Resveratrol Mobilizes Endogenous Copper in Human Peripheral Lymphocytes Leading to Oxidative DNA Breakage: A Putative Mechanism for Chemoprevention of Cancer

A mosquito salivary protein-driven influx of myeloid cells facilitates flavivirus transmission

Mosquitoes transmit many disease-relevant flaviviruses. Efficient viral transmission to mammalian hosts requires mosquito salivary factors. However, the specific salivary components facilitating viral transmission and their mechanisms of action remain largely unknown. Here, we show that a female mosquito salivary gland-specific protein, here named A. aegypti Neutrophil Recruitment Protein (AaNRP), facilitates the transmission of Zika and dengue viruses. AaNRP promotes a rapid influx of neutrophils, followed by virus-susceptible myeloid cells toward mosquito bite sites, which facilitates establishment of local infection and systemic dissemination. Mechanistically, AaNRP engages TLR1 and TLR4 of skin-resident macrophages and activates MyD88-dependent NF-κB signaling to induce the expression of neutrophil chemoattractants. Inhibition of MyD88-NF-κB signaling with the dietary phytochemical resveratrol reduces AaNRP-mediated enhancement of flavivirus transmission by mosquitoes. These findings exemplify how salivary components can aid viral transmission, and suggest a potential prophylactic target.

Anticancer properties of red beetroot hydro-alcoholic extract and its main constituent; betanin on colorectal cancer cell lines

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Red beetroot (Beta vulgaris) contains Betanin as its major betacyanin, possessing wide proapoptotic effects. This study aimed to investigate the anticancer and pro-papoptotic effects of beetroot hydro-alcoholic extract (BHE) and betanin, on colorectal cancer cell lines. BHE and betanin were used to treat Caco-2 and HT-29 colorectal cancer cells. MTT assay, DAPI staining, and FACS-flow cytometry tests were used to determine the half-maximal inhibitory concentration (IC50) and apoptosis-inducing evaluations. Intended genes were assessed by real-time polymerase chain reaction (RT-PCR). The IC50 for HT-29 and Caco-2 cell lines were 92 μg/mL, 107 μg/mL for BHE, and 64 μg/mL, 90 μg/mL for betanin at 48 h, respectively. BHE and betanin significantly inhibited the growth of both cancer cell lines time and dose-dependently. DAPI staining and flow cytometry results revealed significant apoptosis symptoms in treated cancerous cell lines. The expression level of proapoptotic genes (BAD, Caspase-3, Caspase-8, Caspase-9, and Fas-R) in treated HT-29 and Caco-2 cells was higher than in untreated and normal cells. In contrast, the anti-apoptotic gene (Bcl-2) was significantly downregulated. BHE and betanin effectively inhibited cancer cell proliferation and induced apoptosis via the modification of effective genes.

Recent updates on anticancer mechanisms of polyphenols

In today’s scenario, when cancer cases are increasing rapidly, anticancer herbal compounds become imperative. Studies on the molecular mechanisms of action of polyphenols published in specialized databases such as Web of Science, Pubmed/Medline, Google Scholar, and Science Direct were used as sources of information for this review. Natural polyphenols provide established efficacy against chemically induced tumor growth with fewer side effects. They can sensitize cells to various therapies and increase the effectiveness of biotherapy. Further pharmacological translational research and clinical trials are needed to evaluate theirs in vivo efficacy, possible side effects and toxicity. Polyphenols can be used to design a potential treatment in conjunction with existing cancer drug regimens such as chemotherapy and radiotherapy.

Structure of Some Green Tea Catechins and the Availability of Intracellular Copper Influence Their Ability to Cause Selective Oxidative DNA Damage in Malignant Cells

The possible roles of elevated endogenous copper levels in malignant cells are becoming increasingly understood at a greater depth. Our laboratory has previously demonstrated that tea catechins have the ability to mobilize endogenous copper and undergo a Fenton-like reaction that can selectively damage cancer cells. In this communication, by using a diverse panel of malignant cell lines, we demonstrate that the ability of the catechin family [(−)-epigallocatechin-3-gallate (EGCG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (+)-catechin (C)] to induce apoptosis is dependent on their structure. We further confirm that reactive oxygen species (ROS) are the terminal effectors causing copper-mediated DNA damage. Our studies demonstrate the role of cellular copper transporters CTR1 and ATP7A in the survival dynamics of malignant cells post-EGCG exposure. The results, when considered together with our previous studies, highlight the critical role that copper dynamics and mobilization plays in cancer cells and paves the way for a better understanding of catechins as nutraceutical supplements for malignancies.

Imine resveratrol analogs (IRAs): The strong antioxidant that can protect lymphocytes from oxidative damage

Imine resveratrol analogs (IRAs) are promising new agents that can have higher positive effects and, simultaneously, lower negative properties than resveratrol. In this study, three imine hydroxy derivatives (2-((4-hydroxyphenylimino) methyl) phenol [IRA1], 3-((4-hydroxyphenylimino) methyl) phenol [IRA2], and 4-((4-hydroxyphenylimino) methyl) phenol [IRA3]) were prepared and tested in several biological assays. They performed superior to resveratrol in several antioxidant and biological assays, showing high antioxidant capacity and low genotoxicity. Ferric reducing antioxidant power assay (FRAP) and hydroxyl radicals scavenging assay revealed good Fe³⁺ to Fe²⁺ reduction and strong inhibition of hydroxyl radical formation, respectively. High dosage (1 mmol/dm³ ) of IRA2 and IRA3 did not cause genotoxicity in human lymphocytes. Moreover, lymphocytes pretreated with all three IRAs accumulated only very few DNA breaks induced by H₂ O₂ than lymphocytes pretreated with resveratrol. Additionally, the number of detected DNA breaks appearing after removal of damaged DNA bases, 8-oxo-7,8-dihydroguanine (8-oxoG), did not dramatically increase in lymphocytes treated with IRA2. Thus, we concluded that IRAs, especially IRA2, are strong antioxidants with the ability to protect lymphocytes from oxidative damage.

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.

Recent Advancements on Immunomodulatory Mechanisms of Resveratrol in Tumor Microenvironment

Immunomodulation of the tumor microenvironment is emerging as an important area of research for the treatment of cancer patients. Several synthetic and natural agents are being investigated for their ability to enhance the immunogenic responses of immune cells present in the tumor microenvironment to impede tumor cell growth and dissemination. Among them, resveratrol, a stilbenoid found in red grapes and many other natural sources, has been studied extensively. Importantly, resveratrol has been shown to possess activity against various human diseases, including cancer. Mechanistically, resveratrol has been shown to regulate an array of signaling pathways and processes involving oxidative stress, inflammation, apoptosis, and several anticancer effects. Furthermore, recent research suggests that resveratrol can regulate various cellular signaling events including immune cell regulation, cytokines/chemokines secretion, and the expression of several other immune-related genes. In this review, we have summarized recent findings on resveratrol’s effects on immune regulatory cells and associated signaling in various cancer types. Numerous immunomodulatory effects of resveratrol suggest it may be useful in combination with other cancer therapies including immunotherapy for effective cancer management.

