening disease that presents several characteristics. The pathogenesis of depression still remains poorly understood. Moreover, the mechanistic interactions of natural components in treating depression to target autophagy and neuroinflammation are yet to be evaluated. This study overviewed the effects of plant-derived natural components in regulating critical pathways, particularly neuroinflammation and autophagy, associated with depression. A list of natural components, including luteolin, apigenin, hyperforin, resveratrol, salvianolic acid b, isoliquiritin, nobiletin, andrographolide, and oridonin, have been investigated. All peer-reviewed journal articles were searched by Scopus, MEDLINE, PubMed, Web of Science, and Google Scholar using the appropriated keywords, including depression, neuroinflammation, autophagy, plant, natural components, etc. The neuroinflammation and autophagy dysfunction are critically associated with the pathophysiology of depression. Natural components with higher efficiency and lower complications can be used for targeting neuroinflammation and autophagy. These components with different doses showed the beneficial antidepressant properties in rodents. These can modulate autophagy markers, mainly AMPK, LC3II/LC3I ratio, Beclin-1. Moreover, they can regulate the NLRP3 inflammasome, resulting in the suppression of proinflammatory cytokines (e.g., IL-1β and IL-18). Future in vitro and in vivo studies are required to develop novel therapeutic approaches based on plant-derived active components to treat MDD.

Oxidative Stress in Ischemic Heart Disease

One of the novel interesting topics in the study of cardiovascular disease is the role of the oxidation system, since inflammation and oxidative stress are known to lead to cardiovascular diseases, their progression and complications. During decades of research, many complex interactions between agents of oxidative stress, oxidation, and antioxidant systems have been elucidated, and numerous important pathophysiological links to na number of disorders and diseases have been established. This review article will present the most relevant knowledge linking oxidative stress to vascular dysfunction and disease. The review will focus on the role of oxidative stress in endotheleial dysfunction, atherosclerosis, and other pathogenetic processes and mechanisms that contribute to the development of ischemic heart disease.

Cognitive impairments in type 2 diabetes, risk factors and preventive strategies

Mild cognitive impairment (MCI) is a modifiable risk factor in progression of several diseases including dementia and type 2 diabetes. If cognitive impairments are not reversed at an early stage of appearance of symptoms, then the prolonged pathogenesis can lead to dementia and Alzheimer's disease (AD). Therefore, it is necessary to detect the risk factors and mechanism of prevention of cognitive dysfunction at an early stage of disease. Poor lifestyle, age, hyperglycemia, hypercholesterolemia, and inflammation are some of the major risk factors that contribute to cognitive and memory impairments in diabetic patients. Mild cognitive impairment was seen in those individuals of type 2 diabetes, who are on an unhealthy diet. Physical inactivity, frequent alcohol consumptions, and use of packed food products that provides an excess of cheap calories are found associated with cognitive impairment and depression in diabetic patients. Omega fatty acids (FAs) and polyphenol-rich foods, especially flavonoids, can reduce the bad effects of an unhealthy lifestyle; therefore, the consumption of omega FAs and flavonoids may be beneficial in maintaining normal cognitive function. These functional foods may improve cognitive functions by targeting many enzymes and molecules in cells chiefly through their anti-inflammatory, antioxidant, or signaling actions. Here, we provide the current concepts on the risk factors of cognitive impairments in type 2 diabetes and the mechanism of prevention, using omega FAs and bioactive compounds obtained from fruits and vegetables. The knowledge derived from such studies may assist physicians in managing the health care of patients with cognitive difficulties.

Does Resveratrol Play a Role in Decreasing the Inflammation Associated with Contrast Induced Nephropathy in Rat Model?

Contrast is widely used in invasive image examinations such as computed tomography (CT) and angiography; however, the risk of contrast-induced nephropathy (CIN) is high. The aim of this study was to investigate the protective effect of resveratrol in a rat model of CIN. Sprague-Dawley rats were divided into four groups: the control group (0.9% saline infusion only); resveratrol group (RSV, resveratrol, 30 mg/kg); contrast media group (CIN); and resveratrol + contrast media group (RCIN, resveratrol 30 mg/kg 60 min before CIN). CIN was induced via an intravenous injection of a single dose of indomethacin (10 mg/kg), one dose of N-nitro-L-arginine methyl ester (10 mg/kg), and a single dose of contrast medium iopromide (2 g/kg). Blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin (NGAL) were higher in the CIN group compared to the other groups. Histopathological tubule injury scores were also higher in the CIN group compared to the other groups (p < 0.01). NLPR3 in kidney tissue were higher in the CIN group compared to the other groups; however, these results were improved by resveratrol in the RCIN group compared with the CIN group. The expressions of IL-1β and the percentage of apoptotic cells were higher in the CIN group than in the control and RSV groups, but they were lower in the RCIN group than in the CIN group. The expression of cleaved caspase-3 was higher in the CIN group than in the control and RSV groups, but lower in the RCIN group than in the CIN group. Resveratrol treatment attenuated both injury processes and apoptosis and inhibited the inflammasome pathway in this rat CIN model.

Oxyresveratrol protects human lens epithelial cells against hydrogen peroxide-induced oxidative stress and apoptosis by activation of Akt/HO-1 pathway

Oxidative stress induced by hydrogen peroxide (H₂O₂) triggers human lens epithelial cell (HLEC) apoptosis and initiates cataract formation. Oxyresveratrol (Oxy) was reported to possess antioxidant and free radical scavenging activities. Herein, we investigated the effects of Oxy on H₂O₂-induced oxidative stress and apoptosis in HLECs and the associated mechanisms. Cell viability was detected by MTT assay. The oxidative damage was assessed by measuring the activities of superoxide dismutases-1 (SOD-1), catalase (CAT), glutathione reductase (GSH), and malondialdehyde (MDA). Apoptosis was analyzed by flow cytometry analysis. The changed expressions of heme oxygenase-1 (HO-1) and protein kinase B (Akt) pathways were evaluated by qRT-PCR and western blot. We found that exposure to H₂O₂ dose-dependently reduced cell viability, and induced oxidative stress and apoptosis in HLECs, which were reversed by pretreatment with Oxy. Oxy increased p-Akt and HO-1 expressions in H₂O₂-stimulated HLECs. Akt and HO-1 expressions form a regulatory axis and Oxy activated the Akt/HO-1 pathway in H₂O₂-stimulated HLECs. Inhibition of the Akt/HO-1 pathway by LY294002 or ZnPP attenuated the effects of Oxy on oxidative stress and apoptosis in H₂O₂-stimulated HLECs. In conclusion, Oxy protected H₂O₂-induced oxidative stress and apoptosis through activating the Akt/HO-1 pathway, suggesting the protective effect of Oxy against H₂O₂-induced cataract.

