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PubMed2004

New stilbene derivatives from Calligonum leucocladum.

Two new stilbene derivatives, (E)-resveratrol 3-(6' '-galloyl)-O-beta-D-glucopyranoside (1) and (E)-resveratrol 3-(4' '-acetyl)-O-beta-D-xylopyranoside (2), and five known stilbene derivatives (3-7) were isolated from the dried aerial parts of Calligonum leucocladum. Their structures were established on the basis of spectroscopic evidence. Compound 1 showed antioxidant activity and a restorative effect of the inhibition of oxacillin to oxacillin/methicillin-resistant Staphylococcus aureus.

Drug Resistance, Multiple↗
PubMed2005

Antineoplastic agents. 515. Synthesis of human cancer cell growth inhibitors derived from 3,4-methylenedioxy-5,4'-dimethoxy-3'-amino-Z-stilbene.

Further structure-activity relationship (SAR) exploration of 3,4-methylenedioxy-5,4'-dimethoxy-3'-amino-Z-stilbene (1a) derivatives resulted in the efficient synthesis of tyrosine amide hydrochloride 9, two tyrosine amide phosphate prodrugs (3a and 6), and sodium aspartate amide 11. Two additional cancer cell growth inhibitors (14 and 16) were synthesized by employing peptide coupling between amine 1a and the Dap unit of dolastatin 10 (4a) to yield amide 14 followed by Dov-Val-Dil (15) to yield peptide 16. The latter represents a combination of stilbene 1a with the des-Doe tetrapeptide unit of the powerful tubulin assembly inhibitor dolastatin 10. Peptide 16 was examined for potential binding to tubulin in the vinca and/or colchicine regions and found to perform primarily as a relative of dolastatin 10. Amide 14 had anticryptococcal and antibacterial activities.

Amides↗
PubMed1999

New bioactive flavonoids and stilbenes in cubé resin insecticide.

Fractionation of cubé resin from Lonchocarpus utilus and L. urucu roots led to the isolation and identification of 11 minor flavonoids and stilbenes containing the gem-dimethylpyran moiety or a dihydrodiol derivative thereof. The eight new compounds were as follows: the isoflavonoid cis-4'',5''-dihydro-4'',5' '-dihydroxylonchocarpusone (2); four (2S)-6-(gamma, gamma-dimethylallyl)-6'',6''-dimethylpyran[2'',3'':7, 8]flavanones with substituents of 5-hydroxy-3',4'-dimethoxy (3), 5, 3'-dihydroxy-4'-methoxy (4), 5,4'-dihydroxy-3'-methoxy (5), and 3', 4'-dimethoxy (6); and three 6'',6''-dimethylpyran[2'',3'':3', 4']stilbenes with 4-hydroxy-5'-methoxy (9), 3,5'-dimethoxy-4-hydroxy (10) and 3,4,5-trimethoxy (11) substitution patterns. Structure-activity relationships for inhibition of NADH:ubiquinone oxidoreductase activity (bovine heart electron transport particles) and phorbol ester-induced ornithine decarboxylase activity (cultured MCF-7 cells) generally parallel those for cytotoxicity (MCF-7 and Hepa 1clc7 cells).

Animals↗
PubMed2000

Five new stilbene dimers from the lianas of Gnetum hainanense.

Five new stilbene dimers, gnetuhainins A-E (1-5), were isolated together with resveratrol trans-dehydrodimer (6), resveratrol, oxyresveratrol, and (-)-epsilon-viniferin from the lianas of Gnetum hainanense. Their structures and stereochemistry were determined on the basis of their chemical and spectral data. Compounds 1-5 are dimers formed by a resveratrol unit and an oxyresveratrol unit and belong to a new type of oligostilbenes polymerized from two different stilbene units.

Dimerization↗
PubMed1995

The interaction with tubulin of a series of stilbenes based on combretastatin A-4.

A series of stilbenes, based on combretastatin A-4, were synthesised. A structure-activity study was carried out to characterise the interaction of these agents with tubulin. The substitution of small alkyl substituents for the 4'-methoxy group of combretastatin A-4 and the loss of the 3'-hydroxyl group does not have a major effect on the interaction with tubulin. trans-Stilbenes were shown to bind tubulin, but do not inhibit microtubule assembly. This work, together with previous studies, has been used to propose an idealised structure for a tubulin-binding agent of this type.

Animals↗
PubMed2001

Interaction of stilbene disulphonates with cloned K(ATP) channels.

