Challenges in Analyzing the Biological Effects of Resveratrol

Recent Neurotherapeutic Strategies to Promote Healthy Brain Aging: Are we there yet?

Owing to the global exponential increase in population ageing, there is an urgent unmet need to develop reliable strategies to slow down and delay the ageing process. Age-related neurodegenerative diseases are among the main causes of morbidity and mortality in our contemporary society and represent a major socio-economic burden. There are several controversial factors that are thought to play a causal role in brain ageing which are continuously being examined in experimental models. Among them are oxidative stress and brain inflammation which are empirical to brain ageing. Although some candidate drugs have been developed which reduce the ageing phenotype, their clinical translation is limited. There are several strategies currently in development to improve brain ageing. These include strategies such as caloric restriction, ketogenic diet, promotion of cellular nicotinamide adenine dinucleotide (NAD+) levels, removal of senescent cells, 'young blood' transfusions, enhancement of adult neurogenesis, stem cell therapy, vascular risk reduction, and non-pharmacological lifestyle strategies. Several studies have shown that these strategies can not only improve brain ageing by attenuating age-related neurodegenerative disease mechanisms, but also maintain cognitive function in a variety of pre-clinical experimental murine models. However, clinical evidence is limited and many of these strategies are awaiting findings from large-scale clinical trials which are nascent in the current literature. Further studies are needed to determine their long-term efficacy and lack of adverse effects in various tissues and organs to gain a greater understanding of their potential beneficial effects on brain ageing and health span in humans.

Investigation of developmental and reproductive effects of resveratrol in Drosophila melanogaster

Resveratrol is a chemical that attracts attention due to its antioxidative, anti-inflammatory, and estrogenic/antiestrogenic properties. In the present study, it was aimed to investigate developmental and reproductive effects (developmental periods, average numbers of offspring, sex ratios) of resveratrol in Drosophila melanogaster. Their larvae were exposed to 50, 100, and 200 μM of resveratrol. Resveratrol treatments did not affect pupation and maturation rate (P ˃ 0.05) statistically. But the pupation and maturation times were significantly extended at all doses (P ˂ 0.05). Also, 100 and 200 μM resveratrol treatments resulted in a significant decrease in the number of offspring (P ˂ 0.05). The results reveal that resveratrol, which is generally known for its positive effects, may have negative effects on the development and reproduction of invertebrates. The results of this study support the idea that resveratrol may act as an endocrine disruptor, as it is a phytoestrogen.

Chemo-Preventive Action of Resveratrol: Suppression of p53-A Molecular Targeting Approach

Extensive experimental, clinical, and epidemiological evidence has explained and proven that products of natural origin are significantly important in preventing and/or ameliorating various disorders, including different types of cancer that researchers are extremely focused on. Among these studies on natural active substances, one can distinguish the emphasis on resveratrol and its properties, especially the potential anticancer role. Resveratrol is a natural product proven for its therapeutic activity, with remarkable anti-inflammatory properties. Various other benefits/actions have also been reported, such as cardioprotective, anti-ageing, antioxidant, etc. and its rapid digestion/absorption as well. This review aims to collect and present the latest published studies on resveratrol and its impact on cancer prevention, molecular signals (especially p53 protein participation), and its therapeutic prospects. The most recent information regarding the healing action of resveratrol is presented and concentrated to create an updated database focused on this topic presented above.

A Comprehensive Study on the Antimicrobial Properties of Resveratrol as an Alternative Therapy

Resveratrol is a polyphenolic antioxidant whose possible health benefits include anticarcinogenic, antiaging, and antimicrobial properties that have gained significant attention. The compound is well accepted by individuals and has been commonly used as a nutraceutical in recent decades. Its widespread usage makes it essential to study as a single agent as well as in combination with traditional prescription antibiotics as regards to antimicrobial properties. Resveratrol demonstrates the action of antimicrobials against a remarkable bacterial diversity, viruses, and fungus. This report explains resveratrol as an all-natural antimicrobial representative. It may modify the bacterial virulence qualities resulting in decreased toxic substance production, biofilm inhibition, motility reduction, and quorum sensing disturbance. Moreover, in conjunction with standard antibiotics, resveratrol improves aminoglycoside efficacy versus Staphylococcus aureus, while it antagonizes the deadly function of fluoroquinolones against S. aureus and also Escherichia coli. The present study aimed to thoroughly review and study the antimicrobial potency of resveratrol, expected to help researchers pave the way for solving antimicrobial resistance.

