• Food Science of Animal Resources
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• v.41 no.2
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• pp.312-323
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• 2021

The purpose of this study was to use 1H nuclear magnetic resonance (1H NMR) to quantify taste-active and bioactive compounds in chicken breasts and thighs from Korean native chicken (KNC) [newly developed KNCs (KNC-A, -C, and -D) and commercial KNC-H] and white-semi broiler (WSB) used in Samgye. Further, each breed was differentiated using multivariate analyses, including a machine learning algorithm designed to use metabolic information from each type of chicken obtained using 1H-13C heteronuclear single quantum coherence (2D NMR). Breast meat from KNC-D chickens were superior to those of conventional KNC-H and WSB chickens in terms of both taste-active and bioactive compounds. In the multivariate analysis, meat portions (breast and thigh) and chicken breeds (KNCs and WSB) could be clearly distinguished based on the outcomes of the principal component analysis and partial least square-discriminant analysis (R2=0.945; Q2=0.901). Based on this, we determined the receiver operating characteristic (ROC) curve for each of these components. AUC analysis identified 10 features which could be consistently applied to distinguish between all KNCs and WSB chickens in both breast (0.988) and thigh (1.000) meat without error. Here, both 1H NMR and 2D NMR could successfully quantify various target metabolites which could be used to distinguish between different chicken breeds based on their metabolic profile.

• Korean Journal of Oriental Medicine
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• v.14 no.1
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• pp.107-111
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• 2008

Objectives : Cynanchum wilfordii(Asclepiadaceae) has been traditionally used as a tonic, the prevention and treatment of various geriatric diseases in Korea. Acetophenone derivatives from C. wilfordii showed neuroprotective activity. In this study, two acetophenones were isolated and quantitative determination of acetophenones from C. wilfordii has been developed for quality stand. Methods : Three acetophenone derivatives were isolated from methanol extract of C. willfordii by the chromatographic separation. Their structures were identified as cynandione A, 2,5-dihydroxy acetophenone and cynanchone A on the basis of spectral data(MS, $^1H-NMR$, $^{13}C-NMR$) and chemical analysis. HPLC analysis was performed to determine the contents of cynandione A and 2,5-dihydroxyacetophenone in C. wilfordii. Results : According to the results, the contents of cynandione A and 2,5- dihydroxyacetophenone were 0.274%, 0.035% by HPLC, respectively. Conclusions : In these results, we have determined the contents of cynandione A and 2,5-dihydroxyacetophenone in Cynanchum wilfordii, respectively. We hope that this study will contribute to the standardization and quality control of herbal medicine.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.538-545
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• 2001

The ratio of regioisomers in nitration of biphenyl derivatives containing electron-with-drawing group was examined. The ratio of isomers was determined efficiently by quantitative analysis of $^1$H NMR spectrum of product mixture based on $^1$H NMR spectrum of each isomer. Some isomers were isolated after chemical transformation, nitro to amine or carboxylic acid to its ethyl ester, because direct separation was very difficult. To improve the regiselectivity, representative several reaction conditions were tried and the NMR method was applied to determine regioselectivity in nitration of biphenyl derivatives. It was observed that the regioselectivity depend on not only reaction conditions but also position and kind of substituents.

• Journal of the Korean Magnetic Resonance Society
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• v.3 no.2
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• pp.90-99
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• 1999

Doping of boron atoms in graphite has been well known method to increase the discharge capacity as the negative electrode material for lithium secondary battery. Herein, the boron-doped graphites are prepared by mixing 1, 2.5, 5, and 7 wt. % of boron carbide in carbon during the graphitizing process. The structural states of boron in boron-doped graphites are investigated by solid-state 11B NMR spectroscopy. The resonance lines for substitutional boron atoms are identified as the second order quadrupolar powder pattern with the quardrupole coupling constant, QCC = 3.36(2) MHz. The quantitative analysis of 11B NMR spectra with boron-doped graphite has also been performed via simulation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.452-456
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• 2004

Artemisia Herb is the dry aboveground part of Artemisia asiatica (Compositae). This is listed officially in the Korean Herbal Pharmacopoeia and used mainly in stopping all kinds of bleeding, regulating menses and curing menstrual disorders as well as in alleviating pain. Eupatilin and jaceosidin were isolated from Sazabalsuk and Sajuarisuk. and identified by means of spectral methods $(UV,\;^1H\;and\;^{13}C-NMR,\;MS) $ and quantitative analysis using HPLC. Regression equations for two flavonoid component standards obtained from Artemisia asiatica were $y=76069_x\;+\;107329\;(r=0.9999^{**})$ for eupatilin, $y=76651_x\;+\;77399\;(r=0.9996^{**})$ for jaceosidin. The eupatilin content of Sazabalsuk was 240mg, jaceosidin was 10mg in 100 g dry leaves. The Sajuarisuk were 330mg, 123mg in 100g dry leaves, respectively.

