Resveratrol--from the bottle to the bedside?

Resveratrol Delivery from Implanted Cyclodextrin Polymers Provides Sustained Antioxidant Effect on Implanted Neural Probes

Intracortical microelectrodes are valuable tools used to study and treat neurological diseases. Due in large part to the oxidative stress and inflammatory response occurring after electrode implantation, the signal quality of these electrodes decreases over time. To alleviate this response, resveratrol, a natural antioxidant which elicits neuroprotective effects through reduction of oxidative stress, was utilized. This work compares traditional systemic delivery of resveratrol to the novel cyclodextrin polymer (pCD) local delivery approach presented herein, both in vitro and in vivo. The pCD displayed an extended resveratrol release for 100 days, as well as 60 days of free radical scavenging activity in vitro. In vivo results indicated that our pCD delivery system successfully delivered resveratrol to the brain with a sustained release for the entire short-duration study (up to 7 days). Interestingly, significantly greater concentrations of resveratrol metabolites were found at the intracortical probe implantation site compared to the systemic administration of resveratrol. Together, our pilot results provide support for the possibility of improving the delivery of resveratrol in an attempt to stabilize long-term neural interfacing applications.

Resveratrol: Review on its discovery, anti-leukemia effects and pharmacokinetics

Resveratrol, found in variety of plants, is a natural stilbene structure polyphenol. It has various pharmacological effects, such as antioxidation, anti-aging, anti-inflammation, anti-cancer, antiobesity, anti-diabetes, cardioprotection, neuroprotection. Recently, anti-leukemia activities of resveratrol has been studied extensively via its effects on a variety of biological processes involving cell proliferation, apoptosis, autophagy. Current treatments of leukemia mainly rely on intensive chemotherapy or hematopoietic stem cell transplantation, however, these treatments are still with poor survival and high treatment-related mortality. Therefore, it is extremely needed to find relatively non-toxic medicines with minimal side effects but sufficient therapeutic efficacy. Resveratrol is one such potential candidate owing to its reported anti-leukemia effect. In this review, we summarized resveratrol's discovery, sources and isolation methods, administration methods, effects in different types of leukemia, pharmacokinetics and toxicities, aiming to exploit resveratrol as a potential drug candidate for anti-leukemia.

The therapeutic potential of resveratrol: a review of clinical trials

Resveratrol is a nutraceutical with several therapeutic effects. It has been shown to mimic effects of caloric restriction, exert anti-inflammatory and anti-oxidative effects, and affect the initiation and progression of many diseases through several mechanisms. While there is a wealth of in vitro and in vivo evidence that resveratrol could be a promising therapeutic agent, clinical trials must confirm its potential. In this work, we reviewed the current clinical data available regarding the pharmacological action of resveratrol. Most of the clinical trials of resveratrol have focused on cancer, neurological disorders, cardiovascular diseases, diabetes, non-alcoholic fatty liver disease (NAFLD), and obesity. We found that for neurological disorders, cardiovascular diseases, and diabetes, the current clinical trials show that resveratrol was well tolerated and beneficially influenced disease biomarkers. However resveratrol had ambiguous and sometimes even detrimental effects in certain types of cancers and in NAFLD. In most of the clinical trials, the major obstacle presented was resveratrol’s poor bioavailability. Thus, this work provides useful considerations for the planning and design of future pre-clinical and clinical research on resveratrol.

Improved oral delivery of resveratrol using proliposomal formulation: investigation of various factors contributing to prolonged absorption of unmetabolized resveratrol

OBJECTIVES

The objective of this study was to design lipid-based formulation to enhance the absorption of unmetabolized resveratrol (RSV) over adequate time and investigate various factors that contribute to prolonged absorption of RSV.

