• Bulletin of the Korean Chemical Society
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• v.17 no.7
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• pp.625-630
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• 1996

The cobalt-substituted polyoxotungstate [(CoPW11O39)5-] has been used as a catalyst in olefin epoxidation and alkane hydroxylation reactions. The epoxidation of olefins by iodosylbenzene in CH3CN yielded epoxides predominantly with trace amounts of allylic oxidation products. cis-Stilbene was streoselectively oxidized to cis-stilbene oxide with small amounts of trans-stilbene oxide and benzaldehyde formation. The epoxidation of carbamazepine (CBZ) by potassium monopersulfate in aqueous solution gave the corresponding CBZ 10,11-oxide product. Other transition metal-substituted polyoxotungstates (M=Mn2+, Fe2+, Ni2+, and Cu2+) were inactive in the CBZ epoxidation reaction. The cobalt-substituted polyoxotungstate also catalyzed the oxidation of alkanes with m-chloroperbenzoic acid to give the corresponding alcohols and ketones. The presence of CH2Br2 in the hydroxylation of cyclohexane afforded the formation of bromocyclohexane, suggesting the participation of cyclohexyl radical. In the 18O-labeled water experiment, there was no incorporation of 18O into the cyclohexanol product when the hydroxylation of cyclohexane by MCPBA was carried out in the presence of H218O. Some mechanistic aspects are discussed as well.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.682-684
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• 2008

• Journal of Life Science
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• v.22 no.6
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• pp.815-822
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• 2012

Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene), a natural stilbene, is an analogue of resveratrol. Although recent experimental data have revealed the health benefit potency of piceatannol, the molecular mechanisms underlying the anti-cancer activity have not yet been studied in detail. In the present study, the further possible mechanisms by which piceatannol exerts its pro-apoptotic action in cultured human lung cancer A549 cells were investigated. Exposure of A549 cells to piceatannol resulted in growth inhibition and induction of apoptosis. Apoptosis induction of A549 cells by piceatannol showed correlation with proteolytic activation of caspase-3, -8, and -9, and concomitant degradation of activated caspase-3 target proteins such as poly (ADP-ribose) polymerase, phospholipase C-${\gamma}1$, ${\beta}$-catenin, and Inhibitor caspase-activated DNase. The increase in apoptosis by piceatannol treatment was also associated with an increase of pro-apoptotic Bax expression and decrease of anti-apoptotic Bcl-2 and Bcl-xL expression, and caused down-regulation of the inhibitor of apoptosis protein family members and up-regulation of Fas and Fas legend. In addition, piceatannol treatment markedly inhibited the expression of mRNA and proteins of inducible nitric oxide (NO) synthase, and the levels of NO production were progressively down-regulated by piceatannol treatment in a dose-dependent fashion. The results indicate that piceatannol may have therapeutic potential against human gastric cancer cells.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.12-15
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• 2014

Polygonum cuspidatum which is widely distributed in Korea has been used as treatments of dermatitis, gonorrhea, favus athlete's foot, hyperlipidemia and inflammation in traditional medicine. We examined anti-oxidant and antiinflammatory activity by measuring DPPH radical scavenging activity and the inhibition of IFN-${\gamma}$ and LPS-induced NO production in RAW 264.7 murine macrophage cells. We isolated and characterized resveratrol (1), trans-resveratrol 3-O-${\beta}$-Dglucopyranoside (2). Compounds 1 and 2 showed potent activities compared with L-NMMA ($N^G$-monomethyl-L-arginine). These results suggested that the stilbene compounds isolated from Polygonum cuspidatum might be used as antiinflammatory agents.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.194.2-194.2
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• 2003

The inhibitors of prostaglandin biosynthesis and nitric oxide production by corresponding inducible isozyme have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for cancer chemopreventive agents from natural products, we have evaluated the inhibitory potential of PGE$_2$ and NO production in lipopolysaccharide (LPS)-induced mouse macrophage RAW 264.7 cells. As a result, pinosylvin (3,5-dihydroxy-trans-stilbene), a stilbenoid, mainly found from the heartwood and leaves of the Pinus sylvestris, showed potential inhibitory activity of LPS-induced PGE$_2$ and NO production in a dose-dependent manner. (omitted)

