Resveratrol and its analogs: defense against cancer, coronary disease and neurodegenerative maladies or just a fad?

Modulation of bacterial ghosts--induced nitric oxide production in macrophages by bacterial ghost-delivered resveratrol

The present study aimed to investigate the capacity of resveratrol (RV) delivered into macrophages by bacterial ghosts (BGs), representing intact empty nonliving envelopes of Gram-negative bacteria, to modulate nitric oxide (NO) production related to the presence of the pathogen-associated molecular patterns on the surface of BGs. Incubation of the murine macrophage cell line RAW 264.7 with BGs leads to a dose-dependent activation of inducible NO synthase. To modify BG-induced NO formation in RAW 264.7 cells by RV; BGs were loaded with RV (RV-BGs) and incubated with murine macrophages in a dose-dependent manner. RV-BGs delivering RV to the target macrophages significantly reduced BG-induced NO production with concentration of RV more than one order of magnitude lower than the amount of RV capable of reducing NO formation when applied directly. Moreover, no cytotoxic impact of BGs on the viability of RAW 264.7 cells added to macrophages alone or loaded with RV was detected after a mutual 24 h incubation, whereas cell viability slightly decreased (~ 10%) when RV concentrations of 30 μm alone were applied. The results obtained in the present study clearly indicate that the intracellular delivery of RV by BGs significantly enhances the total RV effect.

Optimization of trans-Resveratrol bioavailability for human therapy

We have developed an innovative soluble galenic form to overcome the low absorption of trans-Resveratrol (t-Res) as a dry powder. We present here data on pharmacokinetics, bioavailability, and toxicity of t-Res in human volunteers treated with this soluble form, plus additional data on biological effects in rodents. Fifteen healthy volunteers of both sexes received 40 mg of t-Res in two forms, the soluble formulation (caplets) and the original powder (capsules), in a crossover design. Blood samples were collected at 15 min, 30 min, and every hour for 5 h. Plasma concentrations of t-Res and its metabolites were analyzed by liquid chromatography and mass spectrometry. The single dose (40 mg) of the soluble t-Res was well absorbed and elicited biologically efficient blood levels (0.1-6 μM) for several hours, despite metabolization into glucuronide and sulfate conjugates coupled to renal elimination. In contrast, t-Res administered as a dry powder barely elicited efficient blood levels for a short duration. The new formulation led to 8.8-fold higher t-Res levels in plasma versus the powder. t-Res metabolism was not modified and neither intolerance nor toxicity were observed during the study and the following week. The soluble formulation elicited a robust anti-inflammatory effect in various tissues of mice fed a high-fat diet, while dry powder t-Res was almost inactive. Our data suggest that significant improvements in t-Res bioavailability and efficiency can be obtained by this soluble galenic form, also allowing lower doses. The use of t-Res in human therapy is thus greatly facilitated and the toxicity risk is reduced.

Resveratrol ameliorates ionizing irradiation-induced long-term hematopoietic stem cell injury in mice

Our recent studies showed that total body irradiation (TBI) induces long-term bone marrow (BM) suppression in part by induction of hematopoietic stem cell (HSC) senescence through NADPH oxidase 4 (NOX4)-derived reactive oxygen species (ROS). Therefore, in this study we examined whether resveratrol (3,5,4'-trihydroxy-trans-stilbene), a potent antioxidant and a putative activator of Sirtuin 1 (Sirt1), can ameliorate TBI-induced long-term BM injury by inhibiting radiation-induced chronic oxidative stress and senescence in HSCs. Our results showed that pretreatment with resveratrol not only protected mice from TBI-induced acute BM syndrome and lethality but also ameliorated TBI-induced long-term BM injury. The latter effect is probably attributable to resveratrol-mediated reduction of chronic oxidative stress in HSCs, because resveratrol treatment significantly inhibited TBI-induced increase in ROS production in HSCs and prevented mouse BM HSCs from TBI-induced senescence, leading to a significant improvement in HSC clonogenic function and long-term engraftment after transplantation. The inhibition of TBI-induced ROS production in HSCs is probably attributable to resveratrol-mediated downregulation of NOX4 expression and upregulation of Sirt1, superoxide dismutase 2 (SOD2), and glutathione peroxidase 1 expression. Furthermore, we showed that resveratrol increased Sirt1 deacetylase activity in BM hematopoietic cells; and Ex527, a potent Sirt1 inhibitor, can attenuate resveratrol-induced SOD2 expression and the radioprotective effect of resveratrol on HSCs. These findings demonstrate that resveratrol can protect HSCs from radiation at least in part via activation of Sirt1. Therefore, resveratrol has the potential to be used as an effective therapeutic agent to ameliorate TBI-induced long-term BM injury.

Effect of rain-shelter cultivation of Vitis vinifera cv. Cabernet Gernischet on the phenolic profile of berry skins and the incidence of grape diseases

Rain-shelter cultivation is an effective cultural method to prevent rainfall damage during grape harvest and widely applied in the Chinese rainy regions. In this study we investigated the effect of rain-shelter cultivation on grape diseases and phenolic composition in the skins of Vitis vinifera cv. Cabernet Gernischet grape berries through the comparison with open-field cultivation at two vintages (2010 and 2011). The results showed that rain-shelter cultivation reduced the incidence of grape diseases significantly and delayed the maturation of Cabernet Gernischet fruits. With regards to most of the phenolic compounds identified in this study, their content in grape samples under rain-shelter cultivation was decreased compared to those under open-field cultivation. However, rain-shelter cultivation stimulated the accumulation of dihydroquercetin-3-O-rhamnoside in grape skins during grape maturation. These were related with micrometeorological alterations in vineyards by using plastic covering under rain-shelter cultivation. It suggests the rain-shelter cultivation makes possible the cultivation of “Cabernet Gernischet” grapes in an organic production system, for providing a decrease in the incidence of diseases and the dependence on chemical pesticides in the grape and wine industry.

