• Korean Journal of Food Science and Technology
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• v.45 no.5
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• pp.557-564
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• 2013

We isolated and identified antioxidants from acidic and neutral ethyl acetate fractions of the peel of pear (Pyrus pyrifolia N. cv. Chuhwangbae). We isolated 4 compounds from the methanol extract, by using 3 different types of column chromatography (Sephadex LH-20, silica gel, and octadecylsilane) and preparative HPLC. We identified the isolated compounds as (S)-(+)-2-cis-abscisic acid O-${\beta}$-D-glucopyranosyl ester (compound 1), 1-[4-O-${\beta}$-D-glucopyranosyl]phenyl ethanone (picroside, compound 2), ${\beta}$-sitosterol (compound 3), and ${\beta}$-sitosteryl 3-O-${\beta}$-D-glucopyranoside (compound 4) by nuclear magnetic resonance analysis. We are the first to report the identification of compounds 1, 2, and 4 from pear.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.311-316
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• 2010

It is well-known that electrical field stimulation (EFS)-induced contraction is mediated by a cholinergic mechanism and other neurotransmitters. NO, ATP, calcitonin gene-related peptide (CGRP), and substance P are released by EFS. To investigate the purinergic mechanism involved in the EFS-induced contraction, purinegic receptors antagonists were used. Suramine, a non-selective P2 receptor antagonist, reduced the contraction induced by EFS. NF023 ($10^{-7}{\sim}10^{-4}M$), a selective P2X antagonist, inhibited the contraction evoked by EFS. Reactive blue ($10^{-6}{\sim}10^{-4}M$), selective P2Y antagonist, also blocked the contraction in a dose-dependent manner. In addition, P2X agonist ${\alpha}$,${\beta}$-methylene 5'-adenosine triphosphate (${\alpha}{\beta}MeATP$, $10^{-7}{\sim}10^{-5}M$) potentiated EFS-induced contraction in a dose-dependent manner. P2Y agonist adenosine 5'-[${\beta}$-thio]diphosphate trilithium salt ($ADP{\beta}S$, $10^{-7}{\sim}10^{-5}M$) also potentiated EFS-induced contractions in a dose-dependent manner. Ecto-ATPase activator apyrase (5 and 10 U/ml) reduced EFS-induced contractions. Inversely, 6-N,$N$-diethyl-D-${\beta}$,${\gamma}$- dibromomethylene 5'-triphosphate triammonium (ARL 67156, $10^{-4}M$) increased EFS-induced contraction. These data suggest that endogenous ATP plays a role in EFS-induced contractions which are mediated through both P2X-receptors and P2Y-receptors stimulation in cat esophageal smooth muscle.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.937-941
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• 2006

Ixeris dentata forma albiflora was extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_{2}O$. Eight sesquiterpenes were isolated through repeated silica gel and octadecyl silica gel ($C_{18},\;ODS$) column chromatography of the EtOAc and n-BuOH fractions. Physicochemical analysis using NMR, MS and IR revealed the chemical structures of the sesquiterpenes, which were zaluzanin (1), 9a-hydroxyguaian-4(15), 10(14), 11 (13)-triene-6, 12-olide(2), $3{\beta}-O-{\beta}-D-glucopyranosyl-8{\beta}-hydroxyguaian$-4(15), 10(14)-diene-6, 12-olide (3), $3-O-{\beta}-D-glucopyranosyl-8{\beta}-hydroxyguauan$-10(14)-ene-6, 12-olide (4), ixerin M (5), glucozaluzanin C (6), crepiside I (7), and ixerin D (8). This is the first time that these sesquiterpene lactones have been isolated from this plant. Compounds 1, 2 and 7 revealed relatively high cytotoxicities on human colon carcinoma cell and lung adeno-carcinoma cell, while compounds 5 and 7 showed acyl-CoA: cholesterol acyltransferase (ACAT) inhibitory activity.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.251-257
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• 2004

The root of lxeris dentata forma albiflora was extracted with 80% aqueous MeOH and solvent fractionated with EtOAc, n-BuOH and water, successively. From the EtOAc and n-BuOH fractions, four sesquiterpene compounds were isolated through the repeated silica gel and ODS column chromatographies. The chemical structures were determined as zaluzanin C (1), $9{\alpha}-hydroxyguaian-4(l5),10(14),11(13)-triene-6,12-olide$ (2), $3{\beta}-O-{\beta}-D-glucopyranosyl-8{\alpha}-hydroxyguaian-4(15),10(14 )-diene-6,12-olide$ (3), and $3{\beta}-O-{\beta}- D-glucopyranosyl-8{\beta}hydroxyguaian-10(14)-ene-6,12-olide$ (4) through the interpretation of several spectral data including 2D-NMR. Some showed the inhibitory effects on DGAT (Diacylglycerol acyltransferase), ($IC_{50}$ values of 1, 2: 0.13, 0.10 mM), the catalyzing enzymes of the intracellular esterification of diacylglycerol and FPTase (Famesyl-protein transferase), ($IC_{50}$ values of 1, 2: 0.15, 0.18 mM), the farnesylation enzyme for Ras protein charge of cancer promotion.

• Natural Product Sciences
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• v.11 no.3
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• pp.150-154
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• 2005

The radical scavenging effect of the MeOH extract of Fraxini Cortex on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was examined. The $CH_2Cl_2$-and n-BuOH-soluble fractions of MeOH extract showed the promising DPPH radical scavenging effects, and further purified by silica gel, Sephadex LH-20 column chromatography, and reversed-phase C-18 MPLC to yield five coumarins, esculetin (1), fraxidin (2), fraxetin (3), fraxidin $8-O-{\beta}-D-glucopyranoside$ (fraxin methyl ether) (5), esculin (6), and a secoiridoid oleuropein (4), and a coumarin-secoiridoid escuside (7). Compounds 1, 3, and 4 showed potent DPPH radical scavenging effects, exhibiting $IC_{50}$ values of 14.68, 9.64, and $22.03\;{\mu}M$, respectively. Compounds 6 and 7 also showed moderate effects with $IC_{50}$ values of 147.79 and $72.73\;{\mu}M$, respectively. L-Ascorbic acid was used as a positive control and exhibited the $IC_{50}$ value of $50.31\;{\mu}M$.