• Applied Biological Chemistry
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• v.48 no.3
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• pp.267-272
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• 2005

trans-Cinnamaldehyde, a major component of Cinnamomum cassia, was quantitatively analyzed using the $^1H-NMR$ spectrometry. Applicability of this method was confirmed through observing the variation of chemical shift in the $^1H-NMR$ spectrum of t-cinnamaldehyde and the integration value according to various sample concentrations or running temperatures. When the $^1H-NMR$ spectrometry was run for t-cinnamaldehyde (7.1429 mg/ml) at 19, 25, 30, 40 and $50^{\circ}C$, the chemical shifts of the doublet methine signal due to an aldehyde group were observed at 9.7202, 9.7184, 9.7169, 9.7142 and 9.7124 ppm, respectively, to imply that the running temperature had no significant variation in the chemical shift of the signal. The integration values of the signal were $1.37\;(19^{\circ}C),\;1.37\;(25^{\circ}C),\;1.37\;(30^{\circ}C),\;1.37(40^{\circ}C)$ and $1.37(50^{\circ}C)$, respectively, to also indicate running temperature gave no effect on the integration value. When the sample solutions with various concentrations such as 0.4464, 0.8929, 1.7857, 3.5714, 7.1429 and 14.286 mg/ml were respectively measured for the $^1H-NMR$ at $25^{\circ}C$, the chemical shifts of the aldehyde group were observed at 9.7206, 9.7201, 9.7196, 9.7192, 9.7185 and 9.7174 ppm. Even though the signal was slightly shifted to the high field in proportion to the increase of sample concentration, the alteration was not significant enough to applicate this method. The calibration curve for integration values of the doublet methine signal due to the aldehyde group vs the sample concentration was linear and showed very high regression rate ($r^2=1.0000$). Meantime, the $^1H-NMR$ spectra (7.1429 mg/ml $CDCl_3,\;25^{\circ}C$) of t-cinnamaldehyde and t-2-methoxycinnamaldehyde, another constituent of Cinnamomum cassia, showed the chemical shifts of the aldehyde group as ${\delta}_H$ 9.7174 (9.7078, 9.7270) for the former compound and ${\delta}_H$ 9.6936 (9.6839, 9.7032) for the latter one. The difference of the chemical shift between two compounds was big enough to be distinguished using the NMR spectrometer with 0.45 Hz of resolution. The contents of cinnamaldehyde in Cinnamomum cassia, which were respectively extracted with n-hexane, $CHCl_3$, and EtOAc, were determiend as 94.2 \;mg/g (0.94%), 137.6 mg/g (1.38%) and 140.1 mg/g(1.40%) t-cinnamaldehyde in each extract, respectively, by using the above method.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.1944-1950
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• 2014

Employment of a time consuming, sophisticated calculation using the all-atom force field and generalized-Born implicit solvent model (GBIS) for refinement of NMR structures has become practical through advances in computational methods and capacities. GBIS refinement improves the qualities of the resulting NMR structures with reduced computational times. However, the contribution of GBIS to NMR structures has not been sufficiently studied in a quantitative way. In this paper, we report the effects of GBIS on the refined NMR structures of ubiquitin (UBQ) and GB1 with subsets of distance restraints derived from experimental data. Random omission prepared a series of distance restraints 0.05, 0.1, 0.3, 0.5, and 0.7 times smaller. For each number, we produced five different restraints for statistical analysis. We then recalculated the NMR structures using CYANA software, followed by GBIS refinements using the AMBER package. GBIS improved both the precision and accuracy of all the structures, but to varied levels. The degrees of improvement were significant when the input restraints were insufficient. In particular, GBIS enabled GB1 to form an accurate structure even with distance restraints of 5%, revealing that the root-mean-square deviation was less than 1 ${\AA}$ from the X-ray backbone structure. We also showed that the efficiency of searching the conformational space was more important for finding accurate structures with the calculation of UBQ with 5% distance restraints than the number of conformations generated. Our data will provide a meaningful guideline to judge and compare the structural improvements by GBIS.

• Korean Journal of Pharmacognosy
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• v.51 no.2
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• pp.139-145
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• 2020

The leaves of Diospyros kaki Thunb. were used to treat heart disease and hypotension in traditionally East Asia. The purpose of this study is to simultaneously quantitiative analyze the content of flavonoids in leaves of D. kaki. The isolated flavonoids from the leaves of D. kaki, and the structure of the isolated flavonoids were analyzed based on ¹H and ¹³C NMR spectrum compared to literature data. Simultaneous quantitative analysis of the isolated flavonoids was validated using high performance liquid chromatography (HPLC). Results showed that the calibration curves of the flavonoid compounds were confirmed that they have a large linearity with a correlation coefficient (R²) of 0.99. In the intra-day and inter-day analysis, accuracy and precision of five compounds were measured that accuracy was 94.39 to 114.47% and precision was less than 3.00%. Content analysis showed hyperoside (1.30 ± 0.09%), astragalin (0.81 ± 0.06%), trifoline (1.58 ± 0.07%), quercetin (0.13 ± 0.02%) and kaempferol (1.33 ± 0.25%).

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.305-309
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• 2008

Dehydrocorydaline was isolated from the roots of Corydalis ternata (Papaveraceae) and identified by the comparison the $^1H-$ and $^{13}C$-NMR spectral data with those of authentic sample. The content of dehydrocorydaline was determined by the HPLC analysis based on extraction of ground plant material. Quantitative analysis of dehydrocorydaline in MeOH extract of C. ternata by HPLC showed $1.31{\pm}0.95%$ in 20 samples collected throughout regions of Korea.

• Korean Journal of Pharmacognosy
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• v.48 no.1
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• pp.77-81
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• 2017

The aim of this study was to investigate a validation method for determination of tricin in Phragmites communis ears. Tricin was isolated with chromatographic methods and used as the standard substances for quantitative analysis. The structural determination was characterized by comparing their NMR spectral data with values reported in the literature. For validation, the specificity, linearity, precision, accuracy, detection limits, and quantification limits of tricin was measured by HPLC. The results show that the specificity was satisfied with retention time and diode array detector (DAD) spectrum by analysis of tricin using HPLC. The limits of detection (LOD) for tricin was 0.84 mg/ml. Recovery of tricin was 98.80~108.22% with R.S.D values less than 2%. Intra-day and inter-day precisions of tricin in P. communis ears were 99.96~100.96% and 99.01~100.40%, respectively. Therefore, application of tricin was validated by an analytical method as major compound in P. communis ears.