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PubMed1982

Spectrophotometric assay for mammalian cytosolic epoxide hydrolase using trans-stilbene oxide as the substrate.

A continuous spectrophotometric assay based on the differences in the ultraviolet spectra of trans-stilbene oxide (TSO) and its reaction product 1,2-diphenyl-1,2-ethanediol is described for the measurement of mammalian cytosolic epoxide hydrolase activity. Rates of TSO hydration determined by this method were similar to those obtained by independent analytical methods, and the assay is rapid, reproducible and relatively free from interference.

Animals↗
PubMed1987

Differential induction of cytochrome P-450 by the enantiomers of trans-stilbene oxide.

Optically pure (+)- and (-)-trans-stilbene oxide (TSO) enantiomers were administered to immature male Sprague-Dawley rats. (+)-TSO was the more potent inducer of liver microsomal cytochrome P-450-dependent monooxygenases. The greater potency of (+)-TSO may be explained on the basis of stereoselective metabolism since a far greater concentration of TSO was found in liver microsomes of (+)-TSO-treated rats. Furthermore, of the enzymes known to metabolize TSO, cytosolic epoxide hydrolase turned over the (-)-TSO enantiomer at a faster rate, consistent with the greater persistence of the (+)-enantiomer. Although this report is of chiral effects in potency of enzyme induction, stereoselective metabolism (i.e. disposition) rather than inherent structural characteristics (recognition) may be responsible for these effects.

Animals↗
PubMed1992

Effect of stilbene derivatives on gastric H+, K(+)-ATPase.

The effect of naturally occurring hydroxystilbene, 3,3',4,5-tetrahydroxystilbene (piceatanol), and its derivatives on gastric H+, K(+)-ATPase was studied. Piceatanol inhibited H+, K(+)-ATPase in a dose-dependent manner. The 50% inhibition value was 4.3 x 10(-6) M. It was found from the kinetic study that the inhibition of the enzyme by piceatanol was competitive with respect to ATP and was noncompetitive with respect to K+. Piceatanol also effectively inhibited gastric acid secretion. However, methylation of phenolic hydroxy groups of piceatanol resulted in a complete loss of inhibition of the enzyme and acid secretion, suggesting the role of phenolic hydroxy groups in the inhibition. The study on hydroxystilbene derivatives also showed that phenolic hydroxy groups are important in the interaction with H+, K(+)-ATPase and that stilbenes with neighbouring hydroxy groups are the most effective inhibitors.

Adenosine Triphosphate↗
PubMed1992

Correlation between trans-stilbene oxide-glutathione conjugation activity and the deletion mutation in the glutathione S-transferase class mu gene detected by polymerase chain reaction.

Glutathione S-transferase (GST) class Mu activity was determined in 145 unrelated hospital patients in Berlin by measuring their conjugation activity towards the specific substrate trans-stilbene oxide (TSO) with two substrate concentrations (50 and 250 microM) in homogenates prepared from lymphocytes. Eighty individuals (55.2%) had an activity lower than 10 pmol/min/10(6) lymphocytes and were classified as GST class Mu deficient. In 142 of 145 cases, phenotype was confirmed by the results of a genotyping procedure using the polymerase chain reaction technique. Two fragments of 273 and about 650 bp including one and two introns, respectively, could always be amplified from genomic DNA in individuals with high GST class Mu activity and could not be amplified in persons with impaired glutathione-TSO conjugation activity. This indicates that persons with low activity carry a large deletion mutation within the GST class Mu gene. The enzymatically determined antimode between low and high activity determined as 10 pmol/min/1 million lymphocytes in the assay with 50 microM TSO could be clearly confirmed by genotyping.

Adult↗
PubMed1985

Selective neuronal uptake of 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) and other related substituted stilbenes in vivo: a fluorescent whole cell staining technique.

The uptake of fluorescent stilbene derivatives including 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid (SITS) was shown to occur from the blood or cerebrospinal fluid in the adult albino rat. SITS was found to be internalized in select populations of neurons, especially pyramidal neurons in layers V and VI of neocortex, granule, hilar and pyramidal neurons in the hippocampus, Purkinje neurons of the cerebellar cortex and predominantly large multipolar neurons in the oculomotor nuclei, lateral vestibular nucleus, red nucleus and the medial gigantocellular brainstem reticular formation neurons. The extent and quality of labeling of neuronal somata, dendrites and axons can be exploited with this technique to produce selective, 'Golgi' type labeling in the nervous system. The methods utilized are fast, economical, long lasting and compatible with fluorescence tracers and immunofluorescence techniques.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1989

Stilbenes inhibit exchange of chloride between blood, choroid plexus and cerebrospinal fluid.