Modulation of the tumor microenvironment by natural agents: implications for cancer prevention and therapy

The development of cancer is not just the growth and proliferation of a single transformed cell, but its surrounding environment also coevolves with it. Indeed, successful cancer progression depends on the ability of the tumor cells to develop a supportive tumor microenvironment consisting of various types of stromal cells. The interactions between the tumor and stromal cells are bidirectional and mediated through a variety of growth factors, cytokines, metabolites, and other biomolecules secreted by these cells. Tumor-stromal crosstalk creates optimal conditions for the tumor growth, metastasis, evasion of immune surveillance, and therapy resistance, and its targeting is being explored for clinical management of cancer. Natural agents from plants and marine life have been at the forefront of traditional medicine. Numerous epidemiological studies have reported the health benefits imparted on the consumption of certain fruits, vegetables, and their derived products. Indeed, a significant majority of anti-cancer drugs in clinical use are either naturally occurring compounds or their derivatives. In this review, we describe fundamental cellular and non-cellular components of the tumor microenvironment and discuss the significance of natural compounds in their targeting. Existing literature provides hope that novel prevention and therapeutic approaches will emerge from ongoing scientific efforts leading to the reduced tumor burden and improve clinical outcomes in cancer patients.

Potential Adverse Effects of Resveratrol: A Literature Review

Due to its health benefits, resveratrol (RE) is one of the most researched natural polyphenols. Resveratrol's health benefits were first highlighted in the early 1990s in the French paradox study, which opened extensive research activity into this compound. Ever since, several pharmacological activities including antioxidant, anti-aging, anti-inflammatory, anti-cancerous, anti-diabetic, cardioprotective, and neuroprotective properties, were attributed to RE. However, results from the available human clinical trials were controversial concerning the protective effects of RE against diseases and their sequelae. The reason for these conflicting findings is varied but differences in the characteristics of the enrolled patients, RE doses used, and duration of RE supplementation were proposed, at least in part, as possible causes. In particular, the optimal RE dosage capable of maximizing its health benefits without raising toxicity issues remains an area of extensive research. In this context, while there is a consistent body of literature on the protective effects of RE against diseases, there are relatively few reports investigating its possible toxicity. Indeed, toxicity and adverse effects were reported following consumption of RE; therefore, extensive future studies on the long-term effects, as well as the in vivo adverse effects, of RE supplementation in humans are needed. Furthermore, data on the interactions of RE when combined with other therapies are still lacking, as well as results related to its absorption and bioavailability in the human body. In this review, we collect and summarize the available literature about RE toxicity and side effects. In this process, we analyze in vitro and in vivo studies that have addressed this stilbenoid. These studies suggest that RE still has an unexplored side. Finally, we discuss the new delivery methods that are being employed to overcome the low bioavailability of RE.

Antioxidant, Antiproliferative and Apoptosis-Inducing Efficacy of Fractions from Cassia fistula L. Leaves

: Cassia fistula L. is a highly admirable traditional medicinal plant used for the treatment of various diseases and disorders. The present study was performed to divulge the antioxidant, antiproliferative, and apoptosis-inducing efficacy of fractions from C. fistula leaves. The hexane (CaLH fraction), chloroform (CaLC fraction), ethyl acetate (CaLE fraction), n-butanol (CaLB fraction), and aqueous (CaLA fraction) were sequentially fractionated from 80% methanolic (CaLM extract) of C. fistula leaves. The CaLE fraction was fractionated using column chromatography to yield a pure compound, which was characterized as Epiafzelechin (CFL1) based on 1H, 13C, and DEPT135 NMR. Among these fractions, CaLE and isolated CFL1 fractions exhibited an effective antioxidant potential in Ferric ion reducing power, (2,2'-azino-bis (3-ethylbenzothiazoline -6-sulfonic acid)) cation radical scavenging, and nitric oxide radical scavenging assays. Epiafzelechin was investigated for its antiproliferative effects against MG-63 (osteosarcoma), IMR-32 (neuroblastoma), and PC-3 (prostate adenocarcinoma), and was found to inhibit cell proliferation with a GI50 value of 8.73, 9.15, and 11.8 μM respectively. MG-63 cells underwent apoptotic cell death on treatment with Epiafzelechin as the cells showed the formation of apoptotic bodies, enhanced reactive oxygen species (ROS) generation, mitochondrial membrane depolarization along with an increase in early apoptotic cell population analyzed using Annexin V-FITC/PI double staining assay. Cells showed cell cycle arrest at the G0/G1 phase accompanied by a downregulation in the expression levels of p-Akt (Protein kinase B), p-GSK-3β (Glycogen synthase kinase-3 beta), and Bcl-xl (B-cell lymphoma-extra large) proteins. RT-PCR (Real time-polymerase chain reaction) analysis revealed downregulation in the gene expression level of β-catenin and CDK2 (cyclin-dependent kinases-2) while it upregulated the expression level of caspase-8 and p53 genes in MG-63 cells.

In Vitro Pro-Glycative Effects of Resveratrol and Caffeic Acid

Resveratrol and caffeic acid belong to plant polyphenols and are known for their antioxidant effects. The aim of our research was to study their impact on Maillard reaction. This one occurs when the reducing saccharides react with amino groups of biomolecules including proteins, alter their protein conformation and transform to the variety of advanced glycation end products (AGEs). AGEs exhibit browning and generate fluorescence. There exist expectations that this oxidative protein glycosylation could be prevented by antioxidants. In this study, we incubated bovine serum albumin (BSA) with glucose for 7 days at 37°C and measured characteristic fluorescence and UV absorbance of the formed AGEs. Surprisingly, resveratrol and caffeic acid enhanced transformation of BSA to glycation products, which was confirmed either when cupric Cu(II) or ferric Fe(III) ions in nanomolar concentration were added to the system as pro-oxidant agent.

