Resveratrol supplementation: Where are we now and where should we go?

Effects of exercise training and resveratrol on vascular health in aging

Cardiovascular disease is a leading cause of death in the western world with aging being one of the strongest predictors of cardiovascular events. Aging is associated with impaired vascular function due to endothelial dysfunction and altered redox balance, partly caused by an increased formation of reactive oxygen species combined with a reduction in the endogenous antioxidant capacity. The consequence of these alterations is a reduced bioavailability of nitric oxide (NO) with implications for aspects such as control of vascular tone and low grade inflammation. However, it is not only aging per se but also the accumulative influence of physical inactivity and other life-style factors, which negatively affect the vascular system. Regular physical activity improves NO bioavailability, the redox balance and the plasma lipid profile and, at a functional level, reduces or even reverses a majority of the observed detrimental effects of aging on vascular function. The effects of aging and physical activity on vascular function are, in part, related to alterations in cellular signaling through sirtuin-1, AMPK and the estrogen receptor. The polyphenol resveratrol can activate these same pathways and has, in animals and in vitro models, been shown to act as a partial mimetic of physical activity. However, support for beneficial effects of resveratrol in human is weak and studies even show that resveratrol supplementation, similarly to supplementation with other antioxidants, can counteract the positive effects of physical activity. Regular physical activity remains the most effective way of maintaining and improving vascular health status and caution should be taken regarding potential interference of supplements on training adaptations.

Classical and atypical resistance of cancer cells as a target for resveratrol

The phenomenon of cancer cell resistance to chemotherapeutics is the main cause of insensitivity to anticancer therapy. Thus, the current challenge remains searching for substances sensitising the activity of cytostatic drugs. In this respect, resveratrol is a very promising therapeutic agent. It has pleiotropic effect on cancer cells, which can play a key role in numerous resistance mechanisms, both classical and atypical. The purpose of the present study was to assess the effect of resveratrol on the inhibition of human pancreatic cancer cell proliferation and on the level of cytostatic resistance-associated proteins. The study was performed on human pancreatic cancer cell lines EPP85-181P (control), EPP85-181RDB (daunorubicin resistance) and EPP85-181PRNOV (mitoxantrone resistance). The effect of resveratrol on the viability and proliferation of the studied cell lines was evaluated by SRB assay, whereas cell cycle arrest and cytostatic accumulation by FACS. Western blot analysis was used to determine the level of P-glycoprotein, topoisomerase II α and β and immunofluorescence technique to visualise the proteins in the cells. Resveratrol inhibited proliferation of all studied cell lines. Phase-specific cell cycle arrest depended on the type of cancer cells. Resveratrol decreased the level and activity of P-gp in EPP85-181RDB cells. In EPP85-181PRNOV cells, expression of both TopoII isoforms increased in a statistically significant manner. The results of in vitro studies support the possibility of potential use of resveratrol in breaking cancer cell resistance to chemotherapeutic drugs.

The Protective Effect of Antioxidants Consumption on Diabetes and Vascular Complications

Obesity and diabetes is generally accompanied by a chronic state of oxidative stress, disequilibrium in the redox balance, implicated in the development and progression of complications such as micro- and macro-angiopathies. Disorders in the inner layer of blood vessels, the endothelium, play an early and critical role in the development of these complications. Blunted endothelium-dependent relaxation and/or contractions are quietly associated to oxidative stress. Thus, preserving endothelial function and oxidative stress seems to be an optimization strategy in the prevention of vascular complications associated with diabetes. Diet is a major lifestyle factor that can greatly influence the incidence and the progression of type 2 diabetes and cardiovascular complications. The notion that foods not only provide basic nutrition but can also prevent diseases and ensure good health and longevity is now attained greater prominence. Some dietary and lifestyle modifications associated to antioxidative supply could be an effective prophylactic means to fight against oxidative stress in diabesity and complications. A significant benefit of phytochemicals (polyphenols in wine, grape, teas), vitamins (ascorbate, tocopherol), minerals (selenium, magnesium), and fruits and vegetables in foods is thought to be capable of scavenging free radicals, lowering the incidence of chronic diseases. In this review, we discuss the role of oxidative stress in diabetes and complications, highlight the endothelial dysfunction, and examine the impact of antioxidant foods, plants, fruits, and vegetables, currently used medication with antioxidant properties, in relation to the development and progression of diabetes and cardiovascular complications.

Resveratrol affects DNA damage induced by ionizing radiation in human lymphocytes in vitro

Resveratrol (3,4',5-trihydroxystilbene; RSV) acts on cancer cells in several ways, inducing cell cycle delay and apoptotic death, and enhancing ionizing radiation (IR)-mediated responses. However, fewer studies have examined RSV effects on normal cells. We have treated human lymphocytes in vitro with RSV, either alone or combined with IR, to evaluate its potential use as a radioprotector. We measured the effects of RSV on induction of DNA damage, repair kinetics, and modulation of histone deacetylase activity.