METHODS

Proliposomal formulations containing distearoyl phosphatidyl choline (DSPC) with or without cholesterol were prepared and evaluated. The liposomes obtained from hydration of proliposomal mixture were evaluated for size, zeta, physical appearance and entrapment. The integrity of liposomes in bile salt solution and solubility of RSV in sodium taurocholate solution in the presence of various concentrations of DSPC were evaluated to assess the stability and in varied gastrointestinal conditions. Finally, oral pharmacokinetic studies of liposomal dispersions in comparison with RSV solution were evaluated.

RESULTS

Results revealed that spontaneous formation of liposomes did not occur upon hydration of RSV: DSPC proliposomes rather showed tendency to form loose cotton-like aggregates. Cholesterol aided in the formation of stable liposomes with large negative zeta potential. Release of RSV from liposomes in the presence of taurocholate was dependent on the amount and type of total lipid. Liposomes without cholesterol showed faster release, and release increased as the amount of DSPC in the formulation increased. Solubility studies indicated that DSPC increases the solubility of RSV in the presence of sodium taurocholate, and corroborates that bilayer assembly is disrupted because of interaction between RSV and DSPC. Mixture of RSV:DSPC:Chol at 1:0.25:0.25 formed stable colloidal dispersion with zeta potential -22 and released only 20 - 23% of entrapped RSV when incubated with 20 mM sodium taurocholate. Pharmacokinetic profile revealed that AUC and Cmax were twofold higher than plain RSV.

CONCLUSION

The proliposomal formulation optimized by considering various physicochemical factors and simulated in vitro testing result in significant improvement rate and extent of absorption of unmetabolized RSV.

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.

Resveratrol and cellular mechanisms of cancer prevention

The use of novel and improved chemopreventive and chemotherapeutic agents for the prevention and treatment of cancer is on the rise. Natural products have always afforded a rich source of such agents. Epidemiological evidence suggests that a higher flavonoid intake is associated with low cancer risk. Accumulating data clearly indicate that the induction of apoptosis is an important component in the chemoprevention of cancer by naturally occurring dietary agents. Resveratrol, a naturally occurring polyphenol, demonstrates pleiotropic health benefits, including antioxidant, anti-inflammatory, antiaging, cardioprotective, and neuroprotective activities. Because of these properties and their wide distribution throughout the plant kingdom, resveratrol is envisioned as a potential chemopreventive/curative agent. Currently, a number of preclinical findings from our lab and elsewhere suggest resveratrol to be a promising natural weapon in the war against cancer. Remarkable progress in elucidating the molecular mechanisms underlying the anticancer properties of resveratrol has been achieved. Here, we focus on some of the myriad pathways that resveratrol targets to exert its chemopreventive role and advocate that resveratrol holds tremendous potential as an efficient anticancer drug of the future.

Piceatannol inhibits phorbol ester-induced NF-kappa B activation and COX-2 expression in cultured human mammary epithelial cells

There are multiple lines of evidence supporting that inflammation is causally linked to carcinogenesis. Abnormal upregulation of cyclooxygenase-2 (COX-2), a rate-limiting enzyme in the prostaglandin biosynthesis, has been implicated in carcinogenesis. Trans-3,4,3',5'-tetrahydroxystilbene (piceatannol), a naturally occurring hydroxylated stilbene with potent anti-inflammatory and antioxidative activities, has been shown to inhibit the proliferation of several cancer cells by inducing apoptosis or blocking cell cycle progression. In this study, we examined the effect of piceatannol on activation of the nuclear transcription factor NF-kappa B, one of the major transcription factors that regulate proinflammatory COX-2 gene transcription, in human mammary epithelial (MCF-10A) cells treated with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA). When pretreated to MCF-10A cells, piceatannol markedly inhibited TPA-induced NF-kappa B DNA binding to a greater extent than resveratrol and oxyresveratrol, stilbene analogs structurally related to piceatannol. Piceatannol also inhibited TPA-induced phosphorylation and degradation of Ikappa Balpha as well as nuclear translocation of the phosphorylated form of p65, the functionally active subunit of NF-kappa B. Likewise, TPA-induced expression of COX-2 was abrogated by piceatannol pretreatment. The thiol reducing agent dithiothreitol abolished the inhibitory effects of piceatannol on NF-kappa B DNA binding activity, suggesting that piceatannol may directly modify NF-kappa B or its regulator through reaction with the cysteine thiol(s).