Administration of resveratrol improved Parkinson's disease-like phenotype by suppressing apoptosis of neurons via modulating the MALAT1/miR-129/SNCA signaling pathway

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been implicated in the pathogenesis of Parkinson's disease (PD). In addition, resveratrol was shown to regulate the expression of MALAT1. Therefore, the objective of this study was to clarify the role of resveratrol in PD. During the study, luciferase assays were conducted to determine the effect of resveratrol on the transcription efficiency of MALAT1 promoter as well as the regulatory relationships among MALAT1, miR-129, and SNCA. In addition, real-time PCR, Western blot analysis, MTT and flow cytometry analyses were conducted to investigate the mechanism of resveratrol in PD. Furthermore, a PD mouse model was established to study the role of resveratrol in vivo. It was found that resveratrol increased the number of TH+ cells and the expression of miR-129, while decreasing the expression of MALAT1 and SNCA. In addition, MALAT1 inhibited the expression of miR-129, a negative regulator of SNCA, thus increasing the expression of SNCA. A further mechanistic study revealed that resveratrol inhibited MALAT1 expression by blocking the transcription of the MALAT1 promoter. Finally, MPTP treatment could decrease cell proliferation and increase cell apoptosis, while resveratrol could partly offset the effect of MPTP. In summary, the therapeutic effect of resveratrol in the treatment of PD can be attributed to its ability to modulate the MALAT1/miR-129/SNCA signaling pathway.

Stereocontrolled synthesis of (E)-stilbene derivatives by palladium-catalyzed Suzuki-Miyaura cross-coupling reaction

A general procedure for the stereocontrolled synthesis of (E)-stilbene derivatives by palladium-catalyzed Suzuki-Miyaura cross-coupling reaction of (E)-2-phenylethenylboronic acid pinacol ester with aryl bromides was investigated. (E)-2-Phenylethenylboronic acid pinacol ester was prepared by 9-BBN-catalyzed hydroboration of phenylacetylene with pinacolborane. This reagent undergoes facile palladium-catalyzed cross-coupling with a diverse set of aryl bromides to provide the corresponding (E)-stilbene derivatives in moderate to good yield. The use of the sterically bulky t-Bu₃PHBF₄ ligand was crucial to the successful coupling of electron-rich and electron-poor aryl bromides. Complete stereochemical retention of the (E)-2-phenylethenylboronic acid pinacol ester alkene geometry was observed in all of the (E)-stilbene derivatives synthesized.

The non-canonical functions of the heme oxygenases

Heme oxygenase (HO) isoforms catalyze the conversion of heme to carbon monoxide (CO) and biliverdin with a concurrent release of iron, which can drive the synthesis of ferritin for iron sequestration. Most of the studies so far were directed at evaluating the protective effect of these enzymes because of their ability to generate antioxidant and antiapoptotic molecules such as CO and bilirubin. Recent evidences are suggesting that HO may possess other important physiological functions, which are not related to its enzymatic activity and for which we would like to introduce for the first time the term “non canonical functions”. Recent evidence suggest that both HO isoforms may form protein-protein interactions (i.e. cytochrome P450, adiponectin, CD91) thus serving as chaperone-like protein. In addition, truncated HO-1 isoform was localized in the nuclear compartment under certain experimental conditions (i.e. excitotoxicity, hypoxia) regulating the activity of important nuclear transcription factors (i.e. Nrf2) and DNA repair. In the present review, we discuss three potential signaling mechanisms that we refer to as the non-canonical functions of the HO isoforms: protein-protein interaction, intracellular compartmentalization, and extracellular secretion. The aim of the present review is to describe each of this mechanism and all the aspects warranting additional studies in order to unravel all the functions of the HO system.

Design, syntheses and lipid accumulation inhibitory activities of novel resveratrol mimics

Hispidine was initially discovered from Ficus Hispida for cardiovascular protection. In this paper, hispidine derivatives, which contain a novel resveratrol-like scaffold, have been designed, synthesized, and assayed as agents against lipid accumulations in 3T3-L1 pre-adipocytes. Six hispidine derivatives have the activity of reducing TG in 3T3-L1 adipocytes in dosage-dependent manner. The most active compound can reduce the lipid accumulation up to 78.4% at 10 μM qPCR and Western blotting results demonstrate that the two most active compounds inhibit both lipodenesis and adipogenesis in 3T3-L1 cells through (1) increasing the phosphorylations of AMPK and ACC, promoting SIRT1 expression. These three proteins are key regulators for lipogenesis and energy metabolism. (2) Decreasing the expressions of PPARγ, sREBP-1c, and FABP4, which are pivotal regulators for adipogenesis. Overall, this work proves that hispidine derivatives diminish the lipid accumulation in 3T3-L1 cell line by downregulating lipogenic and adipogenic pathways.

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.

