• Journal of Photoscience
• /
• 제10권1호
• /
• 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.

• Environmental Analysis Health and Toxicology
• /
• 제16권3호
• /
• pp.115-120
• /
• 2001

The predictive screening of various molecular descriptors for predicting cyclooxygenase inhibitor, lipooxygenase inhibitor, leucotriene synthesis inhibitor, leucotriene antagonist activities of Stilbene moieties have been investigated for the application of quantitative structure-activity relationships (QSAR). The biological activities for 36 compounds were computed by the PASS program and molecular descriptors are cited from literatures or calculated, to investigate feasibility of screening relevant descriptors and of their applications among biological endpoints. Fairly good correlations varying from 0.7828 to 0.9032 were obtained using 12 descriptors with 29 Stilbene derivatives and 5 diazo-compounds. Our studies reveal that LogKow, electron density(X), electron density (Y),4th-order valence connectivity and water solubility can be usefully employed to predict biological activities of stilbene derivatives with simple regression models.

• 생약학회지
• /
• 제34권1호통권132호
• /
• pp.25-27
• /
• 2003

In order to clarify the anti-thrombosis activity of rhubarb, we investigated the effect of stilbene derivatives from rhizomes of Rheum undulatun on cyclooxygenase activity. Stilbene derivatives (desoxyrhapontigenin, rhapontigenin, piceatannol) exhibited the inhibitory effects on COX-1, and desoxyrhapontigenin showed inhibitory effect on COX-2. These inhibitory effect may partially contributed to anti-thrombosis activity of rhubarb.

• 생약학회지
• /
• 제31권2호
• /
• pp.245-248
• /
• 2000

As a series of the studies on cultivated Korean rhubarb rhizomes (Rheum undulatum), five stilbene derivatives were screened for inhibitory activity against $5{\alpha}-reductase$. Of these, desoxyrhapontigenin, rhapontigenin, and piceatannol exhibited inhibition, whereas, two other stilbene glycosides, rhaponticin and $piceatannol-3'-O-{\beta}-D-glucopyranoside$ did not show the inhibition.

• 생약학회지
• /
• 제35권2호통권137호
• /
• pp.171-174
• /
• 2004

In order to examine the anti-ohyul (anti-inflammatory) activity of rhubarb, we investigated the effects of stilbene derivatives obtained from rhizomes of Rheum undulatum on the carrageenan-induced hind paw edema in rats. Administration of stilbene aglycon (rhapontigenin) at doses of 50 and 100 mg/kg exhibited the anti- edema effect in dose dependent manner and stilbene glycosides $(rhaponticin,\;piceatannol-3'-O-{\beta}-D-glucopyranoside)$ at a dose of 100 mg/kg also showed inhibitory effect on the carrageenan-induced edema. These inhibitory effects may ascribed, at least in part, to the anti-ohyul activity of rhubarb.

• Journal of Photoscience
• /
• 제8권2호
• /
• pp.79-82
• /
• 2001

2-(p-Diethylaminostyryl)pyrrole (I) and 2-[5-diethylaminothienyl]vinyl]pyrrole (II) derivatives with systematic variation of the acceptors have been synthesized and their first hyperpolarizabilities were measured. The $\beta$ values increased systematically as the aromatic resonance energy decreased. Moreover, the value of $\beta$ for the former increased gradually as the acceptor strength increased. The opposite trend observed in the latter series of compounds has been attributed to the distorted structure caused by the steric hindrance between the N-methyl group and the acceptor moiety.

