Resveratrol Analogues Research Articles

Toward an understanding of the role of a catechol moiety in cancer chemoprevention: The case of copper- and o-quinone-dependent Nrf2 activation by a catechol-type resveratrol analog.

Catechol moieties are commonly present in dietary natural products that exert cancer chemopreventive activity. While the oxidative conversion of catechols into their corresponding o-quinones is generally considered to contribute to their cancer chemopreventive effects, the mechanism of the intracellular conversion has not been fully elucidated. Among resveratrol and its hydroxylated analogs examined, only 3,4-dihydroxy-trans-stilbene exerted cytoprotective effects against t-butylhydroperoxide-induced death of HepG2 cells. This resveratrol analog activated the nuclear factor erythroid-2-related factor 2 (Nrf2) pathway through stimulating phosphorylation of Akt and inducing keap1 modification, thereby resulting in its nuclear translocation and subsequent transcriptional induction of phase II detoxifying enzymes. Its cytoprotective effect through Nrf2 activation was largely abrogated by pretreatment of cells with DTT, a sulfhydryl-containing nucleophile, and neocuproine, a specific chelating agent for copper ions. We identified 3,4-dihydroxy-trans-stilbene as a novel Nrf2 activator that is converted intracellularly into its corresponding o-quinone electrophile by copper ions. The copper-mediated oxidation was required for the Nrf2 activation, subsequent transcriptional induction of phase II detoxifying enzymes and ultimately for cytoprotection. The findings demonstrate a previously underrecognized role for intracellular copper ions in the cancer chemopreventive effects of catechol-containing dietary natural products.

Antioxidant and anti-inflammatory properties of 1,2,4-oxadiazole analogs of resveratrol

The chemopreventive properties of resveratrol are ascribed mostly to its antioxidant activity, in particular its scavenging ability for reactive oxygen species (ROS), and to the inhibition of NF-κB pathway which has also been suggested as an important underlying mechanism of its reported properties. In present study, a small library of nine 1,2,4-oxadiazole-based structural analogs of resveratrol were assayed for their antioxidant and anti-inflammatory activities. Several compounds showed significant inhibitory activities against NF-κB and/or ROS production. Compound 2, incorporating two para-hydroxyphenyl moieties connected by the 1,2,4-oxadiazole ring, was the most active, its potency in inhibiting activation of NF-κB and ROS scavenging abilities surpassing that of resveratrol. Additionally, we elucidated the mechanisms underlying the NF-κB inhibitory activity of compound 2. Finally, in contrast to resveratrol, compound 2 significantly reduced the LPS-induced release of pro-inflammatory cytokines, indicating its prominent anti-inflammatory potential.

Deprotometalation–iodolysis and computed CH acidity of 1,2,3- and 1,2,4-triazoles. Application to the synthesis of resveratrol analogues

1-Aryl- and 2-aryl-1,2,3-triazoles were synthesized by N-arylation of the corresponding azoles using aryl iodides. The deprotometalations of 1-phenyl-1,2,3-triazole and -1,2,4-triazole were performed using a 2,2,6,6-tetramethylpiperidino-based mixed lithium–zinc combination and occurred at the most acidic site, affording by iodolysis the 5-substituted derivatives. Dideprotonation was noted from 1-(2-thienyl)-1,2,4-triazole by increasing the amount of base. From 2-phenyl-1,2,3-triazoles, and in particular from 2-(4-trifluoromethoxy)phenyl-1,2,3-triazole, reactions at the 4 position of the triazolyl, but also ortho to the triazolyl on the phenyl group, were observed. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method. 4-Iodo-2-phenyl-1,2,3-triazole and 4-iodo-2-(2-iodophenyl)-1,2,3-triazole were next involved in Suzuki coupling reactions to furnish the corresponding 4-arylated and 4,2′-diarylated derivatives. When evaluated for biological activities, the latter (which are resveratrol analogues) showed moderate antibacterial activity and promising antiproliferative effect against MDA-MB-231 cell line.