• Korean Journal of Crystallography
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• v.16 no.2
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• pp.102-106
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• 2005

The crystal structure of the title compound has been analyzed by single crystal X-ray diffraction method. The compound crystallized in the triclinic space group $P\bar{1}$ with a=11.300(6) ${\AA}$, c=18.716(10) ${\AA}$, ${\alpha}=82.833(10)^{\circ}$, ${\beta}=83.042(11)^{\circ}$, ${\gamma}=66.139(10)^{\circ}$, $V=2162(2)\;{\AA}^{3}$, Z=2 and R1=0.661 for 10578 unique reflections. The four $C_{5}Me_{5}$ planar groups from a tetrahedron with a mean dihedral angle $70.92(9)^{\circ}$ among them and the $Ti_{4}O_{6}$ cage sits at the center of the tetrahedron. Each Ti atom in the $Ti_{4}O_{6}$ cage is bonded by three bridging oxygen atoms and coordinated by a $C_{5}Me_{5}$ ligand with a mean distance $2.067{\AA}$ from Ti atoms to the centroids of the four five-membered rings. Two oxygen atoms facing each other in $Ti_{4}O_{6}$ cage are $4.051(3){\AA}$ away in average.

• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1102-1108
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• 2006

An in vitro bioassay-guide revealed that the methanol (MeOH) extract of the stem bark of Populus davidiana showed considerable inhibitory activity against cyclooxygenase (COX-1, COX-2). Continuous phytochemical study of the MeOH extract of this plant led to the isolation of ten flavonoids; sakuranetin (1), rhamnocitrin (2), 7-O-methylaromadendrin (3), naringenin (4), eriodictyol (5), aromadendrin (6), kaempferol (7), neosakuranin (8), sakuranin (9) and sakurenetin-5,4'-di-${\beta}$-D-glucopyranoside (10). Their structures were identified on the basis of their physicochemical and spectroscopic analyses. The isolated compounds, 1-10, were tested for their inhibitory activities against COX-1 and COX-2. Compound 7 was found to have potent inhibitory effect on COX-1 and a moderate effect on COX-2, meanwhile, compounds 1-6 showed moderate inhibition against COX-1 only. Moreover, compounds 5-8 exhibited suppressive effects on xanthine oxidase (XO). These results may explain, in part, the traditional uses of P. davidiana in ethnomedicine.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.86-91
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• 2009

In our ongoing search for biological components from the Korea endemic plants, the MeOH extract of Ailanthus altissima leaves (Simaroubaceae) showed cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) dual inhibitory activity by assessing their effects on the production of prostaglandin $D_2$ ($PGD_2$) and leukotriene $C_4$ ($LTC_4$) in mouse bone marrow-derived mast cells (BMMCs). In further study, eight compounds, squalene (1), ${\beta}$-sitosterol (2), scopoletin (3), quercetin (4), luteolin (5), astragalin (6), scopolin (7), and daucosterol (8) were isolated, the chemical structures were elucidated on the basis of physicochemical and spectroscopic data and by comparison with those of published literatures. Among the compounds, 2, 4, and 5 strongly inhibited both the COX-2-dependent PGD2 generation with $IC_{50}$ values of 2.6, 7.3 and 2.5 ${\mu}M$, respectively and the generation of $LTC_4$ in the 5-LOX dependent phase with $IC_{50}$ values of 2.0, 5.1 and 1.8 ${\mu}M$, respectively, which suggest that the anti-inflammatory activity of A. altissima might occur in part via the inhibition of both $PGD_2$ and $LTC_4$ generation by 2, 4 and 5.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.310-310
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• 2012

ZnO thin films were grown on porous silicon (PS) by plasma-assisted molecular beam epitaxy (PA-MBE). The optical properties of the ZnO thin films grown on PS were studied using room-temperature, low-temperature, and temperature-dependent photoluminescence (PL). The full width at half maximum (FWHM) of the near-band-edge emission (NBE) from the ZnO thin films was 98 meV, which was much smaller than that of ZnO thin films grown on a Si substrate. This value was even smaller than that of ZnO thin films grown on a sapphire substrate. The Huang-Rhys factor S associated with the free exciton (FX) emission from the ZnO thin films was found to be 0.124. The Eg(0) value obtained from the fitting was 3.37 eV, with ${\alpha}=3.3{\times}10^{-2}eV/K$ and ${\beta}=8.6{\times}10^3K$. The low- and high-temperature activation energies were 9 and 28 meV, respectively. The exciton radiative lifetime of the ZnO thin films showed a non-linear behavior, which was established using a quadratic equation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.509-513
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• 2003

The radioactive Carbon, C-14, although present in small amount, emits a high energy(up to 0.156MeV) $\beta$ ray and has extremely long half-life(5730years). So special monitoring and management on its generation and discharge is inevitable. A PHWR, due to its own specific designs generates about six times as much C-14 as a PWR does and over 90% of the discharged C-14 comes from the Moderator system and discharged in to the environment through the process of periodic purging of the moderator cover gas system. The present study focussed on the development of effective C-14 scrubber and after production of a test facility and experiments using it, we found that our test facility is very efficient in $CO_2$ removal.