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PubMedDate not supplied

Metabolism of trans-stilbene in rabbits and rats.

The biotransformation of intramuscularly administered 14C-labeled trans-stilbene was investigated in both rabbits and rats. In rabbits radioactivity was excreted (78.8% in 17 days) almost exclusively in the urine. In rats, feces accounted for more than half of the total excretion (80.3% in 19 days). Hydroxylated metabolites in urine and feces were identified by thin-layer chromatography and quantitated by liquid scintillation counting. They were 4-hydroxy and 4,4'-dihydroxystilbene, and the two monomethyl ethers of 3,4-dihydroxystilbene and 4,4'-dihydroxybibenzyl. In addition, four polyhydroxylated metabolites of stilbene and bibenzyl were identified in rat urine by comparison of gas-liquid chromatography retention times of their silyl derivatives with synthetic reference compounds. They were 3,4,4'-trihydroxystilbene, and 3,4-dihydroxy-, 3,4,4'=trihydroxy-, and 3,4,3',4'-tetrahydroxybibenzyl. Oxidative cleavage of trans-stilbene to benzoic acid and 4-hydroxy- and 3,4-dihydroxybenzoic acid was established by the presence of both the free acids and conjugates of these compounds in both rabbit and rat urine. Their glycine conjugates were identified by thin-layer chromatography and quantitated by reverse isotope dilution procedures from unhydrolyzed rabbit and rat urine. Percentages obtained indicate that cleavage of trans-stilbene is more extensive in rabbits (9.5%) than in rats (2.7%).

Animals↗
PubMed1984

Purification and properties of a stilbene synthase from induced cell suspension cultures of peanut.

Stilbene synthase ( resveratrol -forming) converts one molecule of rho- coumaroyl -CoA and three molecules of malonyl-CoA into 3,4',5- trihydroxystilbene . Following selective induction of stilbene synthesis in cell suspension cultures of peanut (Arachis hypogaea), the enzyme was extracted and purified to apparent homogeneity by chromatography on DEAE-cellulose and hydroxylapatite. The enzyme was found to be a dimer of estimated Mr = 90,000 exhibiting under denaturing conditions a subunit Mr of approximately 45,000. The isoelectric point was determined with pI = 4.8. The enzyme's high selectivity towards rho- coumaroyl -CoA (Km = 2 microM) as substrate qualified it as resveratrol -forming stilbene synthase. Structurally related CoA esters, e.g. dihydro-rho- coumaroyl -CoA and cinnamoyl-CoA, were converted less than 1/10 as efficiently as rho- coumaroyl -CoA. Malonyl-CoA (Km = 10 microM) could not be substituted by acetyl-CoA. The purified enzyme was free of chalcone synthase activity. Antibodies raised against stilbene synthase were shown to be monospecific and not to cross-react with chalcone synthase.

Acyltransferases↗
PubMed1994

Structural organization and differential expression of three stilbene synthase genes located on a 13 kb grapevine DNA fragment.

A 13 kb DNA fragment was isolated from a grapevine (Vitis var. Optima) genomic library by hybridizing with elicitor-induced stilbene synthase cDNA as a probe. After fragmentation with Eco RI, subcloning and sequencing, two full-size stilbene synthase genes (Vst1 and Vst2) and the 3' end of a third stilbene synthase gene (Vst3) were located within the 13 kb fragment. Vst1 and Vst2, differing only slightly in the coding region, are distinguished in the intron size and in the structure of the promoter region. The 5' flanking region of gene Vst1 contains a TATAA box at nucleotide -48. The substantial structural differences found for the promoters of the two genes are paralleled by a striking difference in the expression of the two genes in elicitor-treated cells. Moreover, the accumulation upon elicitation of six different stilbene synthase mRNAs was studied and found to differ by two orders of magnitude.

Acyltransferases↗
PubMed1992

Stilbene synthase from Scots pine (Pinus sylvestris).

Stilbene synthases are named according to their substrate preferences. By this definition, enzymes preferring cinnamoyl-CoA are pinosylvin synthases, and proteins with a preference for phenylpropionyl-CoA are dihydropinosylvin synthases. We investigated the assignment of a stilbene synthase cloned from Scots pine (Pinus sylvestris) as dihydropinosylvin synthase and the proposal of an additional pinosylvin synthase [1992, Plant Mol. Biol. 18, 489-503]. The results show that the previous interpretation was misled by several unexpected factors. Firstly, we found that the substrate preference and the activity of the plant-specific protein expressed in E. coli was influenced by bacterial factors. This was reduced by improvement of the expression system, and the subsequent kinetic analysis revealed that cinnamoyl-CoA rather than phenylpropionyl-CoA is the preferred substrate of the cloned stilbene synthase. Secondly, mixing experiments showed that extracts from P. sylvestris contain factor(s) which selectively influenced the substrate preference, i.e. the activity was reduced with phenylpropionyl-CoA, but not with cinnamoyl-CoA. This explained the apparent differences between plant extracts and the cloned enzyme expressed in E. coli. Taken together, the results indicate that the cloned enzyme is a pinosylvin synthase, and there is no evidence for a second stilbene synthase. This study cautions that factors in the natural and in new hosts may complicate the functional identification of cloned sequences.