A facile and rapid access to resveratrol derivatives and their radioprotective activity

A facile and rapid access to resveratrol derivatives has been achieved based on palladium-catalyzed oxidative Heck reaction of aryl boronic acids with styrenes followed by demethylation in moderate to good yields. A series of resveratrol derivatives with various functional groups has been synthesized easily. The radioprotective activity of synthesized compounds has also been evaluated using rat thymocytes. The results revealed that some resveratrol derivatives efficiently protected the thymocytes from radiation-induced apoptosis.

Resveratrol-Mediated Repression and Reversion of Prostatic Myofibroblast Phenoconversion

Background

Resveratrol, a phytoalexin found in berries, peanuts, grapes, and red wine, inhibits oxidation, inflammation, and cell proliferation and collagen synthesis in multiple cell types and or animal models. It represses collagen deposition in the vasculature, heart, lung, kidney, liver, and esophagus in animal models and may have some utility as an anti-fibrotic. Recent studies have shown that increased collagen deposition and tissue stiffness in the peri-urethral area of the prostate are associated with lower urinary tract dysfunction (LUTD) and urinary obstructive symptoms. The aim of this study was to determine whether Resveratrol might be useful to inhibit or revert TGFβ- and/or CXCL12-mediated myofibroblast phenoconversion of prostate fibroblasts in vitro, and therefore whether the use of anti-fibrotic therapeutics might be efficacious for the treatment of LUTD.

Methods

Primary prostate and lung tissues were explanted and fibroblast monolayers expanded in vitro. Primary and N1 immortalized prostate stromal fibroblasts, as well as primary fibroblasts cultured from a normal lung and one affected by idiopathic pulmonary fibrosis (IPF) for comparison, were grown in serum–free defined media supplemented with vehicle, TGFβ or CXCL12, pre- or post-treatment with Resveratrol, and were evaluated using immunofluorescence for alpha smooth muscle actin (αSMA) and collagen I (COL1) protein expression and assessed for cell proliferation, apoptosis, and COL1 and EGR1 transcript expression.

Results

This study showed that low concentrations of Resveratrol (≤50 μM) had no effect on N1 or primary prostate fibroblast cell proliferation, apoptosis, or COL1 or EGR1 gene transcription but repressed and reversed myofibroblast phenoconversion. As expected, these same effects were observed for IPF lung fibroblasts though higher levels of Resveratrol (≥100uM) were required. Taken together, these data suggest that, like lung fibroblasts, prostate fibroblast to myofibroblast phenoconversion can be both repressed and reversed by Resveratrol treatment. Thus, anti-fibrotic therapeutics might be efficacious for the treatment of LUTD.

(Z)-3,5,4'-Trimethoxystilbene Limits Hepatitis C and Cancer Pathophysiology by Blocking Microtubule Dynamics and Cell-Cycle Progression

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related deaths worldwide. Chronic hepatitis C virus (HCV) infection causes induction of several tumors/cancer stem cell (CSC) markers and is known to be a major risk factor for development of HCC. Therefore, drugs that simultaneously target viral replication and CSC properties are needed for a risk-free treatment of advanced stage liver diseases, including HCC. Here, we demonstrated that (Z)-3,5,4'-trimethoxystilbene (Z-TMS) exhibits potent antitumor and anti-HCV activities without exhibiting cytotoxicity to human hepatocytes in vitro or in mice livers. Diethylnitrosamine (DEN)/carbon tetrachloride (CCl4) extensively induced expression of DCLK1 (a CSC marker) in the livers of C57BL/6 mice following hepatic injury. Z-TMS exhibited hepatoprotective effects against DEN/CCl4-induced injury by reducing DCLK1 expression and improving histologic outcomes. The drug caused bundling of DCLK1 with microtubules and blocked cell-cycle progression at G2-M phase in hepatoma cells via downregulation of CDK1, induction of p21(cip1/waf1) expression, and inhibition of Akt (Ser(473)) phosphorylation. Z-TMS also inhibited proliferation of erlotinib-resistant lung adenocarcinoma cells (H1975) bearing the T790M EGFR mutation, most likely by promoting autophagy and nuclear fragmentation. In conclusion, Z-TMS appears to be a unique therapeutic agent targeting HCV and concurrently eliminating cells with neoplastic potential during chronic liver diseases, including HCC. It may also be a valuable drug for targeting drug-resistant carcinomas and cancers of the lungs, pancreas, colon, and intestine, in which DCLK1 is involved in tumorigenesis. Cancer Res; 76(16); 4887-96. ©2016 AACR.