HPLC-DAD-Q-TOF/MS-Based Screening and Analysis of the Multiple Absorbed Bioactive Components in Rat Serum after Oral Administration of Xiexin Tang

Background:

Xiexin Tang (XXT) is a classic Traditional Chinese Medicine (TCM) formula that has been used in herbal clinics for more than 1800 years. Recently, many studies have investigated the pharmacological effects and chemical composition of XXT. However, there is little information about systematic studies on the material basis of its efficacy. In the present study, the serum pharmacochemistry technique and HPLC-DAD-Q-TOF/MS were performed to screen and analyze the multiple absorbed bioactive components and metabolites of orally dosed XXT in rat serum.

Methods:

Bio-samples and herbal extracts were analyzed and detected by HPLC-DAD-Q-TOF/MS. Upon comparison of the chromatograms of the single-constituent decoctions with that of the XXT formulation, the peak quantity and peak intensity of the formulated decoction showed some variation from those of the single-constituent decoctions.

Results:

Twenty-one serum-adsorbed constituents were identified after intragastric administration of herbal extracts, of which 8 originated from Rhei Radix et Rhizoma (RRR), 5 from Coptidis Rhizoma (CR), and 8 from Scutellariae Radix (SR). The results showed that the main adsorbed constituents in the serum were anthraquinones, anthrones, chromones, and butyrophenones, alkaloids, and flavonoids.

Conclusion:

The results demonstrate that an effective and reliable analytical method is set up for screening the bioactive components of Chinese herbal medicine, which provided a meaningful basis for further pharmacology and active mechanism research of XXT.

Sirtuins, brain and cognition: A review of resveratrol effects

Sirtuins (SIRTs) are a protein family with high preservation degree among evolutionary scale. SIRTs are histone deacetylases regulatory enzymes of genetic material deeply involved in numerous physiological tasks including metabolism, brain function and aging. Mammals sirtuins comprise seven enzymatic components (SIRT1–SIRT7). The highest studied sirtuin is SIRT1, which plays an essential position in the prevention and evolution of neuro-disorders. Resveratrol (3,5,4-trihydroxystylbene) (RSV) is a polyphenol, which belongs to a family compounds identified as stilbenes, predominantly concentrated in grapes and red wine. RSV is the must studied Sirtuin activator and is used as food supplementary compound. Resveratrol exhibits strong antioxidant activity, reducing free radicals, diminishing quinone-reductase-2 activity and exerting positive regulation of several endogenous enzymes. Resveratrol is also able to inhibit pro-inflammatory factors, reducing the stimulation of the nuclear factor kB (NF-kB) and the release of endogenous cytokines. Resveratrol treatment can modulate multiple signaling pathway effectors related to programmed cell death, cell survival, and synaptic plasticity. In this context, the present review looks over news and the role of Sirtuins activation and resveratrol effects on modulating target genes, cognition and neurodegenerative disorders.

Modulation of Aquaporins by Dietary Patterns and Plant Bioactive Compounds

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

Calycosin-7-O-β-D-glucoside Attenuates OGD/R-Induced Damage by Preventing Oxidative Stress and Neuronal Apoptosis via the SIRT1/FOXO1/PGC-1α Pathway in HT22 Cells

Neuronal apoptosis induced by oxidative stress is a major pathological process that occurs after cerebral ischemia-reperfusion. Calycosin-7-O-β-D-glucoside (CG) is a representative component of isoflavones in Radix Astragali (RA). Previous studies have shown that CG has potential neuroprotective effects. However, whether CG alleviates neuronal apoptosis through antioxidant stress after ischemia-reperfusion remains unknown. To investigate the positive effects of CG on oxidative stress and apoptosis of neurons, we simulated the ischemia-reperfusion process in vitro using an immortalized hippocampal neuron cell line (HT22) and oxygen-glucose deprivation/reperfusion (OGD/R) model. CG significantly improved cell viability and reduced oxidative stress and neuronal apoptosis. In addition, CG treatment upregulated the expression of SIRT1, FOXO1, PGC-1α, and Bcl-2 and downregulated the expression of Bax. In summary, our findings indicate that CG alleviates OGD/R-induced damage via the SIRT1/FOXO1/PGC-1α signaling pathway. Thus, CG maybe a promising therapeutic candidate for brain injury associated with ischemic stroke.