Novel Aza-resveratrol analogs: synthesis, characterization and anticancer activity against breast cancer cell lines

Novel Aza-resveratrol analogs were synthesized, structurally characterized and evaluated for cytotoxic activity against MDA-MB-231 and T47D breast cancer cell lines, which exhibited superior inhibitory activity than parent resveratrol compound. The binding mechanism of these compounds with estrogen receptor-α was rationalized by molecular docking studies which indicated additional hydrogen binding interactions and tight binding in the protein cavity. Induction of Beclin-1 protein expression in breast cancer cell lines after treatment with newly synthesized resveratrol analogs indicated inhibition of growth of these cell lines through autophagy. The study highlighted the advantage of introducing the imino-linkage in resveratrol motif in enhancing the anticancer potential of resveratrol suggesting that these analogs can serve as better therapeutic agents against breast cancer and can provide starting point for building more potent analogs in future.

Resveratrol Produces Neurotrophic Effects on Cultured Dopaminergic Neurons through Prompting Astroglial BDNF and GDNF Release

Increasing evidence indicated astroglia-derived neurotrophic factors generation might hold a promising therapy for Parkinson's disease (PD). Resveratrol, naturally present in red wine and grapes with potential benefit for health, is well known to possess a number of pharmacological activities. Besides the antineuroinflammatory properties, we hypothesized the neuroprotective potency of resveratrol is partially due to its additional neurotrophic effects. Here, primary rat midbrain neuron-glia cultures were applied to investigate the neurotrophic effects mediated by resveratrol on dopamine (DA) neurons and further explore the role of neurotrophic factors in its actions. Results showed resveratrol produced neurotrophic effects on cultured DA neurons. Additionally, astroglia-derived neurotrophic factors release was responsible for resveratrol-mediated neurotrophic properties as evidenced by the following observations: (1) resveratrol failed to exert neurotrophic effects on DA neurons in the cultures without astroglia; (2) the astroglia-conditioned medium prepared from astroglia-enriched cultures treated with resveratrol produced neurotrophic effects in neuron-enriched cultures; (3) resveratrol increased neurotrophic factors release in the concentration- and time-dependent manners; (4) resveratrol-mediated neurotrophic effects were suppressed by blocking the action of the neurotrophic factors. Together, resveratrol could produce neurotrophic effects on DA neurons through prompting neurotrophic factors release, and these effects might open new alternative avenues for neurotrophic factor-based therapy targeting PD.

Protective effects of resveratrol on sepsis-induced DNA damage in the lymphocytes of rats

Sepsis, often initiated by an infection, is a state of disrupted inflammatory homeostasis. There is increasing evidence that oxidative stress has an important role in the development of sepsis-induced multiorgan failure. Resveratrol (RV) is a polyphenolic compound found in the skin of red fruits, such as mulberries and red grapes, and in peanuts. RV has been reported to have an antioxidant, antiproliferative, and anti-inflammatory properties in various models. It has also been found to inhibit the proliferation of a variety of human cancer cell lines, including breast, prostate, colon, pancreatic, and thyroid. This study has been undertaken to assess the role of RV on the sepsis-induced oxidative DNA damage in the lymphocytes of Wistar albino rats by the standard and formamidopyrimidine DNA glycosylase (Fpg)-modified comet assays. The parameters of tail length, tail intensity, and tail moment were evaluated for the determination of DNA damage. According to the study, the DNA damage was found to be significantly higher in the sepsis-induced rats when compared with the control rats (p < 0.05). The parameters were significantly decreased in the RV-treated sepsis-induced group when compared with the sepsis-induced group. The parameters in the sepsis-induced rats were found to be significantly higher in the Fpg-modified comet assay when compared with the standard comet assay (p < 0.05), and RV treatment decreases the DNA damage in the sepsis-induced rats, suggesting that the oxidative stress is likely to be responsible for DNA damage and RV might have a role in the prevention of sepsis-induced oxidative DNA damage.

Transient transfection of a wild-type p53 gene triggers resveratrol-induced apoptosis in cancer cells

Resveratrol is a promising chemopreventive agent that mediates many cellular targets involved in cancer signaling pathways. p53 has been suggested to play a role in the anticancer properties of resveratrol. We investigated resveratrol-induced cytotoxicity in H1299 cells, which are non-small lung cancer cells that have a partial deletion of the gene that encodes the p53 protein. The results for H1299 cells were compared with those for three cell lines that constitutively express wild-type p53: breast cancer MCF-7, adenocarcinomic alveolar basal epithelia A549 and non-small lung cancer H460. Cell viability assays revealed that resveratrol reduced the viability of all four of these cell lines in a dose- and time-dependent manner. MCF-7, A549 and H460 cells were more sensitive to resveratrol than were H1299 cells when exposed to the drug for 24 h at concentrations above 100 µM. Resveratrol also increased the p53 protein levels in MCF-7 cells without altering the p53 mRNA levels, suggesting a post-translational modulation of the protein. The resveratrol-induced cytotoxicity in these cells was partially mediated by p53 and involved the activation of caspases 9 and 7 and the cleavage of PARP. In H1299 cells, resveratrol-induced cytotoxicity was less pronounced and (in contrast to MCF-7 cells) cell death was not accompanied by caspase activation. These findings are consistent with the observation that MCF-7 cells were positively labeled by TUNEL following exposure to 100 µM resveratrol whereas H1299 cells under similar conditions were not labeled by TUNEL. The transient transfection of a wild-type p53-GFP gene caused H1299 cells to become more responsive to the pro-apoptotic properties of resveratrol, similarly to findings in the p53-positive MCF-7 cells. Our results suggest a possible therapeutic strategy based on the use of resveratrol for the treatment of tumors that are typically unresponsive to conventional therapies because of the loss of normal p53 function.