The synergistic effect of resveratrol in combination with cisplatin on apoptosis via modulating autophagy in A549 cells

Several studies have shown that combination treatment with natural products and chemotherapy agents can improve the sensitivity and cytotoxicity of chemotherapy agents. Resveratrol, a natural product, has many biological effects including antitumor and antiviral activities, as well as vascular protective effect. The aim of this study is to investigate the synergistic anticancer effect of resveratrol in combination with cisplatin and the potential anticancer mechanisms involved in A549 cells. The results obtained from Cell Counting Kit-8 and isobolographic analysis demonstrated that combination of resveratrol and cisplatin resulted in synergistic cytotoxic effects in A549 cells. Results from Hoechst staining, flow cytometry and western blot analysis suggested that resveratrol enhanced cisplatin-mediated apoptosis. Meanwhile, the changes of LC3-II and P62 levels and formation of autophagosome suggested that resveratrol in combination with cisplatin triggered autophagy. More importantly, inhibiting autophagy by 3-methyladenine markedly attenuated the apoptosis caused by combination of resveratrol and cisplatin in A549 cells. Taken together, our study provides the first evidence that resveratrol combined with cisplatin synergistically induce apoptosis via modulating autophagic cell death in A549 cells. These findings also help us to understand the role of natural products in combination with chemotherapy agents in lung cancer.

Cardioprotective Potentials of Plant-Derived Small Molecules against Doxorubicin Associated Cardiotoxicity

Doxorubicin (DOX) is a potent and widely used anthracycline antibiotic for the treatment of several malignancies. Unfortunately, the clinical utility of DOX is often restricted due to the elicitation of organ toxicity. Particularly, the increased risk for the development of dilated cardiomyopathy by DOX among the cancer survivors warrants major attention from the physicians as well as researchers to develop adjuvant agents to neutralize the noxious effects of DOX on the healthy myocardium. Despite these pitfalls, the use of traditional cytotoxic drugs continues to be the mainstay treatment for several types of cancer. Recently, phytochemicals have gained attention for their anticancer, chemopreventive, and cardioprotective activities. The ideal cardioprotective agents should not compromise the clinical efficacy of DOX and should be devoid of cumulative or irreversible toxicity on the naïve tissues. Furthermore, adjuvants possessing synergistic anticancer activity and quelling of chemoresistance would significantly enhance the clinical utility in combating DOX-induced cardiotoxicity. The present review renders an overview of cardioprotective effects of plant-derived small molecules and their purported mechanisms against DOX-induced cardiotoxicity. Phytochemicals serve as the reservoirs of pharmacophore which can be utilized as templates for developing safe and potential novel cardioprotective agents in combating DOX-induced cardiotoxicity.

Antioxidant effects of resveratrol in the cardiovascular system

The antioxidant effects of resveratrol (3,5,4'-trihydroxy-trans-stilbene) contribute substantially to the health benefits of this compound. Resveratrol has been shown to be a scavenger of a number of free radicals. However, the direct scavenging activities of resveratrol are relatively poor. The antioxidant properties of resveratrol in vivo are more likely to be attributable to its effect as a gene regulator. Resveratrol inhibits NADPH oxidase-mediated production of ROS by down-regulating the expression and activity of the oxidase. This polyphenolic compound reduces mitochondrial superoxide generation by stimulating mitochondria biogenesis. Resveratrol prevents superoxide production from uncoupled endothelial nitric oxide synthase by up-regulating the tetrahydrobiopterin-synthesizing enzyme GTP cyclohydrolase I. In addition, resveratrol increases the expression of various antioxidant enzymes. Some of the gene-regulating effects of resveratrol are mediated by the histone/protein deacetylase sirtuin 1 or by the nuclear factor-E2-related factor-2. In this review article, we have also summarized the cardiovascular effects of resveratrol observed in clinical trials.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

At the interface of antioxidant signalling and cellular function: Key polyphenol effects

The hypothesis that dietary (poly)phenols promote well‐being by improving chronic disease‐risk biomarkers, such as endothelial dysfunction, chronic inflammation and plasma uric acid, is the subject of intense current research, involving human interventions studies, animal models and in vitro mechanistic work. The original claim that benefits were due to the direct antioxidant properties of (poly)phenols has been mostly superseded by detailed mechanistic studies on specific molecular targets. Nevertheless, many proposed mechanisms in vivo and in vitro are due to modulation of oxidative processes, often involving binding to specific proteins and effects on cell signalling. We review the molecular mechanisms for 3 actions of (poly)phenols on oxidative processes where there is evidence in vivo from human intervention or animal studies. (1) Effects of (poly) phenols on pathways of chronic inflammation leading to prevention of some of the damaging effects associated with the metabolic syndrome. (2) Interaction of (poly)phenols with endothelial cells and smooth muscle cells, leading to effects on blood pressure and endothelial dysfunction, and consequent reduction in cardiovascular disease risk. (3) The inhibition of xanthine oxidoreductase leading to modulation of intracellular superoxide and plasma uric acid, a risk factor for developing type 2 diabetes.