Acyl Coenzyme A↗
PubMed2005

Vibrational energy flow rates for cis- and trans-stilbene isomers in solution.

Transient electronic absorption following excitation of the first C-H stretching overtone (2nu(CH)) or a C-H stretch-bend combination (nu(CH) + nu(bend)) monitors the flow of vibrational energy in cis-stilbene and in trans-stilbene. Following a rapid initial rise as energy flows into states interrogated by the probe pulse, the absorption decays with two time constants, which are about a factor of 2 longer for the cis-isomer than for the trans-isomer. The decay times for cis-stilbene are tau2(cis) = (2.6 +/- 1.5) ps and tau3(cis) = (24.1 +/- 2.1) ps, and those for trans-stilbene are tau2(trans) = (1.4 +/- 0.6) ps and tau3(trans) = (10.2 +/- 1.1) ps. The decay times are essentially the same in different solvents, suggesting that the relaxation is primarily intramolecular. The two decay times are consistent with the sequential flow of energy through sets of coupled states within the molecule, and the difference in the rates for the two isomers likely reflects differences in coupling among the states arising from the different structures of the isomers. The similarity of the time evolution following excitation of the first C-H overtone at 5990 cm(-1) and the stretch-bend combination at 4650 cm(-1) is consistent with a subset of states, whose structure is similar for the two vibrational excitation energies, controlling the observed flow of energy.

Journal Article↗
PubMed1984

Stilbene Synthase and Chalcone Synthase : Two Different Constitutive Enzymes in Cultured Cells of Picea excelsa.

Cultured cells of Picea excelsa capable of forming stilbenes and flavanoids have been established. Unlike needles of intact plants containing piceatannol (3,3',4',5-tetrahydroxystilbene) and stilbene glycosides the cultured cells converted phenylalanine and p-coumaric acid primarily into resveratrol monomethyl ether (3,4'-dihydroxy-5-methoxystilbene) and naringenin. Partially purified enzyme preparations were assayed for chalcone synthase as well as for stilbene synthase activity converting malonyl-CoA plus p-coumaroyl-CoA into 3,4',5-trihydroxystilbene (resveratrol).Although stilbene synthase and chalcone synthase use the same substrates and exhibit similar molecular properties, i.e. molecular weight and subunit molecular weight, they are two different proteins. This difference was demonstrated by gel electrophoresis and by means of monospecific antibodies.

Journal Article↗
PubMedDate not supplied

The use of liquid membranes in the multi-residue extraction of stilbenes in a variety of biological matrices and their detection with LC-ES-MS.

Supported liquid membrane (SLM) has been used as a sample preparation method in the simultaneous extraction of a mixture of three stilbene compounds in cow's milk, urine, bovine kidney and liver tissues matrices. The stilbene compounds analysed included, dienestrol, diethylstilbestrol and hexestrol. The liquid membrane used for trapping these compounds consisted of 5% tri-n-octylphosphine oxide (TOPO) dissolved in di-n-hexylether/n-undecane (1:1). The extraction efficiencies obtained after enrichment of 1 ng/L stilbenes in variety of biological matrices of milk, urine, liver, kidney and water, ranged from 60 - 70%, 71 - 86%, 69 - 80%, 63 - 7A% and 72 - 93% respectively. The detection limits obtained from urine extraction were 2.1 ng/L, 1.3 ng/L and 3.0 ng/L; from liver and kidney tissues were 2.9 ng/L, 1.6 ng/L and 3.8 ng/L and from milk was 3.2 ng/L, 2.5 ng/L and 4.3 ng/L for hexestrol, dienestrol and diethylstilbestrol respectively.

Animals↗
PubMed1994

Kinetics and stereochemistry of the microsomal epoxide hydrolase-catalyzed hydrolysis of cis-stilbene oxides.