Density functional theory (B3LYP) study of substituent effects on O-H bond dissociation enthalpies of trans-resveratrol derivatives and the role of intramolecular hydrogen bonds

In this paper, 23 substituents with various electron-donating and electron-withdrawing characters were placed in available positions of trans-resveratrol in order to study their effect on the three O-H bond dissociation enthalpies (BDEs) via density functional theory (DFT) with Becke three-parameter exchange and Lee-Yang-Parr correlation (B3LYP). It has been found that the mutual positions of substituents and OH groups affect investigated BDEs substantially. Formation of strong intramolecular hydrogen bonds and suitable spin density distributions in several radicals result in low BDEs. Calculated BDEs have been correlated with Hammett constants, selected geometry parameters, and charge on phenoxy radical oxygen q(O). Found dependences are satisfactorily linear.

Synthesis of novel azo-resveratrol, azo-oxyresveratrol and their derivatives as potent tyrosinase inhibitors

Ten azo compounds including azo-resveratrol (5) and azo-oxyresveratrol (9) were synthesized using a modified Curtius rearrangement and diazotization followed by coupling reactions with various phenolic analogs. All synthesized compounds were evaluated for their mushroom tyrosinase inhibitory activity. Compounds 4 and 5 exhibited high tyrosinase inhibitory activity (56.25% and 72.75% at 50 μM, respectively). The results of mushroom tyrosinase inhibition assays indicate that the 4-hydroxyphenyl moiety is essential for high inhibition and that 3,5-dihydroxyphenyl and 3,5-dimethoxyphenyl derivatives are better for tyrosinase inhibition than 2,5-dimethoxyphenyl derivatives. Particularly, introduction of hydroxyl or methoxy group into the 4-hydroxyphenyl moiety diminished or significantly reduced mushroom tryosinase inhibition. Among the synthesized azo compounds, azo-resveratrol (5) showed the most potent mushroom tyrosinase inhibition with an IC(50) value of IC(50)=36.28 ± 0.72 μM, comparable to that of resveratrol, a well-known tyrosinase inhibitor.

(E)-1-[4-(Methyl-sulfan-yl)phen-yl]-2-(2,3,4-trimeth-oxy-phen-yl)ethene

In the title compound, C(18)H(20)O(3)S, the rings are almost coplanar [inter-ring dihedral angle = 6.6 (2)°]. In the crystal, weak C-H⋯O hydrogen bonds between the meth-oxy groups connect adjacent mol-ecules, giving chains which extend along [001].

Resveratrol promotes neurotrophic factor release from astroglia

Neurotrophic factors such as glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) are considered to contribute to the development, maintenance and survival of neurons, glia and oligodendrocytes. Astroglia are a major source of various neurotrophic factors. Thus, enhancement of astroglia-mediated neurotrophic factor release might hold promising potential for neurological diseases. Resveratrol, a natural non-flavonoid polyphenol found in grapes and red wine, has been recognized to be beneficial for health. Here, rat primary astroglia-enriched cultures were used to investigate the effects of resveratrol-mediated neurotrophic factor release and the related mechanisms. The cultures were treated with 25–100 μmmol/L resveratrol for 12–48 h. Results showed resveratrol increased BDNF and GDNF production in the culture medium. In addition, the production of BDNF in the supernatant of cultures was increased five-fold over control cultures 24 h after resveratrol treatment and then remained high 36 h later. Meanwhile, the production of GDNF was initially increased by up to four-fold 24 h after resveratrol treatment and continued to increase to six-fold at 36 h and remained at a high level till 48 h. Western blot analysis of BDNF and GDNF protein in astroglia at different time points after resveratrol treatment indicated similar increases. Furthermore, resveratrol significantly induced the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP responsive element-binding protein (CREB) in astroglia. Overall, resveratrol is effective in promoting astroglia-derived neurotrophic factor release, and this effect is mediated, at least in part, by the activation of ERK1/2 and CREB.

Resveratrol preconditioning modulates inflammatory response in the rat hippocampus following global cerebral ischemia

Considerable evidence has been accumulated to suggests that blocking the inflammatory reaction promotes neuroprotection and shows therapeutic potential for clinical treatment of ischemic brain injury. Consequently, anti-inflammatory therapies are being explored for prevention and treatment of these diseases. Induction of brain tolerance against ischemia by pretreatment with resveratrol has been found to influence expression of different molecules. It remains unclear, however, whether and how resveratrol preconditioning changes expression of inflammatory mediators after subsequent global cerebral ischemia/reperfusion (I/R). Therefore, we investigated the effect of resveratrol pretreatment on NF-κB inflammatory cascade, COX-2, iNOS and JNK levels in experimental I/R. Adult male rats were subjected to 10 min of four-vessel occlusion and sacrificed at selected post-ischemic time points. Resveratrol (30 mg/kg) pretreatment was injected intraperitoneally 7 days prior to I/R induction. We found that resveratrol treatment before insult remarkably reduced astroglial and microglial activation at 7 days after I/R. It greatly attenuated I/R-induced NF-κB and JNK activation with decreased COX-2 and iNOS production. In conclusion, the neuroprotection of resveratrol preconditioning may be due in part to the suppression of the inflammatory response via regulation of NF-κB, COX-2 and iNOS induced by I/R. JNK was also suggested to play a protective role through in neuroprotection of resveratrol, which may also be contributing to reduction in neuroinflammation. The study adds to a growing literature that resveratrol can have important anti-inflammatory actions in the brain.