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.102-102
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• 2003

The inhibitors of prostaglandin biosynthesis and nitric oxide production by corresponding inducible isozyme have been considered as potential anti-inflammatory and cancer chemopreventive agents. In our continuous search for cancer chemopreventive agents from natural products, we have evaluated the inhibitory potential of PGE$_2$and NO production in lipopolysaccharide (LPS)-induced mouse macrophage RAW264.7 cells. As a result, pinosylvin (3,5-dihydroxy-trans-stilbene), a stilbenoid, mainly found from the heartwood and leaves of the Pinus sylvestris, showed potential inhibitory activity of LPS-induced PGE$_2$and NO production in a dose-dependent manner. Pinosylvin also suppressed the LPS-induced iNOS protein expression. Further study revealed that pinosylvin exhibited antioxidant activity by the DPPH free radical scavenging potential and inhibitory effect of xanthine oxidase activity. In addition, pinosylvin inhibited COX -2 overexpressed human colon cancer cell (HT-29) growth in a time- and dose-dependent manner. These findings suggest that pinosylvin might be a promising candidate for developing cancer chemopreventive agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1226-1234
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• 2012

3,4,3',5'-Tetrahydroxy-trans-stilbene (piceatannol) is a derivative of resveratrol with a variety of biological activities, including anti-inflammatory, anti-proliferative, and anti-cancer activities. We assessed the mechanisms by which piceatannol inhibits inflammatory responses using lipopolysaccharide (LPS)-treated Raw264.7 murine macrophages. Piceatannol (0~10 ${\mu}mol/L$) decreased LPS-induced release of nitric oxide, tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6, IL-$1{\beta}$, and inhibited LPS-induced protein expression of inducible nitric oxide synthase (iNOS). Activation of nuclear factor-kappaB (NF-${\kappa}B$), activator protein (AP)-1, and signal transducer and activator of transcription 3 (STAT3) are crucial steps during an inflammatory response. Piceatannol prevented LPS-induced degradation of inhibitor of ${\kappa}B$ ($I{\kappa}B$), translocation of p65 to the nucleus, and phosphorylation of stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK). Additionally, piceatannol inhibited LPS-induced phosphorylation of STAT3 and IL-6-induced translocation of STAT3 to the nucleus. Furthermore, piceatannol increased the protein and mRNA levels of hemeoxygenase (HO)-1, the rate-limiting enzyme of heme catabolism that plays a critical role in mediating antioxidant and anti-inflammatory effects. Piceatannol further induced antioxidant response elements (ARE)-driven luciferase activity in Raw264.7 cells transfected with an ARE-luciferase reporter construct containing the enhancer 2 and minimal promoter region of HO-1. These results suggest that piceatannol exerts anti-inflammatory effects via the down-regulation of iNOS expression and up-regulation of HO-1 expression.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.3
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• pp.282-287
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• 2008

Gardeniae Fructus (GF) is a fruit of Gardenia jasminoides Ellis (Rubiaceae) which has been used in traditional medicine. It contains not only geniposide but also resveratrol, a kind of stilbene as a natural antioxidant. In this study, we investigated physiological activities of GF extracts by measuring electron donating ability (EDA), nitrite scavenging ability (NSA), super oxide dismutase (SOD)-like activity and inhibitory effect of tyrosinase activity (ITA). As a solvent, it was extracted with water, 50 and 100% ethanol using microwave. At the concentration of 6 mg/mL, EDA was the highest at 50% ethanol extract but the lowest at 100% ethanol extract, $96.43{\pm}0.25%\;and\;77.06{\pm}0.22%$ respectively. NSA showed the strongest activity at 50% ethanol extract like EDA (6 mg/mL: $75.26{\pm}0.28%$). ITAs were below 20% in all samples and their activities reduced according to increasing concentration. Likewise, SOD-like activities decreased with increasing concentration of extracts in all samples. In conclusion, GF extracts showed low SOD-like activities and ITAs but EDAs and NSAs were fairly high; especially EDA of 50% ethanol extract (6 mg/mL) was high as those of 0.1 and 1% L-ascorbic acid. Therefore the results suggest that GF extracts may be useful as potential sources of natural antioxidants.