Anti-cancer effect of resveratrol is associated with induction of apoptosis via a mitochondrial pathway alignment

Resveratrol, a phytoalexin found in the skin of grapes, is believed to have multiple bioactivities including anti-cancer, anti-carcinogenesis and antiinflammatory. The mechanisms by which resveratrol might produce these effects are not well understood. In this study, malignant human pancreatic cancer cells were treated without or with resveratrol in combination with ionizing radiation (IR), and then the mitochondrial function of treated cells was evaluated using several standardized assays. They include the Calcein AM method for mitochondria transition pore; the JC-1 staining method for mitochondria membrane potential; the CM-H2DCFDA method for reactive oxygen species; and the Annexin V/propidium iodide (PI) method for apoptosis/cell death. Our results indicated that (1) pore function was partially intact after resveratrol, but resveratrol probably interfered with the accumulation of intracellular Calcein AM; (2) depolarization of the mitochondria membrane was increased in the resveratrol treated cells, consistent with mitochondrial dysfunction; (3) ROS was slightly increased with resveratrol, a phenomenon that was greatly increased when this agent was combined with IR; and (4) in parallel with the above changes in mitochondrial and drug transport, cells treated with resveratrol showed increased apoptosis as measured by Annexin V/PI staining. In summary, the anti-cancer effect of resveratrol is associated with the damage of mitochondrial function that leads to increased ROS, apoptosis, and possibly intracellular drug accumulation via inhibition of proteins involved in multi-drug resistance (MDR).

RETRACTED: Resveratrol induces apoptosis involving mitochondrial pathways in mouse skin tumorigenesis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Editor-in-Chief. Multiple figures in this article appear to be falsified/fabricated, and can not be verified as the corresponding author does not have the original data. Figure 2. It appears that data has been duplicated in panels V and VI. Figure 3A. Lanes II and VI in the p53 wild band appear to be duplicated. Figure 4A. Lanes I, II, V and VI of the Beta-actin blot appear to be the same data replicated. Figure 4B. The representative blots in the Bcl-2 band, lanes V and VI are identical, as are all lanes in the Beta-actin band. Figure 5B. Lanes III and IV of the Apaf 1 band, when rotated and vertically stretched, are duplicated and appear in Figure 3D as lanes III and IV of the Cytochrome C blot in “Chemopreventive potential of resveratrol in mouse skin tumors through regulation of mitochondrial and PI3K/AKT signaling pathways.” Pharmaceutical Research (2009). Doi: 10.1007/s11095-008-9723-z. Figure 5C. Lanes II and V of the Caspase 9 band appear to be duplicated. Figure 5E. The bands in lane V and VI of the Beta-actin blot are duplicated. Figure 5B and 5C. The Beta-actin lane IV band in 5B and lane IV in 5C appear to be duplicated from Figure 6B in “Hepatoprotective effects of lupeol and mango pulp extract of carcinogen induced alteration in Swiss albino mice.” Molecular Nutrition & Food Research (2007). Doi: 10.1002/mnfr.200600113.

Analysis of signaling pathways in 90 cancer cell lines by protein lysate array

Multiple signal transduction pathways play a crucial role in cancer development, progression, and response to different therapies. An important issue is whether common signal transduction pathways are ubiquitously altered in all cancer types and some unique pathways are involved in different cancer types. Another important issue is whether and how transduction signaling molecules are heterogeneously expressed and activated in different cancer cells within and between cancer cell types.

METHODS

To gain insight into these issues, we assembled a protein lysate array with 90 different cell lines of 12 different cell types. Each sample is diluted 2-fold six times, and samples from the dilution series were printed three times on the array. We then measured the expression levels and phosphorylation status of 52 different signaling proteins with specific antibodies and carried out statistical hierarchical clustering analysis.