Resveratrol analogue 3,4,4',5-tetramethoxystilbene inhibits growth, arrests cell cycle and induces apoptosis in ovarian SKOV-3 and A-2780 cancer cells

In the screening studies, cytotoxicity of 12 methylated resveratrol analogues on 11 human cancer cell lines was examined. The most active compound 3,4,4'5-tetramethoxystilbene (DMU-212) and two ovarian cancer cell lines A-2780 (IC(50)=0.71 μM) and SKOV-3 (IC(50)=11.51 μM) were selected for further investigation. To determine the mechanism of DMU-212 cytotoxicity, its ability to induce apoptosis was examined. DMU-212 arrested cell cycle in the G2/M or G0/G1 phase which resulted in apoptosis of both cell lines. The expression level of 84 apoptosis-related genes was investigated. In SKOV-3 cells DMU-212 caused up-regulation of pro-apoptotic Bax, Apaf-1 and p53 genes, specific to intrinsic pathway of apoptosis, and a decrease in Bcl-2 and Bcl 2110 mRNA expressions. Conversely, in A-2780 cells an increased expression of pro-apoptotic genes Fas, FasL, TNF, TNFRSF10A, TNFRSF21, TNFRSF16 specific to extracellular mechanism of apoptosis was observed. There are no data published so far regarding the receptor mediated apoptosis induced by DMU-212. The activation of caspase-3/7 was correlated with decreased TRAF-1 and BIRC-2 expression level in A-2780 cells exposed to DMU-212. DMU-212 caused a decrease in CYP1A1 and CYP1B1 mRNA levels in A-2780 by 50% and 75%, and in SKOV-3 cells by 15% and 45%, respectively. The protein expression was also reduced in both cell lines. It is noteworthy that the expression of CYP1B1 protein was entirely inhibited in A-2780 cells treated with DMU-212. It can be suggested that different CYP1B1 expression patterns in either ovarian cell line may affect their sensitivity to cytotoxic activity of DMU-212.

Pleiotropic protective effects of phytochemicals in Alzheimer's disease

Alzheimer's disease (AD) is a severe chronic neurodegenerative disorder of the brain characterised by progressive impairment in memory and cognition. In the past years an intense research has aimed at dissecting the molecular events of AD. However, there is not an exhaustive knowledge about AD pathogenesis and a limited number of therapeutic options are available to treat this neurodegenerative disease. Consequently, considering the heterogeneity of AD, therapeutic agents acting on multiple levels of the pathology are needed. Recent findings suggest that phytochemicals compounds with neuroprotective features may be an important resources in the discovery of drug candidates against AD. In this paper we will describe some polyphenols and we will discuss their potential role as neuroprotective agents. Specifically, curcumin, catechins, and resveratrol beyond their antioxidant activity are also involved in antiamyloidogenic and anti-inflammatory mechanisms. We will focus on specific molecular targets of these selected phytochemical compounds highlighting the correlations between their neuroprotective functions and their potential therapeutic value in AD.

Distinct sulfonation activities in resveratrol-sensitive and resveratrol-insensitive human glioblastoma cells

Glioblastoma multiforme (GBM) cells show different responses to resveratrol, for unknown reasons. Our data from human medulloblastoma cells and primary cultures of rat brain cells revealed an inverse correlation of sulfonation activity with resveratrol sensitivities, providing a clue to the underlying mechanisms of the variable sensitivities of GBM cells to resveratrol. In this study, we found that U251 cells were sensitive and LN229 cells were insensitive to resveratrol. Thus, these two cell lines were taken as comparable models for elucidating the influence of sulfonation activities on resveratrol sensitivity. HPLC showed identical resveratrol metabolic patterns in both cell lines. LC/MS and high-resolution mass MS analyses further demonstrated that resveratrol monosulfate generated by sulfotransferases (SULTs) was the major metabolite of human GBM cells. The levels of brain-associated SULT (SULT1A1, SULT1C2, and SULT4A1) expression in U251 cells were lower than those in LN229 cells, suggesting the inverse relationship of SULT-mediated sulfonation activity with high intracellular resveratrol bioavailability and resveratrol sensitivity of human GBM cells. Furthermore, immunohistochemical staining revealed reductions in expression of the three brain-associated SULTs in 72.8%, 47.5% and 66.3% of astrocytomas, respectively. Therefore, the levels of brain-associated SULTs and sulfonation activity mediated by them could be important parameters for evaluating the potential response of human GBM cells to resveratrol, and may have value in the personalized treatment of GBMs with resveratrol.

Resveratrol protects cortical neurons against microglia-mediated neuroinflammation

Neuroinflammation is closely associated with the pathogenesis of neurological disorders. The hallmark of neuroinflammation is considered to be microglial activation. Therefore, inhibition of microglial activation might hold a promising therapy for neurological disorders. Resveratrol, a natural non-flavonoid polyphenol found in grapes and red wine, has been recognized as a bioactive agent with potential benefit for health. Several lines of evidence show that resveratrol could exert neuroprotection against ischemia, seizure, and neurodegenerative diseases. However, the mechanisms underlying its beneficial neuroprotective effects are poorly defined. Here, by using rat primary cortical neuron-glia cultures, results showed that resveratrol attenuated lipopolysaccharide (LPS)-induced cortical neurotoxicity. Further studies revealed that microglia were responsible for resveratrol-mediated neuroprotection. Resveratrol significantly inhibited LPS-induced microglial activation and subsequent production of multiple pro-inflammatory and cytotoxic factors such as tumor necrosis factor-α, nitric oxide, and interleukin-1β. Collectively, resveratrol produced neuroprotection against microglia-induced neurotoxicity. Thus, resveratrol might represent a potential benefit for the treatment of inflammation-related neurological disorders.

