• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.646-651
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• 1995

The correlation between the bitter taste and the surface tension was found for bitter tasting, aqueous solutions. By the Szyszkowski's equation, the surface tension (STR) and taste curves (JND) were derived more clearly using the Techplot program. The specific capillary activity (log b values) for bitter tasting solutions are negatively correlated to the recognition threshold. It was shown that a more bitter substances has greater capillary activity. The correlation between the recognition threshold $(log\;C_{1})$ and the substance specific constant (a and b values) of sensory (JND) and surface tension values indicates good agreement. This means that the model of surface area adsorption in the solution/air system can apply also for the sensory model microvillus membrane in the mouth.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3444-3450
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• 2013

Three phase hollow fiber-liquid phase microextraction (HF-LPME), which is faster, simpler and uses a more environmentally friendly sample-preparation technique, was developed for the analysis of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in human urine. For the effective simultaneous extraction/concentration of NSAIDs by three phase HF-LPME, parameters (such as extraction organic solvent, pH of donor/acceptor phase, stirring speed, salting-out effect, sample temperature, and extraction time) which influence the extraction efficiency were optimized. NSAIDs were extracted and concentrated from 4 mL of aqueous solution at pH 3 (donor phase) into dihexyl ether immobilized in the wall pores of a porous hollow fiber, and then extracted into the acceptor phase at pH 13 located in the lumen of the hollow fiber. After the extraction, 5 ${\mu}L$ of the acceptor phase was directly injected into the HPLC/UV system. Simultaneous chromatographic separation of seven NSAIDs was achieved on an Eclipse XDB-C18 (4.6 mm i.d. ${\times}$ 150 mm length, 5 ${\mu}m$ particle size) column using isocratic elution with 0.1% formic acid and methanol (30:70) at a HPLC-UV/Vis system. Under optimized conditions (extraction solvent, dihexyl ether; $pH_{donor}$, 3; $pH_{acceptor}$, 13; stirring speed, 1500 rpm; NaCl salt, 10%; sample temperature, $60^{\circ}C$; and extraction time, 45 min), enrichment factors (EF) were between 59 and 260. The limit of detection (LOD) and limit of quantitation (LOQ) in the spiked urine matrix were in the concentration range of 5-15 ng/mL and 15-45 ng/mL, respectively. The relative recovery and precision obtained were between 58 and 136% and below 15.7% RSD, respectively. The calibration curve was linear within the range of 0.015-0.96 ng/mL with the square of the correlation coefficient being more than 0.997. The established method can be used to analyse of NSAIDs of low concentration (ng/mL) in urine.

• Bulletin of the Korean Chemical Society
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• v.35 no.2
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• pp.365-370
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• 2014

For real-time monitoring of colloidal nanoparticles (NPs) in aqueous media, a light sheet type dark-field microscopy system combined with a microfluidic concentration gradient generator (${\mu}FCGG$-LSDFM) was developed. Various concentrations of colloidal Au NPs were simultaneously generated with the iFCGG and characterized with the LSDFM setup. The number concentrations and hydrodynamic size distributions were measured via particle counting and tracking analysis (PCA and PTA, respectively) approaches. For the 30 nm Au NPs used in this study, the lower detection limit of the LSDFM setup was 3.6 ng/mL, which is about 400 times better than that of optical density measurements under the same ${\mu}FCGG$ system. Additionally, the hydrodynamic diameter distribution of Au NPs was estimated as $39.7{\pm}12.2nm$ with the PTA approach, which agrees well with DLS measurement as well as the manufacturer's specification. We propose this ${\mu}FCGG$-LSDFM setup with features of automatic generation of NP concentration gradient and real-time monitoring of their physicochemical characteristics (e.g., number concentration, and hydrodynamic size distribution) as an important component of future high-throughput screening or high-content analysis platforms of nanotoxicity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.1009-1015
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• 2000

Fermentative and antioxidative characteristics of red mustard leaf (RML) kimchi, a traditional, fermented Korean vegetable food, were investigated. For the study, RML kimchi was made of RML, with green onion, red pepper, garlic, ginger, and sugar, and fermented at 15$^{\circ}C$. The pH was decreased and total acidity was increased during fermentation. The contents of reducing sugar, total vitamin C, and total Phenol content were 2.36%, 65 mg%, and 59 mg% at the initial stage. Although the content of reducing sugar decreased gradually during fermentation, however, the quantity of ascorbic acid decreased with the tendency of slightly increased at 6 days, and the amount of total phenol was increased. CIE L*, a*, b＊values were increased until 6 days of the fermentation. In order to determine the antioxidative activity of RML kimchi itself, the model systems of RML kimchi were made with cooked beef. TBA values of RML kimchi which was fermented for 6 days showed the lowest level in model systems. Water, n-hexane, methanol extracts of RML kimchi had a considerable antioxidative activity with the inhibition of formation of peroxide during the autoxidation of linoleic acid mixtures in aqueous model systems.