Resveratrol suppresses myofibroblast activity of human buccal mucosal fibroblasts through the epigenetic inhibition of ZEB1 expression

Oral submucous fibrosis (OSF) is a precancerous condition of the oral mucosa without specific therapeutic drugs. We previously demonstrated that the zinc finger E-box binding homeobox 1 (ZEB1) plays a pathogenic role in the induction of the myofibroblast activity of buccal mucosal fibroblasts (BMFs) and contributes to the pathogenesis of OSF. Resveratrol is a natural polyphenolic flavonoid with anti-fibrosis activity in various tissues and has the capability to inhibit ZEB1 in oral cancer cells. We examined the effect of resveratrol on the myofibroblast activity of human primary fibrotic BMFs (fBMFs) derived from OSF tissues. With the collagen contraction assay, resveratrol displayed anti-myofibroblast activity in three fBMF lines. Resveratrol also inhibited the expression of fibrogenic genes at the mRNA and protein levels in a dose- and time-dependent manner. The downregulation of ZEB1 in fBMFs by resveratrol was mediated by epigenetic mechanisms, such as the upregulated expression of miR-200c and the enhancer of zeste homolog 2 (EZH2), as well as the trimethylated lysine 27 of histone H3 (H3K27me3). Resveratrol also increased the binding of H3K27me3 to the ZEB1 promoter. The knockdown of EZH2 in fBMFs caused the upregulation of ZEB1 and suppressed the inhibitory effect of resveratrol. Furthermore, the reversed expression pattern between EZH2 and ZEB1 was observed in 6/8 OSF tissues with twofold upregulation of ZEB1 expression compared with the adjacent normal mucosa. In conclusion, our data suggest that resveratrol epigenetically inhibits ZEB1 expression to suppress the myofibroblast activity of fBMFs and may serve as a dietary supplement for OSF patients.

Restoration of sirt1 function by pterostilbene attenuates hypoxia-reoxygenation injury in cardiomyocytes

Restoration of blood supply to ischemic myocardium causes cardiomyocyte damage, a process known as ischemia-reperfusion injury. Excess reactive oxygen species and intracellular calcium contribute to cell damage but the involvement of sirt1, a versatile protein deacetylase in reperfusion-induced cell damage remains unknown. Here, we found that hypoxia-reoxygenation, an in vitro model of ischemia-reperfusion injury, induced H9c2 cardiomyocyte apoptosis as revealed by caspase-3 assay, Hoechst 33258 staining, flow cytometric analysis and JC-1 staining. Molecular docking analysis showed that, pterostilbene, a natural dimethyl ether derivative of resveratrol, binds to the enzymatic active pocket of sirt1. Importantly, application of pterostilbene at low concentrations of 0.1-3.0 μM rescued H9c2 cells from apoptosis, an effect comparable with resveratrol at 20 μM. Mechanistically, pterostilbene exerted its cardioprotective effects via 1) stimulation of sirt1 activity, since pretreatment of H9c2 cells with splitomicin, an antagonist of sirt1, removed the effects of pterostilbene, and 2) enhancement of sirt1 expression. Therefore, the present study demonstrates that activation of sitr1 during ischemia-reperfusion is cardioprotective and that the natural compound-pterostilbene-could be used therapeutically to alleviate ischemia-reperfusion injury.

Resveratrol preferentially inhibits IgE-dependent PGD2 biosynthesis but enhances TNF production from human skin mast cells

BACKGROUND

Resveratrol, a natural polyphenol found in the skin of red grapes, is reported to have anti-inflammatory properties including protective effects against aging. Consequently, Resveratrol is a common nutritional supplement and additive in non-prescription lotions and creams marketed as anti-aging products. Studies in mice and with mouse bone marrow-derived mast cells (BMMCs) have indicated anti-allergic effects of Resveratrol. However, the effects of Resveratrol on human primary mast cells have not been reported.

METHODS

Human mast cells were isolated and purified from normal skin tissue of different donors. The effect of Resveratrol on IgE-dependent release of allergic inflammatory mediators was determined using various immunoassays, Western blotting, and quantitative real-time PCR.

RESULTS

Resveratrol at low concentrations (≤10 μM) inhibited PGD2 biosynthesis but not degranulation. Accordingly, COX-2 expression was inhibited but phosphorylation of Syk, Akt, p38, and p42/44 (ERKs) remained intact. Surprisingly, TNF production was significantly enhanced with Resveratrol. At a high concentration (100 μM), Resveratrol significantly inhibited all parameters analyzed except Syk phosphorylation.