Metabolic engineering of yeast and plants for the production of the biologically active hydroxystilbene, resveratrol

Resveratrol, a stilbenic compound deriving from the phenyalanine/polymalonate route, being stilbene synthase the last and key enzyme of this pathway, recently has become the focus of a number of studies in medicine and plant physiology. Increased demand for this molecule for nutraceutical, cosmetic and possibly pharmaceutic uses, makes its production a necessity. In this context, the use of biotechnology through recombinant microorganisms and plants is particularly promising. Interesting results can indeed arise from the potential of genetically modified microorganisms as an alternative mechanism for producing resveratrol. Strategies used to tailoring yeast as they do not possess the genes that encode for the resveratrol pathway, will be described. On the other hand, most interest has centered in recent years, on STS gene transfer experiments from various origins to the genome of numerous plants. This work also presents a comprehensive review on plant molecular engineering with the STS gene, resulting in disease resistance against microorganisms and the enhancement of the antioxidant activities of several fruits in transgenic lines.

The effect of dietary zinc--and polyphenols intake on DMBA-induced mammary tumorigenesis in rats

Background

The aim of the study was to investigate the effect of dietary supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein, on the effectiveness of chemically induced mammary cancer and the changes in the content of selected elements (Zn, Cu, Mg, Fe, Ca) in tumors as compared with normal tissue of the mammary gland.

Methods

Female Sprague-Dawley rats were divided into study groups which, apart from the standard diet and DMBA (7,12-dimethyl-1,2- benz[a]anthracene), were treated with zinc ions (Zn) or zinc ions + resveratrol (Zn + resveratrol) or zinc ions + genistein (Zn + genistein) via gavage for a period from 40 days until 20 weeks of age. The ICP-OES (inductively coupled plasma optical emission spectrometry) technique was used to analyze the following elements: magnesium, iron, zinc and calcium. Copper content in samples was estimated in an atomic absorption spectrophotometer.

Results

Regardless of the diet (standard; Zn; Zn + resveratrol; Zn + genistein), DMBA-induced breast carcinogenesis was not inhibited. On the contrary, in the Zn + resveratrol supplemented group, tumorigenesis developed at a considerably faster rate. On the basis of quantitative analysis of selected elements we found - irrespectively of the diet applied - great accumulation of copper and iron, which are strongly prooxidative, with a simultaneous considerable decrease of the magnesium content in DMBA-induced mammary tumors. The combination of zinc supplementation with resveratrol resulted in particularly large differences in the amount of the investigated elements in tumors as compared with their content in normal tissue.

Conclusions

Diet supplementation with zinc and polyphenol compounds, i.e. resveratrol and genistein had no effect on the decreased copper level in tumor tissue and inhibited mammary carcinogenesis in the rat. Irrespectively of the applied diet, the development of the neoplastic process in rats resulted in changes of the iron and magnesium content in the cancerous tissue in comparison with the healthy mammary tissue. The application of combined diet supplementation with zinc ions and resveratrol considerably promoted the rate of carcinogenesis and increased the number of DMBA-induced mammary tumors.

Anti-Inflammatory Effect of Resveratrol by Inhibition of IL-8 Production in LPS-Induced THP-1 Cells

Resveratrol is a polyphenol compound and prominent anti-inflammatory agent found in plants, including the fruits of Morus alba. However, the therapeutic mechanisms of resveratrol remain largely unclear. To gain insight into the biological effects of resveratrol, we examined its influence on LPS-induced IL-8 production in the human monocytic cell line, THP-1. In inflammatory diseases, IL-8 plays a central role in the initiation and maintenance of inflammatory response. In the present study, IL-8 production was measured by ELISA and RT-PCR, while MAPK activation, IκBα degradation, nuclear factor (NF)-κB activation and cyclooxygenase (COX)-2 expression were determined by Western blot analysis. Resveratrol inhibited LPS-induced IL-8 production in a dose-dependent manner. Furthermore, resveratrol inhibited extracellular signal-regulated kinase (ERK) and p38 MAPK phosphorylation, IκBα degradation, NF-κB activation and cyclooxygenase (COX)-2 expression, which suggest that resveratrol inhibits IL-8 secretion by blocking MAPK phosphorylation and NF-κB activation. Taken together, these findings may help elucidate the mechanism by which resveratrol modulates THP-1 cell activation under inflammatory conditions.

Microwave-Assisted Solvent-Free Synthesis of (E)-Stilbenes

An efficient synthesis of a series of stilbenes is reported using 4-nitrotoluene and substituted arylaldehydes as starting materials in the presence of Cs2CO3 and polyethylene glycol under solvent-free microwave irradiation. Compared with conventional method, this strategy exhibited higher stereoselectivity, shorter reaction times and has a lower environmental impact.

Combination effects of digalloylresveratrol with arabinofuranosylcytosine and difluorodeoxycytidine in human leukemia and pancreatic cancer cells

Digalloylresveratrol (DIG) is a newly synthesized agent aimed to combine the biological effects of the natural compounds, gallic acid and resveratrol, which both are free radical scavengers exhibiting anticancer activity. In this study, we investigated the effects of DIG on the growth of human HL-60 leukemia cells and on the colony formation of human BxPC-3 and PANC-1 pancreatic cancer cells. DIG was applied alone and in combination with arabinofuranosylcytosine (Ara-C) or difluorodeoxycytidine (dFdC), depending on the cell line employed. All IC(50) values observed were in the low micromolar range rendering DIG a promising antitumor compound in vitro. Considering the combination experiments, DIG yielded additive effects with Ara-C in HL-60 cells and-to a lesser extent-with dFdC in BxPC-3 and PANC-1 cells. Owing to our results, DIG may be further investigated in vitro and in animals.

