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At least 307 records · Page 17Linked to original sources

Synthesis of stilbene derivatives with inhibition of SARS coronavirus replication.

Stilbene derivatives have wide range of activities. In an effort to find other potential activities of this kind of compounds, 17 derivatives, including resveratrol, were synthesized. Twelve of them were evaluated for their antiviral potential against severe acute respiratory syndrome (SARS)-CoV-induced cytopathicity in Vero E6 cell culture. The result showed that SARS virus was totally inhibited by compounds 17 and 19 (<or=0.5 mg ml(-1)) and no significant cytotoxic effects were observed in vitro.

Animals↗

A study of peroxyoxalate-chemiluminescence of 4,4'-bis{[4,6-bis (2-hydroxyethyl)amino-1,3,5-triazin-2-yl]amino}stilbene-2,2'-disulfonic acid-disodium salt as a novel blue fluorescer.

The chemiluminescence arising from the reaction of bis(2,4,6-trichlorophenyl)oxalate (TCPO) with hydrogen peroxide in the presence of brightener 4,4'-bis{[4,6-bis(2-hydroxyethyl)amino-1,3,5-triazin-2-yl]amino}stilbene-2,2'-disulfonic acid-disodium salt (Triazinyl) has been studied. The influence of concentration of TCPO, hydrogen peroxide, Triazinyl, base catalysts and temperature on the resulting chemiluminescence was investigated. The kinetic parameters for the peroxyoxalate-chemiluminescence (PO-CL) of Triazinyl were evaluated from computer fitting of the resulting intensity-time plots. The activation energies, E(a), were evaluated from temperature dependence of the corresponding rise and fall rate constants.

Fluorescence↗

Stilbene oligomers in roots of Sophora davidii.

Three stilbene oligomers, davidiols A-C were isolated from the roots of Sophora davidii in addition to the seven known phenols, leachianone A, sophoraflavanones G, H and I, miyabenol C, alpha-viniferin and epsilon-viniferin. Their structures and relative configurations were established by means of 2D-NMR spectroscopy including COLOC and PSNOESY.

Magnetic Resonance Spectroscopy↗

Stilbene dimers from the lianas of Gnetum hainanense.

Five stilbene dimers, gnetuhainins F-J, were isolated together with gnetulin, rhapontigenin, isorhapontigenin and gnetol from the lianas of Gnetum hainanense C. Y. Cheng. Their structures and stereochemistry have been established on the basis of spectral evidence, especially 2D NMR spectroscopic techniques.

Molecular Structure↗

A stilbene and dihydrochalcones with radical scavenging activities from Loiseleuria procumbens.

A new dihydrochalcone, 6''-acetylphloridzosid, was isolated from the whole plant of Loiseleuria procumbens (L.) Desv. and identified as 2'-O-(6''-O-acetylglucopyranosyl)-4,4',6'-trihydroxydihydrochal cone by spectroscopic methods. In addition, one stilbene and three other dihydrochalcones were identified as (E)-piceid, phloretin (2',4,4',6'-tetrahydroxydihydrochalcone), phloridzosid (2'-O-glucopyranosyl-4,4',6'-trihydroxydihydrochalcone) and asebotin (2'-O-glucopyranosyl-4'-methoxy-4,6'-dihydroxydihydrochalcone), respectively. Some of these compounds showed scavenging properties towards the 2,2-diphenyl-1-picrylhydrazyl radical and antioxidant properties in a test with lysozyme.

Chalcone↗

Galloylated catechins and stilbene diglucosides in Vitis vinifera cell suspension cultures.

Suspension cultures of Vitis vinifera were found to produce catechins and stilbenes. When cells were grown in a medium inducing polyphenol synthesis, (-)-epicatechin-3-O-gallate, dimeric procyanidin B-2 3'-O-gallate and two resveratrol diglucosides were isolated, together with a new natural compound that was identified as cis-resveratrol-3,4'-O-beta-diglucoside by spectroscopical methods.

Biflavonoids↗

Stilbene derivatives from Gnetum gnemon Linn.

Four stilbene derivatives, gnemonols K and L (resveratrol trimers), M (isorhapontigenin dimer), and gnemonoside K (glucoside of resveratrol trimer) together with eleven known stilbenoids and a lignan were isolated from the acetone, methanol and 70% methanol soluble parts of the root of Gnetum gnemon (Gnetaceae). The structures of the isolates were determined by spectral analysis. The antioxidant activity of the stilbenoids on lipid peroxide inhibition and super oxide scavenging activity were also investigated.

Antioxidants↗

Combined advanced oxidation and biodegradation of industrial effluents from the production of stilbene-based fluorescent whitening agents.

