• 약학회지
• /
• 제38권3호
• /
• pp.300-310
• /
• 1994

Physicochemical properties for the inclusion complex of chenodeoxycholic acid(CDCA) and it's $7{\beta}-hydroxy$ epimer ursodeoxycholic acid(UDCA) with ${\beta}-cyclodextrin({\beta}-CyD)$ were studied. The formation of the complex in the solid state were confimed by polarized microscopy and differential scanning calorimetry(DSC). Proton nuclear magnetic resonance$(^1H-NMR)$spectroscopy showed that CDCA and UDCA form an inclusion complex with ${\beta}-CyD$ in aqueous solution. The 1 : 1 stoichiometry of the complex was dextermined by the continuous variation method. From DSC and $^1H-NMR$ studies, there were not any differences between CDCA and UDCA. Complex of CDCA and UDCA showed increase in solubility and dissolution compared with CDCA and UDCA alone, respectively. Solubility pattern of UDCA complex was pH independent but, CDCA complex was like that of CDCA. Dissolution rate increased markedly in case of UDCA complex compared with CDCA complex, especially in acidic pH value.

• 한국자기공명학회논문지
• /
• 제22권2호
• /
• pp.26-33
• /
• 2018

Xanthium sibiricum is used as a traditional folk medicine for the treatment of cancer, fever, headache, nasal sinusitis, and skin pruritus. This study aimed to identify components from Xanthium sibiricum extracts using an SPE-800MHz NMR-MS hyphenated system. The simultaneous acquisition of MS and NMR spectra from the same chromatographic peaks significantly increases the depth of information acquired for the compound and allows the elucidation of structures that would not be possible using MS or NMR data alone. LC -NMR analysis was conducted using a HPLC separation system coupled to 800 MHz spectrometer equipped with a cryoprobe, and a SPE unit was used to automatically trap chromatographic peaks using a HPLC pump. LC-MS analysis was conducted with a Q-TOF MS instrument using ESI ionization in the negative ion mode. Using the hyphenated analysis, several secondary metabolites were identified, such as 3',5'-O-dicaffeoylquinic acid, 1',5'-O-dicaffeoyl- quinic acid, and ethyl caffeate. These results demonstrate that the SPE-800MHz NMR-MS hyphenated system can be used to identify metabolites within natural products that have complex mixtures.

• 대한화학회지
• /
• 제36권1호
• /
• pp.125-130
• /
• 1992

유기용매에서 리파제의 입체특이성 반응연구를 위하여 리파제의 기질로서 trifluoroethylmandelate를 도안하고 이를 mandelic acid와 trifluoroethanol를 사용하여 알코올과 산에서 에스텔을 합성하는 방법을 도입하여 합성하였다. 합성된 물질이trifluoroethylmandelate임을 $^1H$ NMR과 원소 분석을 통하여 확인하였다. (+)- 와 (-)-trifluoroethylmandelate ($[{\alpha}]_{25}{^D}$)은 각각 +74.0°and -75.4°이었다. 이 합성된 기질을 이용하여 유기용매내에서의 리파제의 입체이성질체에 대한 transesterification 속도는 서로간에 상당한 차이가 나타났다. 반면에 $[{\alpha}]_{25}{^D}$가 낮은 입체 이성질체인 (+)- 와 (-)-methylchloropropionate에서는 리파제의 활성은 있었으나 차이는 없었으며, 높은 $[{\alpha}]_{25}{^D}$를 갖는 methylmadelate는 리파제의 활성도 없었다.