• 원예과학기술지
• /
• 제29권4호
• /
• pp.374-381
• /
• 2011

Stilbene 화합물은 항산화 및 항균 활성을 가지는 폴리페놀계의 천연물이다. 포도를 포함하는 몇몇 종류의 식물에서 stilbene 화합물은 resveratrol의 유도체로서 매우 다양한 형태로 존재한다. 자외선 조사 포도 잎에서 stibene 화합물을 정량 분석하기에 앞서, 먼저 각 stilbene 화합물을 동정하기 위한 실험을 수행하였다. 이를 위하여, 자외선을 심하게 조사한 잎에서 stilbene 배당체를 추출하였다. 추출한 배당체 시료는 ${\beta}$-glucosidase를 이용하여 가수분해한 후, 특정 stilbene 화합물의 질량에 해당하는 m/z에서 HPLC-mass spectrometer를 이용하여 분석하였다. 효소적 가수분해에 의해 chromatogram상에는 glycoside에 해당할 것으로 예상되는 peak의 감소와 aglycone에 해당할 것으로 예상되는 peak 증가가 나타났다. 또한 stilbene 화합물의 광 이성질화를 유도하기 위하여 시료를 일광에 노출하였으며, 광 노출에 의해 trans-isomer에 해당할 것으로 예상되는 peak의 소멸과 cis-isomer에 해당할 것으로 예상되는 peak의 생성이 나타났다. Chromatogram상의 peak의 이러한 증감으로부터 각 peak의 성분을 유추하였다. 이러한 방법으로 포도 잎에서 16종의 stilbene 화합물을 동정할 수 있었으며 자외선을 조사한 포도 잎에서 동정된 화합물에 대한 정량적 분석을 수행하였다. 자외선 조사는 포도 잎에서 총 stilbene 함량의 상당한 증가를 가져왔는데 특히 trans-resveratrol은 수백 배 증가하였다. 또한, resveratrol보다 더 강한 radical 소거 활성을 가지지만 무처리 잎에서는 단지 미량으로만 존재하는 piceatannol의 함량 역시 수십배 증가하였다. 자외선 조사에 의한 이러한 stilbene 함량의 증가는 hormesis 현상으로서 포도의 스트레스 대응 반응의 하나로 생각된다.

• 공업화학
• /
• 제22권4호
• /
• pp.348-352
• /
• 2011

본 연구에서는 펜던트 타입의 고분자인 폴리우레탄에 스틸벤 유도체를 가진 다양한 발색단을 곁가지로 도입하고, 이를 연결하는 방식으로 분자를 디자인하고 합성하였다. 모노머 분자인 N,N-bis(2-hydroxyethyl)amino-4'-cyanostilbene, N,N-bis(2-hydroxyethyl) amino-4'-methoxy stilbene, N,N-bis(2-hydroxyethyl)amino-4'-acetylstilbene, N,N-bis (2-hydroxyethyl) amino stilbene은 Wittig 반응을 이용하여 합성하였고, N,N-bis(2-hydroxyethyl)amino-4'-nitrostilbene는 Knoevenagel 축합반응을 이용하여 합성하였다. 합성된 물질의 흡수 및 형광 스펙트럼의 측정으로부터, 치환기로 전자 끌게 작용기를 도입한 경우 그 정도에 따라 스펙트럼이 장파장으로 이동하며, 반대로 전자 주게 작용기가 도입된 경우는 단파장 이동하는 것을 확인 하였다. 반면, $NO_2$가 치환된 경우 그 자체가 빛을 소멸시키는 쾐쳐로 작용하여 PL이 관측되지 않았다.

• 한국전기전자재료학회논문지
• /
• 제16권12호
• /
• pp.1121-1124
• /
• 2003

We report the photo (PL) and electro luminescence (EL) properties of new conjugated compounds based on imidazole moiety, 4,4' -di(4,5 diphenyl-N-imidazolyl)stilbene(DDPIS) and 4,4'-di(2,4,5-triphenyl-N-imidazolyl)stilbene(DTPIS), as emitting materials. ITO/m-MTDATA/NPB/DDPIS/Alq3/LiF/AI device shows blue EL spectrum at 456 ㎚ and 0.3 cd/ A and turn on voltage at 7 ∼ 8 V. DTPIS shows blue EL spectrum at around λmax=453㎚ and 0.5 cd/A efficiency in ITO/m-MTDATA/NPB/DTPIS/Alq3/LiF/Al device.

• Bulletin of the Korean Chemical Society
• /
• 제31권4호
• /
• pp.971-975
• /
• 2010

Eight hydroxylated stilbene derivatives including resveratrol, desoxyrhapontigenin and piceatannol as potential radical scavenger and tyrosinase inhibitor are synthesized using optimized Wittig-Horner reaction for excellent trans-selectivity in good yields. Antioxidant activity was tested against ABTS radical and tyrosinase inhibitory activity was performed with L-tyrosine as the substrate based on previous procedure with some modification. In general, catecholic stilbenes showed stronger activity against ABTS radical and resorcinolic moiety showed stronger tyrosinase inhibitory activity. Synthetic piceatannol which containing both catecholic and resorcinolic moieties showed the strongest activity in both as ABTS radical scavenger and tyrosinase inhibitor with $IC_{50}$ values of 4.1 and $8.6\;{\mu}M$, respectively.