Multi-Targeting Andrographolide, a Novel NF-κB Inhibitor, as a Potential Therapeutic Agent for Stroke

A key focus in the field of drug discovery has been motivated by the neuroprotection of natural compounds. Cerebral ischemia is a multifaceted pathological process with a series of mechanisms, and a perspective for the development of neuroprotectants from traditional herbal medicine or natural products is a promising treatment for this disease. Natural compounds with the effects of anti-oxidation, anti-inflammation, anti-apoptosis, and neurofunctional regulation exhibit therapeutic effects on experimental ischemic brain injury. Conferring to the pharmacological mechanisms underlying neuroprotection, a study found that androgapholide, a diterpene lactone compound, exhibits varying degrees of neuroprotective activities in both in vitro and in vivo experimental models of stroke. The neuroprotective mechanisms of andrographolide are suggested as: (I) increasing nuclear factor E2-related factor 2-heme oxygenase (Nrf2-HO-1) expression through p38-mitogen activated protein kinase (MAPK) regulation, (II) inducing cerebral endothelial cells (CEC) apoptosis and caspase-3 activation, (III) down regulating Bax, inducible nitric oxide synthase (iNOS), and (IV) inhibiting hydroxyl radical (OH⁻) formation, and activating transcription factor NF-κB signaling pathways. Recently, several researchers have also been trying to unveil the principal mechanisms involved in the neuroprotective effects of andrographolide. Therefore, this review aims to summarize an overview on the neuroprotective effects of andrographolide and exemplifies the essential mechanisms involved. This paper can provide information that andrographolide drug discovery may be a promising strategy for the development of a novel class of neuroprotective drug.

Luteolin alleviates methylglyoxal-induced cytotoxicity in osteoblastic MC3T3-E1 cells

Methylglyoxal (MG), a reactive sugar-derived metabolite, exerts harmful effects by inducing oxidative stress, which aggravates a series of diabetic complications, including osteoporosis. The present study was performed to examine the effects of luteolin, a dietary polyphenolic flavonoid, on MG-induced cytotoxicity in MC3T3-E1 osteoblastic cells. Pretreatment of MC3T3-E1 osteoblastic cells with luteolin prevented MG-induced cell death and production of tumor necrosis factor-alpha, intracellular reactive oxygen species, mitochondrial superoxide, and cardiolipin peroxidation. In addition, luteolin increased the levels of glutathione and nuclear factor erythroid 2-related factor 2 (Nrf2) and decreased the inhibition of heme oxygenase-1 activity by MG. Pretreatment with luteolin prior to MG exposure reduced MG-induced mitochondrial dysfunction and increased the peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and nitric oxide levels, suggesting that luteolin may induce mitochondrial biogenesis. Taken together, these observations indicated that luteolin has potential as a preventive agent against the development of diabetic osteopathy related to MG-induced oxidative stress in diabetes.

Characterization and Functional Analysis of 4-Coumarate:CoA Ligase Genes in Mul-berry

A small, multigene family encodes 4-coumarate:CoA ligases (4CLs) that catalyze the ligation of CoA to hydroxycinnamic acids, a branch point directing metabolites to flavonoid or monolignol pathways. In this study, we characterized four 4CL genes from M. notabilis Genome Database, and cloned four Ma4CL genes from M. atropurpurea cv. Jialing No.40. A tissue-specific expression analysis indicated that Ma4CL3 was expressed at higher levels than the other genes, and that Ma4CL3 was strongly expressed in root bark, stem bark, and old leaves. Additionally, the expression pattern of Ma4CL3 was similar to the trend of the total flavonoid content throughout fruit development. A phylogenetic analysis suggested that Mn4CL1, Mn4CL2, and Mn4CL4 belong to class I 4CLs, and Mn4CL3 belongs to class II 4CLs. Ma4CL genes responded differently to a series of stresses. Ma4CL3 expression was higher than that of the other Ma4CL genes following wounding, salicylic acid, and ultraviolet treatments. An in vitro enzyme assay indicated that 4-coumarate acid was the best substrate among cinnamic acid, 4-coumarate acid, and caffeate acid, but no catalytic activity to sinapate acid and ferulate acid. The results of subcellular localization experiments showed that Ma4CL3 localized to the cytomembrane, where it activated transcription. We used different vectors and strategies to fuse Ma4CL3 with stilbene synthase (STS) to construct four Ma4CL-MaSTS co-expression systems to generate resveratrol. The results indicated that only a transcriptional fusion vector, pET-Ma4CL3-T-MaSTS, which utilized a T7 promoter and lac operator for the expression of MaSTS, could synthesize resveratrol.

Oxyresveratrol abrogates oxidative stress by activating ERK-Nrf2 pathway in the liver

Oxyresveratrol is a polyphenolic phytoalexin produced by plants as an antioxidant. This study investigated the hepatoprotective effects of oxyresveratrol as well as its underlying mechanism of action. Here, we evaluated the protective effects of oxyresveratrol against tert-butyl hydroperoxide (tBHP)-induced severe oxidative stress in HepG2 cells as well as acute liver injury caused by carbon tetrachloride (CCl4) in mice. tBHP-induced reactive oxygen species production and cell death in hepatocytes were blocked by oxyresveratrol, as indicated by MTT, TUNEL, and FACS analyses. Moreover, pretreatment with oxyresveratrol increased nuclear translocation and transactivation of NF-E2-related factor 2 (Nrf2), as assessed by antioxidant response element reporter gene expression and immunofluorescence staining, and transactivated expression of both hemeoxygenase-1 and glutamate-cysteine ligase catalytic subunit. More importantly, oxyresveratrol induced phosphorylation of Nrf2 mediated through activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Further, ERK inhibitors such as PD98059 and U0126 blocked phosphorylation of Nrf2 as well as the protective effect of oxyresveratrol in mitochondria. In mice, oral administration of oxyresveratrol significantly prevented hepatocyte degeneration, inflammatory cell infiltration, as well as elevation of plasma markers such as ALT and AST induced by CCl4 injection. In conclusion, this study confirmed that oxyresveratrol protected hepatocytes against oxidative stress and mitochondrial dysfunction, which might be associated with activation of Nrf2.

Age-Related Cognitive Impairment as a Sign of Geriatric Neurocardiovascular Interactions: May Polyphenols Play a Protective Role?