CONCLUSIONS

Here, we show that Resveratrol at low concentrations exerts its anti-inflammatory properties by preferentially targeting the arachidonic acid pathway. We also demonstrate a previously unrecognized pro-inflammatory effect of Resveratrol--the enhancement of TNF production from human mature mast cells following IgE-dependent activation.

GENERAL SIGNIFICANCE

These findings suggest that Resveratrol as a therapeutic agent could inhibit PGD2-mediated inflammation but would be ineffective against histamine-mediated allergic reactions. However, Resveratrol could potentially exacerbate or promote allergic inflammation by enhancing IgE-dependent TNF production from mast cells in human skin.

Administration of resveratrol for 5 wk has no effect on glucagon-like peptide 1 secretion, gastric emptying, or glycemic control in type 2 diabetes: a randomized controlled trial

BACKGROUND

Resveratrol has been reported to lower glycemia in rodent models of type 2 diabetes associated with the stimulation of glucagon-like peptide 1 (GLP-1), which is known to slow gastric emptying, stimulate insulin secretion, and suppress glucagon secretion and energy intake.

OBJECTIVE

We evaluated the effects of 5 wk of resveratrol treatment on GLP-1 secretion, gastric emptying, and glycemic control in type 2 diabetes.

DESIGN

Fourteen patients with diet-controlled type-2 diabetes [mean ± SEM glycated hemoglobin (HbA1c): 6.4 ± 0.2% (46.4 ± 2.2 mmol/mol)] received resveratrol (500 mg twice daily) or a placebo over two 5-wk intervention periods with a 5-wk washout period in between in a double-blind, randomized, crossover design. Before and after each intervention period (4 visits), body weight and HbA1c were measured, and patients were evaluated after an overnight fast with a standardized mashed-potato meal labeled with 100 μg (13)C-octanoic acid to measure blood glucose and plasma GLP-1 concentrations and gastric emptying (breath test) over 240 min. Daily energy intake was estimated from 3-d food diaries during the week before each visit.

RESULTS

Fasting and postprandial blood glucose and plasma total GLP-1 as well as gastric emptying were similar at each assessment, and the change in each variable from weeks 0 to 5 did not differ between resveratrol and placebo groups. Similarly, changes in HbA1c, daily energy intake, and body weight after 5 wk did not differ between the 2 treatments.

CONCLUSIONS

In patients with diet-controlled type 2 diabetes, 5 wk of twice-daily 500 mg-resveratrol supplementation had no effect on GLP-1 secretion, glycemic control, gastric emptying, body weight, or energy intake. Our observations do not support the use of resveratrol for improving glycemic control. This trial was registered at www.anzctr.org.au as ACTRN12613000717752.

Resveratrol: challenges in analyzing its biological effects

Testing the biological activities of a dietary compound like resveratrol presents various challenges, which are highlighted in this commentary, with some suggested direction for future research, focusing on five challenges: (1) many different cellular effects are observed for resveratrol, but it is not known whether they arise from one point of action (or a few) or whether resveratrol is non-specific in its action; (2) the health-promotion effect of dietary resveratrol is likely a combinatory effect of various bioactive components in the mixture (diet); (3) the known cell biological response to resveratrol is presently based on exposure to short-term high levels, and better in vitro analyses have to be developed; (4) the actual level of resveratrol and resveratrol metabolites present in vitro and in vivo during experiments may be over- and underestimated, respectively, because resveratrol is not very soluble in water; and (5) only a few small clinical studies have been published to date, focusing on the therapeutic effects of resveratrol. Further, clinical trials addressing the disease-preventive effects are especially challenging.

Resveratrol protects mice from paraquat-induced lung injury: The important role of SIRT1 and NRF2 antioxidant pathways

Sirtuin 1 (SIRT1) acts via the deacetylation of a number of crucial transcription factors and has been implicated in various biological processes, including oxidative stress. Previous studies have indicated that nuclear factor, erythroid 2‑like 2 (NRF2) is an effective target of antioxidant therapy for paraquat (PQ) poisoning. However, the association between SIRT1 and NRF2 and their effects in PQ‑induced oxidative stress remains to be elucidated. The current study demonstrated that PQ exposure upregulated the expression of SIRT1 and NRF2 following 6‑ and 24‑h exposure in the lungs of mice. However, long‑term exposure to PQ significantly decreased the expression of SIRT1 and NRF2. Resveratrol is a SIRT1 activator, and strongly enhanced SIRT1 expression and attenuated the lung injury resulting from PQ exposure in the current study. Additionally, treatment with resveratrol upregulated the expression of NRF2 and glutathione, increased the activity of heme oxygenase‑1, superoxide dismutase and catalase, but depleted the expression of malondialdehyde. The present results demonstrated that resveratrol reduced PQ‑induced oxidative stress and lung injury, potentially through the positive feedback signaling loop between SIRT1 and NRF2.