In this study, we tested the effects of the stilbene disulphonates DIDS and SITS on three different types of cloned K(ATP) channel (Kir6.2/SUR1, Kir6.2/SUR2A and Kir6.2DeltaC) heterologously expressed in Xenopus oocytes, with the aim of identifying the part of the channel which is involved in mediating disulphonate inhibition. We found that the inhibitory site(s) for these drugs lies within the Kir6.2 subunit of the channel, although its properties are further modulated by the sulphonylurea (SUR) subunit. In particular, SUR2A reduces both the rate and extent of block, by impairing the ability of DIDS binding to produce channel closure. The disulphonate-binding site interacts with the ATP inhibitory site on Kir6.2 because ATP is able to protect against irreversible channel inhibition by disulphonates. This effect is not mimicked by tolbutamide (at a concentration that interacts with Kir6.2) and is abolished by mutations that render the channel ATP insensitive. A number of point mutations in both the N and C termini of Kir6.2 reduced the extent and reversibility of channel inhibition by SITS. The results are consistent with the idea that residue C42 of Kir6.2 is likely to be involved in covalently linking of SITS to the channel. Other types of Kir channel (Kir1.1, Kir2.1 and Kir4.1) were also irreversibly blocked by DIDS, suggesting that these channels may share common binding sites for these stilbene disulphonates.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1970

Flavin-photosensitized reactions of retinol and stilbene.

1. Retinol and stilbene are both isomerized when they are illuminated anaerobically in the presence of flavins. 2. Triplet quenchers (e.g. oxygen, potassium iodide and paramagnetic ions) inhibit the reaction more efficiently than they quench flavin fluorescence. At 77 degrees C in a diethyl ether-isopentane-ethanol (5:5:2) glass retinol quenches flavin phosphorescence, but not its fluorescence. 3. For the stilbene reaction cis/trans photostationary-state mixtures are obtained with different flavins and these are linearly related to the phosphorescence transition energies of the flavins used. 4. The reaction involves the triplet state of flavin and a scheme for the reaction is suggested. 5. The dependence of the rate of reaction on substrate concentration is explicable in terms of this scheme. 6. The photobleaching of rhodopsin sensitized by flavin is also demonstrated.

Alkanes↗
PubMed1987

The trans-stilbene oxide-active glutathione transferase in human mononuclear leucocytes is identical with the hepatic glutathione transferase mu.

A glutathione transferase from human mononuclear leucocytes with high activity towards trans-stilbene oxide (GT-tSBO) was purified. GT-tSBO is expressed in only about 50% of the individuals studied. As judged from activity measurements, immunological studies and the fact that only those individuals who express glutathione transferase mu have high activity towards trans-stilbene oxide, it is concluded that the hepatic transferase mu is identical with the glutathione transferase (GT-tSBO) in mononuclear leucocytes.

Dinitrochlorobenzene↗
PubMed2001

Novel polyketides synthesized with a higher plant stilbene synthase.

The physiological function of the stilbene synthase (STS) from groundnut (Arachis hypogaea) is the formation of resveratrol. The enzyme uses 4-coumaroyl-CoA, performs three condensations with malonyl-CoA, and folds the resulting tetraketide into a new aromatic ring system. We investigated the capacity for building novel and unusual polyketides from alternative substrates. Three types of products were obtained: (a) complete reaction (stilbene-type), (b) three condensations without formation of an aromatic ring (CTAL-type pyrone derailment), and (c) two condensations (BNY-type pyrone derailment). All product types were obtained from 4-fluorocinnamoyl-CoA and analogs in which the coumaroyl moiety was replaced by furan or thiophene. Only type (b) and (c) products were synthesized from other 4-substituted 4-coumaroyl-CoA analogs (-Cl, -Br, -OCH3). Benzoyl-CoA, phenylacetyl-CoA, and medium chain aliphatic CoA esters were poor substrates, and the majority of the products were of type (c). The results show that minor modifications can be used to direct the enzyme reaction to form a variety of different and new products. Manipulation of the biosynthesis of polyketides by synthetic analogs could lead to the development of a chemical library of pharmaceutically interesting novel polyketides.

Acyl Coenzyme A↗
PubMed1981

Kinetic analysis of the inhibition of anion transport in sarcoplasmic reticulum vesicles by a disulfonic stilbene derivative. Measurement of the change in chloride-diffusion potential by using a fluorescent cyanine dye.

