• Title, Summary, Keyword: enantiomeric composition

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Analysis of Enantiomeric Composition of Chiral Flavor Components from Dried Ginger (Zingiber afficinale Roscoe) (건생강에 함유된 키랄성 향기성분의 이성질체 조성 분석)

  • Seo, Hye-Young;No, Ki-Mi;Shim, Seong-Lye;Ryu, Keun-Young;Han, Kyu-Jae;Gyawali, Rajendra;Kim, Kyong-Su
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.35 no.7
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    • pp.874-880
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    • 2006
  • The volatile compounds of Zingiber officinale Roscoe were extracted by simultaneous steam distillation and extraction (SDE) method and identified with gas chromatigraphy/mass spectrometer (GC/MS) analysis. Enantiomeric compositions of chiral compounds were determined by multidimensional gas chromatography/mass spectrometer (MDGC/MS). A total of 57 compounds were indentified and quantified, including zingiberene, ${\beta}-sesquiphellandrene$, ${\beta}-bisabolene$, $(E,E)-{\alpha}-farnesene$ and ${\alpha}-curcumene$. Among them, zingiberene (38.41%) was founds as the predominantly abundant component. ${\alpha}-Pinene$ and nerolidol in dried ginger were detected by high enantiomeric purity (>96%) for (S)-form, and ${\beta}-pinene$ was detected only (R)-form. The enantiomeric composition of ${\alpha}-terpineol$ revealed 72.0% for (R)-form, and linalool and 4-terpineol showed mixtures of both enantiomers. (S)-Enantiomer was the major enantiomer of limonene having enatiomeric excess of 17.2%. Hence the enantiomeric composition of these compounds can be used as parameter for authenticty control of Zingiber officinale.

Analysis of Volatile Compounds and Enantiomeric Separation of Chiral Compounds of Dried Sancho (Zanthoxylum schinifolium Siebold & Zucc)

  • Seo, Hye-Young;Shim, Sung-Lye;Ryu, Keun-Young;Jung, Min-Seok;Hwang, In-Min;Shin, Dong-Bin;Kwon, Joong-Ho;Schreier, Peter;Kim, Kyong-Su
    • Food Science and Biotechnology
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    • v.18 no.1
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    • pp.18-24
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    • 2009
  • The volatile compounds of dried sancho (Zanthoxylum schinifolium), an aromatic plant were extracted by simultaneous distillation and extraction (SDE) method and identified by gas chromatograph-mass spectrometry (GC-MS). Selected chiral constituents of sancho oil were characterized by enantiodifferentiation using multidimensional gas chromatograph (MDGC)-MS. A total of 57 compounds were identified and quantified, and the major compounds were identified estragole, nonanoic acid, octanoic acid, $\beta$-phellandrenene, and limonene. Among them, estragol (63.9%) was found as the predominantly abundant component of sancho. $\alpha$-pinene and nerolidol, and $\beta$-pinene and linalool were determined to be enantiomerically pure (100%) for their (S)-form and (R)-form, respectively. The enantiomeric composition of limonene in sancho revealed 83.9% purity for the (S)-enantiomer, whereas (E)- and (Z)-rose oxides showed mixtures of both enantiomers. The enantiomeric excess (%) for citronellal was 22.6% with the (R)-enantiomer as major enantiomer. The enantiomeric composition of these compounds can be used as parameter for authenticity control of sancho.

Enantioseparation of Flurbiprofen and Ketoprofen in Patches and in Urine Excretions by Achiral Gas Chromatography

  • Paik, Man-Jeong;Nguyen, Duc-Toan;Kim , Kyoung-Rae
    • Archives of Pharmacal Research
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    • v.27 no.12
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    • pp.1295-1301
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    • 2004
  • The enantiomeric composition tests on flurbiprofen and ketoprofen present in patch products and in urine excretions following patch applications were performed as diastereomeric (R)-(+)- 1-phenylethylamides by achiral gas chromatography and by gas chromatography-mass spectrometry in selected ion monitoring mode. The method for determination of (R)- and (S)-enantiomers in the range from 0.1 to 5.0 ${\mu}$g was linear (r ${\ge}$ 0.9996) with acceptable precision (% RSD ${\le}$5.2) and accuracy (% RE = 0.6 ~ -2.4). The enantiomeric compositions of flurbiprofen in one patch product and of ketoprofen in five different products were identified to be racemic with relatively good precision (${\le}$ 6.4%). The urinary excretion level of (R)-flurbiprofen was two times higher than its antipode, while the comparable excretion levels of (R)- and (S)-enantiomers for ketoprofen were observed.