MiR-520h-mediated FOXC2 regulation is critical for inhibition of lung cancer progression by resveratrol

Resveratrol, a phytochemical found in various plants and Chinese herbs, is associated with multiple tumor-suppressing activities, has been tested in clinical trials. However, the molecular mechanisms involved in resveratrol-mediated tumor suppressing activities are not yet completely defined. Here, we showed that treatment with resveratrol inhibited cell mobility through induction of the mesenchymal-epithelial transition (MET) in lung cancer cells. We also found that downregulation of FOXC2 (forkhead box C2) is critical for resveratrol-mediated suppression of tumor metastasis in an in vitro and in vivo models. We also identified a signal cascade, namely, resveratrol-∣miRNA-520h-∣PP2A/C-∣Akt → NF-κB → FOXC2, in which resveratrol inhibited the expression of FOXC2 through regulation of miRNA-520h-mediated signal cascade. This study identified a new miRNA-520h-related signal cascade involved in resveratrol-mediated tumor suppression activity and provide the clinical significances of miR-520h, PP2A/C and FOXC2 in lung cancer patients. Our results indicated a functional link between resveratrol-mediated miRNA-520h regulation and tumor suppressing ability, and provide a new insight into the role of resveratrol-induced molecular and epigenetic regulations in tumor suppression.

Cellular and molecular effects of resveratrol in health and disease

Resveratrol, a natural polyphenol abundantly found in grape skins and red wine, possesses diverse biochemical and physiological actions, including anti-inflammatory, anti-oxidation, anti-proliferation and promotion of differentiation, and chemopreventive effects. Recently, it is attracting increased attention due to its health benefits, especially in common age-related diseases such as cardiovascular disease, cancer, type 2 diabetes, and neurological conditions. In this review, we discuss the latest cellular and molecular findings that account for the beneficial actions of resveratrol.

Resveratrol, but not dihydroresveratrol, induces premature senescence in primary human fibroblasts

Resveratrol, trans-3,5,4'-trihydroxystilbene, is a polyphenolic compound which has been reported to mimic the gene expression patterns seen in whole animals undergoing dietary restriction. The mechanism of action of resveratrol remains poorly understood, but modulation of both cellular proliferation and apoptosis has been proposed as important routes by which the molecule may exert its effects. This study reports the effects of both resveratrol and dihydroresveratrol (a primary in vivo metabolite) on the proliferative capacity of human primary fibroblasts. No generalised reduction in the growth fraction was observed when fibroblasts derived from three different tissues were treated with resveratrol at concentrations of 10 μm or less. However, concentrations above 25 μm produced a dose-dependent reduction in proliferation. This loss of the growth fraction was paralleled by an increase in the senescent fraction as determined by staining for senescence associated beta galactosidase and dose recovery studies conducted over a 7-day period. Entry into senescence in response to treatment with resveratrol could be blocked by a 30-min preincubation with the p38 MAP kinase inhibitor SB203580. No effects on proliferation were observed when cells were treated with dihydroresveratrol at concentrations of up to 100 μm.

Overexpression of a resveratrol synthase gene (PcRS) from Polygonum cuspidatum in transgenic Arabidopsis causes the accumulation of trans-piceid with antifungal activity

Although resveratrol-forming stilbene synthase (STS) genes have been well characterized in many plant species, there are only a few descriptions about STS genes from Polygonum cuspidatum Sieb. et Zucc, an important medicinal crop in Asian countries. To evaluate the biological functions of a Polygonum cuspidatum resveratrol synthase gene (PcRS), the PcRS gene was expressed in Arabidopsis under the control of Cauliflower mosaic virus (CaMV) 35S promoter. Integration and expression of transgene in the plant genome of Arabidopsis was confirmed by Southern blot and Northern blot analyses. Transgenic plants accumulated a new compound in both the leaves and seeds, which was identified as trans-piceid by high-pressure liquid chromatography (HPLC) and electrospray mass spectrometry (HPLC-ESI-MS). Overexpression of PcRS in transgenic Arabidopsis caused restriction of Colletotrichum higginsianum colonization by inhibition of spore production, resulting in enhanced resistance against C. higginsianum. So, the PcRS gene could be deployed in other crop plants to significantly enhance resistance to fungal pathogens and improve the nutritional quality. In addition, altered seed coat pigmentation and significant reduction in anthocyanin levels were observed in transgenic Arabidopsis, while the expression of endogenous chalcone synthase (CHS) gene was not down-regulated. These results suggest that additional STS activities cause a lack of precursors for CHS which leads to the disturbance of the subsequent flavonoid biosynthesis steps in Arabidopsis.

Acute resveratrol supplementation improves flow-mediated dilatation in overweight/obese individuals with mildly elevated blood pressure

BACKGROUND AND AIMS

Flow-mediated dilatation of the brachial artery (FMD) is a biomarker of endothelial function and cardiovascular health. Impaired FMD is associated with several cardiovascular risk factors including hypertension and obesity. Various food ingredients such as polyphenols have been shown to improve FMD. We investigated whether consuming resveratrol, a polyphenol found in red wine, can enhance FMD acutely and whether there is a dose-response relationship for this effect.

METHODS AND RESULTS

19 overweight/obese (BMI 25-35 kg m(-2)) men or post-menopausal women with untreated borderline hypertension (systolic BP: 130-160 mmHg or diastolic BP: 85-100 mmHg) consumed three doses of resveratrol (resVida™ 30, 90 and 270 mg) and a placebo at weekly intervals in a double-blind, randomized crossover comparison. One hour after consumption of the supplement, plasma resveratrol and FMD were measured. Data were analyzed by linear regression versus log(10) dose of resveratrol. 14 men and 5 women (age 55 ± 2 years, BMI 28.7 ± 0.5 kg m(-2), BP 141 ± 2/89 ± 1 mmHg) completed this study. There was a significant dose effect of resveratrol on plasma resveratrol concentration (P < 0.001) and on FMD (P < 0.01), which increased from 4.1 ± 0.8% (placebo) to 7.7 ± 1.5% after 270 mg resveratrol. FMD was also linearly related to log(10) plasma resveratrol concentration (P < 0.01).