TRPA1 channels as targets for resveratrol and related stilbenoids

A series of twenty resveratrol analogues was synthesized and tested on TRPA1 and TRPV1 channels. None was able to significantly modulate TRPV1 channels. Conversely, most of them exhibited remarkably higher TRPA1 modulating activity than resveratrol. Optimal potency was observed with ortho monoxygenated stilbenes 6 and 17.

Caloric restriction and exercise "mimetics'': Ready for prime time?

Exercise and diet are powerful interventions to prevent and ameliorate various pathologies. The development of pharmacological agents that confer exercise- or caloric restriction-like phenotypic effects is thus an appealing therapeutic strategy in diseases or even when used as life-style and longevity drugs. Such so-called exercise or caloric restriction "mimetics" have so far mostly been described in pre-clinical, experimental settings with limited translation into humans. Interestingly, many of these compounds activate related signaling pathways, most often postulated to act on the common downstream effector peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in skeletal muscle. In this review, resveratrol and other exercise- and caloric restriction "mimetics" are discussed with a special focus on feasibility, chances and limitations of using such compounds in patients as well as in healthy individuals.

Metformin and Resveratrol Inhibited High Glucose-Induced Metabolic Memory of Endothelial Senescence through SIRT1/p300/p53/p21 Pathway

Endothelial senescence plays crucial roles in diabetic vascular complication. Recent evidence indicated that transient hyperglycaemia could potentiate persistent diabetic vascular complications, a phenomenon known as "metabolic memory." Although SIRT1 has been demonstrated to mediate high glucose-induced endothelial senescence, whether and how "metabolic memory" would affect endothelial senescence through SIRT1 signaling remains largely unknown. In this study, we investigated the involvement of SIRT1 axis as well as the protective effects of resveratrol (RSV) and metformin (MET), two potent SIRT1 activators, during the occurrence of "metabolic memory" of cellular senescence (senescent "memory"). Human umbilical vascular endothelial cells (HUVECs) were cultured in either normal glucose (NG)/high glucose (HG) media for 6 days, or 3 days of HG followed by 3 days of NG (HN), with or without RSV or MET treatment. It was shown that HN incubation triggered persistent downregulation of deacetylase SIRT1 and upregulation of acetyltransferase p300, leading to sustained hyperacetylation (at K382) and activation of p53, and subsequent p53/p21-mediated senescent "memory." In contrast, senescent "memory" was abrogated by overexpression of SIRT1 or knockdown of p300. Interestingly, we found that SIRT1 and p300 could regulate each other in response to HN stimulation, suggesting that a delicate balance between acetyltransferases and deacetylases may be particularly important for sustained acetylation and activation of non-histone proteins (such as p53), and eventually the occurrence of "metabolic memory." Furthermore, we found that RSV or MET treatment prevented senescent "memory" by modulating SIRT1/p300/p53/p21 pathway. Notably, early and continuous treatment of MET, but not RSV, was particularly important for preventing senescent "memory." In conclusion, short-term high glucose stimulation could induce sustained endothelial senescence via SIRT1/p300/p53/p21 pathway. RVS or MET treatment could enhance SIRT1-mediated signaling and thus protect against senescent "memory" independent of their glucose lowering mechanisms. Therefore, they may serve as promising therapeutic drugs against the development of "metabolic memory."

Critical review of resveratrol in xenobiotic-induced hepatotoxicity

Use of natural products is increasingly popular. In fact, many patients with liver diseases self-medicate with herbal supplements. Resveratrol (RSV), in particular, is a common natural product that can reduce injury in experimental models of liver disease. Xenobiotic hepatotoxicity is a particularly important area-of-need for therapeutics. Drug-induced liver injury, for example, is the most common cause of acute liver failure (ALF) and ALF-induced deaths in many countries. Importantly, RSV protects against hepatotoxicity in animal models in vivo caused by several drugs and chemicals and may be an effective intervention. Although many mechanisms have been proposed to explain the protection, not all are consistent with other data. Furthermore, RSV suffers from other issues, including limited bioavailability due to extensive hepatic metabolism. The purpose of this article is to summarize recent findings on the protective effects of RSV in xenobiotic-induced liver injury and other forms of liver injury and to provide a critical review of the underlying mechanisms. New mechanisms that are more consistent with data emerging from the toxicology field are suggested. Efforts to move RSV into clinical use are also considered. Overall, RSV is a promising candidate for therapeutic use, but additional studies are needed to better understand its effects.

Prevention of obesity by dietary resveratrol: how strong is the evidence?