Silymarin protects against radiocontrast-induced nephropathy in mice

Silymarin, an extract from Silybum marianum (milk thistle) containing a standardized mixture of flavonolignans that ameliorates some types of liver disease and, more recently, kidney damage, could be used for the ROS-scavenging effect of these antioxidants. Furthermore, contrast-induced nephropathy (CIN) is an iatrogenic impairment of renal function in patients subjected to angiographic procedures for which there is not yet a successful preventative treatment. Recent evidence has shown that this event is related to tubular/vascular injury activated mainly by oxidative stress. However, whether this bioavailable and pharmacologically safe extract protects against CIN is not clear. We proposed to evaluate the possible protective role of the antioxidant silymarin in an experimental model of CIN. Adult male Swiss mice were separated into 6 groups and pretreated orally with silymarin (50, 200 and 300 mg/kg), N-acetylcysteine (200 mg/kg) or vehicle for 5 days before the CIN and control groups. Renal function was analyzed by plasma creatinine, urea and cystatin C levels. Additionally, blood reactive oxygen species (ROS) were evaluated using ROS bioavailability, protein oxidation and DNA damage. Renal oxidative damage was evaluated using apoptosis/cell viability assays and histological analysis. We showed that silymarin preserved renal function and decreased systemic and renal oxidative damage (antigenotoxic and antiapoptotic properties, respectively) in a dose-dependent manner and was superior to conventional treatment with N-acetylcysteine. Histologically, silymarin treatment also had beneficial effects on renal glomerular and tubular injuries. Therefore, silymarin prophylaxis may be an interesting strategy for the prevention of CIN.

Resveratrol and cognitive decline: a clinician perspective

Resveratrol (3,5,4'-trihydroxystilbene) belongs to a family of polyphenolic compounds known as stilbenes, particularly concentrated in grape and red wine. The aim of our review was to critically review the available evidence of resveratrol effects on brain function and its potential impact on therapy. In preclinical models of cognitive decline, resveratrol displays potent antioxidant activity by scavenging free radicals, reducing quinone reductase 2 activity and upregulating endogenous enzymes. Resveratrol also inhibits pro-inflammatory enzyme expression, reduces nuclear factor-κB activation and cytokine release. Treatment with resveratrol can affect multiple signaling pathway effectors involved in cell survival, programmed cell death and synaptic plasticity. Direct and/or indirect activation of the deacetylase sirtuins by resveratrol has also been suggested. In humans, clinical evidence derived from randomized clinical trials suggests that resveratrol is able to improve cerebral blood flow, cerebral vasodilator responsiveness to hypercapnia, some cognitive tests, perceived performances, and the Aβ₄₀ plasma and cerebrospinal fluid level.

Effect of Resveratrol, a Dietary-Derived Polyphenol, on the Oxidative Stress and Polyol Pathway in the Lens of Rats with Streptozotocin-Induced Diabetes

Resveratrol is found in grapes, apples, blueberries, mulberries, peanuts, pistachios, plums and red wine. Resveratrol has been shown to possess antioxidative activity and a variety of preventive effects in models of many diseases. The aim of the study was to investigate if this substance may counteract the oxidative stress and polyol pathway in the lens of diabetic rats. The study was conducted on the rats with streptozotocin-induced type 1 diabetes. After the administration of resveratrol (10 and 20 mg/kg po for 4 weeks), the oxidative stress markers in the lens were evaluated: activity of superoxide dismutase, catalase and glutathione peroxidase, as well as levels of total and soluble protein, level of glutathione, vitamin C, calcium, sulfhydryl group, advanced oxidation protein products, malonyldialdehyde, Total Oxidant Status and Total Antioxidant Reactivity. The obtained results indicate that the administration of resveratrol to the diabetic rats shows antioxidative properties. It is not a result of antiglycaemic activity but resveratrol probably directly affects the antioxidative system. Resveratrol did not affect the polyol pathway in the lens of diabetic rats. Our results may indirectly indicate benefits of consumption of foods as well as dietary supplements containing resveratrol in diminishing oxidative stress in lenses of individuals suffering from diabetes mellitus.