The microsomal epoxide hydrolase (mEH)-catalyzed hydrolysis of cis-4,4'-dimethylstilbene oxide (1a), cis-4,4'-diethylstilbene oxide (1b), cis-4,4'-diisopropylstilbene oxide (1c), and cis-4,4'-dichlorostilbene oxide (1d) have been investigated using rabbit liver microsomal preparations. The kinetic parameters, Km and Vmax, and the absolute stereochemistry of the reactions have been determined and compared with those of cis-stilbene oxide (1e). All epoxides 1a-d are hydrolyzed by mEH with high product enantioselectivity to give (R,R)-(+)-diols with ee > or = 90%. The presence of the substituents on the phenyl rings markedly reduces the rates of mEH catalyzed hydrolysis with respect to cis-stilbene oxide, by increasing Km and reducing Vmax in the cases of 1a, 1b, and 1d, or reducing only the Vmax in the case of 1c. The very low Vmax, together with a persistent ability to fit into the mEH active site, make all these epoxides, and particularly 1c, inhibitors of cis-stilbene oxide hydrolysis. The kinetic and stereochemical results are interpreted on the basis of the proposed topology of the mEH active site.

Animals↗
PubMed1997

Assessment of possible protective roles of selenium, zinc, and cis-stilbene oxide against acute T-2 toxin poisoning: a preliminary report.

The efficacy of two free radical scavengers, selenium and zinc, and a microsomal epoxide hydrolase-inducing agent, cis-stilbene oxide on the acute toxicity of T-2 toxin, a potent cytotoxic trichothecene, was investigated. Mice were pretreated daily for 3 consecutive days with either zinc sulfate (4.4 mg/kg, intraperitoneally [i.p.]), sodium selenite (1, 2, and 3 mg/kg i.p.) or cis-stilbene oxide (50 mg/kg i.p.). A full 24-hr after the final dosing with these agents, mice were given T-2 toxin (2, 2.5, or 3 mg/kg i.p.). The acute lethal toxicity of T-2 toxin (2.5 mg/kg) was reduced by administration of only sodium selenite (3 mg/kg) and cis-stilbene oxide (50 mg/kg). No significant effect on weight gain was observed.

Animals↗
PubMedDate not supplied

Prenylated stilbenes from peanut root mucilage.

Seven prenylated stilbenes were identified by combined HPLC-PAD-APCI/MSn analysis of an extract of mucilage isolated from peanut (Arachis hypogaea L.) root tips. The principal constituent was assigned the structure 4-(3-methyl-but-1-enyl)-3, 5-dimethoxy-4'-hydroxy-trans-stilbene. The common name mucilagin A is proposed for this novel compound. Its concentration in the mucilage was estimated at 250 microg/g (wet weight basis). The large body of literature on the anti-microbial properties of plant-derived stilbenes suggests that compounds detected in peanut mucilage may play a role in regulating root-soil pathogen interactions.

Adhesives↗
PubMed1993

Stilbene disulfonates block ATP-sensitive K+ channels in guinea pig ventricular myocytes.

Effects of stilbene disulfonates on single KATP channel currents were investigated in inside-out and outside-out membrane patches from guinea pig ventricular myocytes. All drugs tested, 4,4'-diisothiocyanatostilbene,2,2'-disulfonic acid (DIDS), 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid (SITS), 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNDS), and 4,4'-diaminostilbene-2,2'-disulfonic acid (DADS), inhibited the KATP channel when they were applied to the intracellular, but not extracellular side of the membrane patch. Inhibitory actions of DIDS and SITS were irreversible, whereas those induced by DNDS and DADS were reversible. KATP channel inhibition was concentration dependent with an order of potency of DIDS > SITS approximately DNDS > DADS; the Hill coefficient was close to unity for each drug. No change in channel conductance was observed during exposure to DIDS or DNDS; however, channel kinetics was altered. Distribution of the open time within bursts and that between bursts could be described by a single exponential relation in the absence and presence of DIDS or DNDS. The time constant of the open time within bursts was not altered, but that between bursts was decreased by DIDS (from 40.0 +/- 8.1 to 29.8 +/- 6.7 msec, P < 0.05) and by DNDS (from 43.1 +/- 9.3 to 31.9 +/- 7.1 msec, P < 0.05). Distributions of closed time within bursts were also fitted to a single exponential function both in the absence and presence of drugs, while those of the closed time between bursts were fitted to a single exponential function in the absence of drugs, but a double exponential function was required in the presence of drugs. The rates of onset and development of channel inhibition by DIDS and DNDS appeared to be concentration dependent; a longer time was required to reach a new steady-state of channel activity as drug concentration was decreased. Inhibition by DIDS or DNDS was regulated by intracellular pH; inhibition was greater during acidic conditions. For DIDS (0.1 mM), the open probability (Po) expressed as a fraction of the value before drug application was 42.9 +/- 8.3% at pH 7.4 and 8.2 +/- 6.6% at pH 6.5 (P < 0.01); corresponding values for DNDS (1 mM) were 39.6 +/- 17.6 and 8.9 +/- 5.8%, respectively (P < 0.01). From these data, we conclude that stilbene disulfonates block the KATP channel by binding to their target site with one-to-one stoichiometry. Similar to glibenclamide, the binding of stilbene disulfonates may reflect interpolation in an "intermediate lipid compartment" between the cytosolic drug and the site of drug action.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1994