Synthesis of Pinacolylboronate-Substituted Stilbenes and their application to the synthesis of boron capped polyenes

A series of novel 4,4,5,5-tetramethyl-2-(4-substitutedstyrylphenyl)-1,3,2 dioxaborolane derivatives has been synthesized. 4-(4,4,5,5-tetramethyl-1,3,2-dioxaboratophenyl)-methyl triphenylphosphonium bromide (4) was treated with 3 equiv of tBuONa, various aldehydes in the presence of DMF, and stirred at room temperature 4–6 h to yield the corresponding boron containing stilbene derivatives 1a-n in 71–94% yields. A one-pot protocol transformation has also been developed and used this methodology to synthesize boron containing resveratrol analogues. Simple and clean reactions, high yield of the products are the salient features of this methodology. We used this reaction to synthesize the boron capped polyenes. These boron containing polyene systems are potential intermediate to synthesize conjugated polyene as new material for LCD (Liquid Crystal Display) technology. The biological testing of these compounds is currently underway to identify potential therapeutic for Neurodegenerative diseases.

Abstract 4648: Differential regulation of estrogen metabolizing CYP1A1 and CYP1B1 enzymes by novel resveratrol analogs in breast cancer cells

Abstract Evidence from epidemiological and experimental studies suggest an association between diets rich in phytoestrogens and reduced risk of breast cancer. Resveratrol, a bioflavonoid, found naturally in grapes, fruits and nuts, has been shown to be a potent chemopreventive agent in vitro. However, poor bioavailability, rapid metabolism and poor specificity limit its use as the preferred anticancer agent. In an attempt to improve the anticancer properties of resveratrol, we synthesized several analogs of resveratrol with appropriate chemical modifications. Of the compounds that were screened for anticancer activity towards breast cancer cells, two analogs, namely, HPIMBD and TIMBD showed better potency and selectivity in inhibiting the growth of breast cancer cell lines while they did not significantly affect the growth of non-neoplastic breast epithelial cell lines. In this study, we investigated the ability of resveratrol and resveratrol analogs in the regulation of estrogen metabolizing genes, cytochrome P450 (Cyp) 1A1, 1B1 and their upstream regulator AhR in breast cancer and non-neoplastic breast epithelial cells. Non-neoplastic breast epithelial cell line MCF-10A and breast cancer cell lines T47D and MDA-MB-231 were treated with resveratrol, HPIMBD or TIMBD. From cells in culture, mRNA and protein was isolated and expression analyses of CYP1A1, CYP1B1 and AhR carried out by PCR and western blot analyses. Unlike resveratrol, HPIMBD and TIMBD significantly induced the mRNA and protein expression levels of CYP1A1 and AhR while they inhibited that of CYP1B1. Also, HPIMBD and TIMBD induced the expression of CYP1A1 in an AhR-dependent fashion while they inhibited CYP1B1 expression of CYP1B1 by a proteosomal degradation pathway. Cyp1A1 preferentially metabolizes estradiol to 2-hydroxyestradiol and Cyp1B1 to 4-hydroxyestradiol. While, 2-hydroxyestradiol and its methylated product are suggested to be chemo-protective, 4-hydroxyestradiol is regarded as a carcinogenic metabolite of estradiol. Taken together, our findings indicate that novel resveratrol analogs HPIMBD and TIMBD differentially regulate the expressions of CYP1A1 and CYP1B1 in breast cancer cells that may have implications in chemoprevention of breast cancer by these analogs. Note: This abstract was not presented at the meeting. Citation Format: Amruta Mukund Ronghe, Anwesha Chatterjee, Subhash Padhye, Hari K. Bhat. Differential regulation of estrogen metabolizing CYP1A1 and CYP1B1 enzymes by novel resveratrol analogs in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4648. doi:10.1158/1538-7445.AM2015-4648

Abstract 4650: Novel resveratrol-analog HPIMBD inhibits breast cancer cell metastasis by reversal of epithelial-mesenchymal transition

