• Horticultural Science & Technology
• /
• v.29 no.4
• /
• pp.374-381
• /
• 2011

Stilbenes are polyphenolic natural products, which have antioxidative and antifungal activities. In some plants, including grapevine, the stilbene compounds, as resveratrol derivatives, exist in very diverse forms. Experiments to identify the individual stilbene compounds were carried out first to quantify them in UV-irradiated grapevine leaves. For this, stilbene glycosides were extracted from grapevine leaves which irradiated intensively with UV light. The glycoside samples were hydrolyzed by ${\beta}$-glucosidase, before analyzed by HPLC-mass spectrometer at each m/z corresponding to the mass of specific stilbenes. As results, in chromatograms, the enzymatic hydrolysis resulted in decrease and increase of the peaks expected for glycosides and aglycones, respectively. The samples were also exposed to sunlight in order to photo-isomerize the stilbene compounds. The light exposure resulted in disappearance and appearance of peaks expected for trans- and cis-isomers of stilbenes, respectively. Such a change of the peaks in chromatograms provided information needed for the inference to peak components. In this way, it was possible to identify 16 kinds of stilbene compounds from grapevine leaves. The identified stilbenes were quantified from grapevine leaves irradiated mildly by UV light. The UV-irradiation increased markedly in the content of stilbene compounds, especially trans-resveratrol by several hundredfold. In addition, piceatannol, which is a mere minor component of stilbenes in control leaves and a more active radical scavenger than resveratrol, was also increased by several tenfold by the treatment. The increase in stilbene contents as influenced by UV irradiation seems to be one of the stress coping responses of grapevine as a hormesis phenomenon.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.5
• /
• pp.427-432
• /
• 1995

A model based on two coupled generalized Langevin equations is proposed to investigate the trans-stilbene photoisomerization dynamics. In this model, a system which has two independent coordinates is considered and these two system coordinates are coupled to the same harmonic bath. The direct coupling between the system coordinates is assumed negligible and these two coordinates influence each other through the frictional coupling mediated by solvent molecules. From the Hamiltonian which is equivalent to the coupled generalized Langevin equations, we obtain the transition state theory rate constants of the stilbene photoisomerization. The rates obtained from this model are compared to experimental results in n-alkane solvents.

• Journal of Photoscience
• /
• v.10 no.1
• /
• pp.149-155
• /
• 2003

The absorption, fluorescence and fluorescence-excitation spectra of concentrated toluene solutions of selected para substituted trans-stilbene derivatives provide strong evidence for aggregation. A red-shifted fluorescence spectrum peaking at 420 nm gains in intensity as the stilbene concentration is increased. The excitation spectrum of this new emission is well to the red of the normal stilbene absorption spectrum, consistent with the appearance of a red shifted shoulder in the UV spectrum. Formation of a fluorescent ground state dimer (or higher aggregate) is proposed to account for these observations. The presence of polar substituents is crucial to the formation of this ground state complex.

• Archives of Pharmacal Research
• /
• v.26 no.4
• /
• pp.253-257
• /
• 2003

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.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.2
• /
• pp.218-221
• /
• 1997

When phenylation of styrene was carried out in the presence of Pd(OAc)2 and PPh3 in benzene, trans-stilbene was obtained in good yield (566%) with high selectivity (98%) under mild condition (55 ℃, 50 psi O2, 20 h). Since trans-stilbene could be produced not only from benzene but also from phenyl group of PPh3 by migration of its phenyl group to Pd, the competitiveness of benzene and the migratory aptitude of aryl group of triarylphosphine toward styrene has been investigated with various phosphines (PR3: P(p-C6H4CH3)3, P(p-C6H4OCH3)3, P(p-C6H4F)3, P(p-C6H4Cl)3, P(C6H5)3, P(C6H11)3, P(OC4H9n)3, P(CH2C6H5)3 and P(C6F5)3). The yield and selectivity toward trans-stilbene are increased as the basicity of the phosphines increases. The composition of arylated olefin from arylphosphine, in turn, increases as the electronegativity of the substituent on the aryl group of arylphosphines increases.

• Archives of Pharmacal Research
• /
• v.24 no.6
• /
• pp.597-600
• /
• 2001

Based on the potential cancer chemoprebentive activity of resveratrol, a trihydroxystilbene with the induction of quinone reductase activeity this study was designed to determine if stilbene-related compounds were inducers of phase ll detoxifying metabolic enzyme quinone reductase (QR) in the mouse hepatoma Hepa 1c1c7 cells. Among the thirteen compounds tested, several compounds including 3,4,5,3',5'-pentamethoxy-trans-stibene were found to potentially induce QR activity in this cell line. In addition, substitution with 3-thiofurane ring instead of phenyl ring in the stilbene skeleton also exhibited potential induction of QR activity. This result will give primary information to design the potential inducers of QR activity in the stilbene analogs.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.6
• /
• pp.692-698
• /
• 1991

The reaction path Smoluchowski equation approach developed in a recent work to calculate the rate constant for a diffusive multidimensional barrier crossing process is extended to incorporate the configuration-dependent diffusion matrix. The resulting formalism is then applied to the investigation of stilbene photoisomerization dynamics. Adapting a model two-dimensional potential and a model diffusion matrix proposed by Agmon and Kosloff [J. Phys. Chem.,91 (1987) 1988], we derive an eigenvalue equlation for the relaxation rate constant of the stilbene photoisomerization. This eigenvalue equation is solved numerically by using the finite element method. The advantages and limitations of the present method are discussed.