RESULTS

The most significant finding based on the cluster analysis was that the cell lines did not group based on tumor types, suggesting that the signaling pathways studied were commonly activated in most of the tumor types cultured in vitro. As expected, related proteins associated with specific signaling pathways clustered together, and analysis of the 30 most differentially expressed proteins revealed the PI3-K signaling pathway was upregulated in several different tumor types and the VEGF-angiogenesis pathway was downregulated in hematopoetic cancers. Another important observation, with clinical implications was that EGFR was the most heterogeneous among all the cell lines. We also observed signaling pathways unique to specific types of cancers such as the inverse relationship between p16ink and Rb, and the EGFR mediated pathway activation characteristic of pancreatic cancers.

CONCLUSIONS

Using reverse phase lysate array analysis in this study, we were able to determine potential relationships and signaling pathways, both common and unique, to different types of cancer using cell lines in vitro. This data could be utilized for mining information related to an individual cancer of interest and combined with morphological and genomic profiles would help in creating a combination of expression markers and/or functional signaling maps for specific cancer diagnosis and therapy.

A prospective analysis of alcohol consumption and onset of perimenopause

OBJECTIVES

We prospectively assessed the association between alcohol consumption and onset of perimenopause in women of late reproductive age using data from the Harvard Study of Moods and Cycles. Specific types of alcoholic beverages - red wine, white wine, beer, and liquor - were evaluated.

METHODS

Among 502 women aged 36-45 years residing in seven Boston communities, we assessed self-reported perimenopausal symptoms over a 5-year period. The onset of perimenopause was defined using changes in menstrual characteristics. We administered a semiquantitative food frequency questionnaire at enrollment to measure regular alcohol consumption during the past year. Hazard ratios (HRs) and 95% confidence intervals were derived from Cox regression models.

RESULTS

No association was found between total alcohol consumption and time to perimenopause. Compared with women consuming <1 alcoholic drink per month, HRs for those drinking red wine in quantities of 1-3 glasses per month, 1 glass per week, or >or=2 glasses per week were all below 1.0, after accounting for other sources of alcohol. Among never smokers, the inverse association with red wine was stronger and a positive association was observed with liquor consumption although numbers were small. No associations were observed with white wine or beer.

CONCLUSION

While there was no association between total alcohol consumption and onset of perimenopause, there was some suggestion of an inverse association between red wine and risk of perimenopause, particularly among never smokers.

Pro-oxidant Activity of Low Doses of Resveratrol Inhibits Hydrogen Peroxide-Induced Apoptosis

We have recently shown that efficient apoptotic signaling is a function of a permissive intracellular milieu created by a decrease in the ratio of superoxide to hydrogen peroxide and cytosolic acidification. Resveratrol, a phytoalexin found in grapes and wines, triggers apoptosis in some systems and inhibits the death signal in others. In this regard, the reported inhibitory effect on hydrogen peroxide-induced apoptosis has been attributed to its antioxidant property. Here, we provide evidence that exposure of human leukemia cells to low concentrations of resveratrol (4-8 micro M) inhibits caspase activation and DNA fragmentation induced by incubation with hydrogen peroxide or upon triggering apoptosis with a novel compound that kills via intracellular hydrogen peroxide production. At these concentrations, resveratrol elicits pro-oxidant properties as evidenced by an increase in intracellular superoxide concentration. This pro-oxidant effect is further supported by our observations that the drop in intracellular superoxide and cytosolic acidification induced by hydrogen peroxide is completely blocked in cells preincubated with resveratrol. Thus, the inhibitory effect of resveratrol on hydrogen peroxide-induced apoptosis is not due to its antioxidant activity, but contrarily via a pro-oxidant effect that creates an intracellular environment nonconducive for apoptotic execution.