Disulfonic stilbenes (DIDS and SITS) were used to probe the nature of Cl transport in choroid plexus (CP) of adult rats. DIDS was more effective than SITS in reducing in vitro choroid cell [Cl]. Intravenously- or intraventricularly-administered DIDS substantially decreased 36Cl transport from blood to CP to CSF. Rate of CSF renewal was diminished nearly 30% by DIDS. These inhibitory findings implicate an anion antiporter for mediating Cl flux (and thus water) between blood and CSF.

Animals↗
PubMed1988

Elimination of Na+ and GTP regulation of alpha 2-adrenoceptor-agonist interactions in rat kidney membranes by 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS).

Pretreatment of rat kidney membranes with 4,4'-diisothiocyano-2,2'-stilbene disulfonic acid (DIDS) did not affect the Bmax but reduced the affinity of the receptors for antagonist by less than 2-fold. However, such treatment reduced the affinity of the receptors for agonist by several fold by preventing the formation of agonist-receptor-Gi-protein complex. The modulatory effects of GTP and Na+ on alpha 2-adrenoceptor-agonist interactions were also abolished. These results suggest that DIDS acts at multiple sites on alpha 2-adrenoceptor-adenylate cyclase complex.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1978

Immunofluorescence studies with 4-acetamido-4'-isothiocyanato stilbene-2,2'-disulphonic acid (SITS).

The application of the fluorochrome 4-acetamido-4'-isothiocyanato stilbene-2,2'-disulphonic acid (SITS) in immunofluorescence was studied. The optimal excitation wave length is 350 nm, and optimal fluorescence is obtained at 420 nm. After purification of the commercial compound, conjugation is performed in a strong buffer at pH 9.0-9.5. SITS conjugates were very satisfactory for immunofluorescence studies of the cytoplasmic antigens of cell preparations, but their blue emission was difficult to distinguish from autofluorescence in sections of human tissues. Good results with immunofluorescence on membrane bound antigens were obtained by using an ultra-violet laser beam as light source. SITS can be used simultaneously with FITC and TRITC conjugates thus making it possible to show three antigens in one preparation.

Cell Membrane↗
PubMed1994

Induction of micronuclei by stilbene-type and steroidal estrogens in Syrian hamster embryo and ovine seminal vesicle cells in vitro.

The induction of micronuclei (MN) is a known effect of the carcinogenic estrogen diethylstilbestrol (DES). We have now tested the time course and dose dependence of MN induction by DES and its analogs 3',3"-DES, indenestrol A (IA), indenestrol B (IB) or by the steroidal estrogen 17 beta-estradiol (E2) and by the clastogenic compound 4-nitroquinoline-N-oxide (NQO) in two primary mammalian cell culture systems. All compounds induced MN in Syrian hamster embryo and ovine seminal vesicle cells with compound-specific time courses and dose dependences. DES induced a maximum MN frequency 12 h post treatment, whereas with all other estrogens the highest MN frequency was observed 3-6 h after removal of the compound. The maximum MN frequency after NQO treatment occurred at 24 h or later. Of the stilbene estrogens tested, only DES caused an increase of the mitotic index. Further characterization of the MN by indirect immunofluorescence microscopy using CREST antikinetochore antibodies revealed that 92-99% of the DES-induced MN but only 0-2% of the NQO-induced MN contained CREST-reactive kinetochores. Since kinetochore-positive MN are indicative of whole chromosomes/chromatids and kinetochore-negative MN of acentric chromosomal fragments, our findings support the view that DES acts as a pure aneuploidogen and NQO as a pure clastogen in the two cell systems. In the case of 3',3"-DES, IA, IB and E2, 41-68% of the induced MN contained CREST-reactive kinetochores. As the time courses of MN induction are not compatible with those of clastogenic agents, it is proposed that these estrogens induce MN containing chromatids/chromosomes with altered kinetochore structures.

Animals↗
PubMed1985

False-positive results in the radioimmunoassay detection of stilbene derivatives after administration of fluorinated corticosteroids to animals.