Resveratrol modulates the blood plasma levels of Cu and Zn, the antioxidant status and the vascular response of thoracic arteries in copper deficient Wistar rats

Copper (Cu) deficiency plays an important role in the development of cardiovascular disorders. Resveratrol (RSV) possesses pleiotropic cardiovascular benefits; however, the mechanism(s) by which RSV exerts protective effects are not completely understood. Male Wistar rats at 6 weeks of age were fed for 8 weeks with a Cu deficient diet (no added Cu, Cu = 0). In addition, Cu deficient rats were supplemented with RSV (500 mg/kg of diet, n = 9). Blood and intestinal samples were taken for further analysis together with internal organs and thoracic arteries. RSV supplementation resulted in elevated blood plasma levels of Cu (x2.1) and Zn (x1.1), in an increased activity of superoxide dismutase (SOD, x1.5) and ferric reducing antioxidant power (FRAP, x1.2). Meanwhile, markers of lipid peroxidation expressed as malondialdehyde (MDA, x1.5) and lipid hydroperoxides (LOOH, x1.1) were also increased in a significant way. Food intake, body weight, blood glucose, catalase, ceruloplasmin, lipid profile and intestinal samples were not modified. RSV enhanced the vasoconstriction of isolated thoracic arteries to noradrenaline (x1.4), potentiated the vasodilation to acetylcholine (ACh, x1.4) and increased the sensitivity to sodium nitroprusside (SNP). In addition, preincubation with the cyclooxygenase (COX)-inhibitor, indomethacin, potentiated the ACh-induced vasodilation, which was more pronounced in animals not supplemented with RSV. The K_ATP channel opener, pinacidil, induced a similar response in both studied groups. In conclusion, this study demonstrates that RSV supplementation influences oxidative stress and the antioxidant status, which may modify the vascular response in Cu deficiency.

Biological Activity of New Cichoric Acid-Metal Complexes in Bacterial Strains, Yeast-Like Fungi, and Human Cell Cultures In Vitro

Cichoric acid (CA) belongs to the group of polyphenols, which occurs in a variety of plant species and it is characterized by anticancer, antibacterial, and antiviral properties. Selected polyphenols have the ability to combine with metal ions to form chelate complexes that reveal greater biological activity than free compounds. In order to study possible antimicrobial and anticancer effect of CA and its complexes with copper(II)/zinc(II)/nickel(II)/cobalt(II) we decided to conduct cytotoxicity tests to estimate the most effective concentrations of tested compounds. The results of the presented study demonstrated, for the first time, that the treatment with newly synthesized CA-metal complexes has anticancer and antimicrobial effects, which were examined in seven different cell lines: MCF-7, MDA-MB-231, and ZR-75-1 breast cancer cell lines, A375 melanoma cell line, DLD-1 cell line, LN-229 cell line, FN cell line; five bacterial strains: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, Proteus vulgaris, Lactobacillus rhamnosus, yeast Sacchcaromyces boulardii, and pathogenic yeast-like fungi Candida albicans. The presented study indicates that CA-metal complexes could be considered as a potential supplementary tool in anticancer therapy, however, because of their possible toxic activity on fibroblasts, they should be used with caution. Some of the tested complexes have also preservative properties and positive influence on normal non-pathogenic microorganisms, which was demonstrated in selected microbial strains, therefore they may serve as food preservatives of natural origin with cytoprotective properties.

Baicalein, as a Prooxidant, Triggers Mitochondrial Apoptosis in MCF-7 Human Breast Cancer Cells Through Mobilization of Intracellular Copper and Reactive Oxygen Species Generation

Background

Baicalein, a natural flavonoid derived from traditional Chinese herb Scutellaria baicalensis Georg (known as Huang Qin in Chinese), has been reported to exhibit notable antitumor activity in various cancer cells, including breast cancer. However, the detailed mechanisms underlying its induced apoptosis as a prooxidant in breast cancer cells are still unknown.

Materials and methods

In this study, we investigated the effect of endogenous copper on cytotoxic activity of baicalin against human breast cancer MCF-7 cells in vitro.

Results

Baicalein could remarkably reduce the cell viability in both dose- and time-dependent manners in MCF-7 cells but with lower cytotoxic effects on normal breast epithelial cells, MCF-10A. Such cell death could be prevented by pretreatment with Cu (I)-specific chelator neocuproine (Neo) and reactive oxygen species (ROS) scavengers. Meanwhile, baicalein could induce MCF-7 cell morphological changes, promote apoptotic cell death and increase the apoptotic cell number. Moreover, DCHF-DA staining, flow cytometry and Western blotting analyses proved that baicalein triggered the mitochondrial-dependent apoptotic pathway, as indicated by enhancement the level of intracellular ROS, disruption of mitochondrial membrane potential (ΔΨm), downregulation of anti-apoptotic protein Bcl-2, upregulation of pro-apoptotic protein Bax, release of cytochrome C and activation of caspase-9 and caspase-3 in MCF-7 cells. The pretreatment with Neo remarkably weakened these effects of baicalein. Furthermore, we confirmed that the prooxidant action of baicalein involved the direct production of hydroxyl radicals through redox recycling of copper ions.

Conclusion

These findings suggested that baicalein, acting as a prooxidant, could trigger apoptosis in MCF-7 cells occurs via the ROS-mediated intrinsic mitochondria-dependent pathway.

The interaction between resveratrol and two forms of copper as carbonate and nanoparticles on antioxidant mechanisms and vascular function in Wistar rats

BACKGROUND

Experimental studies have emphasized that cardiovascular alterations can be improved by the long-term use of resveratrol (trans-3,5,4'-trihydroxystilbene; RSV) as well as dietary copper (Cu) intake.

METHODS

Male Wistar rats were supplemented for 8 weeks with Cu (6.5 mg/kg diet) as either nanoparticles (40 nm, CuNPs) or carbonate (CuCO3). Half of the studied animals were supplemented with RSV (500 mg/kg diet). Vascular function and blood plasma antioxidant status, expressed as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), lipid hydroperoxides (LOOH) and malondialdehyde (MDA) were analyzed. The activity of ceruloplasmin (Cp), lipid profile, fasting glucose, and concentrations of Cu and zinc (Zn) were analyzed.

RESULTS

RSV supplementation resulted in the elevated activity of SOD and decreased CAT, GPx and LDL-cholesterol in both groups. RSV supplementation on CuNPs increased the participation of vasoconstrictor prostanoids and decreased ACh-induced vasodilation, while the participation of hyperpolarizing mechanism(s) was restored by activating KATP channels. Blood plasma glucose was decreased. RSV supplementation on CuCO3 enhanced ACh- and SNP-induced vasodilation and decreased NA-induced vasoconstriction. The lipid profile was improved, as well as Zn concentration. Meanwhile, Cu and Cp, and the markers of lipid peroxidation, reflected as LOOH and MDA, were decreased.