Three different industrial wastewaters from the production of stilbene-based fluorescent whitening agents were investigated with regard to the applicability of advanced oxidation processes combined with biodegradation. Oxidation processes included the application of ozone, hydrogen peroxide, UV-radiation and Fenton's reagent (Fe(2+)/H(2)O(2)). Characterization of the combined chemical-biological treatment was done by sum parameters and HPLC analysis. In addition, toxicity was determined using the luminescence inhibition test. Results showed that processes producing OH-radicals without the need of UV-irradiation proved to be suited for the oxidation of all three wastewaters. H(2)O(2)/UV processes were ineffective due to the high inner filter effect of the effluents. Comparing the combined oxidative-biological process with biological treatment, the applied pre-oxidation steps did not always lead to a significant improvement of the biological degradation. In one case, an inverted treatment starting with biodegradation followed by oxidation turned out to be the preferable procedure. After oxidation with ozone or ozone combined with UV-irradiation, an increase in toxicity was partly observed indicating the formation of toxic intermediate products. In some cases samples had to be diluted before the biodegradation step to achieve a better biodegradability.

Biodegradation, Environmental↗

A new stilbene glycoside from Elephantorrhiza goetzei.

A new stilbene glycoside, 5-methoxy-(E)-resveratrol 3-O-rutinoside (1) was isolated from the root bark of Elephantorrhiza goetzei, along with known compounds, namely gallic acid, (E)-resveratrol, (+/-)-catechin, (+/-)-gallocatechin and oleanene triterpenoids. The combined ethyl acetate-methanol extract exhibited high lethality against brine shrimp larvae (LC(50) 10.8 ppm) compared to the isolates, some of which were not active.

Animals↗

Stilbenes from Sphaerophysa salsula.

A new stilbene, (trans)-4-[2-(3, 5-dimethoxyphenyl) ethenyl]-1,2-benzenediol (1), was isolated from the whole herbs of Sphaerophysa salsula, together with (trans)-4-[2-(3, 5-dimethoxy phenyl) ethenyl]-2-methoxyphenol (2) and daucosterol. The structure of 1 was determined on the basis of spectroscopic evidences.

Fabaceae↗

Artoindonesianins N and O, new prenylated stilbene and prenylated arylbenzofuran derivatives from Artocarpus gomezianus.

A new prenylated stilbene, named artoindonesianin N (1) and a new prenylated arylbenzofuran, named artoindonesianin O (2), were isolated from Artocarpus gomezianus Wall. ex Trec. (Moraceae). Their structures were elucidated as 1 and 2 on the basis of spectroscopic evidence. Along with these new compounds, a known phenolic compound was also isolated from this plant and identified as oxyresveratrol (3).

Artocarpus↗

Programmed cell death (PCD) associated with the stilbene motif of arotinoids: discovery of novel apoptosis inducer agents possessing activity on multidrug resistant tumor cells.

Considering that the stereochemistry of the C9-C10 alkenyl portion of natural 9-cis-RA, as the one of the olefinic moiety of the previously described isoxazole retinoid 4, seems of particular importance for their apoptotic activity, we prepared a novel class of TTNPB analogues bearing both the cis or trans configuration of the alkenyl portion. The compounds were evaluated in vitro for their cytotoxic and apoptotic activities. We discovered that the cis-TTNPB 9c possesses apoptotic activity comparable with that of the retinoid 4. Moreover, the amino arotinoid 16c showed potent apoptotic activity in HL60 promyelocytic leukemia cells. Interestingly, 16c proved to be a particularly potent apoptosis-inducing agent active in multidrug resistant (MDR) cell lines. Therefore, to the best of our knowledge, 16c may represent the first known aminoarotinoid endowed with potent apoptotic activity in MDR cells. Taken together, these results seem to point out that the cis-stilbene motif of arotinoids may be at least an important feature in conferring cytotoxic and apoptotic activity to this class of compounds.

Antineoplastic Agents↗

Antitumor agents. Part 3: synthesis and cytotoxicity of new trans-stilbene benzenesulfonamide derivatives.

A new series of trans-stilbene benzenesulfonamide derivatives were designed and synthesized as potential antitumor agents. These new compounds were evaluated in the National Cancer Institute's 60 human tumor cell line in vitro screen. Compounds 9-13 were cytotoxic against several cell lines. Notably, two compounds, 9 and 12, demonstrated selective cytotoxic activity against BT-549 breast cancer (GI(50)=0.205 microM) and HT-29 colon cancer (GI(50)=0.554 microM), respectively.

Antineoplastic Agents↗

Structure-requirements of isocoumarins, phthalides, and stilbenes from Hydrangeae Dulcis Folium for inhibitory activity on histamine release from rat peritoneal mast cells.

