• The Korean Journal of Food And Nutrition
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• v.16 no.1
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• pp.60-65
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• 2003

An antioxidant compound was obtained from the water extract of the stem bark from Rhus verniciflua, which has been used in traditional folk remedies. The compound was purified by HPLC, using DEAE, CN and ODS columns. The chemical structure of the compound was identified as gallic acid (3,4,5-hydroxylbenzoic acid) by spectral data including UV, IR, EI (HR)-MS, $^1$H-NMR, $\^$13/C-NMR and elemental analyzer. This compound was found show cytotoxicity against HeLa cell ( IC$\_$50/ : 8.5$\mu\textrm{g}$/$m\ell$).

• Journal of the Korean Chemical Society
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• v.63 no.2
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• pp.78-84
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• 2019

High-resolution $^1H$ NMR spectroscopic technique has been widely used as one of the most powerful analytical tools in food chemistry as well as to define molecular structure. The $^1H$ NMR spectra-based metabolomics has focused on classification and chemometric analysis of complex mixtures. The principal component analysis (PCA), an unsupervised clustering method and used to reduce the dimensionality of multivariate data, facilitates direct peak quantitation and pattern recognition. Using a combination of these techniques, the various green teas and black teas brewed were investigated via metabolite profiling. These teas were characterized based on the leaf size and country of cultivation, respectively.

• Journal of Korea Technology Innovation Society
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• v.2 no.3
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• pp.94-106
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• 1999

In Korea Basic Science Institute(KBSI) the remote data analysis system is developed for the joint use of advanced equipments. This system enables the researchers to access the datas which are produced at KBSI and analyse them by Java program on the Web,. Except Web browser such as Internet Explorer or Netscape Navigator no additional softwares are required for analysing data. We have developed remote data analysis systems for five major equipments which KBSI supports for the researchers, The systems which are developed are those for NMR spectrometer High Reso-lution Tandem mass Spectrometer Microscopic Imaging System DNA Sequencer and Natural Ra-dioactivity Measruement System, These programs work on any computer platform and any operat-ing system only if the internet is available. This remote data analysis system will be served as a part of Collaboratory the remote collaborative system.

• Journal of the Korean Magnetic Resonance Society
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• v.17 no.1
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• pp.11-18
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• 2013

Rapid advances of computational power and method have made it practical to apply the time-consuming calculations with all-atom force fields and sophisticated potential energies into refining NMR structure. Added to the all-atom force field, generalized-Born implicit solvent model (GBIS) contributes substantially to improving the qualities of the resulting NMR structures. GBIS approximates the effects that explicit solvents bring about even with fairly reduced computational times. Although GBIS is employed in the final stage of NMR structure calculation with experimental restraints, the effects by GBIS on structures have been reported notable. However, the detailed effect is little studied in a quantitative way. In this study, we report GBIS refinements of ubiquitin and GB1 structures by six GBIS models of AMBER package with experimental distance and backbone torsion angle restraints. Of GBIS models tested, the calculations with igb=7 option generated the closest structures to those determined by X-ray both in ubiquitin and GB1 from the viewpoints of root-mean-square deviations. Those with igb=5 yielded the second best results. Our data suggest that the degrees of improvements vary under different GBIS models and the proper selection of GBIS model can lead to better results.

• Journal of the Korean Magnetic Resonance Society
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• v.9 no.1
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• pp.29-37
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• 2005

Intra-cellular drug uptake in Xenopus laevis oocyte has been elucidated using localized MR spectroscopy (MRS) and PFG NMR techniques at a 600 $MH_z$(Bruker, 14.1 T) NMR spectrometer. The localized MRS has been done with a homemade probe, and shows the intra-cellular uptake of nicotinamide. The self-diffusion of the molecule in Xenopus oocyte was obtained by PFG NMR technique. The measured data are well fitted with a linear combination of two exponential functions, which shows that there are two types of drug molecules, intra-and extra-cellular molecules. Diffusion coefficients of intra- and extra-cellular drug molecules are 3.7 $\times$ $10^{-11}$ $\m^{2}/s$and 6.4 $\times$ $10^{-10}$ $\m^{2}/s$, respectively. In the weighting factors there is shown that about 5% of drug molecule is inside the cells. These techniques can be used for drug screening in molecule-, cell-, and tissue-based preclinical test.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.115-124
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• 2007

A series of α, β-unsaturated ketones are synthesized by Crossed - Aldol condensation reaction, from ecofriendly 6-methoxy-2-naphthyl ketones and substituted benzaldehydes under solvent free conditions using silica-sulfuric acid as a catalytic reagent. The yields of ketones are more than 90% and the catalyst was reusable for further run. There is no appreciable decrease in the yield of product and the activity of catalyst. These chalcones were characterized by their physical constants and spectral data (IR, 1H-, 13C-NMR and Mass). These spectral data are subjected to correlate various Hammett substituent constants with single and multiparameter correlation equations. From the results of statistical analysis the influence of electronic effects of substituents on the spectral data of the ketones were explained.