Abstract Epithelial-mesenchymal transition (EMT) is a biological process that mediates a phenotypical change in the polarized epithelial cells to mesenchymal cells. The process of EMT increases a cell's migratory and invasive properties. It is well documented that the process of EMT plays a very critical role in cancer metastasis. The objective of this study was to characterize the role of a novel Resveratrol analog 4-(E)-{4-hydroxyphenylimino)-methylbenzene, 1,2-diol} (HPIMBD) on EMT in human breast cancer cells. Human breast cancer cells MDA-MB-231 were treated with Resveratrol (Res) and HPIMBD for up to 48 hours. Protein expression levels of E-cadherin, matrix metalloproteases (MMPs), snail, slug, zeb1/2 and nuclear migration of β-catenin were quantified after treatment with Res or HPIMBD and compared with that of the vehicle-treated control cells. mRNA expression levels of β-catenin and wnt-7b were also quantified. Migration MDA-MB-231 cells was determined after treatment with Res or HPIMBD by wound healing assay. Treatment with HPIMBD significantly up-regulated E-cadherin protein expression levels. The up-regulation of E-cadherin by HPIMBD was associated with suppression of snail, slug and Zeb1 protein levels. HPIMBD significantly down-regulated mRNA expression levels of β-catenin and wnt-7b. Furthermore, HPIMBD restricted nuclear migration of β-catenin. Treatment of breast cancer cells with HPIMBD resulted in down-regulation of MMP3 and MMP9 but not MMP2 protein expression levels. Treatment with HPIMBD also prevented breast cancer cell migration. Our studies demonstrtae that HPIMBD decreases the metastatic properties of breast cancer cells by inhibition of EMT and down-regulation of wnt/β catenin pathway. These findings suggest that HPIMBD may have a potential in inhibtion of EMT and may be explored as as a potential therapy to prevent breast cancer metastasis. Note: This abstract was not presented at the meeting. Citation Format: Anwesha Chatterjee, Amruta Ronghe, Subhash Padhye, Hari K. Bhat. Novel resveratrol-analog HPIMBD inhibits breast cancer cell metastasis by reversal of epithelial-mesenchymal transition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4650. doi:10.1158/1538-7445.AM2015-4650

피세아타놀에 의한 YD-15 구강암세포의 세포자가사멸 유도 효과

Piceatannol (trans-3,4,3',5'-trihydroxystilbene), a natural stilbene, is an analogue of resveratrol. In the present study, possible mechanisms by which piceatannol exerts its pro-apoptotic action in cultured human oral cancer YD-15 cells were investigated. To investigate whether or not piceatannol has effects on cancer cell viability, human oral YD-15 cells were treated with piceatannol (0, 50, and 100 μM). Piceatannol treatment (100 μM) showed the strongest inhibition of cell proliferation and reduced cell viability in a dose-dependent manner. Chromatin condensation detected by DAPI staining significantly increased in a concentration-dependent manner, indicating apoptosis. Piceatannol treatment activated initiator Bax (pro-apoptotic) and cPARP in a concentration-dependent manner. Further, piceatannol induced down-regulation of Bcl-2 (anti-apoptotic). We also evaluated the activity of piceatannol against oral cavity cancer tumors in mice. Piceatannol-treated nude mice bearing YD-15 xenograft tumors exhibited significantly reduced tumor volume and weight due to the potent effect of piceatannol on tumor cell apoptosis, as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay. Immunohistochemistry staining showed elevated expression of cleaved-caspase-3 as well as reduced expression of Ki-67 in the piceatannol-treated group. Therefore, piceatannol can be developed as a cancer preventive medicine due to its growth inhibitory effects and induction of apoptosis in human oral cancer cells.

Epigenetic potential of resveratrol and analogs in preclinical models of prostate cancer.

Lifestyle, particularly diet, is a risk factor for prostate cancer. Dietary polyphenols such as resveratrol possess anticancer properties and therefore have chemopreventive and therapeutic potential. Resveratrol has pleiotropic effects, exerting its biological activity through multiple pathways and targets, including those associated with cancer. Numerous studies have demonstrated the anticancer effects of resveratrol and, to a lesser extent, its analogs, in tissue culture, while in vivo observations are limited. Here, we provide a concise summary of our results on epigenetic mechanisms of resveratrol and analogs mediated through regulation of chromatin modifier metastasis-associated protein 1 (MTA1) and microRNAs (miRNAs), and highlight the anticancer effects of these compounds in preclinical models of prostate cancer. We suggest that the identified stilbene responsive mechanism-based biomarkers, such as MTA1 and oncogenic miRNAs, may become indicative of treatment efficacy in prostate cancer. Resveratrol analogs with better bioavailability, conferring superior pharmacological potencies and greater anticancer effects, may become stronger candidates for clinical development.