Coupled Column Chromatography in Chiral Separation of Salmeterol

  • Kim, Kyeong-Ho;Yun, Hyeong-Won;Kim, Hyun-Ju;Park, Hyun-Ji;Choi, Pok-Wha
    • Archives of Pharmacal Research
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    • v.21 no.2
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    • pp.212-216
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    • 1998
  • A coupled achiral-chiral high-performance liquid chromatographic system has been developed for the determination of the enantiomers of salmeterol, S-(+)-salmeterol and R-(-)-salmeterol in urine. THe salmeterol was separated from the interfering components in urine and quantified on the silica column, and the enantiomeric composition was determined on a Sumichiral OA-4700 chiral stationary phase. The two columns were connected by a switching valve equipped with a silica precolumn. The two columns wer connected by a switching valve equipped with a silica precolumn. The precolumn was used to concentrate the salmeterol in the eluent from the achiral column before backflushing onto the chiral phase. The coupled system was validated.

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Polyacrylamide Gel Immobilization of Porcine Liver Esterase for the Enantioselective Production of Levofloxacin

  • Lee, Sang-Yoon;Min, Byung-Hyuk;Song, Seong-Won;Oh, Sun-Young;Lim, Sang-Min;Kim, Sang-Lin;Kim, Dong-Il
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.3
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    • pp.179-182
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    • 2001
  • Porcine liver esterase was immobilized in polyacrylamide gel for the enantioselective production of levofloxacin from ofloxacin butyl ester. The initial activity of immobilized esterase was found to be significantly affected by the polyacrylamide gel composition. The optimum concentrations of monomer and crosslinker were determined to be 20% and 8.3%, respectively. The activity of immobilized esterase was 55.4% compared to a free enzyme. Enantiomeric excess was maintained at 60%, almost the same level as that of free enzyme. In addition, the immobilized esterase could be used repeatedly up to 10 times without experiencing any severe loss of activity and enantioselectivity.

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Resolution of Tocainide and Its Analogues on Liquid Chromatographic Chiral Stationary Phases Based on (+)-(18-Crown-6)-2,3,11,12-tetracarboxylic Acid

  • Hyun, Myung-Ho;Min, Hye-Jung;Cho, Yoon-Jae
    • Bulletin of the Korean Chemical Society
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    • v.24 no.7
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    • pp.911-915
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    • 2003
  • Two liquid chromatographic chiral stationary phases (CSPs) based on (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid were successfully applied in the resolution of racemic tocainide and its analogues. In the resolution of tocainide, especially, the CSP containing N-CH₃ amide tethering groups was quite effective, showing clear baseline resolution (RS: 2.66) with reasonable enantioselectivity ( a: 1.25). Consequently, the CSP containing N-CH₃ amide tethering groups is expected to be useful to monitor the enantiomeric composition of tocainide in clinical samples. In addition, the chromatographic behaviors for the resolution of tocainide and its analogues on the two CSPs were found controllable by varying the content and the type of organic and acidic modifiers in aqueous mobile phase.

Chiral Separation of Basic Compounds on Sulfated β-Cyclodextrin-Coated Zirconia Monolith by Capillary Electrochromatography

  • Hong, Jong-Seong;Park, Jung Hag
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1809-1813
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    • 2013
  • Sulfated ${\beta}$-cyclodextrin (SCD)-coated zirconia monolith was used as the chiral stationary phase in capillary electrochromatography for enantiomeric separation of basic chiral compounds. SCD adsorbed on the zirconia surface provided a stable chiral stationary phase in reversed-phase eluents. Retention, chiral selectivity and resolution of a set of six basic chiral compounds were measured in eluents of varying pH, composition of methanol and buffer. Optimum mobile phase condition for the separation of the compounds was found to be methanol content of 30%, buffer concentration of 30 mM and pH of 4.0.