CONCLUSION

Acute resveratrol consumption increased plasma resveratrol concentrations and FMD in a dose-related manner. This effect may contribute to the purported cardiovascular health benefits of grapes and red wine.

Mechanisms regulating enhanced human leukocyte antigen class II-mediated CD4 + T cell recognition of human B-cell lymphoma by resveratrol

Malignant B-cells express measurable levels of human leukocyte antigen (HLA) class II proteins, but often escape immune recognition by CD4 + T cells. Resveratrol (Resv) has been the focus of numerous investigations due to its potential chemopreventive and anti-cancer effects, but it has never been tested in the regulation of immune components in B-cell tumors. Here, we show for the first time that Resv treatment enhances HLA class II-mediated immune detection of B-cell lymphomas by altering immune components and class II presentation in tumor cells. Resv treatment induced an up-regulation of both classical and non-classical HLA class II proteins (DR and DM) in B-lymphoma cells. Resv also altered endolysosomal cathepsins (Cat S, B and D) and a thiol reductase (GILT), increasing HLA class II-mediated antigen (Ag) processing in B-cell lymphomas and their subsequent recognition by CD4 + T cells. Mechanistic study demonstrated that Resv treatment activated the recycling class II pathway of Ag presentation through up-regulation of Rab 4B protein expression in B-lymphoma cells. These findings suggest that HLA class II-mediated immune recognition of malignant B-cells can be improved by Resv treatment, thus encouraging its potential use in chemoimmunotherapy of B-cell lymphoma.

Natural polyphenols may ameliorate damage induced by copper overload

The effect of the simultaneous exposure to transition metals and natural antioxidants frequently present in food is a question that needs further investigation. We aimed to explore the possible use of the natural polyphenols caffeic acid (CA), resveratrol (RES) and curcumin (CUR) to prevent damages induced by copper-overload on cellular molecules in HepG2 and A-549 human cells in culture. Exposure to 100μM/24h copper (Cu) caused extensive pro-oxidative damage evidenced by increased TBARS, protein carbonyls and nitrite productions in both cell types. Damage was aggravated by simultaneous incubation with 100μM of CA or RES, and it was also reflected in a decrease on cellular viability explored by trypan blue dye exclusion test and LDH leakage. Co-incubation with CUR produced opposite effects demonstrating a protective action which restored the level of biomarkers and cellular viability almost to control values. Thus, while CA and RES might aggravate the oxidative/nitrative damage of Cu, CUR should be considered as a putative protective agent. These results could stimulate further research on the possible use of natural polyphenols as neutralizing substances against the transition metal over-exposure in specific populations such as professional agrochemical sprayers and women using Cu-intrauterine devices.

Pharmacokinetics, oral bioavailability, and metabolic profile of resveratrol and its dimethylether analog, pterostilbene, in rats

PURPOSE

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a naturally occurring polyphenol with a broad range of possible health benefits, including anti-cancer activity. However, the biological activity of resveratrol may be limited by poor absorption and first-pass metabolism: only low plasma concentrations of resveratrol are seen following oral administration, and metabolism to glucuronide and sulfate conjugates is rapid. Methylated polyphenol analogs (such as pterostilbene [3,5-dimethoxy-4'-hydroxy-trans-stilbene], the dimethylether analog of resveratrol) may overcome these limitations to pharmacologic efficacy. The present study was designed to compare the bioavailability, pharmacokinetics, and metabolism of resveratrol and pterostilbene following equimolar oral dosing in rats.

METHODS

The agents were administered orally via gavage for 14 consecutive days at 50 or 150 mg/kg/day for resveratrol and 56 or 168 mg/kg/day for pterostilbene. Two additional groups were dosed once intravenously with 10 and 11.2 mg/kg for resveratrol and pterostilbene, respectively. Plasma concentrations of agents and metabolites were measured using a high-pressure liquid chromatograph-tandem mass spectrometer system. Noncompartmental analysis was used to derive pharmacokinetic parameters.

RESULTS

Resveratrol and pterostilbene were approximately 20 and 80% bioavailable, respectively. Following oral dosing, plasma levels of pterostilbene and pterostilbene sulfate were markedly greater than were plasma levels of resveratrol and resveratrol sulfate. Although plasma levels of resveratrol glucuronide exceeded those of pterostilbene glucuronide, those differences were smaller than those of the parent drugs and sulfate metabolites.

CONCLUSIONS

When administered orally, pterostilbene demonstrates greater bioavailability and total plasma levels of both the parent compound and metabolites than does resveratrol. These differences in agent pharmacokinetics suggest that the in vivo biological activity of equimolar doses of pterostilbene may be greater than that of resveratrol.

Synthesis and biological evaluation of hydroxylated 3-phenylcoumarins as antioxidants and antiproliferative agents

Based on the observed biological activities of coumarins and resveratrol, we synthesized fourteen hydroxylated 3-phenylcoumarins (stilbene-coumarin hybrids) including six novel ortho-hydroxy-methoxy substituted derivatives, 1-14, by Perkin reaction. We characterized these compounds concerning their antioxidant activity against 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced pBR322 DNA strand breakage, and their antiproliferative effects on human promyelocytic leukemia HL-60 and human lung adenocarcinoma epithelial A549 cells. Structure-activity relationship information suggests that the introduction of ortho-hydroxy-methoxy groups and ortho-dihydroxy groups on the aromatic A ring could efficiently improve antiproliferative activity. Interestingly, a new derivative, 6-methoxy-7-hydroxy-3-(4'-hydroxyphenyl)coumarin, 9, behaved as a poor antioxidant but appeared to be the most potent antiproliferative agent among the compounds examined, and this activity was mediated by deregulation in cell cycle and induction of apoptosis.