Resveratrol analogue 3,4,4'-trihydroxy-trans-stilbene induces apoptosis and autophagy in human non-small-cell lung cancer cells in vitro.

To investigate the effects of 3,4,4'-trihydroxy-trans-stilbene (3,4,4'-THS), an analogue of resveratrol, on human non-small-cell lung cancer (NSCLC) cells in vitro. Cell viability of NSCLC A549 cells was determined by MTT assay. Cell apoptosis was evaluated using flow cytometry and TUNEL assay. Cell necrosis was evaluated with LDH assay. The expression of apoptosis- or autophagy-associated proteins was measured using Western blotting. The formation of acidic compartments was detected using AO staining, neutral red staining and Lysotracker-Red staining. LC3 punctae were analyzed with fluorescence microscopy. Treatment with 3,4,4'-THS (10-80 μmol/L) concentration-dependently inhibited the cell viability. It did not cause cell necrosis, but induced apoptosis accompanied by up-regulation of cleavaged PARP, caspase3/9 and Bax, and by down-regulation of Bcl-2 and surviving. It also increased the formation of acidic compartments, LC3-II accumulation and GFP-LC3 labeled autophagosomes in the cells. It inhibited the mTOR-dependent pathway, but did not impair autophagic flux. 3,4,4'-THS-induced cell death was enhanced by the autophagy inhibitors 3-MA (5 mmol/L) or Wortmannin (2 μmol/L). Moreover, 3,4,4'-THS treatment elevated the ROS levels in the cells, and co-treatment with 3-MA further elevated the ROS levels. 3,4,4'-THS-induced apoptosis and autophagy in the cells was attenuated by NAC (10 mmol/L)Conclusion:3,4,4'-THS induces both apoptosis and autophagy in NSCLC A549 cells in vitro. Autophagy inhibitors promote 3,4,4'-THS-induced apoptosis of A549 cells, thus combination of 3,4,4'-THS and autophagy inhibitor provides a promising strategy for NSCLC treatment.

Biological and computational evaluation of resveratrol inhibitors against Alzheimer’s disease

It has been reported that beta amyloid induces production of radical oxygen species and oxidative stress in neuronal cells, which in turn upregulates β-secretase (BACE-1) expression and beta amyloid levels, thereby propagating oxidative stress and increasing neuronal injury. A series of resveratrol derivatives, known to be inhibitors of oxidative stress-induced neuronal cell death (oxytosis) were biologically evaluated against BACE-1 using homogeneous time-resolved fluorescence (TRF) assay. Correlation between oxytosis inhibitory and BACE-1 inhibitory activity of resveratrol derivatives was statistically significant, supporting the notion that BACE-1 may act as pivotal mediator of neuronal cell oxytosis. Four of the biologically evaluated resveratrol analogs demonstrated considerably higher activity than resveratrol in either assay. The discovery of some “hits” led us to initiate detailed docking studies associated with Molecular Dynamics in order to provide a plausible explanation for the experimental results and understand their molecular basis of action.

Resveratrol and Cancer

Resveratrol is a stilbene substance, belonging to the superfamily of phytoalexins, which are compounds synthesized by plants when stress occurs, usually an infection. It is abundant in red wine, red grapes, blueberries, peanuts and pistachios. Resveratrol induces p53-dependent apoptosis. A novel resveratrol analogue, HS-1793, has recently been demonstrated to inhibit vascular endothelial growth factor (VEGF) in human prostate cancer cells. Pterostilbene, an analog of resveratrol, has been demonstrated to exert both autophagy and apoptosis in human bladder and breast cancer cell lines. It has also been found to cause accumulation of autophagic vacuoles as well as promote cell death via a mechanism involving lysosomal membrane permeabilization in human melanoma, colon, lung and breast cancer cell lines. Identification of a receptor site for resveratrol in cancer cells, supports the potential of this compound as a therapeutic agent. The receptor could also serve as a vehicle for studies of future resveratrol analogues. Resveratrol has also been documented to overcome chemo-resistance by inhibiting NF- κ B and STAT3 pathway. Resveratrol has shown much promise in preclinical trials and because of its good safety profile it may be an ideal chemo-preventive and chemotherapeutic agent.