Synthesis of solid enantioselective macromer of trimesic acid for the enantiomeric separation of chiral alcohols

  • Ingole, Pravin G.;Bajaj, Hari C.;Singh, Kripal
    • Advances in materials Research
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    • v.2 no.1
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    • pp.51-64
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    • 2013
  • Enantioselective macromer of trimesic acid was prepared using S(-) menthol with trimesoyl chloride on polyimide (PI) ultrafiltration membrane. The chemical composition of macromer as well as polyimide ultrafiltration membrane was determined by ATR-FTIR Spectroscopy. The optical resolution of chiral alcohols was performed in pressure driven process. The effect of monomer solutions concentration, effect of air-drying time of S(-) menthol solution, effect of reaction time, effect of operating pressure, effect of feed concentration of racemate on the performance of macromer was studied. The synthesised material exhibits separation of chiral alcohols (menthol ~23% and sobrelol ~21%).

Enzymatic Formation of Guaiacylglycerol 8-O-4'-(Coniferyl Alcohol) Ether from Coniferyl Alcohol with Enzyme Preparations of Eucommia ulmoides

  • Alam, Md. Shameul;Katayama, Takeshi;Suzuki, Toshisada;Sultana, Deeder;Sultana, Saima;Hossain, Md. Daud
    • Journal of Crop Science and Biotechnology
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    • v.11 no.1
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    • pp.45-50
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    • 2008
  • Lignans and neolignans are optically active plant secondary metabolites. Research on biosynthesis of lignans has already been advanced especially for the formation of (+) pinoresinol but information on the biosynthesis of 8-O-4'- neolignans is still limited. Moreover, the chemical structure(position of substituents on aromatic rings) and stereochemistry of 8-O-4' neolignans is not clear. Katayama and Kado discovered that incubation of cell-free extracts from E. ulmoides with coniferyl alcohol in the presence of hydrogen peroxide gave (+)-erythro- and (-)-threo- guaiacylglycerol 8-O-4'-(coniferyl alcohol) ether (GGCE)(diastereomeric ratio, 3:2) which is the first report on enzymatic formation of optically active -8-O-4' neolignans from an achiral monolignol. In this aspect, enzymatic formation of guaiacyl 8-O-4' neolignan is noteworthy to clarify its stereochemistry from incubation of coniferyl alcohol with enzyme prepared from Eucommia ulmoides. In this experiment, soluble and insoluble enzymes prepared from E. ulmoides were incubated with 30 mM coniferyl alcohol(CA) for 60 min. The enzyme catalyzed GGCE, dehydrodiconiferyl alcohol(DHCA), and pinoresinol identified by reversed phase HPLC. Consequently, diastereomeric compositions of GGCE were determined as erythro and threo isomer. Enantiomeric composition was determined by the chiral column HPLC. Both enzyme preparations enantioselectively formed (-)-erythro, (+)-erythro and (+)-threo, (-)-threo-GGCEs respectively.

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Liquid Chromatographic Resolution of Vigabatrin and Its Analogue γ-Amino Acids on Chiral Stationary Phases Based on (3,3'-Diphenyl-1,1'-binaphthyl)-20-crown-6

  • Choi, Hee-Jung;Cho, Hwan-Sun;Lee, Su-Jin;Hyun, Myung-Ho
    • Bulletin of the Korean Chemical Society
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    • v.32 no.spc8
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    • pp.3017-3021
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    • 2011
  • Two chiral stationary phases (CSPs) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 bonded covalently to silica gel were applied for the first time to the resolution of racemic vigabatrin and its analogue ${\gamma}$-amino acids and the resolution results were compared to those on the commercially available Crownpak CR(+) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 coated dynamically onto octadecylsilica gel. While vigabatrin was not resolved at all on Crownpak CR(+), it was resolved quite well on the two CSPs. Among four vigabatrin analogue ${\gamma}$-amino acids, only two were resolved on Crownpak CR(+), but three were resolved on the CSP (CSP 1) containing residual silanol groups and all of four were resolved on the CSP (CSP 2) containing residual silanol group-protecting n-octyl groups. The improved lipophilicity in CSP 2 was proposed to be responsible for its superiority to CSP 1 for the resolution of vigabatrin and analogue ${\gamma}$-amino acids. In addition, the composition of aqueous mobile phase was found to affect the chiral recognition behaviors for the resolution of vigabatrin and analogue ${\gamma}$-amino acids on CSP 2.