CONCLUSION

The use of RSV during CuCO3 intake improves vascular responses, the lipid profile and the antioxidant mechanism(s). The beneficial role of RSV was not observed in the CuNP group and decreased ACh-induced vasodilation and increased participation of vasoconstrictor prostanoids in the vascular regulation were noticed.

Homeostatic changes of some trace elements in geriatric rats in the condition of oxidative stress induced by aluminum and the beneficial role of resveratrol

BACKGROUND

Elderly individuals are exposed to trace element imbalances due to the reduced capacity of their organism to utilize minerals in a direct relationship with many circumstances.

OBJECTIVES AND METHODS

The aim of this study was to assess the protective role of resveratrol upon the homeostatic changes of some trace elements in geriatric rats in the condition of oxidative stress induced by aluminum exposure. Forty Wistar rats, 18-20 months old, were divided randomly into four groups (n = 10): control (C) - receiving 1 ml of physiologically saline (P.S.) via intraperitoneal (i.p) administration, E1 - 1 ml of P.S. and 1000 ppb aluminum sulphate (AS) in drinking water ad libitum, E2 - 20 mg/kg^-1 resveratrol, i.p. and 1000 ppb AS in drinking water, E3 - 20 mg/kg^-1 resveratrol i.p. The groups C and E3 received distilled water as drinking water ad libitum. The i.p administrations were once a week for four weeks period. The levels of oxidative stress marker's were analyzed (glutathione, glutathione' peroxidase, superoxide dismutase, and catalase) of the proteins' (total protein, albumin, and hemoglobin) in serum and also the levels of the main trace elements (copper, zinc, iron, selenium, manganese and magnesium) in blood, liver, kidney and spleen.

RESULTS

Significant decrease (p < 0.05) of total protein (TP), albumin (ALB), catalase (CAT), increase significant (p < 0.05) of glutathione reductase (GSH-r), glutathione peroxidase (GPx) and superoxide dismutase (SOD) in E1 groups, compared with control, E2, and E3 groups was ascertained. There were also observed significant (p < 0.05) decreases in Cu, Zn, Fe and Mg, not significant (p > 0.05) increase of Se and Mn in blood, significant (p < 0.01) increase of Cu, Zn, Mg, Se, Mn in kidney and liver and Fe, in spleen of geriatric rats from E1 group compared to the control group. Insignificant differences (p > 0.05) were recorded in groups which received resveratrol (E2 and E3) compared to the control group, but significant differences (p < 0.05), especially in blood and liver samples, compared to E1.

CONCLUSIONS

The results suggest that resveratrol can prevent the homeostatic imbalance of trace elements in geriatric rats in the condition of oxidative stress induced by aluminum exposure.

Copper homeostasis as target of both consolidated and innovative strategies of anti-tumor therapy

BACKGROUND

Copper was reported to be involved in the onset and progression of cancer. Proteins in charge of copper uptake and distribution, as well as cuproenzymes, are altered in cancer. More recently, proteins involved in signaling cascades, regulating cell proliferation, and anti-apoptotic protein factors were found to interact with copper. Therefore, therapeutic strategies using copper complexing molecules have been proposed for cancer therapy and used in clinical trials.

OBJECTIVES

This review will focus on novel findings about the involvement of copper and cupro-proteins in cancer dissemination process, epithelium to mesenchymal transition and vascularization. Particularly, implication of well-established (e.g. lysil oxidase) or newly identified copper-binding proteins (e.g. MEMO1), as well as their interplay, will be discussed. Moreover, we will describe recently synthesized copper complexes, including plant-derived ones, and their efficacy in contrasting cancer development.

CONCLUSIONS

The research on the involvement of copper in cancer is still an open field. Further investigation is required to unveil the mechanisms involved in copper delivery to the novel copper-binding proteins, which may identify other possible gene and protein targets for cancer therapy.

Copper Mediates Anti-Inflammatory and Antifibrotic Activity of Gleevec in Hepatocellular Carcinoma-Induced Male Rats

The elevated level of copper is one of the hallmark features of cancer cells in most of the types of cancer. In the present study, this feature has been targeted to investigate if coadministration of exogenous copper (Cu⁺) and its chelating agent like disulfiram (DSF⁺) influence the antineoplastic activity of the anticancer drug, Gleevec (GLV⁺), in hepatocellular carcinoma (HCC)-induced rats via immunomodulation. After the treatment, the level of proinflammatory interleukins (IL-1, 2, 6, and 7), anti-inflammatory interleukin (IL-10) concomitant with transcription factors (NF-kB and TNF-a), and the apoptotic marker (cleaved PARP) was estimated. The cancer-induced group without treatment (CN⁺) demonstrated abnormally elevated level of all proinflammatory cytokines and transcription factors concomitant with a compromised level of cleaved PARP as compared to the control normal (CN^-). The detailed histological analysis also supported the results exhibiting extensive inflammation and tissue fibrosis confirming the second stage of HCC. Cu+, DSF⁺, and GLV⁺ displayed mild improvement in most of the parameters, but the combination group GLV + Cu⁺ demonstrated remarkable recovery in histology and most of the parameters tended towards the CN^- followed by GLV + DSF⁺. Therefore, the management of copper level is critical in realizing the antineoplastic activity of GLV up to its full potential in cancer treatment. These findings will help in improving chemoimmunotherapy and personalized cancer treatment.

Regulation of Cell Signaling Pathways and miRNAs by Resveratrol in Different Cancers

Genomic and proteomic studies have helped improve our understanding of the underlying mechanism(s) of cancer development and progression. Mutations, overexpressed oncogenes, inactivated/downregulated tumor suppressors, loss of apoptosis, and dysregulated signal transduction cascades are some of the well-studied areas of research. Resveratrol has gained considerable attention in the last two decades because of its pleiotropic anticancer activities. In this review, we have summarized the regulation of WNT, SHH (sonic hedgehog)/GLI (glioma-associated oncogene homolog), TGFβ1 (transforming growth factor beta 1)/SMAD, NOTCH, TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), STAT (signal transducer and activator of transcription), and microRNAs by resveratrol in different cancers. The importance of these signaling pathways in cancer progression, along with their modulation by resveratrol, is discussed. Further, we also evaluate the mechanisms and implications of the downregulation of oncogenic miRNAs and the upregulation of tumor suppressor miRNAs by resveratrol, both of which also define its ability to inhibit tumor growth and metastasis. It is envisioned that designing effective clinical trials will be helpful for the identification of resveratrol responders and non-responders and the elucidation of how this phytochemical can be combined with current therapeutic options to improve their clinical efficacy and reduce off-target effects.

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.