It is known that endothelial dysfunction plays an important role in the development and progression of cardiovascular diseases implicated also in cognitive decline. Experimental studies pointed to the fact that the modification of NO levels via NOS activity may affect the blood pressure level as well as several higher nervous functions—for example, learning and memory. There are emerging evidences from in vitro and animal studies suggesting that polyphenols may potentially have a protective effect on the development of neurodegenerative diseases and may improve cognitive function as well as positively affecting the blood pressure regulatory mechanisms. This review accentuates the need for precisely defined clinically controlled studies as well as for use of adequate experimental procedures discriminating between the human higher brain functions and the only overall activation of the brain cortex. The physiological neurocardiovascular interactions are implicated in the increased healthy life span as well.

Polyphenol Stilbenes: Molecular Mechanisms of Defence against Oxidative Stress and Aging-Related Diseases

Numerous studies have highlighted the key roles of oxidative stress and inflammation in aging-related diseases such as obesity, type 2 diabetes, age-related macular degeneration (AMD), and Alzheimer's disease (AD). In aging cells, the natural antioxidant capacity decreases and the overall efficiency of reparative systems against cell damage becomes impaired. There is convincing data that stilbene compounds, a diverse group of natural defence phenolics, abundant in grapes, berries, and conifer bark waste, may confer a protective effect against aging-related diseases. This review highlights recent data helping to clarify the molecular mechanisms involved in the stilbene-mediated protection against oxidative stress. The impact of stilbenes on the nuclear factor-erythroid-2-related factor-2 (Nrf2) mediated cellular defence against oxidative stress as well as the potential roles of SQSTM1/p62 protein in Nrf2/Keap1 signaling and autophagy will be summarized. The therapeutic potential of stilbene compounds against the most common aging-related diseases is discussed.

Lipoic acid and N-acetylcysteine prevent ammonia-induced inflammatory response in C6 astroglial cells: The putative role of ERK and HO1 signaling pathways

Hyperammonemia induces significant changes in the central nervous system (CNS) in direct association with astroglial functions, such as oxidative damage, glutamatergic excitotoxicity, and impaired glutamine synthetase (GS) activity and pro-inflammatory cytokine release. Classically, lipoic acid (LA) and N-acetylcysteine (NAC) exhibit antioxidant and anti-inflammatory activities by increasing glutathione (GSH) biosynthesis and decreasing pro-inflammatory mediator levels in glial cells. Thus, we evaluated the protective effects of LA and NAC against ammonia cytotoxicity in C6 astroglial cells. Ammonia decreased GSH levels and increased cytokine release and NFκB transcriptional activation. LA and NAC prevented these effects by the modulation of ERK and HO1 pathways. Taken together, these observations show that LA and NAC prevent the ammonia-induced inflammatory response.

Ammonia-induced oxidative damage in neurons is prevented by resveratrol and lipoic acid with participation of heme oxygenase 1

Ammonia is a metabolite that, at high concentrations, is implicated in neurological disorders, such as hepatic encephalopathy (HE), which is associated with acute or chronic liver failure. Astrocytes are considered the primary target of ammonia toxicity in the central nervous system (CNS) because glutamine synthetase (GS), responsible for ammonia metabolism in CNS, is an astrocytic enzyme. Thus, neuronal dysfunction has been associated as secondary to astrocytic impairment. However, we demonstrated that ammonia can induce direct effects on neuronal cells. The cell viability was decreased by ammonia in SH-SY5Y cells and cerebellar granule neurons. In addition, ammonia induced increased reactive oxygen species (ROS) production and decreased GSH intracellular content, the main antioxidant in CNS. As ammonia neurotoxicity is strongly associated with oxidative stress, we also investigated the potential neuroprotective roles of the antioxidants, resveratrol (RSV) and lipoic acid (LA), against ammonia toxicity in cerebellar granule neurons. RSV and LA were able to prevent the oxidative damage induced by ammonia, maintaining the levels of ROS production and GSH close to basal values. Both antioxidants also decreased ROS production and increased GSH content under basal conditions (in the absence of ammonia). Moreover, we showed that heme oxygenase 1 (HO1), a protein associated with protection against stress conditions, is involved in the beneficial effects of RSV and LA in cerebellar granule neurons. Thus, this study reinforces the neuroprotective effects of RSV and LA. Although more studies in vivo are required, RSV and LA could represent interesting therapeutic strategies for the management of HE.

Efficacy of prophylactic flavan-3-ol in permanent focal ischemia in 12-mo-old mice

The consumption of flavan-3-ol-containing foods, including (-)-epicatechin (EC), has been linked to lower incidence of cardiovascular disease and stroke. We previously demonstrated nuclear transcription factor erythroid 2p45-related factor-2 (Nrf2) -dependent EC efficacy in reducing stroke-induced deficits in 2-mo-old mice; yet stroke is primarily a disease of the elderly. Because neuroinflammation, oxidative stress, and vascular dysfunction are hallmarks of aging, we tested whether Nrf2 mediates EC efficacy in aging mice through modulation of glial responses and blood brain barrier permeability. First, we compared anastomosis in naïve wild-type and C57BL/6 Nrf2(-/-) mice to identify potential differences in cerebrovascular architecture. Data showed no significant differences in the number of anastomoses or mean intersection points, indicating similar gross vascular physiology. To assess efficacy and mechanisms of protection, wild-type or Nrf2(-/-) mice were administered the minimum effective EC dose established in our previous studies before the permanent distal middle cerebral artery occlusion. Similar to previous results with young mice, 12-mo-old wild types also showed significant reductions in infarct volume (41.01 ± 29.57%) and improved performance in removing adhesive tape relative to vehicle-treated controls, whereas a trend toward protection was observed in Nrf2(-/-). However, EC did not reduce immunoreactivity for the microglia/macrophage marker anti-ionized calcium-binding adapter molecule 1, suggesting that dampened activation/recruitment did not account for EC protection. Furthermore, there were no differences in mouse IgG extravasation or spontaneous hemorrhage between EC-treated groups. These data demonstrate that EC protection occurs independent of microglia/macrophage modulation or blood brain barrier preservation, suggesting that the glial cell responses in young mice are compensatory to another, and potentially novel, protective mechanism.