A Resveratrol Analogue Promotes ERKMAPK-Dependent Stat3 Serine and Tyrosine Phosphorylation Alterations and Antitumor Effects In Vitro against Human Tumor Cells.

(E)-4-(3,5-dimethoxystyryl)phenyl acetate (Cmpd1) is a resveratrol analog that preferentially inhibits glioma, breast, and pancreatic cancer cell growth, with IC50 values of 6-19 μM. Notably, the human U251MG glioblastoma tumor line is the most sensitive, with an IC50 of 6.7 μM, compared with normal fibroblasts, which have an IC50 > 20 μM. Treatment of U251MG cells that harbor aberrantly active signal transducer and activator of transcription (Stat) 3 with Cmpd1 suppresses Stat3 tyrosine705 phosphorylation in a dose-dependent manner in parallel with the induction of pserine727 Stat3 and extracellular signal-regulated kinase/mitogen-activated protein kinase 1/2 (pErk1/2(MAPK)). Inhibition of pErk1/2(MAPK) induction by the mitogen-activated protein/extracellular signal-regulated kinase kinase inhibitor PD98059 [2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one] blocked both the pserine727 Stat3 induction and ptyrosine705 Stat3 suppression by Cmpd1, indicating dependency on the mitogen-activated protein/extracellular signal-regulated kinase kinase-Erk1/2(MAPK) pathway for Cmpd1-induced modulation of Stat3 signaling. Cmpd1 also blocked epidermal growth factor-stimulated pStat1 induction, whereas upregulating pSrc, pAkt, p-p38, pHeat shock protein 27, and pmammalian target of rapamycin levels. However, pJanus kinase 2 and pEpidermal growth factor receptor levels were not significantly altered. Treatment of U251MG cells with Cmpd1 reduced in vitro colony formation, induced cell cycle arrest in the G2/M phase and cleavage of caspases 3, 8, and 9 and poly(ADP ribose) polymerase, and suppressed survivin, myeloid cell leukemia 1, Bcl-xL, cyclin D1, and cyclin B1 expression. Taken together, these data identify a novel mechanism for the inhibition of Stat3 signaling by a resveratrol analog and suggest that the preferential growth inhibitory effects of Cmp1 occur in part by Erk1/2(MAPK)-dependent modulation of constitutively active Stat3.

Resveratrol-salicylate derivatives as selective DNMT3 inhibitors and anticancer agents

Resveratrol is a natural polyphenol with plethora of biological activities. Resveratrol has previously shown to decrease DNA-methyltransferase (DNMT) enzymes expression and to reactivate silenced tumor suppressor genes. Currently, it seems that no resveratrol analogs have been developed as DNMT inhibitors. Recently, we reported the synthesis of resveratrol-salicylate derivatives and by examining the chemical structure of these analogs, we proposed that these compounds could exhibit DNMT inhibition especially that they resembled NSC 14778, a compound we previously identified as a DNMT inhibitor by virtual screening. Indeed, using in vitro DNMT inhibition assay, some of the resveratrol-salicylate analogs we screened in this work that showed selective inhibition against DNMT3 enzymes which were greater than resveratrol. A molecular docking study revealed key binding interactions with DNMT3A and DNMT3B enzymes. In addition, the most active analog, 10 showed considerable cytotoxicity against three human cancer cells; HT-29, HepG2 and SK-BR-3, which was greater than resveratrol. Further studies are needed to understand the anticancer mechanisms of these derivatives.

A resveratrol analog termed 3,3',4,4',5,5'-hexahydroxy-trans-stilbene is a potent HIV-1 inhibitor.

HIV resistance to current anti-HIV drugs and drug toxicity have created a need for new anti-HIV agents. We have examined and characterized a synthetic resveratrol analog, termed 3,3',4,4',5,5'-hexahydroxy-trans-stilbene (M8), for potential anti-HIV activity. Here, we demonstrate that M8 possesses potent anti-HIV activity against several HIV variants with EC50 values in the low μM range. M8 was shown to act at a very early step of HIV entry prior to fusion to host cells. These results demonstrate that this novel resveratrol derivative possesses potent anti-HIV-1 activity and may have a mechanism of action that is different from current anti-HIV-1 drugs including entry inhibitors. Further structure-guided design might lead to the development of newer improved resveratrol derivatives that could have value either in therapy or as microbicides to prevent the sexual transmission of HIV-1.