• 약학회지
• /
• 제40권4호
• /
• pp.422-427
• /
• 1996

The anti-Ex-A IgG was specifically labeled with stable isotopes, DL-His-2,4-$d_2$, L-Phe-$d_5$, L-Trp-$d_5$, L-Tyr-2,6-$d_2$ and L-[1-$^{13}C$]Trp, by growing hybridoma cell in serum-free medium. By use of NMR spectroscopy with selectively labeled Fab fragment, we applied a paratope mapping on antigen-antibody complex. Assignments of the observed carbonyl carbon resonances have been determined by using $^{13}C$-$^{15}N$ double labeling method in order to assign the Trp resonances. Photo CIDNP was also applied to investigate the antigen-binding site(s) on the surface residues of antibody. We found that Trp 36, which is located at the $V_H$ domain, is an important residue to bind to Ex-A, however, two Tyr on the surface of anti-Ex-A IgG plays no crucial role to bind to antigen. On the basis of these results, we demonstrate that stable isotope-aided NMR strategy can be extended to molecular structural analyses of the complex of an Fab fragment and a protein antigen.

• 대한의용생체공학회:학술대회논문집
• /
• 대한의용생체공학회 1995년도 춘계학술대회
• /
• pp.223-226
• /
• 1995

Polymers have been developed and applied in many biomedical areas as well as engineering and industrial fields. The first essential to achieve successful development and applications is that properties of such polymer materials would be investigated. In many cases, such investigations are accomplished by observing polymeric behavior arising from the environmental changes such as pH, temperature, and ionic concentration. It has long been known that NMR is extremely sensitive to many biochemical and physical changes occurring in the polymer samples. In the present study we focus our study on NMR Microimaging, which is one of the important NMR applications, to characterize the swelling effect by observing the time dependent spatial variations of polymer specimens. For the samples three kinds of polyvinyl alcohol (PVA) specimens are prepared with different degrees of cross linking density. $^1H$ NMR microimages are acquired as a function of time to visualize the swelling behavior as well as volumetric changes occurring in the specimens. From the acquired time dependent images, the swelling process is exploited.

• Bulletin of the Korean Chemical Society
• /
• 제19권5호
• /
• pp.501-503
• /
• 1998

In this work, we applied the 1D $11^B$ nutation NMR method for the analysis of the local structural environments in powdered borosilicates $(SiO_2-B_2O_3)$. Spin dynamics during a rf irradiation for spin I=3/2 was analytically calculated with a density ma trix formalism. Spectral simulation programs were written in MATLAB on a PC. Two borosilicates prepared by the sol-gel process at different stabilization temperature were used for the 1D $11^B$ nutation NMR experiment. The $11^B$ NMR parameters, quadrupole coupling constants $(e^2qQ/h)$ and asymmetry parameters (η), for each borosilicate were extracted from the nonlinear least-squares fitting. The effects of heat treatments on the local structures of boron sites in borosilicates were discussed.

• Journal of Microbiology and Biotechnology
• /
• 제15권6호
• /
• pp.1330-1336
• /
• 2005

Polyhydroxyalkanoic acid (PHA) inclusion bodies were analyzed in situ by $^{13}C$-nuclear magnetic resonance ($^{13}C$-NMR) spectroscopy. The PHA inclusion bodies studied were composed of poly(3-hydroxybutyrate) or poly(3hydroxybutyrate-co-4-hydroxybutyrate), which was accumulated in Hydrogenophaga pseudoflava, and medium-chain-length PHA (MCL-PHA), which was accumulated in Pseudomonas fluorescens BM07 from octanoic acid or 11-phenoxyundecanoic acid (11-POU). The quantification of the $^{13}C$-NMR signals was conducted against a standard compound, sodium 2,2-dimethyl-2-silapentane-5-sulfonate (DSS). The chemical shift values for the in vivo NMR spectral peaks agreed well with those for the corresponding purified PHA polymers. The intracellular degradation of the PHA inclusions by intracellular PHA depolymerase(s) was monitored by in vivo NMR spectroscopy and analyzed in terms of first-order reaction kinetics. The H. pseudoflava cells were washed for the degradation experiment, transferred to a degradation medium without a carbon source, but containing 1.0 g/l ammonium sulfate, and cultivated at $35^{\circ}C$ for 72 h. The in vivo NMR spectra were obtained at $70^{\circ}C$ for the short-chain-length PHA cells whereas the spectra for the aliphatic and aromatic MCL-PHA cells were obtained at $50^{\circ}C\;and\;80^{\circ}C$, respectively. For the H. pseudoflava cells, the in vivo NMR kinetics analysis of the PHA degradation resulted in a first-order degradation rate constant of 0.075/h ($r^{2}$=0.94) for the initial 24 h of degradation, which was close to the 0.050/h determined when using a gas chromatographic analysis of chloroform extracts of sulfuric acid/methanol reaction mixtures of dried whole cells. Accordingly, it is suggested that in vivo $^{13}C$-NMR spectroscopy is an important tool for studying intracellular PHA degradation in terms of kinetics.