Obesity is a pandemic problem worldwide. Dietary polyphenolic compounds show promise in preventing obesity. Resveratrol (RSV), one of the most extensively studied polyphenol compounds, has been shown to exert anti-obesity effects in various animal studies and also in several human studies. The fat-lowering effects of RSV may result from its ability to inhibit adipogenesis, suppress lipogenesis, stimulate lipolysis, promote apoptosis, and increase fatty acid oxidation and thermogenesis, as well as the recently demonstrated induction of the browning of white adipose tissue (WAT). These anti-obesity effects of RSV likely depend on its ability to activate AMP-activated protein kinase (AMPK), a key enzyme regulating cellular energy metabolism. Consumption of fruits such as berries, grapes and nuts, which contain high levels of RSV and other polyphenols, might help to reduce obesity.

N-Monosubstituted Methoxy-oligo(ethylene glycol) Carbamate Ester Prodrugs of Resveratrol

Resveratrol is a natural polyphenol with many interesting biological activities. Its pharmacological exploitation in vivo is, however, hindered by its rapid elimination via phase II conjugative metabolism at the intestinal and, most importantly, hepatic levels. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, hydrolysis, and in vivo pharmacokinetic behavior of resveratrol prodrugs in which the OH groups are engaged in an N-monosubstituted carbamate ester linkage. As promoiety, methoxy-oligo(ethylene glycol) groups (m-OEG) (CH₃–[OCH₂CH₂]_n–) of defined chain length (n = 3, 4, 6) were used. These are expected to modulate the chemico-physical properties of the resulting derivatives, much like longer poly(ethylene glycol) (PEG) chains, while retaining a relatively low MW and, thus, a favorable drug loading capacity. Intragastric administration to rats resulted in the appearance in the bloodstream of the prodrug and of the products of its partial hydrolysis, confirming protection from first-pass metabolism during absorption.

Resveratrol and anti-atherogenic effects

The role of inflammation and oxidative stress in atherosclerosis development has been increasingly well recognized over the past decade. Inflammation has a significant role at all stages of atherosclerosis, including initiation, progression and plaque formation. Resveratrol is a naturally occurring polyphenolic compound found in grape products, berry fruits and red wine. Its ability to behave therapeutically as a component of red wine has attracted wide attention. Accumulating evidence suggests that it is a highly pleiotropic molecule that modulates numerous targets and molecular functions. Epidemiological studies indicate that the Mediterranean diet, rich in resveratrol, is associated with a reduced risk of atherosclerosis. Resveratrol is believed to decrease circulating low-density lipoprotein cholesterol levels, reduce cardiovascular disease risk; it reduces lipid peroxidation, platelet aggregation and oxidative stress. Resveratrol is considered a safe compound, since no significant toxic effects have been demonstrated after administration of a broad range of concentrations, and an effective anti-atherogenic agent.

How Phytochemicals Prevent Chemical Carcinogens and/or Suppress Tumor Growth?

Phytochemicals are a powerful group of chemicals that are derived from natural resource, especially with plants origin. They have shown to exhibit chemoprevention and chemotherapeutic effects not only in cell lines and in animal models of cancer but also some of them are in the clinical trial phase I and II. Despite numerous reports of these phytochemical effects on cancer, an overview of the mechanisms of their action and their effects on various cellular and molecular functions important in the inhibition of cancer progression has been lacking. In this review, we attempt to catalogue various studies to examine the effect of phytochemicals in cancer initiation, promotion, signaling, and epigenetic changes. Because of the numerous studies in these topics, we only pointed out to some examples in each section.

Genetics and pharmacology of longevity: the road to therapeutics for healthy aging

Aging can be defined as the progressive decline in tissue and organismal function and the ability to respond to stress that occurs in association with homeostatic failure and the accumulation of molecular damage. Aging is the biggest risk factor for human disease and results in a wide range of aging pathologies. Although we do not completely understand the underlying molecular basis that drives the aging process, we have gained exceptional insights into the plasticity of life span and healthspan from the use of model organisms such as the worm Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Single-gene mutations in key cellular pathways that regulate environmental sensing, and the response to stress, have been identified that prolong life span across evolution from yeast to mammals. These genetic manipulations also correlate with a delay in the onset of tissue and organismal dysfunction. While the molecular genetics of aging will remain a prosperous and attractive area of research in biogerontology, we are moving towards an era defined by the search for therapeutic drugs that promote healthy aging. Translational biogerontology will require incorporation of both therapeutic and pharmacological concepts. The use of model organisms will remain central to the quest for drug discovery, but as we uncover molecular processes regulated by repurposed drugs and polypharmacy, studies of pharmacodynamics and pharmacokinetics, drug-drug interactions, drug toxicity, and therapeutic index will slowly become more prevalent in aging research. As we move from genetics to pharmacology and therapeutics, studies will not only require demonstration of life span extension and an underlying molecular mechanism, but also the translational relevance for human health and disease prevention.