Assessing Antioxidant Capacity in Brain Tissue: Methodologies and Limitations in Neuroprotective Strategies

The number of putative neuroprotective compounds with antioxidant activity described in the literature continues to grow. Although these compounds are validated using a variety of in vivo and in vitro techniques, they are often evaluated initially using in vitro cell culture techniques in order to establish toxicity and effective concentrations. Both in vivo and in vitro methodologies have their respective advantages and disadvantages, including, but not limited to, cost, time, use of resources and technical limitations. This review expands on the inherent benefits and drawbacks of in vitro and in vivo methods for assessing neuroprotection, especially in light of proper evaluation of compound efficacy and neural bioavailability. For example, in vivo studies can better evaluate the effects of protective compounds and/or its metabolites on various tissues, including the brain, in the whole animal, whereas in vitro studies can better discern the cellular and/or mechanistic effects of compounds. In particular, we aim to address the question of appropriate and accurate extrapolation of findings from in vitro experiment-where compounds are often directly applied to cellular extracts, potentially at higher concentrations than would ever cross the blood-brain barrier-to the more complex scenario of neuroprotection due to pharmacodynamics in vivo.

[Effect of resveratrol on the fundus oculi. An overview]

Resveratrol is a polyphenol with various properties. Oncological studies have shown an excellent anti-carcinogenic effect. Due to many overlaps between tumor-mediating signaling pathways and those which mediate neovascularization and proliferation in retinal diseases, this review intends to focus on studies about the application of resveratrol in diseases of the eye fundus in vitro and in vivo. Resveratrol has been well investigated in cell culture studies and animal models. Ophthalmological in vitro and in vivo investigations have shown a large variety of possible effects without toxic side effects and antiproliferative and immune modulatory effects in particular were observed. There is general consensus that the target protein of resveratrol is NF-κB. Clinical studies are needed to confirm these effects observed in cell culture and animal models. The exact mechanism of resveratrol remains unknown and seems to vary between cell types, tissues and the pathophysiological environment.

Resveratrol inhibits Kv2.2 currents through the estrogen receptor GPR30-mediated PKC pathway

Resveratrol (REV) is a naturally occurring phytoalexin that inhibits neuronal K+ channels; however, the molecular mechanisms behind the effects of REV and the relevant α-subunit are not well defined. With the use of patch-clamp technique, cultured cerebellar granule cells, and HEK-293 cells transfected with the Kv2.1 and Kv2.2 α-subunits, we investigated the effect of REV on Kv2.1 and Kv2.2 α-subunits. Our data demonstrated that REV significantly suppressed Kv2.2 but not Kv2.1 currents with a fast, reversible, and mildly concentration-dependent manner and shifted the activation or inactivation curve of Kv2.2 channels. Activating or inhibiting the cAMP/PKA pathway did not abolish the inhibition of Kv2.2 current by REV. In contrast, activation of PKC with phorbol 12-myristate 13-acetate mimicked the inhibitory effect of REV on Kv2.2 by modifying the activation or inactivation properties of Kv2.2 channels and eliminated any further inhibition by REV. PKC and PKC-α inhibitor completely eliminated the REV-induced inhibition of Kv2.2. Moreover, the effect of REV on Kv2.2 was reduced by preincubation with antagonists of GPR30 receptor and shRNA for GPR30 receptor. Western blotting results indicated that the levels of PKC-α and PKC-β were significantly increased in response to REV application. Our data reveal, for the first time, that REV inhibited Kv2.2 currents through PKC-dependent pathways and a nongenomic action of the oestrogen receptor GPR30.

Resveratrol protects C6 astrocyte cell line against hydrogen peroxide-induced oxidative stress through heme oxygenase 1

Resveratrol, a polyphenol presents in grapes and wine, displays antioxidant and anti-inflammatory properties and cytoprotective effect in brain pathologies associated to oxidative stress and neurodegeneration. In previous work, we demonstrated that resveratrol exerts neuroglial modulation, improving glial functions, mainly related to glutamate metabolism. Astrocytes are a major class of glial cells and regulate neurotransmitter systems, synaptic processing, energy metabolism and defense against oxidative stress. This study sought to determine the protective effect of resveratrol against hydrogen peroxide (H₂O₂)-induced cytotoxicity in C6 astrocyte cell line, an astrocytic lineage, on neurochemical parameters and their cellular and biochemical mechanisms. H₂O₂ exposure increased oxidative-nitrosative stress, iNOS expression, cytokine proinflammatory release (TNFα levels) and mitochondrial membrane potential dysfunction and decreased antioxidant defenses, such as SOD, CAT and creatine kinase activity. Resveratrol strongly prevented C6 cells from H₂O₂-induced toxicity by modulating glial, oxidative and inflammatory responses. Resveratrol per se increased heme oxygenase 1 (HO1) expression and extracellular GSH content. In addition, HO1 signaling pathway is involved in the protective effect of resveratrol against H₂O₂-induced oxidative damage in astroglial cells. Taken together, these results show that resveratrol represents an important mechanism for protection of glial cells against oxidative stress.

Pharmacokinetics, tissue distribution and excretion study of resveratrol and its prodrug 3,5,4'-tri-O-acetylresveratrol in rats

3,5,4'-Tri-O-acetylresveratrol (TARES) synthesized by acetylating three hydroxyl groups of resveratrol (RES) is a prodrug of RES. The aim of this study was to investigate and compare the pharmacokinetics, tissue distribution and excretion of TARES and RES in rats following a single intragastric gavage (i.g.) administration. After RES is transformed into TARES, its pharmacokinetic properties are improved, such as the t1/2 has been prolonged and the AUC has been enhanced. And TARES follows linear plasma pharmacokinetics across the investigated dosage range in rats (77.5-310 mg/kg). The major distribution tissues of TARES or RES in rats were liver, spleen, heart and lung. TARES can increase the content of RES in lung significantly. There was no long-term accumulation of RES in rat tissues. Whether we administrated to rats of equimolar TARES or RES, total recoveries of RES in urine and feces within 36 h were low (0.99% or 0.07% in urine and 1.69% or 0.15% in feces).

