• 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$).

• Applied Biological Chemistry
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• v.47 no.2
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• pp.270-273
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• 2004

Two prenylated flavonoids were isolated from a chloroform extract of the root bark of Cudrania tricuspidata. Both compounds (1, 2) showed antibacterial activity against Gram positive bacteria, Staphylococcus aureus, Bacillus subtilis and Bacillus cereus. Their structures were determined as euchrestaflavanone B (1) and euchrestaflavanone C (2) on the basis of $^1H\;NMR,\;^{13}C\;NMR$ and long-range coupling NMR techniques.

• Analytical Science and Technology
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• v.13 no.1
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• pp.49-54
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• 2000

The 8-hydroxyquinoline derivative of silica gel has been prepared through the 5 step reaction. We carried out infrared as well as nuclear magnetic resonance spectrometric characterization of products taken from each step of reaction. IR study of bare silica gel showed free and hydrogen bonded hydroxyl. From the 1st step reaction, we observed IR bands for N-H and C-H as well as NMR peaks for three methylene carbons in APTS group. From the 2nd step, we observed IR bands for carbonyl, nitro and aromatic carbon group with NMR peaks for aliphatic, aromatic and carbonyl carbons. The reduction of $NO_2$ group to $NH_2$ group is confirmed by IR and NMR from 3rd step reaction. In the last step, the immobilization of 8-quinolinol is confirmed by disappearance of $N{\equiv}N$ IR peak observed in 4th step.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.5
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• pp.702-706
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• 1995

A major component(compound A) in the ethylacetate fraction exhibited a strong antimicrobial activity was identified by UV, IR, FABMS and NMR. The compound A showed strong absorbance at 209, 259 and 359nm, indicating a flavonoid ring structure. IR spectrum possessed absorbance of OH at 3400∼3300cm-1, ketone at around 1650cm-1, and aromatic C=C at around 1660cm-1. Molecular weight of the compound A calculated as 478 from the information of m/z 479(M＋H)+ and m/z 477(M-H)+ in the FABMS spectrum. Molecular formula of this compound was found to be C22H22O12 from m/z 479.1220(＋3.1mmu for C22H23O12) of HRFABMS spectrum and from 13C-NMR spectrum. 1H-NMR and 13C-NMR spectra of the compound A revealed aromatic proton and benzene rings. Distortionless enhancement by polarization transfer(DEPT) exhibited that the compound A possessed 10 quaternary carbons and 3 substituted benzene rings including a methoxy group substitution. The compound A was identified as isorhamnetin 3-O-β-glucopyranoside by spectrophotometric methods in conjunction with 1H-1H COSY, 1H-13C COSY and HMBC, which revealed a flavone with OH group at 3, 5, 7, and 4' and methoxy group at 3' positions esterified to glucose.

• Journal of the Mineralogical Society of Korea
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• v.20 no.2 s.52
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• pp.97-102
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• 2007

NMR experiments with various pulse repetition delay time were carried out for the $^{15}N\;and\;^{13}C$ of a natural gem diamond and synthetic diamonds. The natural gem diamond had a weak $^{13}C$ peak at 34.1ppm when 30 second pulse repetition delay time was applied. Similar but more prominent $^{13}C$ peaks were observed at 34.2 ppm with 0.5 second pulse repetition delay time and at 34.7 ppm with 50 second pulse repetition delay time for the synthetic diamonds. Any meaningful $^{15}N$ peak was not observed for either natural or synthetic diamonds due to extremely low content of the $^{15}N$. Significant relationship was observed between relative spin-lattice relaxation times we estimated and the content of impurities. however, it was not possible to distinguish natural diamond from synthetic diamonds due to very similar characteristics of their $^{13}C$ NMR signals except relative spin-lattice relaxation times.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.352-357
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• 2013