We examined the structure-activity relationships of isocoumarins, phthalides and stilbenes isolated from Hydrangeae Dulcis Folium and related compounds for the inhibition of histamine release in rat peritoneal mast cells. The activities of isocoumarins such as thunberginols A and B were more potent than those of dihydroisocoumarins such as hydrangenol and thunberginol G. The double bond at the 3-position seemed to be essential to potentiate the activity. The hydroxyl groups at the 8-, 3'- and 4'-positions of isocoumarin were essential for the activity, while the hydroxyl group at the 6-position was scarcely needed. Since the activities of benzylidenephthalides such as thunberginol F were more potent than those of hydramacrophyllols A and B, the presence of a double bond at the 3-position was needed to increase the activity. Moreover, the hydroxyl group at the 8-position was essential for the activity. On the time course study, thunberginols A, B and F completely inhibited histamine release by pretreatment at 100 microM for 1 to 15 min, whereas DSCG inhibited histamine release only following 1-min pretreatment at 1000 microM. These results suggested that the mechanisms of the inhibitory effect of thunberginols are different from that of DSCG.

Animals↗

Rotamerism and electronic spectra of aza-derivatives of stilbene and diphenylbutadiene. A combined experimental and theoretical study.

The experimental results on the rotameric equilibrium and electronic spectra of aza-derivatives of trans-stilbene and 1,4-diphenylbutadiene, have been rationalized by a theoretical study which combines simple ab initio calculations of molecular energies for the ground state with a theoretical analysis of the splitting of the conjugation band developed at CS INDO CI level. All results indicate that the stable conformer of each ortho aza-derivative is that corresponding to A species. As suggested by the 1H-NMR experiments, the ab initio geometry of ZE-2-pyridylphenylbutadiene is consistent with the presence of the N.H intramolecular hydrogen bond. As regards the Franck-Condon excited states of aza-derivatives, our theoretical results show that the first singlet excited state has (piH, piL*) character in all compounds except for E-4,4'-dipyridylethene, where S1 has (n, pi*) character in non-polar solvent. In this last compound, the theoretical study of solvatochromism indicates a crossing between the 1(n, piL*) and 1(piH, piL*) states which occurs in solvents of high polarity. The inclusion of the most important doubly- and triply-excited configurations in the CI calculations shows that the 1A(g)- excited state is above the spectral region analyzed.

Butadienes↗

External anions regulate stilbene-sensitive proton transport in placental brush border vesicles.

The mechanism for HCO3-(-)independent proton permeability in microvillus membrane vesicles (MVV) isolated from human placenta was examined by using the entrapped pH indicator 6-carboxyfluorescein (6CF). Proton fluxes (JH) across MVV were determined in response to induced pH and anion gradients from the time course of 6CF fluorescence, the MVV buffer capacity, and the 6CF vs. pH calibration. In the absence of anions, JH was 12 +/- 2 nequiv s-1 (mg of protein)-1 (pHin 7.4, pHout 6.0, MVV voltage-clamped with K+/valinomycin, 23 degrees C), corresponding to a proton permeability coefficient of 0.02 cm/s, with an activation energy of 9.1 +/- 0.3 kcal/mol. JH was inhibited 20% by dihydro-4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (H2DIDS) with KI = 8 microM [( Cl-]out = 0 mM). For a 0.5-unit pH gradient JH increased from 1.5 to 4.6 nequiv s-1 (mg of protein)-1 as the internal MVV pH was increased (5.5-7.5). External Cl-, Br-, and I- (but not SO4(2-) and PO4-) increased JH 1.3-2.5-fold for both inwardly and outwardly directed pH gradients with KD = 1.0 +/- 0.4 mM (Br-) and greater than 100 mM (Cl-). This increase was blocked by 100 microM H2DIDS but not by amiloride or furosemide. Internal Cl- did not alter JH induced by pH gradients nor were proton fluxes induced by anion gradients in the absence of a pH gradient. Experiments in which JH was driven by membrane potentials (induced by valinomycin and K+ gradients) indicated that proton transport was voltage-sensitive. These experiments demonstrate a stilbene-sensitive electrogenic proton transport mechanism in MVV that is regulated allosterically by anions at an external binding site.

Biological Transport↗

Method for the quantitative extraction of resveratrol and piceid isomers in grape berry skins. Effect of powdery mildew on the stilbene content.

A simple method for the quantitative extraction of resveratrol and its glycosides from grape berry skins has been developed. Optimal conditions for the extraction were investigated. Type of solvent, time, and temperature assayed influenced resveratrol and piceid yield. Adequate extraction was attained with ethanol/water (80:20 v/v) maintained at 60 degrees C for 30 min. Recovery (>96%) and reproducibility (6.83-15.13%) were satisfactory. After extraction, resveratrol and piceid isomers were quantified by high-performance liquid chromatography coupled to a ultraviolet-visible diode array detector. The amounts detected in 13 samples of 7 different varieties analyzed were, on average, 92.33 microg/g of dry skin for cis-piceid, 42.19 microg/g of dry skin for trans-piceid, and 24.06 microg/g of dry skin for trans-resveratrol. cis-Resveratrol was not detected in any sample. In grape berries infected by powdery mildew the contentw of these compounds were considerably increased and the degree of infection was positively related to their stilbene content.

Anticarcinogenic Agents↗