Potential neuroprotective effects of oxyresveratrol against traumatic injury

Oxyresveratrol is a potent antioxidant and free-radical scavenger found in mulberry wood (Morus alba L.) with demonstrated protective effects against cerebral ischemia. We analyzed the neuroprotective ability of oxyresveratrol using an in vitro model of stretch-induced trauma in co-cultures of neurons and glia, or by exposing cultures to high levels of glutamate. Cultures were treated with 25 μM, 50 μM or 100 μM oxyresveratrol at the time of injury. Trauma produced marked neuronal death when measured 24 h post-injury, and oxyresveratrol significantly inhibited this death. Microscopic examination of glia suggested signs of toxicity in cultures treated with 100 μM oxyresveratrol, as demonstrated by elevated S-100B protein release and a high proportion of cells with condensed nuclei. Cultures exposed to glutamate (100 μM) for 24 h exhibited ~ 37% neuronal loss, which was not inhibited by oxyresveratrol. These results show that the two pathologies of high glutamate exposure and trauma are differentially affected by oxyresveratrol treatment in vitro. Further studies using oxyresveratrol in trauma models are warranted, as toxicity to glia could be beneficial by inhibiting reactive gliosis, which often occurs after trauma.

Therapeutic targets of brain insulin resistance in sporadic Alzheimer's disease

Growing evidence supports roles for brain insulin and insulin-like growth factor (IGF) resistance and metabolic dysfunction in the pathogenesis of Alzheimer's disease (AD). Whether the underlying problem stems from a primary disorder of central nervous system (CNS) neurons and glia, or secondary effects of systemic diseases such as obesity, Type 2 diabetes, or metabolic syndrome, the end-results include impaired glucose utilization, mitochondrial dysfunction, increased oxidative stress, neuroinflammation, and the propagation of cascades that result in the accumulation of neurotoxic misfolded, aggregated, and ubiquitinated fibrillar proteins. This article reviews the roles of impaired insulin and IGF signaling to AD-associated neuronal loss, synaptic disconnection, tau hyperphosphorylation, amyloid-beta accumulation, and impaired energy metabolism, and discusses therapeutic strategies and lifestyle approaches that could be used to prevent, delay the onset, or reduce the severity of AD. Finally, it is critical to recognize that AD is heterogeneous and has a clinical course that fully develops over a period of several decades. Therefore, early and multi-modal preventive and treatment approaches should be regarded as essential.

Involvement of estrogen receptors in the resveratrol-mediated increase in dopamine transporter in human dopaminergic neurons and in striatum of female mice

Treatment with resveratrol (RSV) has been shown to protect vulnerable neurons after various brain injuries and in neurodegenerative diseases. The mechanisms for the effects of RSV in brain are not fully understood, but RSV may affect the expression of various gene products. RSV is structurally related to the synthetic estrogen, diethylstilbestrol so the effects of RSV may be gender-specific. Here we studied the role of RSV in the regulation of dopamine transporter (DAT) in the striatum using male and female mice. The basic levels of DAT in the striatum showed no sex difference, but the levels increased significantly by RSV (20 mg/kg i.p.) in female but not in male mice. Pretreatment of mice with the selective estrogen receptor (ER), ERα- and ERβ antagonist ICI 182,780, led to a complete block of RSV effect on DAT protein levels, suggesting that ERs are involved in the up-regulation of DAT by RSV. Similar data was also obtained in culture using human MESC2.10 and mouse SN4741 dopaminergic cells after treatment with RSV. Data further showed that RSV specifically induced gene transcription of DAT in the dopaminergic cells. These results show that estrogen receptors are involved in the up-regulation of DAT by RSV in the dopaminergic neurons, demonstrating a sex-dependent effect of RSV in the brain that may be of clinical importance. This article is part of a Special Issue entitled 'Post-Traumatic Stress Disorder'.

Resveratrol-activated AMPK/SIRT1/autophagy in cellular models of Parkinson's disease

Excessive misfolded proteins and/or dysfunctional mitochondria, which may cause energy deficiency, have been implicated in the etiopathogenesis of Parkinson's disease (PD). Enhanced clearance of misfolded proteins or injured mitochondria via autophagy has been reported to have neuroprotective roles in PD models. The fact that resveratrol is a known compound with multiple beneficial effects similar to those associated with energy metabolism led us to explore whether neuroprotective effects of resveratrol are related to its role in autophagy regulation. We tested whether modulation of mammalian silent information regulator 2 (SIRT1) and/or metabolic energy sensor AMP-activated protein kinase (AMPK) are involved in autophagy induction by resveratrol, leading to neuronal survival. Our results showed that resveratrol protected against rotenone-induced apoptosis in SH-SY5Y cells and enhanced degradation of α-synucleins in α-synuclein-expressing PC12 cell lines via autophagy induction. We found that suppression of AMPK and/or SIRT1 caused decrease of protein level of LC3-II, indicating that AMPK and/or SIRT1 are required in resveratrol-mediated autophagy induction. Moreover, suppression of AMPK caused inhibition of SIRT1 activity and attenuated protective effects of resveratrol on rotenone-induced apoptosis, further suggesting that AMPK-SIRT1-autophagy pathway plays an important role in the neuroprotection by resveratrol on PD cellular models.

Resveratrol modulates astroglial functions: neuroprotective hypothesis

Resveratrol, a redox active compound present in grapes and wine, has a wide range of biological effects, including cardioprotective, chemopreventive, and anti-inflammatory activities. The central nervous system is a target of resveratrol, which can pass the blood-brain barrier and induce neuroprotective effects. Astrocytes are one of the most functionally diverse groups of cells in the nervous system, intimately associated with glutamatergic metabolism, transmission, synaptic plasticity, and neuroprotection. In this review, we focus on the resveratrol properties and response to oxidative insult on important astroglial parameters involved in brain plasticity, such as glutamate uptake, glutamine synthetase activity, glutathione content, and secretion of the trophic factor S100B.