Inhibition of osteoblastic Smurf1 promotes bone formation in mouse models of distinctive age-related osteoporosis

Bone morphogenetic protein (BMP) signaling is essential for osteogenesis. However, recombinant human BMPs (rhBMPs) exhibit large inter-individual variations in local bone formation during clinical spinal fusion. Smurf1 ubiquitinates BMP downstream molecules for degradation. Here, we classify age-related osteoporosis based on distinct intraosseous BMP-2 levels and Smurf1 activity. One major subgroup with a normal BMP-2 level and elevated Smurf1 activity (BMP-2ⁿ/Smurf1^e) shows poor response to rhBMP-2 during spinal fusion, when compared to another major subgroup with a decreased BMP-2 level and normal Smurf1 activity (BMP-2^d/Smurf1ⁿ). We screen a chalcone derivative, i.e., 2-(4-cinnamoylphenoxy)acetic acid, which effectively inhibits Smurf1 activity and increases BMP signaling. For BMP-2ⁿ/Smurf1^e mice, the chalcone derivative enhances local bone formation during spinal fusion. After conjugating to an osteoblast-targeting and penetrating oligopeptide (DSS)₆, the chalcone derivative promotes systemic bone formation in BMP-2ⁿ/Smurf1^e mice. This study demonstrates a precision medicine-based bone anabolic strategy for age-related osteoporosis.

BMP promotes bone formation but its efficacy is limited in some patients. Here, the authors show that osteoporosis patients with a poor response to BMP have increased expression of Smurf1, which targets BMP effectors for degradation, and demonstrate that its chemical inhibition enhances BMP-mediated bone formation in mice.

MiR-663, a MicroRNA Linked with Inflammation and Cancer That Is under the Influence of Resveratrol

Resveratrol (trans-3,5,4′-trihydroxystilbene, RSV) is a non-flavonoid dietary polyphenol with antioxidant, anti-inflammatory and anti-cancer properties that is primarily found in red berries. While RSV displays many beneficial effects in vitro, its actual effects in vivo or in animal models remain passionately debated. Recent publications suggest that RSV pleiotropic effects could arise from its capability to regulate the expression and activity of microRNAs, short regulators themselves capable of regulating up to several hundreds of target genes. In particular, RSV increases microRNA miR-663 expression in different human cell lines, suggesting that at least some of its multiple beneficial properties are through the modulation of expression of this microRNA. Indeed, the expression of microRNA miR-663 is reduced in certain cancers where miR-663 is considered to act as a tumor suppressor gene, as well as in other pathologies such as cardiovascular disorders. Target of miR-663 include genes involved in tumor initiation and/or progression as well as genes involved in pathologies associated with chronic inflammation. Here, we review the direct and indirect effects of RSV on the expression of miR-663 and its target transcripts, with emphasise on TGFβ1, and their expected health benefits, and argue that elucidating the molecular effects of different classes of natural compounds on the expression of microRNAs should help to identify new therapeutic targets and design new treatments.

Rationale for assessing the therapeutic potential of resveratrol in hematological malignancies

Promising results from pre-clinical studies on the naturally-occurring polyphenol resveratrol have generated considerable interest and somewhat excessive expectations regarding the therapeutic potential of this compound for treating or preventing various diseases, including cardiovascular and neurodegenerative disorders and cancer. Resveratrol has potent inhibitory activity in vitro against various tumor types, including cell lines derived from virtually all blood malignancies. Pharmacological studies have shown that resveratrol is safe for humans but has poor bioavailability, due to its extensive hepatic metabolism. Curiously, a substantial proportion of the orally administered resveratrol can reach the bone marrow compartment. Notably, various pathways dysregulated in blood cancers are known to be molecular targets of resveratrol, thus substantiating the potential utility of this agent in blood malignancies. In this review, we primarily focus on the scientific evidence that supports the potential utility of resveratrol for the management of select hematological malignancies. In addition, potential clinical trials with resveratrol are suggested.

Food Components in Health Promotion and Disease Prevention

The current obesity epidemic with its deleterious effects on public health and the increase in the prevalence of non-communicable diseases in our aging society have dramatically increased public awareness of nutrition-related health issues. On one hand, food components, such as fat, sugar, flavors, and spices, are major determinants of the hedonic value of food, and the constant and almost ubiquitous availability of good-tasting food in our affluent societies promotes overeating and weight gain. On the other hand, several food components, including flavoring compounds and the active ingredients of many plants, such as spices and herbs (e.g., polyphenols and capsaicinoids) or thylakoids, supposedly can decrease food intake and affect gastrointestinal function and metabolism. These substances may act as antioxidants, may stimulate the release of incretins and, hence, insulin, and may improve insulin sensitivity or decrease plasma levels of lipids. Such beneficial effects are often difficult to demonstrate in epidemiological studies because they may occur only at supraphysiological doses and/or when the purified compounds are administered, but they can be present under certain circumstances. This review discusses the putative mechanisms of the health-promoting and disease-preventing effects of some food components and their potential physiological relevance, primarily with respect to counteracting obesity and type 2 diabetes.