Antitumor activity of resveratrol is independent of Cu(II) complex formation in MCF-7 cell line

Resveratrol (Rsv) is widely reported to possess anticarcinogenic properties in a plethora of cellular and animal models having limited toxicity toward normal cells. In the molecular level, Rsv can act as a suppressive agent for several impaired signaling pathways on cancer cells. However, Fukuhara and Miyata have shown a non-proteic reaction of Rsv, which can act as a prooxidant agent in the presence of copper (Cu), causing cellular oxidative stress accompanied of DNA damage. After this discovery, the complex Rsv-Cu was broadly explored as an antitumor mechanism in multiples tumor cell lines. The aim of the study is to explore the anticarcinogenic behavior of resveratrol-Cu(II) complex in MCF-7 cell line. Selectivity of Rsv binding to Cu ions was analyzed by HPLC and UV-VIS. The cells were enriched with concentrations of 10 and 50µM CuSO₄ solution and treated with 25µM of Rsv. Copper uptake after enrichment of cells, as its intracellular distribution in MCF-7 line, was scanned by ICP-MS and TEM-EDS. Cell death and intracellular ROS production were determined by flow cytometry. Different from the extracellular model, no relationship of synergy between Rsv-Cu(II) and reactive oxidative species (ROS) production was detected in vitro. ICP-MS revealed intracellular copper accumulation to both chosen concentrations (0.33±0.09 and 1.18±0.13ppb) but there is no promotion of cell death by Rsv-Cu(II) complex. In addition, significant attenuation of ROS production was detected when cells were exposed to CuSO₄ after Rsv treatment, falling from 7.54% of ROS production when treated only with Rsv to 3.07 and 2.72% with CuSO₄. Based on these findings antitumor activity of resveratrol when in copper ions presence, is not mediated by Rsv-Cu complex formation in MCF-7 human cell line, suggesting that the antitumoral reaction is dependent of a cancer cellular model.

Multiple repair pathways mediate cellular tolerance to resveratrol-induced DNA damage

Resveratrol (RSV) has been reported to exert health benefits for the prevention and treatment of many diseases, including cancer. The anticancer mechanisms of RSV seem to be complex and may be associated with genotoxic potential. To better understand the genotoxic mechanisms, we used wild-type (WT) and a panel of isogenic DNA-repair deficient DT40 cell lines to identify the DNA damage effects and molecular mechanisms of cellular tolerance to RSV. Our results showed that RSV induced significant formation of γ-H2AX foci and chromosome aberrations (CAs) in WT cells, suggesting direct DNA damage effects. Comparing the survival of WT with isogenic DNA-repair deficient DT40 cell lines demonstrated that single strand break repair (SSBR) deficient cell lines of Parp1^-/-, base excision repair (BER) deficient cell lines of Polβ^-/-, homologous recombination (HR) mutants of Brca1^-/- and Brca2^-/- and translesion DNA synthesis (TLS) mutants of Rev3^-/- and Rad18^-/- were more sensitive to RSV. The sensitivities of cells were associated with enhanced DNA damage comparing the accumulation of γ-H2AX foci and number of CAs of isogenic DNA-repair deficient DT40 cell lines with WT cells. These results clearly demonstrated that RSV-induced DNA damage in DT40 cells, and multiple repair pathways including BER, SSBR, HR and TLS, play critical roles in response to RSV- induced genotoxicity.

Cancer Chemoprevention by Phytochemicals: Nature's Healing Touch

Phytochemicals are an important part of traditional medicine and have been investigated in detail for possible inclusion in modern medicine as well. These compounds often serve as the backbone for the synthesis of novel therapeutic agents. For many years, phytochemicals have demonstrated encouraging activity against various human cancer models in pre-clinical assays. Here, we discuss select phytochemicals—curcumin, epigallocatechin-3-gallate (EGCG), resveratrol, plumbagin and honokiol—in the context of their reported effects on the processes of inflammation and oxidative stress, which play a key role in tumorigenesis. We also discuss the emerging evidence on modulation of tumor microenvironment by these phytochemicals which can possibly define their cancer-specific action. Finally, we provide recent updates on how low bioavailability, a major concern with phytochemicals, is being circumvented and the general efficacy being improved, by synthesis of novel chemical analogs and nanoformulations.

Modulatory potential of resveratrol during lung inflammatory disease

Neutrophils are the first cells to achieve the sites of infection or inflammation in the lungs. The massive accumulation of these cells is associated with acute and chronic lung injury. Therefore, they have been implicated in the pathogenesis of many lung diseases through the release of reactive oxygen intermediates, proteolytic enzymes and Neutrophil Extracellular Traps (NETs). The excessive and continuous release of NETs, fibers composed by decondensed chromatin coated with neutrophil proteins, are associated to the impairment of lung function in different pathological settings. Flavonoids inhibit the respiratory burst of neutrophils in mammals. However, one of these flavonoids, resveratrol has a particular chemical property. It reduce Cu(II) to Cu(I) form with concomitant formation of reactive oxygen species, which can produce DNA breakage as reported in several in vitro models. We hypothesize that direct resveratrol administration in lungs can cleave DNA in NETs, improving lung function during acute airway infections or chronic inflammatory lung diseases. If the hypothesis is correct, the control of NET formation can be used to reduce the inflammatory environment in lung after neutrophil stimuli. Additionally, the production of proinflammatory cytokines by neutrophils could be also diminished by resveratrol administration. In this sense, this flavonoid provides a multifaceted opportunity for treatment of lung diseases with strong or chronic neutrophil activation.

Role of oxidative stress and antioxidants in daily nutrition and human health

Diet may be defined as a complex process that should involve a deeper comprehension of metabolism, energy balance, and the molecular pathways involved in cellular stress response and survival, gut microflora genetics, enzymatic polymorphism within the human population, and the role of plant-derived polyphenols in this context. Metabolic syndrome, encompassing pathologies with a relatively high morbidity, such as type 2 diabetes, obesity, and cardiovascular disease, is a bullet point of the big concern about how daily dietary habits should promote health and prevent metabolic impairments to prevent hospitalization and the need for health care. From a clinical point of view, very few papers deal with this concern, whereas most of the evidence reported focuses on in vitro and animal models, which study the activity of phytochemicals contained in the daily diet. A fundamental issue addressed by dietitians deals with the role exerted by redox-derived reactive species. Most plant polyphenols act as antioxidants, but recent evidence supports the idea that these compounds primarily activate a mild oxidative stress to elicit a positive, beneficial response from cells. How these compounds may act upon the detoxifying system exerting a scavenging role from reactive oxygen or nitrogen species is still a matter of debate; however, it can be argued that their role is even more complex than expected, acting as signaling molecules in the cross-talk mitochondria-endoplasmic reticulum and in enzymatic pathways involved in the energetic balance. In this relationship, a fundamental role is played by the brain-adipose tissue-gut axis. The aim of this review was to elucidate this topic and the state of art about the role of reactive species in cell signaling and the function of metabolism and survival to reappraise the role of plant-derived chemicals.