Resveratrol causes Cdc2-tyr15 phosphorylation via ATM/ATR-Chk1/2-Cdc25C pathway as a central mechanism for S phase arrest in human ovarian carcinoma Ovcar-3 cells

Resveratrol is one of the most extensively studied cancer chemopreventive agents; however, its mechanisms of action are not completely understood. Here, we observed that resveratrol induces S phase arrest via Tyr15 phosphorylation of Cdc2 in human ovarian carcinoma Ovcar-3 cells. Overexpression of Cdc2AF, a mutant resistant to Thr14 and Tyr15 phosphorylation, ablated resveratrol-induced S phase arrest. Further upstream, we observed that resveratrol causes phosphorylation of cell division cycle 25C (Cdc25C) tyrosine phosphatase via the activation of checkpoint kinases Chk1 and Chk2, which in turn were activated via ATM (ataxia telangiectasia mutated)/ATR (ataxia telangiectasia-Rad3-related) kinase in response to DNA damage, as resveratrol also increased phospho-H2A.X (Ser139), which is known to be phosphorylated by ATM/ATR in response to DNA damage. The involvement of these molecules in resveratrol-induced S phase was also supported by the studies showing that addition of ATM/ATR inhibitor caffeine reverses resveratrol-caused activation of ATM/ATR-Chk1/2 as well as phosphorylation of Cdc25C, Cdc2 and H2A.X, and S phase arrest. In additional studies assessing whether observed effects of resveratrol are specific to Ovcar-3 cells, we observed that it also induces S phase arrest and H2A.X (Ser139) phosphorylation in other ovarian cancer cell lines PA-1 and SKOV-3, albeit at different levels; whereas, resveratrol showed only marginal S phase arrest in normal human foreskin fibroblasts with undetectable level of phospho-H2A.X (Ser139). These findings for the first time identify that resveratrol causes Cdc2-tyr15 phosphorylation via ATM/ATR-Chk1/2-Cdc25C pathway as a central mechanism for DNA damage and S phase arrest selectively in ovarian cancer cells, and provide a rationale for the potential efficacy of ATM/ATR agonists in the prevention and intervention of cancer.

Anticancer activity of resveratrol on implanted human primary gastric carcinoma cells in nude mice

AIM: To investigate the apoptosis of implanted primary gastric cancer cells in nude mice induced by resveratrol and the relation between this apoptosis and expression of bcl-2 and bax.

METHODS: A transplanted tumor model was established by injecting human primary gastric cancer cells into subcutaneous tissue of nude mice. Resveratrol (500 mg/kg, 1000 mg/kg and 1500 mg/kg) was directly injected beside tumor body 6 times at an interval of 2 d. Then changes of tumor volume were measured continuously and tumor inhibition rate of each group was calculated. We observed the morphologic alterations by electron microscope, measured the apoptotic rate by TUNEL staining method, detected the expression of apoptosis-regulated genes bcl-2 and bax by immunohistoch-emical staining and PT-PCR.

RESULTS: Resveratrol could significantly inhibit carcinoma growth when it was injected near the carcinoma. An inhibitory effect was observed in all therapeutic groups and the inhibition rate of resveratrol at the dose of 500 mg/kg, 1000 mg/kg and 1500 mg/kg was 10.58%, 29.68% and 39.14%, respectively. Resveratrol induced implanted tumor cells to undergo apoptosis with apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation, nucleus fragmentation. The inhibition rate of 0.2 mL of normal saline solution, 1 500 mg/kg DMSO, 500 mg/kg resveratrol, 1000 mg/kg resveratrol, and 1500 mg/kg resveratrol was 13.68±0.37%, 13.8±0.43%, 48.7±1.07%, 56.44±1.39% and 67±0.96%, respectively. The positive rate of bcl-2 protein of each group was 29.48±0.51%, 27.56±1.40%, 11.86±0.97%, 5.7±0.84% and 3.92±0.85%, respectively by immunohistochemical staining. The positive rate of bax protein of each group was 19.34±0.35%, 20.88±0.91%, 40.02±1.20%, 45.72±0.88% and 52.3±1.54%, respectively by immunohistochemical staining. The density of bcl-2 mRNA in 0.2 mL normal saline solution, 1500 mg/kg DMSO, 500 mg/kg resveratrol, 1000 mg/kg resveratrol, and 1500 mg/kg resveratrol decreased progressively and the density of bax mRNA in 0.2 mL normal saline solution, 1500 mg/kg DMSO, 500 mg/kg resveratrol, 1000 mg/kg resveratrol, and 1500 mg/kg increased progressively with elongation of time by RT-PCR.