Supplementation with Resveratrol and Curcumin Does Not Affect the Inflammatory Response to a High-Fat Meal in Older Adults with Abdominal Obesity: A Randomized, Placebo-Controlled Crossover Trial

Background

High-fat meals induce postprandial inflammation. Resveratrol is a polyphenol known to prevent comorbidities associated with cardiovascular disease and exerts an anti-inflammatory action. There is also an increasing body of evidence supporting the role of curcumin, a polyphenol from the curcuminoid family, as a modulator of proinflammatory processes.

Objective

The objectives of this study were to investigate the following: 1) the bioavailability of resveratrol consumed in combination with curcumin after consumption of a high-fat meal; and 2) the acute combined effects of this combination on the postprandial inflammatory response of subjects with abdominal obesity.

Methods

In a double blind, crossover, randomized, placebo-controlled study, 11 men and 11 postmenopausal women [mean ± SD age: 62 ± 5 y; mean ± SD body mass index (in kg/m2): 29 ± 3] underwent a 6-h oral fat tolerance test on 2 occasions separated by 1-2 wk: once after consumption of a dietary supplement (200 mg resveratrol and 100 mg curcumin, Res/Cur) and once after consumption of a placebo (cellulose). Plasma concentrations of total resveratrol and its major metabolites as well as inflammatory markers, adhesion molecules, and whole blood NFκB1 and PPARA gene expression were measured during both fat tolerance tests.

Results

Kinetics of resveratrol and identified metabolites revealed rapid absorption patterns but also relatively limited bioavailability based on free resveratrol concentrations. Supplementation with Res/Cur did not modify postprandial variations in circulating inflammatory markers (C-reactive protein, IL-6, IL-8, monocyte chemoattractant protein-1) and adhesion molecules [soluble E-selectin, soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble intercellular adhesion molecule-1] compared to placebo (PTreatment×Time > 0.05). However, Res/Cur significantly decreased the cumulative postprandial response of sVCAM-1, compared to placebo (incremental area under the curve -4643%, P = 0.01). Postprandial variations of whole-blood PPARA and NFKB1 gene expression were not different between Res/Cur and placebo treatments.

Conclusions

Acute supplementation with Res/Cur has no impact on the postprandial inflammation response to a high-fat meal in abdominally obese older adults. Further studies are warranted to examine how resveratrol and curcumin may alter the vascular response to a high-fat meal. This trial was registered at clinicaltrials.gov as NCT01964846.

Resveratrol strongly enhances the retinoic acid-induced superoxide generating activity via up-regulation of gp91-phox gene expression in U937 cells

The membrane bound cytochrome b₅₅₈ composed of gp91-phox and p22-phox proteins, and cytosolic proteins p40-, p47-and p67-phox are important components of superoxide (O₂^-)-generating system in phagocytes. Here, we describe that resveratrol, a pleiotropic phytochemical belonging to the stilbenoids, dramatically activates the O₂^--generating system during retinoic acid (RA)-induced differentiation of human monoblastic leukemia U937 cells to macrophage-like cells. When U937 cells were cultured in the presence of RA and resveratrol, the O₂^--generating activity increased more than 5-fold compared with that in the absence of the latter. Semiquantitative RT-PCR showed that co-treatment with RA and resveratrol strongly enhanced transcription of the gp91-phox compared with those of the RA-treatment only. On the other hand, immunoblot analysis revealed that co-treatment with RA and resveratrol caused remarkable accumulation of protein levels of gp91-phox (to 4-fold), p22-phox (to 5-fold) and p47-phox (to 4-fold) compared with those of the RA-treatment alone. In addition, ChIP assay suggested that resveratrol participates in enhancing the gene expression of gp91-phox via promoting acetylation of Lys-9 residues and Lys-14 residues of histone H3 within chromatin around the promoter regions of the gene. These results suggested that resveratrol strongly enhances the RA-induced O₂^--generating activity via up-regulation of gp91-phox gene expression in U937 cells.

Resveratrol in the foodomics era: 1:25,000

Resveratrol is probably the most investigated plant secondary metabolite ever. An epidemiological study known as the French paradox showed a correlation between red wine intake and low mortality due to coronary heart diseases, and the red wine substance resveratrol was claimed to play a key role. Since then, several hundred resveratrol studies have been conducted to demonstrate its antioxidant and other beneficial properties. In the foodomics era, considering a complex foodome including over 25,000 substances that make up the human diet, it appears to be outdated to pursue the hunt for biological activities one function/compound at a time. First, nature is multivariate, and the effect of any one molecule will have to be modulated by its carrying matrix, its bioavailability, and synergies with other molecules. Second, a large number of targeted studies have the tendency to become biased, as they tend to retain only the data that the researchers think are relevant and thus increase the chances of spurious correlations. In this concise review, we retrace the research toward a more inductive, holistic, and multivariate path.