Resveratrol and derivatives for the treatment of atrial fibrillation

Resveratrol is a bioactive polyphenol, found in grapes, red wine, and peanuts, and has recently garnered much media and scientific attention for its diverse beneficial health effects as a nutritional supplement or nutraceutical. Of particular interest are the well-documented cardioprotective effects of resveratrol that are mediated by diverse mechanisms, including its antioxidant and vascular effects. However, it is now becoming clear that resveratrol may also exhibit direct effects on cardiac function and rhythm through modulation of signaling pathways that regulate cardiac remodeling and ion channel activity that controls cardiac excitability. Resveratrol may therefore possess antiarrhythmic properties that contribute to the cardiovascular benefits of resveratrol. Atrial fibrillation (AF) is the most common cardiac arrhythmia, although current therapies are suboptimal. Our laboratory has been studying resveratrol's effects on cardiac ion channels and remodeling pathways, and we initiated a drug development program aimed at generating novel resveratrol derivatives with improved efficacy against AF when compared to currently available therapeutics. This review therefore focuses on the effects of resveratrol and new derivatives on a variety of cardiac ion channels and molecular pathways that contribute to the development and maintenance of atrial fibrillation.

Natural Compounds Modulating Mitochondrial Functions

Mitochondria are organelles responsible for several crucial cell functions, including respiration, oxidative phosphorylation, and regulation of apoptosis; they are also the main intracellular source of reactive oxygen species (ROS). In the last years, a particular interest has been devoted to studying the effects on mitochondria of natural compounds of vegetal origin, quercetin (Qu), resveratrol (RSV), and curcumin (Cur) being the most studied molecules. All these natural compounds modulate mitochondrial functions by inhibiting organelle enzymes or metabolic pathways (such as oxidative phosphorylation), by altering the production of mitochondrial ROS and by modulating the activity of transcription factors which regulate the expression of mitochondrial proteins. While Qu displays both pro- and antioxidant activities, RSV and Cur are strong antioxidant, as they efficiently scavenge mitochondrial ROS and upregulate antioxidant transcriptional programmes in cells. All the three compounds display a proapoptotic activity, mediated by the capability to directly cause the release of cytochrome c from mitochondria or indirectly by upregulating the expression of proapoptotic proteins of Bcl-2 family and downregulating antiapoptotic proteins. Interestingly, these effects are particularly evident on proliferating cancer cells and can have important therapeutic implications.

The Old Made New: Natural Compounds against Erectile Dysfunction

The interest toward sex-related diseases keeps growing through the years. In this review, we focus our attention on erectile dysfunction (ED), a condition that caught much attention especially after the introduction on the market of phosphodiesterase 5 inhibitors such as the well-known sildenafil. Here, we briefly describe both the etiology of ED and the available treatments, examining then extensively some natural derivatives that, coming from traditional medicine, could represent promising starting points for the development of alternative remedies. In fact, herbal remedies from several parts of the world have been traditionally known for long, and were recently reconsidered and are now being studied to demonstrate their eventual potential in the treatment of ED. Among the various examples reported in the literature and reviewed here, plants and extracts containing polyphenols—especially a class of compounds called kraussianones—appear to be particularly effective and promising against ED.

Neurohormetic phytochemicals: An evolutionary-bioenergetic perspective

The impact of dietary factors on brain health and vulnerability to disease is increasingly appreciated. The results of epidemiological studies, and intervention trials in animal models suggest that diets rich in phytochemicals can enhance neuroplasticity and resistance to neurodegeneration. Here we describe how interactions of plants and animals during their co-evolution, and resulting reciprocal adaptations, have shaped the remarkable characteristics of phytochemicals and their effects on the physiology of animal cells in general, and neurons in particular. Survival advantages were conferred upon plants capable of producing noxious bitter-tasting chemicals, and on animals able to tolerate the phytochemicals and consume the plants as an energy source. The remarkably diverse array of phytochemicals present in modern fruits, vegetables spices, tea and coffee may have arisen, in part, from the acquisition of adaptive cellular stress responses and detoxification enzymes in animals that enabled them to consume plants containing potentially toxic chemicals. Interestingly, some of the same adaptive stress response mechanisms that protect neurons against noxious phytochemicals are also activated by dietary energy restriction and vigorous physical exertion, two environmental challenges that shaped brain evolution. In this perspective article, we describe some of the signaling pathways relevant to cellular energy metabolism that are modulated by 'neurohormetic phytochemicals' (potentially toxic chemicals produced by plants that have beneficial effects on animals when consumed in moderate amounts). We highlight the cellular bioenergetics-related sirtuin, adenosine monophosphate activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and insulin-like growth factor 1 (IGF-1) pathways. The inclusion of dietary neurohormetic phytochemicals in an overall program for brain health that also includes exercise and energy restriction may find applications in the prevention and treatment of a range of neurological disorders.