During routine inspections, indications were found that the therapeutic use of fluocortolone or dexamethasone can cause false-positive results in the detection of stilbene derivatives by radioimmunoassay (RIA) in samples of animal origin. After experimental application of the fluorinated corticosteroids to rabbits or calves, the assumed false-positive RIA results were confirmed. The kinetics after application of dexamethasone were concomitant with the elimination of radioactive [3H]dexamethasone. Furthermore, it could be demonstrated that [3H]dexamethasone was transformed in the faeces of rabbits and calves. The metabolites formed were not completely separated by the extraction procedure used for the RIA and seemed to be responsible for the false-positive results.

Animals↗
PubMed1981

Induction of drug-metabolizing enzymes and toxicity of trans-stilbene oxide in rat liver and kidney.

The effect of trans-stilbene oxide (TSO) on organ function and morphology and on drug-metabolizing enzymes was determined in male Sprague-Dawley rats. TSO (300 or 600 mg/kg) was administered i.p., once daily for 5 consecutive days. At a dose of 3400 mg/kg, TSO did no alter body weight, but increased liver weight. The higher dose (600 mg/kg) markedly decreased body weight. TSO treatment (300 mg/kg) induced several drug-metabolizing enzymes. Epoxide hydrolase activity was enhanced in the liver, kidney and lung. In contrast, arylhydrocarbon hydroxylase activity was not significantly altered. Glutathione S-transferase activity, with 1-chloro-2,4-dinitrobenzene as substrate, and uridine diphosphoglucuronyl transferase activity, with p-nitrophenol as substrate, were also increased in the liver and kidney after TSO treatment. It appears that TSO induces hepatic and renal enzyme activities in a similar manner. Treatment with the higher dose of TSO depressed accumulation of p-amino-hippurate by renal cortical slices and increased blood urea nitrogen concentration. Histological examination of kidney sections after treatment with TSO revealed no abnormality. The lower dose led to negligible alteration in liver and the higher dose resulted in mild to moderate hepatic cellular.

Animals↗
PubMed1984

Effect of dietary trans-stilbene oxide on hepatic and renal drug-metabolizing enzyme activities and bromobenzene-induced toxicity in male Sprague-Dawley rats.

The effect of dietary trans-stilbene oxide (TSO) on hepatic and renal xenobiotic metabolizing-enzyme activities and bromobenzene-induced toxicity was quantified in adult male Sprague-Dawley rats. Rats were fed a regular diet or the same diet supplemented with 2.5 g TSO/kg diet for 10 days. TSO treatment did not alter hepatic or renal arylhydrocarbon hydroxylase activity, but significantly increased glutathione S-transferase and uridine diphosphoglucuronyl transferase activities in both organs. In addition, TSO increased hepatic, but not renal, epoxide hydrolase activity. The same treatment did not produce adverse effects on renal or hepatic functions, but markedly potentiated bromobenzene hepatotoxicity. A single dose of bromobenzene (0.2 ml/kg) caused a slight increase in serum glutamic pyruvic transaminase (SGPT) activity and minor hepatic necrosis in animals fed the control diet; the same dose of bromobenzene markedly increased SGPT activity and produced severe hepatic necrosis in the TSO-fed animals.

Animals↗
PubMed1995

Effects of stilbenes isolated from medicinal plants on arachidonate metabolism and degranulation in human polymorphonuclear leukocytes.

Studies were made on the effects of stilbene derivatives isolated from medicinal plants on arachidonate metabolism and degranulation in human polymorphonuclear leukocytes (PMN-L). Resveratrol (3,4',5-trihydroxystilbene) isolated from the roots of Reynoutria japonica was found to inhibit the 5-lipoxygenase products 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), 5,12-dihydroxy-6,8,10,14-eicosatetraenoic acid (5,12-diHETE) and leukotriene C4(LTC4); its concentrations for 50% inhibition (IC50) were 8.90 x 10(-6) M, 6.70 x 10(-6) M and 1.37 x 10(-6) M, respectively. The IC50 of 5-HETE, 5,12-diHETE and LTC4 formations of synthetic 3,3',4-trihydroxystilbene were 5.90 x 10(-6) M, 6.30 x 10(-7) M and 8.80 x 10(-7) M, respectively. Moreover, they inhibited the release of lysosomal enzyme such as lysozyme and beta-glucuronidase induced by calcium ionophore A 23187 from human PMN-L at 10(-3)-10(-4) M.

