• Journal of the Korean Chemical Society
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• v.33 no.1
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• pp.46-54
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• 1989

The extraction method and quantitative analysis for the fat-soluble vitamins present in food stuffs and vitamin products have been investigated. The simultaneous separation and analysis of the vitamins by reverse phase high performance liquid chromatographic method was conducted using an isocratic elution with methanol : water (95 : 5) eluent on a Novapak $C_{18}$ column. The detection of vitamins was achieved by a variable wavelength UV detector. To improve the detection sensitivity detection wavelengths were set at the highest absorption bands such as 330, 265, 285, and 290nm for the respective vitamins. The analysis for the fat-soluble vitamins was finished within 40 minutes. Alkaline hydrolysis and enzymatic hydrolysis were investigated for the sample preparation; and liquid-liquid extraction and liquid-solid extraction were attempted for the extraction of vitamins. Both hydrolysis methods were turned out to be appropriate for the analysis for vitamins A, D, and E, while for the analysis of vitamin K the enzymatic hydrolysis method demonstrated better results. Diethyl ether, pentane, and n-hexane were found to give higher recovery for the liquid-liquid extraction and silica cartridge for the liquid-solid extraction.

• Preventive Nutrition and Food Science
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• v.14 no.4
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• pp.354-357
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• 2009

Three compounds, vanillic acid, p-hydroxylcinnamic acid, p-hydroxybenzaldehyde have been isolated from the ethylacetate extract of Sparganium stoloniferum Buch.-Ham roots using silica gel open column chromatography, preparative thin-layer chromatography (pTLC) and reverse phase high performance liquid chromatography. The structures of the compounds were established on the basis of IR, extensive 1D NMR, and MS analyses. The ethylacetate (EtOAc) extract, vanillic acid, and p-hydroxybenzaldehyde showed $\alpha$-glucosidase inhibition activity of 72.71%, 20.13%, and 30.42%, at the concentration of 10 ${\mu}g/mL$, respectively. The EtOAc extract exhibited strong antioxidant activity with an $IC_50$ value of 24.37 ${\mu}g/mL$ against DPPH radical scavenging activity, the vanillic acid, p-hydroxylcinnamic acid, and p-hydroxybenzaldehyde with an $IC_50$ value of 2.10 ${\mu}M$, 1.59 ${\mu}M$, and 2.72 ${\mu}M$ against DPPH, respectively.

• Journal of Microbiology and Biotechnology
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• v.30 no.1
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• pp.93-100
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• 2020

A bacterial strain inhibiting the growth of Vibrio anguillarum, the causative agent of vibriosis, was isolated from fish intestines. The isolated strain HS36 was identified as Aerococcus urinaeequi based on the characteristics of the genus according to Bergey's Manual of Systematic Bacteriology and by 16S rRNA sequencing. The growth rate and antibacterial activity of strain HS36 in shaking culture were higher than those in static culture, while the optimal pH and temperature for antibacterial activity were 7.0 and 30℃, respectively. The active antibacterial substance was purified from a culture broth of A. urinaeequi HS36 by Sephadex G-75 gel chromatography, Sephadex G-25 gel chromatography, and reverse-phase high-performance liquid chromatography. Its molecular weight, as estimated by Tricine SDS-polyacrylamide gel electrophoresis, was approximately 1,000 Da. The antibacterial substance produced by strain HS36 was stable after incubation for 1 h at 100℃. Although its antibacterial activity was optimal at pH 6-8, activity was retained at a pH range from 2 to 11. The purified antibacterial substance was inactivated by proteinase K, papain, and β-amylase treatment. The newly purified antibacterial substance, classified as a class II bacteriocin, inhibited the growth of Klebsiella pneumoniae, Salmonella enterica, and Vibrio alginolyticus.

• Journal of the Korean Magnetic Resonance Society
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• v.16 no.1
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• pp.34-45
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• 2012

Melanocortin-4 receptor (MC4R) subtype is associated with obese humans. Especially, in a patient with severe early-onset obesity, novel heterozygous mutation in the MC4R gene was detected, resulting in an exchange of aspartic acid to asparagine in $90^{th}$ amino acid residue located in the predicted second trans-membrane domain (TM2). Mutations in the melanocortin-4 receptor (MC4R) gene are the most frequent monogenic causes of severe obesity which have been described as heterozygous with loss of function. In order to compare structure difference between MC4R wild type (MC4R-TM2-wt) and mutant (MC4R-TM2-D90N), we designed both MC4R-TM2-wt and MC4R-TM2-D90N construct in pET 21b vector. In this study, we optimized high-yield purification procedure for recombinant TM2-D90N. Eluted recombinant protein was resolubilized under urea condition for thrombin cleavage reaction and we conducted the high-performance liquid chromatography (HPLC) with reverse phase column under 1% acetonitrile, 0.01% TFA buffer solution. The molecular size of purified target peptide was confirmed by Tricine-SDS page analysis. To characterize MC4R-TM2-D90N, we have performed $^{15}N$-isotope labeling of peptide using M9 media and purified labeled target peptide for hetero-nuclear NMR spectroscopy.