The characterization of the anion transport system in sarcoplasmic reticulum (SR) vesicles was performed by kinetic analysis of the reversible inhibition of gluconate efflux by a disulfonic stilbene derivative; 4-acetamido-4'-isothiocyano-stilbene-2,2'-disulfonate (SITS). The gluconate efflux in SR vesicles was measured by following the change in Cl- ion-diffusion potential due to the mutual diffusion of Cl- and gluconate- using a potential probe; 3,3'-dipropylthiadicarbocyanine iodide (diS-C3-(5)). The main results are as follows. (1) Gluconate efflux was increased by intravesicular gluconate- and was decreased by both extravesicular gluconate- and extravesicular Cl-. (2) Gluconate efflux was depressed when membrane potential became inside-negative. (3) SITS reacted with the site of the anion transport system from the outside of the vesicles and one molecule of SITS inhibited each transport unit. (4) Extravesicular Cl- competed with SITS at the common site of the anion transport system. The dissociation constants for Cl- and SITS are 70 mM and 0.048 microM, respectively. (5) The inhibition of gluconate efflux by SITS was noncompetitive with both intravesicular gluconate and extravesicular gluconate. These results suggest that the anion transport system in SR vesicles can be described by a carrier-mediated transport model in which anions are transported by a mobile transport site accompanied by a net negative charge.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed2000

Gene induction of stilbene biosynthesis in Scots pine in response to ozone treatment, wounding, and fungal infection.

The S-adenosyl-L-methionine:pinosylvin-O-methyltransferase (PMT) gene was sequenced from Scots pine (Pinus sylvestris). The open reading frame is arranged in two exons spaced by one 102-bp intron. Promoter regulatory elements such as two "CAAT" boxes and one "TATA" box were identified. Several cis-regulatory elements were recognized: stress-responsive elements (Myb-responsive elements) as well as G, H, and GC boxes. Moreover, elicitor-responsive elements (W boxes) and a sequence resembling the simian virus 40 enhancer core were found. In phloem and needles of control trees, the transcripts of stilbene synthase (STS) and PMT were hardly detectable. Increased ozone fumigation up to 0.3 microL L(-1) enhanced the transcript level of STS and PMT in needles but not in healthy phloem. Wounding, e.g. mock inoculation, of stem-phloem was characterized by a transient increase in STS and PMT transcripts, which was more pronounced in the case of fungal inoculation. Combination of fungal-challenge or mock treatment with ozone resulted in a positive interaction at 0.3 microL L(-1). Scots pine stilbene formation appeared to be induced via STS and PMT gene expression upon ozone and fungal stress as well as wounding. The broad stress-responsiveness is in agreement with the range of various cis-acting elements detected in the STS and PMT promoters.

Acyltransferases↗
PubMed1988

Inhibition of H,K-ATPase and Na,K-ATPase by DIDS, a disulphonic stilbene derivative.

Disulphonic stilbenes are effective inhibitors of an anion exchanger which is present in the plasma membranes of many cells (Cabantchik et al. 1978). In the present study, the effects of 4,4'-diisothiocyano-2,2'-disulphonic stilbene acid (DIDS) on the transport activity of the hydrochloric acid pump isolated from pig stomach (H,K-ATPase, EC 3.6.1.36) were tested. Half-maximal inhibition of proton transport carried out by the H,K-ATPase in the isolated vesicles was observed at micromolar concentrations of DIDS. The effects of DIDS on the adenosine-trisphosphatase and p-nitrophenyl-phosphatase activities of isolated H,K-ATPase were also studied and compared with those of the kinetically and structurally related Na,K-ATPase (EC 3.6.1.37). Half-maximal inhibition of the enzymatic activities of both enzymes were observed in the micromolar range of DIDS. The lipid bilayer of the gastric vesicle membrane is highly asymmetric and the original cytosolic side is facing the outside of the vesicle. Since DIDS does not readily cross the membrane, it is most likely that DIDS exerts its inhibitory effects by modifying the transport ATPases on their cytosolic sides.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

Disulphonic stilbene block of cystic fibrosis transmembrane conductance regulator Cl- channels expressed in a mammalian cell line and its regulation by a critical pore residue.