• Archives of Pharmacal Research
• /
• v.24 no.5
• /
• pp.441-445
• /
• 2001

Resveratrol, a trihydroxystilbene found in grapes and several plants, has been shown to be active in inhibiting multistage carcinogenic process. Using resveratrol as the prototype, we synthesized several analogs and evaluated their growth inhibitory effect using cultured human cancer cells. In the present report we show that one of the resveratrol analogs, 3, 5,2',4'-tetramethoxy-trans-stilbene, potentiated the inhibition of cancer cell growth. Prompted by the strong growth Inhibitory activity of the compound ($IC_{50}$; $0.8{\mu}$ g/ml) compared to resveratrol ($IC_{50}$; $18{\mu}$ug/ml) in cultured human colon cancer cells (Col2), we performed an action mechanism study using the compound. The compound induced the accumulation of cellular DNA contents in the sub-CO phase DNA contents of the cell cycle by in a time-dependent manner. The morphological changes were also consistent with an apoptotic process. This result indicated that the compound induced apoptosis of cancer cells, and may be a candidate for use in the development of potential cancer chemotherapeutic or cancer chemopreventive agents.

• Biomolecules & Therapeutics
• /
• v.15 no.2
• /
• pp.95-101
• /
• 2007

Resveratrol (3,5,4’-trihydroxy-trans-stilbene), a naturally occurring phytoallexin abundant in grapes and several plants, has been shown to be active in inhibiting proliferation and inducing apoptosis in several human cancer cell lines. On the line of the biological activity of resveratrol, a variety of resveratrol analogs were synthesized and evaluated for their growth inhibitory effects against several human cancer cell lines. In the present study, we found that one of the resveratrol analogs, 3,4,5-trimethoxy-4’-bromo-cis-stilbene, markedly suppressed human colon cancer cell proliferation (EC$_{50}$ = 0.01 ${\mu}$g/ml), and the inhibitory activity was superior to its corresponding trans-isomer (EC$_{50}$ = 1.6 ${\mu}$g/ml) and resveratrol (EC$_{50}$ = 18.7 ${\mu}$g/ml). Prompted by the strong growth inhibitory activity in cultured human colon cancer cells (Col2), we investigated its mechanism of action. 3,4,5-Trimethoxy-4’-bromo-cis-stilbene induced arrest of cell cycle progression at G2/M phase and increased at sub-G1 phase DNA contents of the cell cycle in a time- and dose-dependent manner. Colony formation was also inhibited in a dose-dependent manner, indicating the inhibitory activity of the compound on cell proliferation. Moreover, the morphological changes and condensation of the cellular DNA by the treatment of the compound were well correlated with the induction of apoptosis. These data suggest the potential of 3,4,5-trimethoxy-4’-bromo-cis-stilbene might serve as a cancer chemotherapeutic or chemopreventive agent by virtue of arresting the cell cycle and inducing apoptosis for the human colon cancer cells.

• Preventive Nutrition and Food Science
• /
• v.7 no.4
• /
• pp.447-450
• /
• 2002

Previously, a methanol extract from seeds of Paeonia lactiflora was shown to have a potent inhibitory activities against tyrosinase and soybean lipoxygenase (SLO). Seven stilbenes, trans-resveratrol-4-Ο-$\beta$-D-glucoside, trans resveratrol, trans-$\varepsilon$-viniferin, cis-$\varepsilon$-viniferin, gnetin H, suffruticosol A and B were isolated from the seeds as active principles for inhibition of the enzymatic activity. Among them, the resveratrol trimer, gnetin H exhibited the most potent inhibitory activities against tyrosinase and SLO, respectively. Additionally, the resveratrol dimers, trans-$\varepsilon$-viniferin and cis-$\varepsilon$-viniferin exhibited significant inhibitory activity against the two oxidative enzymes. Meanwhile, three other stilbene derivatives, such as trans-resveratrol, suffruticosol A and suffruticosol B had also weak inhibition activity. The least inhibitory activity was observed in transresveratrol-4-Ο-$\beta$-D-glucoside. These results suggest that resveratrol dimers and trimer in the seeds of Paeonia lactiflora are potentially useful therapeutic agents against pathological disorders such as hyperpigmentation and inflammation.