Anticancer Evaluation of 3,4,5,4'-trans-tetramethoxystilbene (DMU-212) and Its Analogs Against an Extensive Panel of Human Tumor Cell Lines

DMU-212, a methoxylated resveratrol analog, has significant anticancer activity, and selectively targets tumor cells. A library of E-diarylstilbenes structurally related to DMU-212 has been synthesized and evaluated for anticancer activity against a large panel of 45 human cancer cell lines. From this study, DMU-212 (3a) exhibited an average growth inhibitory effect (GI50) of 3.5 M against all the human cancer cell lines in the panel, and was particularly effective against the four cancer cell lines: SNB-75 (CNS), MDA-MB-435 (melanoma), A498 (renal), and MCF7 (breast), with GI50 values of 1.88, 1.04, 0.74 and 1.66 µM, respectively. Also, the 4’-chloro analog of DMU-212, 3d, exhibited 98 and 80 percent growth inhibition against MDA-MB-435 (melanoma) and K-562 (leukemia) cancer cell lines at a concentration of 10 M. Further investigation of DMU-212 and its analogs may provide novel therapeutic avenues for treatment of a variety of human cancers. Keywords: Resveratrol, DMU-212, anticancer, growth inhibition, cytotoxicity, diarylstilbenes.

Structural modification of resveratrol leads to increased anti-tumor activity, but causes profound changes in the mode of action

(Z)-3,5,4′-Trimethoxystilbene (Z-TMS) is a resveratrol analog with increased antiproliferative activity towards a number of cancer cell lines compared to resveratrol, which has been shown to inhibit tubulin polymerization in vitro. The purpose of this study was to investigate if Z-TMS still shows potential for the prevention of metabolic diseases as known for resveratrol.Cell growth inhibition was determined with IC50 values for Z-TMS between 0.115μM and 0.473μM (resveratrol: 110.7μM to 190.2μM). Flow cytometric analysis revealed a G2/M arrest after Z-TMS treatment, whereas resveratrol caused S phase arrest. Furthermore, Z-TMS was shown to impair microtubule polymerization. Beneficial effects on lipid accumulation were observed for resveratrol, but not for Z-TMS in an in vitro steatosis model. (E)-Resveratrol was confirmed to elevate cAMP levels, and knockdown of AMPK attenuated the antiproliferative activity, while Z-TMS did not show significant effects in these experiments. SIRT1 and AMPK activities were further measured indirectly via induction of the target gene small heterodimer partner (SHP). Thereby, (E)-resveratrol, but not Z-TMS, showed potent induction of SHP mRNA levels in an AMPK- and SIRT1-dependent manner, as confirmed by knockdown experiments.We provide evidence that Z-TMS does not show beneficial metabolic effects, probably due to loss of activity towards resveratrol target genes. Moreover, our data support previous findings that Z-TMS acts as an inhibitor of tubulin polymerization. These findings confirm that the methylation of resveratrol leads to profound changes in the mode of action, which should be taken into consideration when conducting lead structure optimization approaches.

Pterostilbene, an Active Constituent of Blueberries, Stimulates Nitric Oxide Production via Activation of Endothelial Nitric Oxide Synthase in Human Umbilical Vein Endothelial Cells.

Endothelial dysfunction, a key process in development of cardiovascular diseases, is largely due to reduced nitric oxide (NO) derived from endothelial NO synthase (eNOS). Resveratrol has been reported to stimulate NO production via estrogen receptor α (ERα) activation in endothelial cells. Here, we investigated whether two natural methylated analogs of resveratrol, pterostilbene (Pts) and trans-3,5,4'-trimethoxystilbene (TMS), similarly to resveratrol, could influence endothelial NO release in human umbilical vein endothelial cells (HUVECs). In HUVECs exposed to Pts or TMS, NO production and phosphorylation of eNOS, protein kinase B (Akt), and ERα were measured by using a fluorimetric NO assay kit and Western blot analysis, respectively. Dimethylated Pts, but not trimethylated TMS, stimulated dose-dependent NO production via eNOS phosphorylation. Pts also stimulated dose-dependent phosphorylation of Akt, but not of ERα. NO production and eNOS phosphorylation in response to Pts were significantly abolished by the phosphoinositide 3-kinase (PI3K)/Akt inhibitor LY294002, but not by the ERα antagonist ICI182780. Our results suggest that Pts, but not TMS, is capable of inducing eNOS phosphorylation and the subsequent NO release, presumably, by activating PI3K/Akt pathway. The potential efficacy of Pts, an active constituent of blueberries, may aid in the prevention of cardiovascular diseases characterized by endothelial dysfunction.