Arachidonic Acid↗
PubMed2006

Proteasome-independent down-regulation of estrogen receptor-alpha (ERalpha) in breast cancer cells treated with 4,4'-dihydroxy-trans-stilbene.

Treatment of cells with estrogens and several pure ERalpha antagonists rapidly induces down-regulation of the alpha-type estrogen receptor (ERalpha) in the nucleus by mechanisms that are sensitive to the proteasome inhibitors, MG132 and clasto-lactacystin-beta-lactone. Hence, it is believed that these ER ligands induce down-regulation of ERalpha by proteasome-dependent mechanisms, which serve to control both the amount of transcriptional activity and the level of ligand-bound ERalpha in cells. In this study, we observed that treatment of cultured MCF-7 and T47D human breast cancer cells with the low affinity ER ligand, 4,4'-dihydroxy-trans-stilbene (4,4'-DHS), inhibited the transcriptional activity of ERalpha and induced slow and gradual decrease in the amount of ERalpha protein (henceforth referred to as down-regulation of ERalpha). The 4,4'-DHS-induced down-regulation of ERalpha in MCF-7 cells involved a mechanism that was insensitive to the two most specific proteasome inhibitors, clasto-lactacystin-beta-lactone and epoxomycin, but sensitive to MG132 at concentrations exceeding that required for maximal inhibition of the proteasome in MCF-7 cells. Therefore, 4,4'-DHS appears to induce down-regulation of ERalpha by a proteasome-independent mechanism. Here, we present data to show that both 4-OH and 4'-OH are critical for the ability of 4,4'-DHS to induce down-regulation of ERalpha and suggest that 4,4'-DHS provides a useful scaffold for development of novel ERalpha antagonists.

Base Sequence↗
PubMed2004

Synthesis and biological evaluation of stilbene-based pure estrogen antagonists.

Replacement of one of the ethyl substituents in diethylstilbestrol by side chains with functional groups converted this potent estrogen into pure antiestrogens with the potential for the treatment of breast cancer. These agents completely suppressed estrogen receptor-mediated gene activation and inhibited the growth of estrogen-sensitive MCF-7 breast cancer cells in submicromolar concentrations. The most potent derivative displayed similar activity as fulvestrant (ICI 182,780) in vitro and in the mouse uterine weight test. Obviously, the stilbene structure can act as a substitute for estradiol in the development of pure estrogen antagonists.

Animals↗
PubMed2006

Aza-stilbenes as potent and selective c-RAF inhibitors.

The synthesis of several novel aza-stilbene derivatives was carried out. The compounds were tested for their c-RAF enzyme inhibition. Compound 27 possesses significant potency against c-RAF and demonstrates selectivity over other protein kinases. A hypothesis for the binding mode, activity, and selectivity is proposed.

Aza Compounds↗
PubMed2006

Synthesis of radiolabeled stilbene derivatives as new potential PET probes for aryl hydrocarbon receptor in cancers.

New carbon-11 and fluorine-18 labeled stilbene derivatives, cis-3,5-dimethoxy-4'-[11C]methoxystilbene (4'-[11C]8a), cis-3,4',5-trimethoxy-3'-[11C]methoxystilbene (3'-[11C]8b), trans-3,5-dimethoxy-4'-[11C]methoxystilbene (4'-[11C]10a), trans-3,4',5-trimethoxy-3'-[11C]methoxystilbene (3'-[11C]10b), cis-3,5-dimethoxy-4'-[18F]fluorostilbene (4'-[18F]12a), and trans-3,5-dimethoxy-4'-[18F]fluorostilbene (4'-[18F]13a), were designed and synthesized as potential PET probes for aryl hydrocarbon receptor (AhR) in cancers.

Animals↗
PubMed2006

Synthesis and antimicrobial activity of new (E)-4-[piperidino (4'-methylpiperidino-, morpholino-) N-alkoxy]stilbenes.

The synthesis of twenty-one new (E)-4-[piperidino-(4;-methylpiperidino-, morpholino-)N-alkoxy] stilbenes is reported. The compounds were tested for antimicrobial activities against Gram-negative, Gram-positive bacteria, and fungi. In particular, compounds 3b, 3c, 3f, 3g, 3h, 3k, 3l showed good antibacterial activity against Staphylococcus aureus and 3h, 3k, 3m, 3n also against Bacillus subtilis, as well as 3h, 3n also against Streptococcus faecalis.

Anti-Infective Agents↗