• 한국식품과학회지
• /
• 제39권1호
• /
• pp.77-82
• /
• 2007

쑥갓의 항산화 활성을 알아보기 위해 쑥갓 총 메탄올추출물의 아질산염 소거작용과 SOD 유사활성을 측정하였다. 아질산염 소거작용과 SOD 유사활성을 가지고 있는 총 메탄올 추출물로부터 클로로포름, n-부탄올 및 물 분획물을 제조하여 각각의 활성을 측정하였다. pH가 1.5일 때의 클로로포름 분획물의 $IC_{50}$값은 39ppm으로 가장 우수한 아질산염 소거작용을 보였으며, vitamin C와 chlorogenic acid의 $IC_{50}$값이 15ppm과 36ppm일 때 클로로포름 분획물은 양성대조군인 chlorogenic acid와 동등한 소거작용을 보였다. 아질산염 소거작용에 대하여 유의성 있게 높은 활성을 나타낸 클로로포름 분획물을 silica gel 컬럼크로마토그래피와 sephadex LH-20 컬럼크로마토그래피를 이용하여 분획의 활성성분인 compound I을 분리하였다. 분리된 compound를 $^{1}H-NMR$과 $^{13}C-NMR$ spectral data를 통하여 구조를 동정한 결과 compound I은 ${\beta}-sitosterol-O-{\beta}-D-glucoside$임을 확인하였다. Compound I과 그 aglycone인 ${\beta}-sitosterol$의 아질산염 소거작용과 SOD 유사활성은 다소 차이가 있었다. 양성대조군으로 사용한 vitamin C와 chlorogenic acid의 $IC_{50}$값이 pH 1.5에서 각각 15ppm과 36ppm일때 compound I의 $IC_{50}$값이 335ppm, ${\beta}-sitosterol$의 $IC_{50}$값이 41ppm으로 가수분해된 aglycone이 아질산염 소거작용이 훨씬 높았다. SOD 유사활성의 경우 vitamin C와 chlorogenic acid의 $EC_{50}$ 값은 38ppm, 449ppm으로 이와 비교시 ${\beta}-sitosterol$과 배당체의 $EC_{50}$ 값은 1,291ppm과 2,000ppm 이상으로 나타났다.

• 대한화학회지
• /
• 제52권5호
• /
• pp.468-475
• /
• 2008

• 한국식품영양과학회지
• /
• 제25권1호
• /
• pp.76-79
• /
• 1996

생강나무 (Libdera obtusiloba BL.)의 페놀성 화합물들을 분리하기 위하여 잎고 줄기의 MeOH 엑스로부터 계통 분획한 EtOAc 분획물은 silica gel column chro-matography로 분리하여 2종의 화합물을 얻었다. IR, UV,$^1H-NMR$, $^13C-NMR$ 등의 분석을 행하여 화학구조를 밝힌 결과 이들 화합물의 화학구조는 잎에서 $quer-cetin-3-O-\alpha-L-rhamnopyranoside(quercitrin),$ 줄기에서는 quercetin $3-O-\beta-D-galactoyranoside(hyperoside)로$ 각각 결정하였다. 이 화합물들은 생강나무에서 처음으로 분리하였다.