Differential neuroprotective activity of two different grape seed extracts

Glutamate excitotoxicity is one of the major events that takes place during various neurotoxic injuries such as brain ischemia. We prepared grape seed extracts, from two different varieties, containing high amounts of polyphenols but little resveratrol. Their neuroprotective effects were investigated using primary culture of neonatal mouse hippocampal neurons treated with an excitotoxic concentration of glutamate. Koshu, a white, local variety of V. vinifera, alleviated the acute inactivation of Erk1/2 and dendrite retraction in cultured hippocampal neurons exposed to a toxic concentration of glutamate (1.0 ng/ml). By contrast, Muscat Bailey A, a red, hybrid variety (Muscat Humburg × Bailey), failed to show any neuroprotective effect. Unlike brain-derived neurotrophic factor and other neuroprotective cytokines, Koshu extract did not induce Akt phosphorylation. Koshu extract also augmented neuron survival rate 24 hours after glutamate toxicity. The comparison of polyphenols between the two samples by liquid chromatography/time-of-flight mass spectrometry demonstrated that Koshu had higher amounts of low molecular weight polyphenols along with several Koshu-specific procyanidin oligomers. These data suggest the presence of high affinity molecular targets for polyphenols in hippocampal neurons, which induce neuroprotective effects in a manner different from BDNF, and the importance of low molecular weight polyphenols and/or procyanidin oligomers for neuroprotection.

Natural compounds from traditional medicinal herbs in the treatment of cerebral ischemia/reperfusion injury

More and more attention in the field of drug discovery has been focused on the neuroprotection of natural compounds from traditional medicinal herbs. Cerebral ischemia is a complex pathological process involving a series of mechanisms, and a framework for the development of neuroprotectants from traditional herb medicine is a promising treatment for cerebral ischemia. Natural compounds with the effects of anti-oxidation, anti-inflammation, calcium antagonization, anti-apoptosis, and neurofunctional regulation exhibit preventive or therapeutic effects on experimental ischemic brain injury. According to the pharmacological mechanisms underlying neuroprotection, we evaluated natural products from traditional medicinal herbs that exhibit protective effects on ischemic brain injury and characterized the promising targets.

Antioxidant properties and neuroprotective capacity of strawberry tree fruit (Arbutus unedo)

Berries contain significant amounts of phytochemicals, including polyphenols, which are reported to reduce cancer risk, coronary heart disease and other degenerative diseases. These effects are mainly attributed to the antioxidant capacity of polyphenols found in berries. Strawberry tree (Arbutus unedo) berries are used in folk medicine but seldom eaten as fresh fruits. Their phenolic profile and antioxidant capacity reveal a high potential, but they are not well characterized as a “health promoting food”. The aim of this study was to assess the antioxidant properties of the edible strawberry tree fruit in vitro and in a neurodegeneration cell model. Raspberry (Rubus idaeus), a well documented health-promoting fruit, was used as a control for comparison purposes. A. unedo yielded a similar content in polyphenols and a slightly lower value of total antioxidant capacity in comparison to R. idaeus. Although the chemically-measured antioxidant activity was similar between both fruits, R. idaeus increased neuroblastoma survival in a neurodegeneration cell model by 36.6% whereas A. unedo extracts caused no effect on neuroblastoma viability. These results clearly demonstrate that a promising level of chemically-determined antioxidant activity of a plant extract is not necessarily correlated with biological significance, as assessed by the effect of A. unedo fruit in a neurodegeneration cell model.

Preformulation stability of trans-resveratrol and trans-resveratrol glucoside (Piceid)

Resveratrol and resveratrol glucoside (piceid) were evaluated in a preformulation stability study. An HPLC assay was used for the analysis of stressed/reference samples. Samples of solid, crystalline material were held under the following conditions: 40 degrees C/75% RH (both open and protected), ambient fluorescent light (open), 70 degrees C (open), and exposed using a light cabinet to achieve ICH conditions for UV/fluorescent light. Both compounds were found to be stable out to 3 months for both accelerated and ambient conditions with negligible degradation. Exposure to UV and fluorescent light under ICH conditions did not significantly degrade the solid materials for UV exposure at 3 times the ICH limit and for fluorescent light exposure at 1 times the ICH limit. The results presented demonstrate crystalline resveratrol and piceid are stable solids. No evidence of oxidation of either material by atmospheric oxidants was seen. The data reported may help to clarify widely held beliefs that resveratrol is unstable and extremely sensitive to oxidation/degradation.

The role of mitochondria in the pathophysiology of skeletal muscle insulin resistance

Multiple organs contribute to the development of peripheral insulin resistance, with the major contributors being skeletal muscle, liver, and adipose tissue. Because insulin resistance usually precedes the development of type 2 diabetes mellitus (T2DM) by many years, understanding the pathophysiology of insulin resistance should enable development of therapeutic strategies to prevent disease progression. Some subjects with mitochondrial genomic variants/defects and a subset of lean individuals with hereditary predisposition to T2DM exhibit skeletal muscle mitochondrial dysfunction early in the course of insulin resistance. In contrast, in the majority of subjects with T2DM the plurality of evidence implicates skeletal muscle mitochondrial dysfunction as a consequence of perturbations associated with T2DM, and these mitochondrial deficits then contribute to subsequent disease progression. We review the affirmative and contrarian data regarding skeletal muscle mitochondrial biology in the pathogenesis of insulin resistance and explore potential therapeutic options to intrinsically modulate mitochondria as a strategy to combat insulin resistance. Furthermore, an overview of restricted molecular manipulations of skeletal muscle metabolic and mitochondrial biology offers insight into the mitochondrial role in metabolic substrate partitioning and in promoting innate adaptive and maladaptive responses that collectively regulate peripheral insulin sensitivity. We conclude that skeletal muscle mitochondrial dysfunction is not generally a major initiator of the pathophysiology of insulin resistance, although its dysfunction is integral to this pathophysiology and it remains an intriguing target to reverse/delay the progressive perturbations synonymous with T2DM.