Antitumour activity of resveratrol on human melanoma cells: A possible mechanism related to its interaction with malignant cell telomerase

BACKGROUND

trans-Resveratrol (tRES) is a polyphenolic stilbene found in plant products which has attracted great attention because of its antioxidant, anti-inflammatory and anticancer properties.

METHODS

The possible correlation between tRES-induced suppression of melanoma cell growth and its influence on telomerase expression has been investigated by biological assays. Moreover, in order to gain new knowledge about possible mechanisms of action of tRES as antineoplastic agent, its interaction with biologically relevant secondary structure-forming DNA sequences, its aggregation properties and copper-binding activity have been studied by CD, UV and fluorescence spectroscopies.

RESULTS

Biological assays have confirmed that growth inhibitory properties of tRES well correlate with the reduction of telomerase activity and hTERT gene transcript levels in human melanoma cells. Biophysical studies in solution have proved that tRES binds all the studied DNA model systems with low affinity, however showing high ability to discriminate G-quadruplex vs. duplex DNA. In addition, tRES has shown no propensity to form aggregates in the explored concentration range and has been found able to bind Cu²⁺ ions with a 2:1 stoichiometry.

CONCLUSIONS

From these biological and biophysical analyses it has emerged that tRES produces cytotoxic effects on human melanoma cells and, at a molecular level, is able to bind Cu²⁺ and cancer-involved G-quadruplexes, suggesting that multiple mechanisms of action could be involved in its antineoplastic activity.

GENERAL SIGNIFICANCE

Expanding the knowledge on the putative mechanisms of action of tRES as antitumour agent can help to develop novel, effective tRES-based anticancer drugs.

Resveratrol derivatives as a pharmacological tool

Prodrugs of resveratrol are under development. Among the long-term goals, still largely elusive, are (1) modulating physical properties (e.g., water-soluble derivatives bearing polyethylene glycol chains), (2) changing distribution in the body (e.g., galactosyl derivatives restricted to the intestinal lumen), (3) increasing absorption from the gastrointestinal tract (e.g., derivatives imitating the natural substrates of endogenous transporters), and (4) hindering phase II metabolism (e.g., temporarily blocking the hydroxyls), all contributing to (5) increasing bioavailability. The chemical bonds that have been tested for functionalization include carboxyester, acetal, and carbamate groups. A second approach, which can be combined with the first, seeks to reinforce or modify the biochemical activities of resveratrol by concentrating the compound at specific subcellular sites. An example is provided by mitochondria-targeted derivatives. These proved to be pro-oxidant and cytotoxic in vitro, selectively killing fast-growing and tumor cells when supplied in the low micromolar range. This suggests the possibility of anticancer applications.

Cancer Chemoprevention by Resveratrol: The p53 Tumor Suppressor Protein as a Promising Molecular Target

Increasing epidemiological and experimental evidence has demonstrated an inverse relationship between the consumption of plant foods and the incidence of chronic diseases, including cancer. Microcomponents that are naturally present in such foods, especially polyphenols, are responsible for the benefits to human health. Resveratrol is a diet-derived cancer chemopreventive agent with high therapeutic potential, as demonstrated by different authors. The aim of this review is to collect and present recent evidence from the literature regarding resveratrol and its effects on cancer prevention, molecular signaling (especially regarding the involvement of p53 protein), and therapeutic perspectives with an emphasis on clinical trial results to date.

The Repeated Administration of Resveratrol Has Measurable Effects on Circulating T-Cell Subsets in Humans

Preclinical studies have shown that resveratrol exerts immunomodulatory effects with potential clinical value in the amelioration of autoimmune disorders and cancer prevention; however, little is known about the in vivo effects of this naturally occurring polyphenol on human immune cells. We assessed the effects of repeated doses of resveratrol (1000 mg/day for 28 days) on circulating immune cells in healthy Japanese individuals. Resveratrol was safe and well tolerated and was associated with significant increases in the numbers of circulating γδ T cells and regulatory T cells and resulted in small, yet significant, decreases in the plasma levels of the proinflammatory cytokines TNF-α and MCP-1 and a significant increase in the plasma antioxidant activity compared with the corresponding antioxidant baseline activity and with that in four control individuals. In in vitro studies, resveratrol significantly improved the growth of γδ T cells and regulatory T cells. These findings demonstrate that resveratrol has some clear biological effects on human circulating immune cells. Further studies are necessary to interpret the long-term immunological changes associated with resveratrol treatment.