Determination of naturally occurring resveratrol analog trans-4,4'-dihydroxystilbene in rat plasma by liquid chromatography-tandem mass spectrometry: application to a pharmacokinetic study.

trans-4,4'-Dihydroxystilbene (DHS) is a naturally occurring resveratrol analog that displayed promising anti-cancer activities in pre-clinical studies. To further probe its therapeutic potential, a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the measurement of DHS in rat plasma using electrospray ionization and multiple reaction monitoring in its negative ion mode. This analytical method demonstrated excellent linearity (R(2) > 0.99), selectivity, sensitivity (with a lower limit of quantification of 2.0 ng/mL), accuracy (both intra- and inter-day analytical recovery within 100 ± 15%) and precision (both intra- and inter-day relative standard deviation within 10%). The pharmacokinetic profiles of DHS were subsequently assessed in Sprague-Dawley rats. Following intravenous injection (4 mg/kg), DHS had a moderate apparent volume of distribution of the central compartment (V(c) = 887 ± 297 mL/kg), clearance (Cl = 44.7 ± 5.1 mL/min/kg) and a relatively short mean transit time (MTT = 24.1 ± 8.8 min). When it was given as an oral suspension (10 mg/kg), DHS was absorbed slowly (t max 180 or 300 min) with very limited plasma exposure and absolute oral bioavailability (F = 2.22 ± 0.72%). On the other hand, when DHS was fully solubilized by hydroxypropyl-β-cyclodextrin, it was absorbed rapidly (t(max) 30 or 45 min) with more than 15-fold increase in maximal plasma concentration (C(max)), plasma exposure (AUC(0→last)) and bioavailability (F = 36.3 ± 4.8%). Statistical comparison provided clear evidence that DHS was better than resveratrol from the perspective of pharmacokinetics. In conclusion, further explorations of DHS as an anti-cancer agent are warranted.

HO-1 Signaling Activation by Pterostilbene Treatment Attenuates Mitochondrial Oxidative Damage Induced by Cerebral Ischemia Reperfusion Injury.

quinone oxidoreductase 1 (NQO1) and glutathione S-transferases (GSTs), which are induced by PTE. PTE also promoted a well-preserved mitochondrial membrane potential (MMP), mitochondria complex I activity, and mitochondria complex IV activity, increased the mitochondrial cytochrome c level, and decreased the cytosolic cytochrome c level. However, this PTE-elevated mitochondrial function was reversed by ZnPP or HO-1 siRNA treatment. In summary, our results demonstrate that PTE treatment attenuates cerebral IRI by reducing IR-induced mitochondrial oxidative damage through the activation of HO-1 signaling.

Heteroaromatic analogs of the resveratrol analog DMU-212 as potent anti-cancer agents.

Heteroaromatic analogs of DMU-212 (8-15) have been synthesized and evaluated for their anti-cancer activity against a panel of 60 human cancer cell lines. These novel analogs contain a trans-3,4,5-trimethoxystyryl moiety attached to the C2 position of indole, benzofuran, benzothiazole or benzothiophene ring (8, 11, 13 and 14, respectively) and showed potent growth inhibition in 85% of the cancer cell lines examined, with GI50 values <1 μM. Interestingly, trans-3,4- and trans-3,5-dimethoxystyryl DMU-212 analogs 9, 10, 12 and 15 exhibited significantly less growth inhibition than their 3,4,5-trimethoxystyryl counterparts, suggesting that the trans-3,4,5-trimethoxystyryl moiety is an essential structural element for the potent anti-cancer activity of these heterocyclic DMU-212 analogs. Molecular modeling studies showed that the four most active compounds (8, 11, 13 and 14) all bind to the colchicine binding site on tubulin, and that their binding modes are similar to that of DMU-212.