Mobilization of Intracellular Copper by Gossypol and Apogossypolone Leads to Reactive Oxygen Species-Mediated Cell Death: Putative Anticancer Mechanism

There is compelling evidence that serum, tissue and intracellular levels of copper are elevated in all types of cancer. Copper has been suggested as an important co-factor for angiogenesis. It is also a major metal ion present inside the nucleus, bound to DNA bases, particularly guanine. We have earlier proposed that the interaction of phenolic-antioxidants with intracellular copper leads to the generation of reactive oxygen species (ROS) that ultimately serve as DNA cleaving agents. To further validate our hypothesis we show here that the antioxidant gossypol and its semi-synthetic derivative apogossypolone induce copper-mediated apoptosis in breast MDA-MB-231, prostate PC3 and pancreatic BxPC-3 cancer cells, through the generation of ROS. MCF10A breast epithelial cells refractory to the cytotoxic property of these compounds become sensitized to treatment against gossypol, as well as apogossypolone, when pre-incubated with copper. Our present results confirm our earlier findings and strengthen our hypothesis that plant-derived antioxidants mobilize intracellular copper instigating ROS-mediated cellular DNA breakage. As cancer cells exist under significant oxidative stress, this increase in ROS-stress to cytotoxic levels could be a successful anticancer approach.

Combinatorial phenotypic screen uncovers unrecognized family of extended thiourea inhibitors with copper-dependent anti-staphylococcal activity

The continuous rise of multi-drug resistant pathogenic bacteria has become a significant challenge for the health care system. In particular, novel drugs to treat infections of methicillin-resistant Staphylococcus aureus strains (MRSA) are needed, but traditional drug discovery campaigns have largely failed to deliver clinically suitable antibiotics. More than simply new drugs, new drug discovery approaches are needed to combat bacterial resistance. The recently described phenomenon of copper-dependent inhibitors has galvanized research exploring the use of metal-coordinating molecules to harness copper's natural antibacterial properties for therapeutic purposes. Here, we describe the results of the first concerted screening effort to identify copper-dependent inhibitors of Staphylococcus aureus. A standard library of 10 000 compounds was assayed for anti-staphylococcal activity, with hits defined as those compounds with a strict copper-dependent inhibitory activity. A total of 53 copper-dependent hit molecules were uncovered, similar to the copper independent hit rate of a traditionally executed campaign conducted in parallel on the same library. Most prominent was a hit family with an extended thiourea core structure, termed the NNSN motif. This motif resulted in copper-dependent and copper-specific S. aureus inhibition, while simultaneously being well tolerated by eukaryotic cells. Importantly, we could demonstrate that copper binding by the NNSN motif is highly unusual and likely responsible for the promising biological qualities of these compounds. A subsequent chemoinformatic meta-analysis of the ChEMBL chemical database confirmed the NNSNs as an unrecognized staphylococcal inhibitor, despite the family's presence in many chemical screening libraries. Thus, our copper-biased screen has proven able to discover inhibitors within previously screened libraries, offering a mechanism to reinvigorate exhausted molecular collections.

A paradoxical relationship between Resveratrol and copper (II) with respect to degradation of DNA and RNA

Resveratrol (R), a plant polyphenol, is known to reduce Cu (II) to Cu (I) generating reactive oxygen species that can cleave plasmid DNA. Here we report a surprising observation of a paradoxical relationship between R and Cu whereby plasmid DNA cleaving / degrading activity of R-Cu increased progressively as the ratio of R to Cu was increased i.e., the concentration of Cu was successively reduced with respect to a fixed concentration R. Whereas cleavage of plasmid DNA occurred at low molar ratios of R to Cu, at higher ratios, complete degradation of DNA was achieved. By further increasing the ratio, whereby the concentration of Cu was reduced to very low levels, the DNA degrading activity of R-Cu was lost. This paradoxical relationship is also seen with respect to eukaryotic genomic DNA and RNA. Since R-Cu may have anti-cancer and anti-viral activities, our findings may not only help to improve the therapeutic efficacy of R-Cu but also reduce its toxic side effects with the use of low concentration of Cu.

A paradoxical relationship between Resveratrol and copper (II) with respect to degradation of DNA and RNA

Resveratrol (R), a plant polyphenol, is known to reduce Cu (II) to Cu (I) generating reactive oxygen species that can cleave plasmid DNA. Here we report a surprising observation of a paradoxical relationship between R and Cu whereby plasmid DNA cleaving / degrading activity of R-Cu increased progressively as the ratio of R to Cu was increased i.e., the concentration of Cu was successively reduced with respect to a fixed concentration R. Whereas cleavage of plasmid DNA occurred at low molar ratios of R to Cu, at higher ratios, complete degradation of DNA was achieved. By further increasing the ratio, whereby the concentration of Cu was reduced to very low levels, the DNA degrading activity of R-Cu was lost. This paradoxical relationship is also seen with respect to eukaryotic genomic DNA and RNA. Since R-Cu may have anti-cancer and anti-viral activities, our findings may not only help to improve the therapeutic efficacy of R-Cu but also reduce its toxic side effects with the use of low concentration of Cu.

Effect of tannic acid, resveratrol and its derivatives, on oxidative damage and apoptosis in human neutrophils

In this study we compared the antioxidant and DNA protective activity of tannic acid and stilbene derivatives, resveratrol, 3,5,4(')-trimethoxystilbene (TMS) and pterostilbene in human neutrophils stimulated to oxidative burst by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in relation to apoptosis induction. All polyphenols within the concentration range 1-100 μM reduced the intracellular ROS and H2O2 production in the TPA-stimulated cells. Tannic acid was the most effective polyphenol in protection against DNA damage induced by TPA. In the resting neutrophils resveratrol and to lesser extent other polyphenols increased DNA damage and increased the level of p53. Pretreatment of the TPA-stimulated cells with tannic acid or stilbenes led to the induction of apoptosis. The most significant effect was observed as a result of treatment with TMS and resveratrol. These compounds appeared the most effective inducers of p53 in the TPA-challenged neutrophils, what may suggest that pro-apoptotic activity of these stilbenes might be related to p53 activation. Overall, the results of our present study demonstrate that tannic acid and stilbenes modulate the ROS production, ultimately leading to cell apoptosis in human neutrophils stimulated to oxidative burst. In resting neutrophils they exhibit pro-oxidant activity, which is accompanied by p53 induction.