Comparison of -nitro versus -amino 4,4'-substituents of disulfonic stilbenes as chloride channel blockers.

We showed previously that the disulfonic stilbene DNDS (4,4'-dinitrostilben-2,2'-disulfonic acid) was a potent blocker of outwardly rectifying chloride channels (ORCC). The studies reported here were designed to quantify the relationship between electron withdrawal by the 4,4'-substituents and blocker potency. Specifically we compared the blocking effects and molecular properties of the symmetrically substituted 4,4'-diaminostilben-2, 2'-disulfonic acid (DADS) and the hemi-substituted 4-amino, 4'-nitrostilben-2,2'-disulfonic acid (ANDS) with those of DNDS. Blockade was studied using outwardly rectifying colonic chloride channels incorporated into planar lipid bilayers. DADS was 430-fold and ANDS 44-fold less potent than DNDS as blockers of ORCC. Amplitude distribution analysis revealed that all three disulfonic stilbenes act as open channel blockers. Furthermore, this kinetic analysis indicated that the lower potency of DADS and ANDS was due to an increase in off rate. These results support the conclusion that the 4,4'-substituents make an important contribution to blockade by stabilizing the channel-blocker complex. Isopotential electron contour maps illustrated the dramatic shift in charge at the 4,4'-poles of the disulfonic stilbene molecule from electronegative in DNDS to electropositive in DADS as well as the bipolar contour of ANDS. Thus, the greater potency of DNDS results from the symmetric electronegative regions at the 4,4'-poles of the molecule. We hypothesize that the channel protein has two corresponding electropositive areas at the blocker binding site.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed2002

Cytotoxic and antimutagenic stilbenes from seeds of Paeonia lactiflora.

Cytotoxic and antimutagenic effects of a novel cis-epsilon-viniferin and five known stilbenes, transresveratrol, trans-epsilon-viniferin, gnetin H, suffruticosols A and B, isolated from the seeds of Paeonia lactiflora Pall. (Paeoniaceae) were determined against five different cancer cell lines, and mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Salmonella typhimurium TA100, respectively. Six stilbenes showed cytotoxic activity in a dose-dependent manner, and especially did potent cytotoxic activity against C6 (mouse glioma) cancer cell with IC50 values ranging from 8.2 to 20.5 microg/ml. trans-Resveratrol showed significant cytotoxic activity against HepG2 (liver hepatoma) and HT-29 (colon) human cancer cell lines with IC50 values of 11.8 and 25.2 g/ml, respectively. In contrast, trans-epsilon-viniferin and cis--viniferin, and gnetin H exhibited marked cytotoxic activity against Hela (cervicse) and MCF-7 (breast) human cancer cell lines with IC50 values of 20.4, 21.5, and 12.9 microg/ml, respectively. However, suffruticosol A and B had less cytotoxic effect against all cancer cells except C6. Meanwhile, six stilbenes exerted antimutagenic activity in a dose-dependent fashion. Of them, trans-resveratrol exhibited the strongest antimutagenic effect against MNNG with IC50 value of 27.0 microg/plate, while other five resveratrol oligomers also did moderate antimutagenic activity with IC50 values ranging from 31.7 to 35.2 microg/plate.

Animals↗
PubMed2003

Synthesis and evaluation of cytotoxicity of stilbene analogues.

Resveratrol analogs were newly synthesized and evaluated for cytotoxicity in cultured human lung and colon cancer cells. 3,5,4-Trimethoxy-trans-stilbene and 3,5,2',4'-tetramethoxy-trans-stilbene were found to be more potent rather than resveratrol. 3,4,5-Trimethoxy-4'-bromo-cis-stilbene was the most active among the test compounds.

Antineoplastic Agents↗
PubMed2001

Determination of flavonoids and stilbenes in red wine and related biological products by HPLC and HPLC-ESI-MS-MS.