1. The disulphonic stilbenes 4,4'-dinitrostilbene-2,2'-disulphonic acid (DNDS) and 4,4'-diisothiocyanostilbene-2,2'-disulphonic acid (DIDS) were shown to cause a voltage-dependent inhibition of macroscopic cystic fibrosis transmembrane conductance regulator (CFTR) Cl- currents expressed in baby hamster kidney cells when applied to the cytoplasmic face of the membrane. These compounds are known to be relatively ineffective at blocking CFTR from the extracellular side of the membrane. 2. Mutation of a positively charged arginine, previously suggested to be located in the channel pore (R347), to a negatively charged aspartate significantly reduced the affinity of block by both DNDS and DIDS, suggesting that this residue contributes to the binding site for disulphonic stilbenes. 3. It is suggested that the CFTR Cl- channel may contain a relatively large inner vestibule in which a number of large anions bind and block Cl- permeation. Arginine 347 may be involved in anion binding within this region.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1979

Acriflavine-Feulgen stilbene staining: a procedure for automated cervical cytology with a television based system (LEYTAS).

A sample preparation and staining procedure for automated cytology with a TV based system (LEYTAS) is described. It consists of a centrifugation technique and automated acriflavine-Feulgen stilbene staining of cervical specimens. The advantages of using both the fluorescence and the absorption image of acriflavine-Feulgen stilbene stained cervical cells for a television based system are discussed.

Acriflavine↗
PubMed2001

Study on anti-Oketsu activity of rhubarb II. Anti-allergic effects of stilbene components from Rhei undulati Rhizoma (dried rhizome of Rheum undulatum cultivated in Korea).

Methanol extract (RM-ext) obtained from the dried rhizome of Rheum undulatum was screened for activity in experimental models of type I allergy. RM-ext exhibited the inhibition on 48-h homologous passive cutaneous anaphylaxis (PCA) in rats and an antigen-induced histamine release from rat peritoneal mast cells. Among nine stilbenes isolated from RM-ext, seven inhibited the histamine release. Rhapontigenin (compound 1), piceatannol (2) and piceatannol 3'-beta-D-glycoside (6) with oral administration showed the inhibition on PCA. Compounds 1 and 2 exhibited the inhibitory effect on sheep red blood cell-induced delayed-type hyper sensitivity (SRBC-DTH) of type IV allergic model. These results indicated that the rhizome of Rheum undulatum inhibits the allergic reactions and that these inhibitory effects may be partially attributable to the stilbenes mentioned above.

Animals↗
PubMed2006

Inhibitory activity of plant stilbene oligomers against DNA topoisomerase II.

The inhibitory activity of 40 stilbene oligomers isolated from six plant species against topoisomerase II was evaluated, of which nine compounds showed a potent inhibitory effect, stronger than daunorubicin, a topoisomerase II inhibitor, used as an anti-cancer drug. The specificity of active stilbene oligomers on topoisomerase II was assessed by their effect on DNA restriction enzyme. In particular, specific inhibitory activity was observed in alpha-viniferin 13-O-beta-glucopryranoside (2) and hemsleyanol C (13).

Animals↗
PubMed2001

An approach to a chiral cycloalkanone-mediated asymmetric epoxidation of stilbene with oxone.

Chiral and C2-symmetric seven-membered cycloalkanones 2--6 bearing 1,2-diphenylethane-1,2-diamine and cyclohexane-1,2-diamine backbones were synthesized and evaluated their asymmetry inductive behaviours in an asymmetric epoxidation of stilbene with oxone. Although the reaction of the ketones 2 and 3 of a 1,2-diphenylethane-1,2-diamine backbone gave stilbene oxide in trace to 31% yield, those of the ketones 4-6 of a cyclohexane-1,2-diamine backbone gave the epoxide in satisfactorily high yield up to 98%. It is noteworthy that both reactions with use of stoichiometric and substoichiometric amounts of a ketone 4 gave the epoxide in the essentially same enantioselectivity, 17 and 18%. Eleven-membered cyclic ketones 7 and 8 bearing a binaphthalene backbone were also synthesized and examined their behaviours, while the enantioselectivity turned out to be marginal.

Azepines↗
PubMed2003

A new stilbene with tyrosinase inhibitory activity from Chlorophora excelsa.

A new stilbene, 4-[(2"E)-7"-hydroxy-3",7"-dimethyloct-2"-enyl]-2',3,4',5-tetrahydroxy-trans-stilbene (1), and the known compound chlorophorin (2) were isolated from the heartwood of Chlorophora excelsa. Both 1 and 2 showed tyrosinase inhibitory activity with IC(50) values of 96 and 1.3 microM, respectively.

Monophenol Monooxygenase↗