• YAKHAK HOEJI
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• v.51 no.3
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• pp.174-178
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• 2007

A reverse-phase high performance liquid chromatography method with electrospray ionization and detection by mass spectrometry is described for the simultaneous determination of doxifluridine and its active metabolite 5-flu-orouracil (5-FU) in monkey serum. The method has greater sensitivity and simpler process than previous published methods with good accuracy and precision. A proper liquid/liquid extraction was used to extract simultaneously doxifluridine and 5-FU which has considerable difference in the polarity. Extracts were analyzed using LC/MS/MS providing a short analysis time within 5 min. The lower limit of quantification was validated at 10.0 ng/ml of serum for both doxifluridine and 5-FU. Accuracy and precision of quality control (QC) samples for both analytes met FDA Guidance criteria of ±15% for average QC accuracy with coefficients of variation less than 15%. The method will be applicable for preclinical studies and bioequivalence studies.

• Journal of Applied Biological Chemistry
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• v.58 no.4
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• pp.303-309
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• 2015

${\gamma}$-Aminobutyric acid (GABA) content in fermented plant products and their main plant materials (aerial part of Acanthopanax sessiliflorus, fruit of Crataegus pinnatifida, and whole plant of Morus alba) was determined by high-performance liquid chromatography. GABA was quantified using a reverse-phase column with a gradient elution program (water:acetonitrile =90:10 to 0:100 for 40 min). UV detection was conducted at 280 nm. GABA content was measured in fermented plant products (15.07 mg/g), aerial part of A. sessiliflorus (4.49 mg/g), fruit of C. pinnatifida (10.59 mg/g), and whole plant of M. alba (2.31 mg/g). The presence of GABA in fermented plant products, including A. sessiliflorus, C. pinnatifida, and M. alba is important in industrial application for health supplements.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.266-273
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• 1991

Hirudin, a 65-amino acid protein isolated from the salivary gland of the bloodsucking leech, Hirudo medicinalis, is a potent thrombin-specific inhibitor and blocks the thrombin-mediated conversion of fibrinogen to fibrin in clot formation. We have studied the gene expression and secretion of hirudin in yeast. Saccharomyces cerevisiae. A gene coding for hirudin was synthesized based on the amino acid sequence and cloned into a yeast expression vector $YEG{\alpha}-1$ containing the ${\alpha}-mating$ factor pre-pro leader sequence and galactose-inducible promoter, GALl0. Recombinant S. cerevisiae was found to secrete biologically active hirudin into the extracellular medium. The secreted recombinant hirudin was recovered from the culture medium and purified with ultrafiltration and reverse phase high performance liquid chromatography. Approximately 1 mg of hirudin per liter was produced under suboptimal culture conditions and brought to about 90% purity in two steps of purification.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.417-422
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• 1998

Loxoprofen sodium (sodium 2-[4-(2-oxocyclopentylmethyl)phenyl] propionate dehydrate) is a nonsteroidal antiinflammatory drug of $\alpha$-phenyl propionic acid derivative. To test the bioequivalence of loxoprofen, the pharmacokinetic parameters of new preparation of loxoprofen, LENOX was compared with LOXONIN as a reference drug. Fourteen healthy volunteers were entered to the stydy (Yonsei University College of Medicine, Severance Hospital IRB approval No. 9608). They were administered 60 mg of loxoprofen in 2$\times$2 cross-over design. There was one week of drug-free interval between doses. The blood sample was taken on schedule up to 8 hours, and the plasma concentration loxoprofen was measured by reverse phase high-performance liquid chromatography (HPLC) with UV-detector. There were no significant difference between two preparations when AUC, Cmax, and Tmax were compared by ANOVA. The mean differences of AUC, Cmax, and Tmax were within 20% of the reference drug: the values were 2.22,5.61, and 12.50%, respectively. The confidence limits of AUC and Cmax but not Tmax satisfied the bioequivalence criteria. These results suggest that the tested LENOX is bioequivalent to the reference drug.

• Animal cells and systems
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• v.10 no.3
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• pp.163-167
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• 2006

Reverse-Phase High-performance Liquid Chromatography (RP-HPLC) based technique is one of the most sensitive techniques to detect the antibiotics present in honey. In the southern part of Tamilnadu, India, majority of the farmlands are occupied by plantations such as coconut, banana and rubber. A variety of antimicrobial compounds and antibiotics, which have been reported in pollen, nectar and other floral parts of the plant, gets accumulated in honey through honeybees (Apis mellifera). We have collected the nectar samples from banana (Musa paridasiaca) and rubber (Ficus elastica) flowers and the honey from honey hives of banana and rubber cultivated areas. The extracted nectar and honey samples are subjected to RP-HPLC analysis with authentic antibiotic standards. Nectar and honey samples showed 4-17, 11-29 ${\mu}g/kg$ of streptomycin, 2-29, 3-44 ${\mu}g/kg$ of ampicillin and 17-34, 26-48 ${\mu}g/kg$ of kanamycin respectively.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.16 no.1
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• pp.40-46
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• 1990

A method was described for the analysis of Artemisia extract in cosmetic soap. Esculetin-6-methylether was used as indicator ingredient for analysis of Artemisia extract. It was isolated from the plant and purified with silicagel column. The structure was conformed with IR, NMR and MASS spectroscopy. The Artemisia extract in sample was isolated with chloroform and interfering com- pounds were eliminated with silicagel column. The Artemisia extract was determined by reverse phase high- performance liquid chromatography with a fluorescence detector and a solvent system of H2O/THF/MeOH. The recorveries of Artemisia extract were 93.9-106.1% in the cosmetic soap.