This study estimates the classification criteria which distinguishes the types of omega-3 health functional foods, fish oils and fish oil usages through $^{13}C$-NMR spectra and fatty acids contents analysis. The major fatty acids of omega-3, eicosapentaenoic acid (EPA, $C_{20:5}$) and docosahexaenoic acid (DHA, $C_{22:6}$) are being analyzed. 10 ethyl ester (EE) forms and 10 triglyceride (TG) forms are the most common types of fish oils for 20 omega-3 products. Gas chromatography (GC) analysis generally shows the matching EPA and DHA contents of the products listed on the notation. But EE form contents of EPA and DHA are higher and are more varied than the TG form. Most of the samples of EPA/DHA ratio show different content ratios of indicated on the products when comparing with standards. The $^{13}C$-NMR analysis of EPA and DHA on sn-1,3 and sn-2 carbonyl peak position with fish oil triglycerides display whether the reconstituted triglycerides (rTG) are being confirmed or not. As a result of the 9 TG form, the 10 TG products showed similar values: EPA sn-1, 3; 13.46~15.66, sn-2; 3.00~4.52, DHA sn-1, 3; 2.43~4.40, sn-2; 3.84~6.36. But one product showed lower contents (EPA: sn-1, 3; 5.88, sn-2; 2.86, DHA sn-1, 3; 2.29, sn-2; 5.95) of EPA, thus it can be considered a different type of oil and only matched six products according to the label. This study is intended to provide basic materials which identify the status for the types and quality of omega-3 fish oil products according to fatty acids profiles and the $^{13}C$-NMR spectrum confirmed the location specificity of EPA and DHA.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.615-617
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• 2005

[ $^{13}C$ ] NMR spectra were obtained for pure $CH_4$ hydrate in order to identify hydrate structure and cage occupancy of guest molecule. The NMR technique can provide both qualitative and quantitative hydrate characteristics. The moles of methane captured into pure $CH_4$ hydrate per mole of water were found to be similar to the full occupancy value. The overall results drawn from this study can be usefully applied to storage and transportation of natural gas.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.183-189
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• 2006

A series of substituted styryl 4-methoxy-1-naphthyl ketones [(2E)-1-(4-methoxy-1-naphthyl)-3-phenyl-2-propen-1-ones] were synthesized using facile method of microwave assisted condensation reaction. The yield of chalcones is more than 90%. They are characterized by their physical constants, micro analysis, infrared (KBr, 4000-400 cm？1) and NMR both 1H and 13C spectral data. From infrared spectra, the s-cis and s-trans stretching vibrations of carbonyl group, from NMR spectra the ethylenic proton and carbon chemical shifts (ppm) are assigned. These spectral data are correlated with various Hammett substituent constants. From the results of statistical analysis the effect of substituents on CO, ？ and ？ proton and carbons are explained.

• Analytical Science and Technology
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• v.16 no.4
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• pp.283-291
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• 2003

Humic and fulvic acids present in soils of different depth were extracted and their acidic functional groups and structural characteristics were analyzed and compared. The purpose of this study was to present a basic data needed to evaluate the effect of humic substances on depth distribution and migrational behaviour of radioactive elements deposited on soil. Acidic functional groups of the humic and fulvic acids were analyzed by pH titration method, and their proton exchange capacity (PEC, $mq\;g^{-1}$) and average $pK_a$ values were obtained. Structural characteristics of the humic and fulvic acids were analyzed using their CPMAS $^{13}C$ NMR spectra and elemental composition data. pH titration data showed that fulvic acids have higher acidic functional group contents ranging from 5.5 to $7.0meq\;g^{-1}$ compared with that of humic acids ($3.8{\sim}4.8meq\;g^{-1}$). From depth profiles, it has been found that PEC values of humic acids in deeper soil (> 8 cm) were higher than those at the surface soils. Elemental compositions (H/C ratio) and spectral features ($C_{arom}/C_{aliph}$ ratio) obtained from CPMAS $^{13}C$ NMR spectra showed that the aromatic character in humic acids was a relatively higher than that of fulvic acids, while lower in carboxyl carbon content. The aromatic character and carboxyl carbon contents of humic acids tend to increase as soil depth increased, but those of fulvic acid showed little differences by the soil depth range.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1993.04a
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• pp.85-96
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• 1993

합성세제의 주원료로 많이 사용되고 있는 알킬벤젠 생산시 발생되는 부산물은 극한지 및 특수 산업용 윤활유의 합성 윤활기유로서 좋은 효과를 갖는다는 사실은 잘 알려져 있다. 알킬벤젠은 여러가지 방향족 화합물들의 혼합물로써 이루어져 있으며 그 조성은 그들을 기유로한 윤활유의 품질에 많은 영향을 미친다. 그러므로 그 조성분석을 위한 신속, 정확한 방법은 대단히 중요하다. 본 연구에서는 합성기유로서 사용될 수 있는 몇가지 알킬벤젠들에 대하여 $^{13}C-NMR$을 이용하여 그 조성을 분자구조적인 측면에서 구조파라미터에 따라서 관찰하고 그들의 윤활기유로서의 산화안정성 및 열안정성에 대하여 비교 관찰하였다.