CONCLUSION: Resveratrol is able to induce apoptosis of transplanted tumor cells. This apoptosis may be mediated by down-regulating apoptosis-regulated gene bcl-2 and up-regulating the expression of apoptosis-regulated gene bax.

Chemotherapeutic potential of the chemopreventive phytoalexin resveratrol

The last couple of decades have seen a tremendous increase in interest in the biological properties of natural products as a means to identify novel small compounds that could have potential in clinical medicine. To that end, flavonoids- and flavonoid-like compounds percolate to the top due to their presence in diet constituents and reported beneficial effects on diverse biological processes and disease conditions. As such, the plant polyphenolic antibiotic resveratrol, found in grapes, nuts and wines, has been the focus of many studies aimed at understanding its full range of health beneficial effects. The interest in this compound stems from the earlier observations describing the therapeutic benefits of roots of the oriental medicinal plant from which resveratrol was first isolated. Being a constituent of grapes and wines, the initial work was focused on linking resveratrol to the beneficial cardiovascular effects of moderate wine intake, however, since its reported cancer chemopreventive activity in a murine model of carcinogenesis, there has been a heightened interest in understanding the anti-cancer activity of resveratrol. As a result, a substantial amount of data strongly suggests that resveratrol could affect the process of carcinogenesis through a variety of different mechanisms in different tumor cell types. However, a couple of recent reports provide evidence to the contrary. This critical review attempts to summarize some of these findings and discuss the clinical potential of this compound or its derivatives in the light of the recent conflicting reports.

Resveratrol induces apoptosis in human esophageal carcinoma cells

AIM: To investigate the apoptosis in esophageal cancer cells induced by resveratrol, and the relation between this apoptosis and expression of Bcl-2 and Bax.

METHODS: In in vitro experiments, MTT assay was used to determine the cell growth inhibitory rate. Transmission electron microscope and TUNEL staining method were used to quantitatively and qualitively detect the apoptosis status of esophageal cancer cell line EC-9706 before and after the resveratrol treatment. Immunohistochemical staining was used to detect the expression of apoptosis-regulated gene Bcl-2 and Bax.

RESULTS: Resveratrol inhibited the growth of esophageal cancer cell line EC-9706 in a dose-and time-dependent manner. Resveratrol induced EC-9706 cells to undergo apoptosis with typically apoptotic characteristics, including morphological changes of chromatin condensation, chromatin crescent formation, nucleus fragmentation and apoptotic body formation. TUNEL assay showed that after the treatment of EC-9706 cells with resveratrol (10 mmol·L^-1) for 24 to 96 hs, the AIs were apparently increased with treated time (P < 0.05). Immunohistochemical staining showed that after the treatment of EC-9706 cells with resveratrol (10 mmol·L^-1) for 24 to 96 hs, the PRs of Bcl-2 proteins were apparently reduced with treated time (P < 0.05) and the PRs of Bax proteins were apparently increased with treated time (P < 0.05).

CONCLUSION: Resveratrol is able to induce the apoptosis in esophageal cancer. This apoptosis may be mediated by down-regulating the apoptosis-regulated gene Bcl-2 and up-regulating the expression of apoptosis-regulated gene bax.

