• Bulletin of the Korean Chemical Society
• /
• 제18권2호
• /
• 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.

• 한국약용작물학회:학술대회논문집
• /
• 한국약용작물학회 2007년도 춘계학술발표회
• /
• pp.203-204
• /
• 2007

• 약학회지
• /
• 제43권2호
• /
• pp.233-236
• /
• 1999

In order to clarify the anti-Ohyul activity of rhubarb, we investigated the effects of water extract from rhizomes of four different rhubarb on blood platelet aggregation induced by arachidonic acid, ADP, collagen and PAF in vitro. The cultivated Korean rhubarb rhizomes (Rheum undulatum) exhibited the most potent inhibitory action on the aggregation induced by arachidonic acid and also among the four fractions, stilbene components containing part showed strong inhibitory action. These inhibitory effect may partially contributed to anti-Ohyul activity of rhubarb.

• Bulletin of the Korean Chemical Society
• /
• 제29권9호
• /
• pp.1800-1802
• /
• 2008

• Nuclear Engineering and Technology
• /
• 제55권3호
• /
• pp.1021-1030
• /
• 2023

We propose an overall procedure for measuring and unfolding fast neutron spectra using a trans-stilbene scintillation detector. Detector characterization was described, including the information on energy calibration, detector resolution, and nonproportionality response. The digital charge comparison method was used for the investigation of neutron-gamma Pulse Shape Discrimination (PSD). A pair of values of 600 ns pulse width and 24 ns delay time was found as the optimized conditions for PSD. A fitting technique was introduced to increase the trans-stilbene Proton Response Function (PRF) by 28% based on comparison of the simulated and experimental electron-equivalent distributions by the Cf-252 source. The detector response matrix was constructed by Monte-Carlo simulation and the spectrum unfolding was implemented using the iterative Bayesian method. The unfolding of simulated and measured spectra of Cf-252 and AmBe neutron sources indicates reliable, stable and no-bias results. The unfolding technique was also validated by the measured cosmic-ray induced neutron flux. Our approach is promising for fast neutron detection and spectroscopy.

• Food Science and Biotechnology
• /
• 제17권3호
• /
• pp.675-678
• /
• 2008

Permeability of resveratrol, piceid, rhapontigenin, and rhaponticin in Caco-2 cell assays using high-performance liquid chromatography were compared. Caco-2 cell monolayers were used to evaluate the transport rates of stilbene analogues from the apical to the basolateral sides. All stilbenes experimented in this study were transported to the basolateral side by times. For comparing the permeability of 4 stilbenes, we calculated the slope of the cumulative concentration of each stilbene in basolateral sides over time, resulting in those values of resveratrol, piceid, rhapontigenin, and rhaponticin with $3.766{\times}10^{-5}$, $4.330{\times}10^{-6}$, $5.430{\times}10^{-5}$, and $2.458{\times}10^{-5}\;{\mu}M/sec$, respectively. Apparent permeability coefficient of resveratrol and rhapontigenin were calculated to $9.994{\times}10^{-6}$ and $1.441{\times}10^{-6}\;cm/sec$, respectively, while those of piceid and rhaponticin were to $1.149{\times}10^{-7}$ and $6.523{\times}10^{-7}\;cm/sec$, respectively. These results suggest that aglycones would be absorbed more effectively than glycosides in stilbenoids.

• Archives of Pharmacal Research
• /
• 제24권5호
• /
• 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.

• Archives of Pharmacal Research
• /
• 제28권9호
• /
• pp.1027-1030
• /
• 2005

The antidiabetic-activity-guided fractionation and isolation of the $80\%$ EtOH extracts obtained from cultivated Korean Rhubarb rhizomes (Rheum undulatum, Polygonaceae) led to the isolation and characterization of one stilbene, desoxyrhapontigenin(1) and two anthraquinones, emodin (2) and chrysophanol (3). Their structures were established by chemical and spectroscopic methods. Compounds 1, 2, and 3 inhibited postprandial hyperglycemia by 35.8, 29.5, $42.3\%$, respectively.

• 생약학회지
• /
• 제36권4호통권143호
• /
• pp.257-262
• /
• 2005

This study was carried out to obtain the basic information that can be used to index rhubarbs in six regions of China and Korea. The anthraquinone and stilbene contest in various rhubarb produced in th different area were quantitatively analysed by HPLC. The average of sennoside A content of the Chinghai rhubarb was higher than that of the other palmata rhubarbs(high-quality rhubarbs) produced in China. As a result, the order of the sennoside A content was 1) Chinghai rhubarb, 2) Tsuchan rhubarb, 3)Kansu rhubarb 4) Neimenggu rhubarb. On the other hand, the total stilbenes content of each of the cultivated Korean rhubarb(Rheum undulatum) were higher than that of the Chinese rhapontica rhubarb(low-quality rhubarbs).

• 식물병연구
• /
• 제20권3호
• /
• pp.189-195
• /
• 2014

Genetic engineering is being used to enhance disease resistance and nutritional value of crops including rice plant. Considering the fast-growing agricultural biotechnology and rapidly increasing global area of transgenic crops, the risk evaluation on environment is necessary. In this study, we surveyed the difference of disease occurrence between transgenic rice variety, Iksan526 transformed with peanut stilbene synthase gene and non-transgenic rice varieties, Dongjin and Nampyeong in the field. Moreover, the possibility of gene transfer from transgenic rice to bacterial and fungal pathogens was investigated. The results of this study indicated that there was no significant difference in the occurrence and severity of the diseases between Iksan526 and Dongjin or Nampyeong. In addition, the results suggested that rice pathogen, such as Xanthomonas oryzae pv. oryzae, Rhizoctonia solani and Magnaporthe grisea did not take up stilbene synthase and bar genes under natural conditions. Moreover the transformed DNA was not transferred to the pathogens even in repetitive contacts.