Mobilization of copper ions in human peripheral lymphocytes by catechins leading to oxidative DNA breakage: A structure activity study

Epidemiological studies suggest that dietary consumption of plant polyphenols is related to a lower incidence of various cancers. Among these compounds catechins (present in green tea and other beverages) are considered to be potent inducers of apoptosis and cytotoxicity to cancer cells. Thus these compounds can be used as leads to synthesize novel anticancer drugs with greater bioavailability. In view of this in this paper we have examined the chemical basis of cytotoxicity of catechins by studying the structure-activity relationship between catechin (C), epicatechin (EC), epigallocatechin (EGC) and epigallocatechin-3-gallate (EGCG). Using single cell alkaline gel electrophoresis (comet assay) we have established the relative efficiency of cellular DNA breakage as EGCG>EGC>EC>C. We also show that cellular DNA breakage is the result of mobilization of copper ions bound to chromatin and the generation of reactive oxygen species. Further the relative DNA binding affinity order was confirmed using molecular docking and thermodynamic studies by studying the interaction of catechins with calf thymus DNA. The results suggest that the synthesis of any novel anti cancer molecule based on the structure of catechins should have as many galloyl moieties as possible resulting in an increased number of hydroxyl groups that may facilitate the binding of the molecule to cellular DNA.

Properties of Resveratrol: In Vitro and In Vivo Studies about Metabolism, Bioavailability, and Biological Effects in Animal Models and Humans

Plants containing resveratrol have been used effectively in traditional medicine for over 2000 years. It can be found in some plants, fruits, and derivatives, such as red wine. Therefore, it can be administered by either consuming these natural products or intaking nutraceutical pills. Resveratrol exhibits a wide range of beneficial properties, and this may be due to its molecular structure, which endow resveratrol with the ability to bind to many biomolecules. Among these properties its activity as an anticancer agent, a platelet antiaggregation agent, and an antioxidant, as well as its antiaging, antifrailty, anti-inflammatory, antiallergenic, and so forth activities, is worth highlighting. These beneficial biological properties have been extensively studied in humans and animal models, both in vitro and in vivo. The issue of bioavailability of resveratrol is of paramount importance and is determined by its rapid elimination and the fact that its absorption is highly effective, but the first hepatic step leaves little free resveratrol. Clarifying aspects like stability and pharmacokinetics of resveratrol metabolites would be fundamental to understand and apply the therapeutic properties of resveratrol.

Resveratrol induced inhibition of Escherichia coli proceeds via membrane oxidation and independent of diffusible reactive oxygen species generation

Resveratrol (5-[(E)-2-(4-hydroxyphenyl)ethenyl]benzene-1,3-diol), a redox active phytoalexin with a large number of beneficial activities is also known for antibacterial property. However the mechanism of action of resveratrol against bacteria remains unknown. Due to its extensive redox property it was envisaged if reactive oxygen species (ROS) generation by resveratrol could be a reason behind its antibacterial activity. Employing Escherichia coli as a model organism we have evaluated the role of diffusible reactive oxygen species in the events leading to inhibition of this organism by resveratrol. Evidence for the role of ROS in E. coli treated with resveratrol was investigated by direct quantification of ROS by flow cytometry, supplementation with ROS scavengers, depletion of intracellular glutathione, employing mutants devoid of enzymatic antioxidant defences, induction of adaptive response prior to resveratrol challenge and monitoring oxidative stress response elements oxyR, soxS and soxR upon resveratrol treatment. Resveratrol treatment did not result in scavengable ROS generation in E. coli cells. However, evidence towards membrane damage was obtained by potassium leakage (atomic absorption spectrometry) and propidium iodide uptake (flow cytometry and microscopy) as an early event. Based on the comprehensive evidences this study concludes for the first time the antibacterial property of resveratrol against E. coli does not progress via the diffusible ROS but is mediated by site-specific oxidative damage to the cell membrane as the primary event.

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Resveratrol possesses antibacterial property among a myriad of properties.

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However the reasons behind its antibacterial property remains poorly understood.

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We investigated the role of its redox property against the bacterium Escherichia coli.

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We reveal the process is free of diffusible reactive oxygen species (ROS).

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The initial event encompasses membrane damage.

Topoisomerase II-targeting properties of a grapevine-shoot extract and resveratrol oligomers

Grapevine-shoot extracts (GSE), containing trans-resveratrol and resveratrol oligomers, are commercially available as food supplements. Considering the topoisomerase-targeting properties of trans-resveratrol, the question of whether GSE affect these enzymes, thereby potentially causing DNA damage, was addressed. In a decatenation assay, GSE potently suppressed the catalytic activity of topoisomerase IIα (≥5 μg/mL). The resveratrol oligomers ε-viniferin, r2-viniferin, and hopeaphenol, isolated from GSE, were also identified as topoisomerase IIα inhibitors. In the in vivo complexes of enzyme to DNA (ICE) bioassay, neither GSE, r2-viniferin, nor hopeaphenol affected the level of enzyme-DNA intermediates in A431 cells, thus representing catalytic inhibitors rather than topoisomerase poisons. GSE caused moderate DNA strand breaks (≥25 μg/mL) in the comet assay. Taken together, GSE presumably acts as a catalytic inhibitor of topoisomerase II with r2-viniferin and hopeaphenol as potentially contributing constituents. However, the increase of FPG-sensitive sites points to an additional mechanism that may contribute to the DNA-damaging properties of GSE constituents.

Evaluation of blueberry juice in mouse azoxymethane-induced aberrant crypts and oxidative damage

Blueberry is a plant with a number of nutritional and biomedical capabilities. In the present study we initially evaluated the capacity of its juice (BJ) to inhibit the number of aberrant crypts (AC) induced with azoxymethane (AOM) in mouse. BJ was administered daily by the oral route to three groups of animals during four weeks (1.6, 4.1, and 15.0 μL/g), respectively, while AOM (10 mg/kg) was intraperitoneally injected to the mentioned groups, twice a week, in weeks two and three of the assay. We also included two control groups of mice, one administered distilled water and the other the high dose of BJ. A significant increase of AC was observed in the AOM treated animals, and a mean protection of 75.6% was determined with the two low doses of BJ tested; however, the high dose of the juice administered together with AOM increased the number of crypts more than four times the value observed in animals administered only AOM. Furthermore, we determined the antioxidant potential of BJ with an ex vivo DPPH assay and found a dose-dependent decrease with a mean of 19.5%. We also determined the DNA oxidation/antioxidation by identifying 8-hydroxy-2'-deoxyguanosine adducts and found a mean decrease of 44.3% with the BJ administration with respect to the level induced by AOM. Our results show a complex differential effect of BJ related to the tested doses, opening the need to further evaluate a number of factors so as to determine the possibility of a cocarcinogenic potential.