To investigate probable health benefits of flavonoids and stilbenes in red wine a new reversed-phase (RP) high-performance liquid-chromatographic (HPLC) method with enhanced separation efficiency and improved selectivity, sensitivity, and speed has been established for determination of the flavonoids quercetin, myricetin and kaempferol and the stilbenes cis- and trans-resveratrol, in a single run . UV-absorbance, fluorescence (FLD), and mass-spectrometric (MS) detection were also evaluated. UV-absorbance detection at 320 nm for stilbenes and 377 nm for flavonoids enables their determination up to the nanogram range with a linearity of R2>0.9999 (linear range 50 ng mL(-1)-50 microg mL(-1)). Calculated values of average recoveries were between 95 and 105% for all analytes. For resveratrol, fluorescence detection was highly selective and twice as sensitive as UV detection, and linearity was satisfactory (R2>0.9996; linear range see UV detection). For the detection of the hydrophilic glycosidic compounds piceid and rutin, which are coeluted with other hydrophilic ingredients, the validated RP HPLC system was coupled to a quadrupole ion-trap mass-spectrometer (MS) via an electrospray interface (ESI) with 25% ammonia solution as sheath liquid. MS detection was, highly linear (R2>0.9878; linear range 50 ng mL(-1)-50 microg mL(-1)) for all investigated analytes and the limits of detection were in the low nanogram range. Compared with UV detection MS detection resulted in a 200% increase in signal intensity for myricetin and 400% increases for quercetin and kaempferol, but equal signal intensity for resveratrol. Calculated values of average recoveries were 102% for myricetin and 79% for piceid. Collision induced dissociation (CID) was also used to obtain characteristic fragmentation fingerprints to facilitate qualitative and quantitative analysis even in complex matrices. Finally, this hyphenated HPLC-ESI-MS method was highly suitable and an essential improvement compared with UV- and fluorescence detection.

Chromatography, High Pressure Liquid↗
PubMed2007

Antiplasmodial activity of novel stilbene derivatives isolated from Parthenocissus tricuspidata from South Korea.

New stilbene glycoside, piceid-(1-->6)-beta-D -glucopyranoside (compound 2, Fig. 1), was isolated from the MeOH extract of the leaves of Parthenocissus tricuspidata (Vitaceae) together with four known compounds, piceid (compound 1, Fig. 1), resveratrol (compound 3, Fig. 1), longistylin A (compound 4, Fig. 1), and longistylin C (compound 5, Fig. 1). Their structures were determined spectroscopically, particularly by 2D nuclear magnetic resonance (NMR) spectroscopic and chemical analysis. The antiplasmodial activity of isolated compounds were determined in vitro against a chloroquine-sensitive strain of Plasmodium falciparum (D10). Among the compounds isolated, piceid-(1-->6)-beta-D-glucopyranoside (2) had the most potential inhibition, with inhibitory concentration (IC(50)) values of 5.3 microM. To our knowledge, antiplasmodial activity of functional group position of stilbene is now being reported for the first time in this study. The result shows that the 3, 4'-position in stilbenes might play an essential role in antiplasmodial activity.

Animals↗
PubMed1980

The proliferation of hepatocytes and the lipid composition of the endoplasmic reticulum after induction of drug-metabolizing enzymes with trans-stilbene oxide.

Three aspects of the induction of drug-metabolizing enzymes brought about by trans-stilbene oxide have been investigated. (1) The liver hypertrophy in rats treated with trans-stilbene oxide was found to result solely from an increase in the number of cells in this organ, without any increase in the size of each individual cell. (2) Administration of trans-stilbene oxide also produces a 27% increase in the phospholipid content of the hepatic endoplasmic reticulum, i.e., a limited proliferation of this organelle occurs. (3) Furthermore, induction causes changes in the lipid composition of the endoplasmic reticulum. The cholesterol content is decreased, the relative content of sphingo-myelin is also lowered, and a number of changes in the fatty-acid composition occur as well. All of these effects would tend to increase the fluidity of the phospholipid bilayer of the endoplasmic-reticulum membrane and may thus affect drug metabolism.

Animals↗
PubMed1992

Pine stilbene synthase cDNA, a tool for probing environmental stress.

Stilbene synthase cDNAs were isolated from a pine (Pinus sylvestris) cDNA library. Poly(A)+RNA required for the preparation was obtained from young seedlings challenged with Botrytis cinerea. A full-length cDNA encoding pinosylvin-forming stilbene synthase was sequenced, and the deduced amino acid sequence was compared with sequences of resveratrol-forming stilbene synthases. The cDNA coding for the key enzyme of pinosylvin formation is a valuable tool for detecting early effects of environmental stress in pine needles.

Acyltransferases↗