Resveratrol Attenuates Copper and Zinc Homeostasis and Ameliorates Oxidative Stress in Type 2 Diabetic Rats

Diabetes is a common metabolic disorder characterized by elevated blood glucose level. Trace element homeostasis causes disturbances in diabetes due to hyperglycemia. Superoxide dismutase (SOD), an antioxidant enzyme, contains zinc and copper ions as its cofactors. Defects in SOD level and activity have been observed in diabetes. Resveratrol (RSV) has displayed hypoglycemic effects and is proven to improve oxidative stress. The aim of the present study was to examine the possible effects of RSV on blood glucose level, serum copper and zinc levels, SOD, and a number of other oxidative markers in type 2 diabetic rats. Diabetes was induced in male Wistar rats with administration of streptozotocin and nicotine amide. The studied groups containing six animals per group were as follows: group 1 normal control group; group 2 diabetic control group; groups 3, 4, and 5 diabetic rats that received 1, 5, and 10 mg/kg body weight of RSV, respectively for 30 days. Serum glucose, copper, zinc, SOD activity, total oxidant status (TOS) as well as thiol groups were all measured. Blood glucose in RSV treated groups significantly decreased. Similarly, copper significantly decreased in diabetic groups treated with RSV. Treatment with 10 mg/kg RSV resulted in significantly increased serum zinc. Furthermore, Cu/Zn ratio was observed to decrease in treated groups compared with untreated diabetic control group. RSV treated groups revealed an increased level of SOD activity as well as improved oxidative status. In summary, the results showed that RSV has potential hypoglycemic effect, attenuates trace element homeostasis, and consequently increases SOD activity level.

During yeast chronological aging resveratrol supplementation results in a short-lived phenotype Sir2-dependent

Resveratrol (RSV) is a naturally occurring polyphenolic compound endowed with interesting biological properties/functions amongst which are its activity as an antioxidant and as Sirtuin activating compound towards SIRT1 in mammals. Sirtuins comprise a family of NAD⁺-dependent protein deacetylases that are involved in many physiological and pathological processes including aging and age-related diseases. These enzymes are conserved across species and SIRT1 is the closest mammalian orthologue of Sir2 of Saccharomyces cerevisiae. In the field of aging researches, it is well known that Sir2 is a positive regulator of replicative lifespan and, in this context, the RSV effects have been already examined. Here, we analyzed RSV effects during chronological aging, in which Sir2 acts as a negative regulator of chronological lifespan (CLS). Chronological aging refers to quiescent cells in stationary phase; these cells display a survival-based metabolism characterized by an increase in oxidative stress. We found that RSV supplementation at the onset of chronological aging, namely at the diauxic shift, increases oxidative stress and significantly reduces CLS. CLS reduction is dependent on Sir2 presence both in expired medium and in extreme Calorie Restriction. In addition, all data point to an enhancement of Sir2 activity, in particular Sir2-mediated deacetylation of the key gluconeogenic enzyme phosphoenolpyruvate carboxykinase (Pck1). This leads to a reduction in the amount of the acetylated active form of Pck1, whose enzymatic activity is essential for gluconeogenesis and CLS extension.

Hydroxystilbenes and methoxystilbenes activate human aryl hydrocarbon receptor and induce CYP1A genes in human hepatoma cells and human hepatocytes

Natural polyphenol resveratrol (trihydroxystilbene) is a partial agonist of human aryl hydrocarbon receptor AhR, thereby, displaying a plethora of biological effects. Biological activities of metoxylated and hydroxylated stilbenes were studied in the past. The aim of the current study was to describe the effects of 13 different hydroxy- and methoxystilbenes, including their cis/trans isomers on the transcriptional activity of AhR and the expression of CYP1A genes in hepatic cancer cells HepG2 and in primary human hepatocytes. Techniques of gene reporter assays, qRT-PCR, Simple Western blotting by Sally Sue™ and electrophoretic mobility shift assay EMSA were employed. All compounds activated AhR, but their efficacies, potencies and dose-response profiles differed substantially. The strongest activators of AhR and inducers of CYP1A1 in HepG2 cells were DMU-212 ((E)-3,4,5,4´-tetramethoxystilbene), trans-piceatannol, cis-piceatannol, trans-trismethoxyresveratrol and trans-pinostilbene. While DMU-212 and trans-trismethoxyresveratrol also induced CYP1A1 and CYP1A2 in primary human hepatocytes, the effects of trans-piceatannol, cis-piceatannol and trans-pinostilbene weaned off. On the other hand, trans-4-methoxystilbene was strong CYP1A inducer in hepatocytes but not in HepG2 cells. Differences between effects of stilbenes in HepG2 cells and human hepatocytes are probably due to the extensive phase I and phase II xenobiotic metabolism in human hepatocytes. The data obtained may be of toxicological relevance.