Effects of resveratrol on biomarkers of oxidative stress and on the activity of delta aminolevulinic acid dehydratase in liver and kidney of streptozotocin-induced diabetic rats

The present study investigated the effects of resveratrol (RV), a polyphenol with potent antioxidant properties, on oxidative stress parameters in liver and kidney, as well as on serum biochemical parameters of streptozotocin (STZ)-induced diabetic rats. Animals were divided into six groups (n = 8): control/saline; control/RV 10 mg/kg; control/RV 20 mg/kg; diabetic/saline; diabetic/RV10 mg/kg; diabetic/RV 20 mg/kg. After 30 days of treatment with resveratrol the animals were sacrificed and the liver, kidney and serum were used for experimental determinations. Results showed that TBARS levels were significantly increased in the diabetic/saline group and the administration of resveratrol prevented this increase in the diabetic/RV10 and diabetic/RV20 groups (P < 0.05). The activities of catalase (CAT), superoxide dismutase (SOD) and aminolevulinic acid dehydratase (δ-ALA-D) and the levels of non protein thiols (NPSH) and vitamin C presented a significant decrease in the diabetic/saline group when compared with the control/saline group (P < 0.05). The treatment with resveratrol was able to prevent these decrease improving the antioxidant defense of the diabetic/RV10 and diabetic/RV20 groups (P < 0.05). In addition, the elevation in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and γ-glutamiltransferase (γ-GT) activities as well as in levels of urea, creatinine, cholesterol and triglycerides observed in the diabetic/saline group were reverted to levels close to normal by the administration of resveratrol in the diabetic/RV10 and diabetic/RV20 groups (P < 0.05). These findings suggest that resveratrol could have a protector effect against hepatic and renal damage induced by oxidative stress in the diabetic state, which was evidenced by the capacity of this polyphenol to modulate the antioxidant defense and to decrease the lipid peroxidation in these tissues.

Stilbenes and tyrosol as target compounds in the assessment of antioxidant and hypolipidemic activity of Vitis vinifera red wines from southern Brazil

The contents of stilbene monomers, cis-resveratrol, trans-resveratrol, cis-piceid, trans-piceid, and tyrosol, were quantified in Vitis vinifera red wines, cvs. Cabernet Franc, Merlot, Sangiovese, and Syrah, 2006 and 2007 vintages, from the São Joaquim region, a new grape-growing region at southern Brazil. Moreover, the effect of chronic consumption of these wines on the antioxidant and hypolipidemic activities was monitored in C57BL6 LDL receptor knockout mice and treated with a hypercholesterolemic diet. Red wines from this region had substantial levels of resveratrols (the predominant forms were glycoside and trans) and tyrosol. Biomonitoring of antioxidant and hypolipidemic activities in vivo revealed that consumption of these wines increased the antioxidant capacity and reduced the hypercholesterolemia and hypertriglyceridemia promoted by the hypercholesterolemic diet. Significant correlations were found between the increase of antioxidant capacity markers, the decrease of lipid levels promoted by wine consumption, and the contents of stilbenes and tyrosol, supporting the important biological activity of these compounds.

A modern approach to the treatment of mitochondrial disease

The treatment of mitochondrial disease varies considerably. Most experts use a combination of vitamins, optimize patients' nutrition and general health, and prevent worsening of symptoms during times of illness and physiologic stress. We agree with this approach, and we agree that therapies using vitamins and cofactors have value, though there is debate about the choice of these agents and the doses prescribed. Despite the paucity of high-quality scientific evidence, these therapies are relatively harmless, may alleviate select clinical symptoms, and theoretically may offer a means of staving off disease progression. Like many other mitochondrial medicine physicians, we have observed significant (and at times life-altering) clinical responses to such pharmacologic interventions. However, it is not yet proven that these therapies truly alter the course of the disease, and some experts may choose not to use these medications at all. At present, the evidence of their effectiveness does not rise to the level required for universal use. Based on our clinical experience and judgment, however, we agree that a therapeutic trial of coenzyme Q10, along with other antioxidants, should be attempted. Although individual specialists differ as to the exact drug cocktail, a common approach involves combinations of antioxidants that may have a synergistic effect. Because almost all relevant therapies are classified as medical foods or over-the-counter supplements, most physicians also attempt to balance the apparent clinical benefit of mitochondrial cocktails with the cost burden that these supplements pose for the family.

Greater effectiveness of ε-viniferin in red wine than its monomer resveratrol for inhibiting vascular smooth muscle cell proliferation and migration

Resveratrol is a strong candidate for explaining an irreversible correlation between red wine consumption and coronary heart disease. The present study examined the effect of ε-viniferin, a dehydrodimer of resveratrol, on vascular smooth muscle cells (VSMCs), because ε-viniferin functions are poorly understood in spite of its comparable content to resveratrol in red wines and grapes. Both ε-viniferin and resveratrol inhibited platelet-derived growth factor-induced cell proliferation, migration, and reactive oxygen species (ROS) production, in addition to inducing nitric oxide generation. ε-Viniferin was more effective than resveratrol in these effects, except for inhibiting ROS production. The compounds also increased the expression of the antioxidant enzyme, hemeoxygenase-1, via transcription factor Nrf2. The phosphatidylinositol 3-kinase-Akt pathway was implicated in resveratrol-dependent nuclear Nrf2 accumulation, whereas extracellular signal-regulated kinase and p38 were involved in ε-viniferin-induced Nrf2 accumulation. These data suggest that ε-viniferin may function more effectively than resveratrol in different mechanisms and cooperatively with resveratrol in preventing atherosclerosis.