• Korean Journal of Pharmacognosy
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• v.31 no.1
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• pp.34-38
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• 2000

Three compounds were isolated from the roots of Astragalus membranaceus (Leguminosae). On the basis of spectroscopic evidences, the structures were characterized as $3-0-{\beta}-D-xylopyranosyl-(2',3'-O-diacetyl)-6-0-{\beta}-D-glucopyranosyl-3{\beta},6{\alpha},16{\beta},25-tetrahydroxy-20(R)$,24(S)-epoxy-cycloartane(Astragaloside I), $3-0-{\beta}-D-xylopyranosyl-(2'-O-acetyl)-6-0-{\beta}-D-glucopyranosyl-3{\beta},6{\alpha},16{\beta},25-tetrahydroxy-20(R)$,24(S)-epoxy-cycloartane(Astragaloside II), $3-0-{\beta}-D-xylopyranosyl-(2',4'-O-diacetyl)-6-0-{\beta}-D-glucopyranosyl-3{\beta},6{\alpha},16{\beta},25-tetrahydroxy-20(R)$,24(S)-epoxycycloartane(Isoastragaloside I). Full data of NMR including HMBC and 1D-TOCSY experiment of these compounds were reported for the first time.

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.235-244
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• 2012

Nuclear magnetic resonance (NMR) logging has been considered one of the most complicated nevertheless, one of the most powerful logging methods for the characterization on of both rocks and natural fluids in formation. NMR measures magnetized signals (polarization and relaxation) between the properties of hydrogen nucleus called magnetic moment and applied magnetic fields. The measured data set contains two important petrophysical properties such as density of hydrogen in the fluids inside the pore space and the distinct decay rate for fluid type. Therefore, after the proper data processing, key petrophysical information, not only the quantities and properties of fluids but also supplies of rock characterization in a porous medium, could be archived. Thus, based on this information, several ongoing researches are being developed in estimating aspects of reservoir productivity information, permeability and wettability since it is the key to having correct interpretation. This study goes through the basic theory of NMR at first, and then reviews NMR logging tools as well as their technical characteristics. This paper also briefly discusses the basic knowledge of NMR simulation algorithm by using Random walk.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2413-2418
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• 2013

Forensic and legal medicine require reliable data to indicate excessive alcohol consumption. Ethanol is oxidatively metabolized to acetate by alcohol dehydrogenase and non-oxidatively metabolized to ethyl glucuronide (EtG), ethyl sulfate (EtS), phosphatidylethanol, or fatty acid ethyl esters (FAEE). Oxidative metabolism is too rapid to provide biomarkers for the detection of ethanol ingestion. However, the non-oxidative metabolite EtG is a useful biomarker because it is stable, non-volatile, water soluble, highly sensitive, and is detected in body fluid, hair, and tissues. EtG analysis methods such as mass spectroscopy, chromatography, or enzyme-linked immunosorbent assay techniques are currently in use. We suggest that nuclear magnetic resonance (NMR) spectroscopy could be used to monitor ethanol intake. As with current conventional methods, NMR spectroscopy doesn't require complicated pretreatments or sample separation. This method has the advantages of short acquisition time, simple sample preparation, reproducibility, and accuracy. In addition, all proton-containing compounds can be detected. In this study, we performed $^1H$ NMR analyses of urine to monitor the ethanol and EtG. Urinary samples were collected over time from 5 male volunteers. We confirmed that ethanol and EtG signals could be detected with NMR spectroscopy. Ethanol signals increased immediately upon alcohol intake, but decreased sharply over time. In contrast, EtG signal increased and reached a maximum about 9 h later, after which the EtG signal decreased gradually and remained detectable after 20-25 h. Based on these results, we suggest that $^1H$ NMR spectroscopy may be used to identify ethanol non-oxidative metabolites without the need for sample pretreatment.

• Journal of the Korean Magnetic Resonance Society
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• v.20 no.3
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• pp.95-101
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• 2016

Apolipoprotein B-100 (Apo-B100) is a major component of low density lipoprotein (LDL). Apo B-100 protein has 4,536 amino acid sequence and these amino acids are classified into peptide groups A to G with subsequent 20 amino acids (P1-P302). The peptide groups were act as immunoglobulin (Ig) antigens which oxidized via malondialdehyde (MDA). The mimetic peptide P1 (EEEMLENVSLVCPKDAT RFK) out of D-group peptides carrying the highest value of IgG antigens were selected for structural studies that may provide antigen specificity. Circular Dichroism (CD) spectra were measured for peptide secondary structure in the range of 190-250 nm. Experimental results show that P1 exhibit partial of ${\beta}-sheet$ and random coil structure. Homonuclear (COSY, TOCSY, NOESY) 2D-NMR experiments were carried out for NMR signal assignments and structure determination for P1. On the basis of these completely assigned NMR spectra and distance data, distance geometry (DG) and Molecular dynamics (MD) were carried out to determine the structures of P1. The proposed structure was selected by comparisons between experimental NOE spectra and back calculated 2D NOE results from determined structure showing acceptable agreement. The total Root-Mean-Square-Deviation (RMSD) value of P1 obtained upon superposition of all atoms was in the range $0.33{\AA}$. The solution state P1 has mixed structure of ${\beta}-sheet$ (Glu[1] to Cys[12]) and random coil (Pro[13] to Lys[20]). These NMR results are well consistent with secondary structure from experimental results of circular dichroism. Structural studies based on NMR may contribute to the studies of atherosclerosis and observed conformational characteristics of apo B-100 in LDL using monoclonal antibodies.