Resveratrol regulates neuronal glucose uptake and insulin sensitivity via P21-activated kinase 2 (PAK2)

We have recently reported P21-activated kinase 2 (PAK2), a serine/threonine kinase as a negative regulator of neuronal glucose uptake and insulin sensitivity. Resveratrol (RSV), a natural polyphenol with anti-oxidative, anti-inflammatory and anti-diabetic properties, regulates PAK2 activity in HepG2 and ESC-B5 cell apoptosis. However, regulation of PAK2 by RSV in neuronal insulin signaling pathway, if any, is still unknown. In the present study, RSV treatment significantly increased PAK2 activity under insulin-sensitive and insulin-resistant condition, along with a marked decrease in glucose uptake in differentiated N2A cells. Pretreatment with AMPK inhibitor, followed by RSV treatment resulted in reduction in PAK2 activity whereas glucose uptake showed an increase. However, pretreatment with Akt inhibitor and then RSV exposure significantly increased PAK2 activity, with a corresponding decrease in glucose uptake. RSV treatment increased AMPK activity and decreased Akt activity. In conclusion, RSV negatively regulates neuronal glucose uptake and insulin sensitivity via PAK2.

Curcumin and Resveratrol in the Management of Cognitive Disorders: What is the Clinical Evidence?

A growing body of in vitro and in vivo evidences shows a possible role of polyphenols in counteracting neurodegeneration: curcumin and resveratrol are attractive substances in this regard. In fact, epidemiological studies highlight a neuroprotective effect of turmeric (rhizome of Curcuma longa L.), the main source of curcumin. Moreover, the consumption of red wine, the main source of resveratrol, has been related to a lower risk of developing dementia. In this review, we analyzed the published clinical trials investigating curcumin and resveratrol in the prevention or treatment of cognitive disorders. The ongoing studies were also described, in order to give an overview of the current search on this topic. The results of published trials (five for curcumin, six for resveratrol) are disappointing and do not allow to draw conclusions about the therapeutic or neuroprotective potential of curcumin and resveratrol. These compounds, being capable of interfering with several processes implicated in the early stages of dementia, could be useful in preventing or in slowing down the pathology. To this aim, an early diagnosis using peripheral biomarkers becomes necessary. Furthermore, the potential preventive activity of curcumin and resveratrol should be evaluated in long-term exposure clinical trials, using preparations with high bioavailability and that are well standardized.

Convergent Effects of Resveratrol and PYK2 on Prostate Cells

Resveratrol, a dietary polyphenol, is under consideration as chemopreventive and chemotherapeutic agent for several diseases, including cancer. However, its mechanisms of action and its effects on non-tumor cells, fundamental to understand its real efficacy as chemopreventive agent, remain largely unknown. Proline-rich tyrosine kinase 2 (PYK2), a non-receptor tyrosine kinase acting as signaling mediator of different stimuli, behaves as tumor-suppressor in prostate. Since, PYK2 and RSV share several fields of interaction, including oxidative stress, we have investigated their functional relationship in human non-transformed prostate EPN cells and in their tumor-prone counterpart EPN-PKM, expressing a PYK2 dead-kinase mutant. We show that RSV has a strong biological activity in both cell lines, decreasing ROS production, inducing morphological changes and reversible growth arrest, and activating autophagy but not apoptosis. Interestingly, the PYK2 mutant increases basal ROS and autophagy levels, and modulates the intensity of RSV effects. In particular, the anti-oxidant effect of RSV is more potent in EPN than in EPN-PKM, whereas its anti-proliferative and pro-autophagic effects are more significant in EPN-PKM. Consistently, PYK2 depletion by RNAi replicates the effects of the PKM mutant. Taken together, our results reveal that PYK2 and RSV act on common cellular pathways and suggest that RSV effects on prostate cells may depend on mutational-state or expression levels of PYK2 that emerges as a possible mediator of RSV mechanisms of action. Moreover, the observation that resveratrol effects are reversible and not associated to apoptosis in tumor-prone EPN-PKM cells suggests caution for its use in humans.