Resveratrol-induced limitation of dysfunction of mitochondria isolated from rat brain in an anoxia-reoxygenation model

Resveratrol protection on the main functions of purified rat brain mitochondria submitted to anoxia-reoxygenation was investigated. Resveratrol (<0.1 microM) reversed partly (23.3%) the respiratory control ratio (RCR) decrease by protecting both states 3 and 4. This effect was both observed when resveratrol was added before anoxia or reoxygenation. Resveratrol fully inhibited the release of cytochrome c in a concentration-dependent manner and significantly decreased the superoxide anion (O2(0-)) production at a concentration of 1 nM. The mitochondrial membranes damaged after the anoxia-reoxygenation were partly protected (about 70%) by resveratrol at 0.1 microM. The oxygen consumption of mitochondria in presence of NADH and cytochrome c was significantly inhibited by resveratrol with a low EC50 of 18.34 pM. Resveratrol inhibited the CCCP-induced uncoupling from about 20%. The effects of resveratrol on oxidative phosphorylation parameters were also investigated in rats after pretreatment (0.4, 2 and 10 mg/kg/day) for one week. After the isolation of brain mitochondria, the RCR was significantly less decreased in the resveratrol group compared to the control group. These results showed that resveratrol could preserve the mitochondrial functions with at least three mechanisms: antioxidant properties, action on complex III and a membrane stabilizing effect.

Comparative antiproliferative and apoptotic effects of resveratrol, epsilon-viniferin and vine-shots derived polyphenols (vineatrols) on chronic B lymphocytic leukemia cells and normal human lymphocytes

Trans-resveratrol, its dimer epsilon-viniferin and two preparations of vineatrol (a grape-derived polyphenol fraction isolated from vine-shots extracts) were compared for their effects on the proliferation and survival of normal and leukemic human lymphocytes. The two different batches of vineatrol (vineatrol 10 and 25%) was obtained by HPLC fractionation and contained 10 and 25% trans-resveratrol, respectively. The different polyphenols were added to cultures of leukemic cells from chronic B cell malignancies (B-cell chronic lymphocytic leukemia, B-CLL or hairy cell leukemia, HCL) or normal peripheral blood-derived mononuclear cells (PBMC) as a control. The different polyphenols displayed anti-proliferative effect on the leukemic cells, as estimated by the observed inhibition of tritiated thymidine uptake and the reduction of cell recovery. Vineatrol 10% was the most potent whereas vineatrol 25% and resveratrol displayed comparable activity, epsilon-viniferin only exhibiting slight effets. The same order of potency was observed for their capacity to induce apoptosis in leukemic B cells. In contrast, the survival of normal peripheral blood mononuclear cells (PBMC) was little affected in the presence of these polyphenolic compounds and higher concentrations were required in order to elicit cell death. Polyphenol-driven apoptosis in chronic leukemic B cells was shown to correlate with an activation of caspase 3, a drop in the mitochondrial transmembrane potential, a reduction in the expression of the anti-apoptotic protein bcl-2, as well as a reduction in the expression of the inducible nitric oxide synthase (iNOS). Our data therefore indicate that vine-shoots may be a convenient and natural source of material for the purification of resveratrol and other polyphenolic compounds of putative therapeutic interest.

Anti-hepatoma activity of resveratrol in vitro

AIM: To study the anti-tumor effect of resveratrol alone and the synergistic effects of resveratrol with 5-FU on the growth of H22 cells line in vitro

METHODS: The number of cells was measured by MTT method,the morphological changes of H₂₂ cells were investigated under microscopy and electron microscopyq.

RESULTS: Resveratrol inhibited the growth of hepatoma cells line H₂₂ in a dose- and time-dependent manner. IC₅₀ of the resveratrol on H₂₂ cells was 6.57 mg·L^-1. The synergistic anti-tumor effects of resveratrol with 5-FU increased to a greater extent than for H22 cells treated with 5-FU alone (70.2% vs 28.4%)(P < 0.05). Under microscope and electron microscope, characteristics of apoptosis such as typical apoptotic bodies were commonly found in tumor cells in the drug-treated groups.

CONCLUSION: Resveratrol can suppresses the growth of H₂₂ cells in vitro, its anti-tumor activity may occur through the induction of apoptosis.