Protective effects of resveratrol and quercetin against MPP+ -induced oxidative stress act by modulating markers of apoptotic death in dopaminergic neurons

Reactive oxygen species produced by oxidative stress may participate in the apoptotic death of dopamine neurons distinctive of Parkinson's disease. Resveratrol, a red wine extract, and quercetin, found mainly in green tea, are two natural polyphenols, presenting antioxidant properties in a variety of cellular paradigms. The aim of this study was to evaluate the effect of resveratrol and quercetin on the apoptotic cascade induced by the administration of 1-methyl-4-phenylpyridinium ion (MPP(+)), a Parkinsonian toxin, provoking the selective degeneration of dopaminergic neurons. Our results show that a pre-treatment for 3 h with resveratrol or quercetin before MPP(+) administration could greatly reduce apoptotic neuronal PC12 death induced by MPP(+). We also demonstrated that resveratrol or quercetin modulates mRNA levels and protein expression of Bax, a pro-apoptotic gene, and Bcl-2, an anti-apoptotic gene. We then evaluated the release of cytochrome c and the nuclear translocation of the apoptosis-inducing factor (AIF). Altogether, our results indicate that resveratrol and quercetin diminish apoptotic neuronal cell death by acting on the expression of pro- and anti-apoptotic genes. These findings support the role of these natural polyphenols in preventive and/or complementary therapies for several human neurodegenerative diseases caused by oxidative stress and apoptosis.

Protection by tetrahydroxystilbene glucoside against cerebral ischemia: involvement of JNK, SIRT1, and NF-kappaB pathways and inhibition of intracellular ROS/RNS generation

Many natural polyphenolic compounds have been shown to attenuate reactive oxygen/nitrogen species (ROS/RNS) formation and protect against ischemia/reperfusion injury both in vitro and in vivo. 2,3,5,4'-tetrahydroxystilbene-2-O-beta-D-glucoside (TSG), an active component of the rhizome extract from Polygonum multiflorum, exhibits antioxidative and anti-inflammatory effects. Here, we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD-R) and an in vivo ischemic model of middle cerebral artery occlusion (MCAO) to investigate the neuroprotective effects of TSG on ischemia/reperfusion brain injury and the related mechanisms. We demonstrated that OGD-R-induced neuronal injury, intracellular ROS generation, and mitochondrial membrane potential dissipation were reversed by TSG. The elevation of H2O2-induced [Ca2+]i was also attenuated by TSG. Inhibition of the c-Jun N-terminal kinase (JNK) and Bcl-2 family-related apoptotic signaling pathway was involved in the neuroprotection afforded by TSG. Meanwhile, TSG inhibited iNOS mRNA expression induced by OGD-R, which may be mediated by the activation of SIRT1 and inhibition of NF-kappaB activation. In vivo studies further demonstrated that TSG significantly reduced the brain infarct volume and the number of positive cells by TUNEL staining in the cerebral cortex compared to the MCAO group. Our study indicates that TSG protects against cerebral ischemia/reperfusion injury through multifunctional cytoprotective pathways.

The protective role of HO-1 and its generated products (CO, bilirubin, and Fe) in ethanol-induced human hepatocyte damage

It has been reported that naturally occurring quercetin exerts hepatoprotective effects through heme oxygenase-1 (HO-1) induction. However, the precise mechanism of how ethanol-associated liver damage is counteracted by quercetin-enhanced HO-1 metabolism still remains unclear. To further decipher the protective role of quercetin on ethanol-induced liver damage, we treated human hepatocytes with quercetin and various (end) products of the HO-1 pathway. Our data clearly showed that quercetin treatment attenuated ethanol-induced damage, whereas hemoglobin and zinc protoporphyrin 9 (ZnPP) abolished such effects. Iron-II aggravated ethanol toxicity and was only partially reduced by quercetin. In contrast, carbon monoxide (CO) dose dependently inhibited ethanol-induced cytochrome P450 2E1 (CYP 2E1) activity and hepatotoxicity but had no influence on CYP 2E1 protein expression. Similarly, hemoglobin dramatically stimulated CYP 2E1 activity but not the protein expression in quercetin- and ethanol-cotreated hepatocytes. ZnPP significantly promoted CYP 2E1 protein expression in the presence and absence of CO treatment but inhibited ethanol-induced CYP 2E1 activation following CO incubation in quercetin- and ethanol-cotreated hepatocytes. These results suggested that quercetin virtually attenuated ethanol-derived oxidative damage via HO-1 induction. Heme degradation and CO release may mediate the protective effects through inhibiting ethanol-induced CYP 2E1 synthesis and enzymatic activity, respectively.

Vascular action of polyphenols

Dietary patterns are widely recognised as contributors to cardiovascular and cerebrovascular disease. Endothelial function, the elastic properties of large arteries and the magnitude and timing of wave reflections are important determinants of cardiovascular performance. Several epidemiological studies suggest that the regular consumption of foods and beverages rich in flavonoids is associated with a reduction in the risk of several pathological conditions ranging from hypertension to coronary heart disease, stroke and dementia. The impairment of endothelial function is directly related to ageing and an association between decreased cerebral perfusion and dementia has been shown to exist. Cerebral blood flow (CBF) must be maintained to ensure a constant delivery of oxygen and glucose as well as the removal of waste products. Increasing blood flow is one potential way for improving brain function and the prospect for increasing CBF with dietary polyphenols is extremely promising. The major polyphenols shown to have some of these effects in humans are primarily from cocoa, wine, grape seed, berries, tea, tomatoes (polyphenolics and nonpolyphenolics), soy and pomegranate. There has been a significant paradigm shift in polyphenol research during the last decade. This review summarises our current knowledge in this area and points the way for the development of new types of functional foods targeted to brain health through improving vascular health.