Is the oxidative DNA damage level of human lymphocyte correlated with the antioxidant capacity of serum or the base excision repair activity of lymphocyte?

A random screening of human blood samples from 24 individuals of nonsmoker was conducted to examine the correlation between the oxidative DNA damage level of lymphocytes and the antioxidant capacity of serum or the base excision repair (BER) activity of lymphocytes. The oxidative DNA damage level was measured with comet assay containing Fpg/Endo III cleavage, and the BER activity was estimated with a modified comet assay including nuclear extract of lymphocytes for enzymatic cleavage. Antioxidant capacity was determined with trolox equivalent antioxidant capacity assay. We found that though the endogenous DNA oxidation levels varied among the individuals, each individual level appeared to be steady for at least 1 month. Our results indicate that the oxidative DNA damage level is insignificantly or weakly correlated with antioxidant capacity or BER activity, respectively. However, lymphocytes from carriers of Helicobacter pylori (HP) or Hepatitis B virus (HBV) tend to give higher levels of oxidative DNA damage (P < 0.05). Though sera of this group of individuals show no particular tendency with reduced antioxidant capacity, the respective BER activities of lymphocytes are lower in average (P < 0.05). Thus, reduction of repair activity may be associated with the genotoxic effect of HP or HBV infection.

The relationship of copper to DNA damage and damage prevention in humans

Copper ions are well suited to facilitate formation of reactive oxygen species (ROS) that can damage biomolecules, including DNA and chromatin. That this can occur in vitro with isolated DNA or chromatin,or by exposure of cultured mammalian cells to copper complexed with various agents, has been well demonstrated. Whether that is likely to occur in vivo is not as clear. This review addresses the question of whether and how copper ions or complexes – in forms that could be present in vivo, damage DNA and chromosome structure and/or promote epigenetic changes that can lead to pathology and diseases, including cancer and neurological conditions such as Alzheimer's disease, Lewy body dementias, and spongiform encephalopathies. This question is considered in light of our knowledge that copper-dependent enzymes are important contributors to antioxidant defense, and that the mammalian organism has robust mechanisms for maintaining constant levels of copper not only in body fluids but in its major organs. Overall,and except in unusual genetic states that lead to copper overload in specific cells (particularly those in liver), it appears that excessive intake of copper is not a significant factor in the development of disease states.

[Resveratrol: distribution, properties and perspectives]

Resveratrol is a natural polyphenol which can be found in many plants and fruits, such as peanuts, mulberries, blueberries and, above all, in grapes and red wine. Its synthesis is regulated by the presence of stressful factors, such as fungal contamination and ultra-violet radiation. In plants, it plays a role as a phytoalexin, showing a capacity to inhibit the development of certain infections. Plant extracts which contain resveratrol have been employed by traditional medicine for more than 2000 years. Resveratrol was first isolated, and its properties were initially studied with scientific methods, thirty years ago. Its in vitro properties have been extensively studied and demonstrated. It is worth highlighting its activity as an anti-cancer agent, platelet anti-aggregation agent, anti-inflammatory, antiallergenic, etc. The activity of its in vivo properties are not so clear. There are many studies that report benefits on the cardiovascular system, illnesses such as diabetes, and in longevity. However, other authors did not find any agreement between in vitro and in vivo studies. This discrepancy is due to the bioavailability of resveratrol. After an oral dose, it has been demonstrated that the absorption is very high, but the metabolic pathways leave just a little free resveratrol in blood, therefore the bioavailability in the target tissues is very low and the concentrations used in in vitro studies are not found in these tissues. Thus, resveratrol is a very active molecule for maintaining health, but due to the low bioavailability not all the in vitro effects can be translated to in vivo. This opens a new potential approach, seeking derivatives of resveratrol that can be measured in the desired tissues.

Resveratrol-sensitized UVA induced apoptosis in human keratinocytes through mitochondrial oxidative stress and pore opening

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a polyphenol compound, is derived from natural products such as the skin of red grapes, blueberries and cranberries. Resveratrol not only exhibits antioxidant, cardioprotection, and anti-aging properties, but can also inhibit cancer cell growth and induce apoptosis. It has been shown that resveratrol inhibits the activation of Nf-κB and subsequently down regulates the expression of Nf-κB regulated genes such as interleukin-2 and Bcl-2, leading to cell cycle arrest and increased apoptosis in multiple myeloma cells. In the skin, resveratrol has been reported to sensitize keratinocytes to UVA induced apoptosis. However, the effect of resveratrol on opening of the mitochondrial permeability transition pore has not been previously examined. Our data show that UVA (14 J/cm(2)) along with resveratrol causes massive oxidative stress in mitochondria. As a consequence of oxidative stress, the mitochondrial membrane potential decreases which results in opening of the mitochondrial pores ultimately leading to apoptosis in human keratinocytes. These results may have clinical implications for development of future chemotherapeutic treatment for tumors of the skin.

Resveratrol protects mouse embryonic stem cells from ionizing radiation by accelerating recovery from DNA strand breakage

Resveratrol has elicited many provocative anticancer effects in laboratory animals and cultured cells, including reduced levels of oxidative DNA damage, inhibition of tumor initiation and progression and induction of apoptosis in tumor cells. Use of resveratrol as a cancer-preventive agent in humans will require that its anticancer effects not be accompanied by damage to normal tissue stem or progenitor cells. In mouse embryonic stem cells (mESC) or early mouse embryos exposed to ethanol, resveratrol has been shown to suppress apoptosis and promote survival. However, in cells exposed to genotoxic stress, survival may come at the expense of genome stability. To learn whether resveratrol can protect stem cells from DNA damage and to study its effects on genomic integrity, we exposed mESC pretreated with resveratrol to ionizing radiation (IR). Forty-eight hours pretreatment with a comparatively low concentration of resveratrol (10 μM) improved survival of mESC >2-fold after exposure to 5 Gy of X-rays. Cells pretreated with resveratrol sustained the same levels of reactive oxygen species and DNA strand breakage after IR as mock-treated controls, but repaired DNA damage more rapidly and resumed cell division sooner. Frequencies of IR-induced mutation at a chromosomal reporter locus were not increased in cells pretreated with resveratrol as compared with controls, indicating that resveratrol can improve viability in mESC after DNA damage without compromising genomic integrity.