• Herbal Formula Science
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• v.24 no.3
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• pp.131-152
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• 2016

Objectives ： This study was to evaluate Sibjeondaebo-tang’s(Shiquan dabutang) effect to rat hypothyroidism which induced by 6-n-propyl-2-thiouracil(PTU)Methods ： Aqueous extracts of Sibjeondaebo-tang(Shiquan dabutang)(21.29%) were administered by oral dose of 300 and 150 mg/kg(rat’s body weight) for 42 days from 2 weeks before start of PTU treatment. During this moment the body weight, thyroid gland weights, liver weight, serum thyroid hormone, lipid content and liver antioxidant defense system were measured with histopathological changes of thyroid glands, Liver and these result were compared with LevoT₄ 0.5mg/kg treated ratsResults ： As a result of PTU treatment, marked decreases of body weight, liver weight, serum thyroid hormone levels of T₃, T₄, triglyceride content and liver CAT activation were observed with marked increases of thyroid gland weight, thyroid gland hormone TSH, activate liver H₂O₂ and SOD, serum Total cholesterol, HDL and AST amount were admitted. In addition, marked hyperplasia of follicular cells with reduce of follicular colloid contents and sizes were showed at histopathological inspections. These PTU-induces histopathological changes related to hypothyroidism were significantly reduced by treatment of both different dosages of Sibjeondaebo-tang(Shiquan dabutang).Conclusions： This study suggest that Sibjeondaebo-tang(Shiquan dabutang) extracts have favorable effect on the thyroid hormone productions with beneficial effect on hypothyroidism medicated by modulatory effects on antioxidant defense system.

• The Journal of Korean Medicine
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• v.19 no.2
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• pp.244-270
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• 1998

This study was performed to investigate an anti-HBV activities of the aqueous extracts from 10 Korean herbal medicines in the HepG2 2.2.15 cell culture system and the results were as follows: 1. The extracts of 6 plants (Herba Artemisiae Capillaris, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi) decreased, significantly and dose-dependently, the levels of extracellular HBV virion in the concentrations (10, 100, 500 and $1,000\;{\mu}g/m{\ell}$) tested. 2. However, others (Radix lsatidis, Lignum Sappan, Herba Lysimachiae and Fructus Lycii) did not show any effect either on the replication of HBV or on the levels of virion DNA in the culture media of HepG2 2.2.15 cell. 3. Among the 6 plants which showed the inhibitory potency on the production of extracellular HBV virion, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi except Herba Artemisiae Capillaris also showed the inhibition of the replication of intracellular HEV DNA in the range of $100{\sim}500\;{\mu}g/m{\ell}$. Considering the above results, it is thought that 6 plants(Herba Artemisiae Capillaris, Radix et Rhizoma Rhei, Cortex Cinnamomi, Fructus Chebulae, Fructus Rubi and Radix Rubi) possess the anti-HBV activities in the HepG2 2.2.15 cell culture system. We thus suggest that these plants possess a potential as a therapeutic agent for the chronic viral hepatitis. These results might be useful as a basic data for the development of the new preventive drugs for HBV diseases.

• Korean Journal of Food Science and Technology
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• v.22 no.1
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• pp.56-60
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• 1990

The changes in the partition coefficient of model proteins (lysozyme, myoglobin, conalbumin, bovine serum albumin) in an aqueous two-phase system formed by polyethylene glycol and dextran were examined in order to improve the capacity of counter current distribution for the protein fractionation and concentration. The protein distribution patterns in CCD with 30 tubes varied with the pH of the system, and both theoretical and measured values agreed well. From the mixture of model protein, pure BSA fraction was appeared at the upper-phase of 14th tube having pH 4.5, pure myoglobin at the lower-phase of the 16th be with pH 6.5 and conalbumin at the lower-phase of 4th tube with pH 12. The result indicated the possible use of CCD method for protein fractionation, if the partition coefficient of proteins was manipulated by pH and other means.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.512-523
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• 2018

Background: 20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD. Methods: MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model. Results: A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient $r^2=0.929-0.947$). Conclusion: The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.

• KSBB Journal
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• v.5 no.2
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• pp.95-100
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• 1990

Ethanol fermentations of inulin by K.fraglis in aqueous two-phase system of PEG/Dextran were performed not only to investigate the characteristics of partition of ethanol, sugar, and cell in the upper phase and the bottom phase but also to compare the fermentation properties with those of single phase system. In the range of 1 to 3 wt% of Dextran, ethanol fermentability and ethanol productivity reduced according to the increase of the molecular weight of PEG. But the cell yield and the cell productivity showed the opposite trend. In the region of 6 to 10 wt% of PEG, the increase of the concentration of PEG, caused the minute decrease of ethanol productivity but the remarkable augmentation of cell productivity. According to the increase of the molecular weight of PEG, the partition coefficient of inulin slightly decreased. But with the increment of the concentration of Dextran, the partition coefficient and the partition yield of inulin in the bottom Phase represented the trends of increase.

• BMB Reports
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• v.29 no.6
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• pp.519-524
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• 1996

Peptidylprolyl cis-trans isomerase (PPlase) catalyzes the cis-trans isomerization of prolyl peptide and facilitates the folding of cellular proteins and peptides. PPlase consists of two distinct immunophilins, each specifically binding to the immunosupressive drug cyclosporin A (CsA) or FK506, respectively. A PPlase was isolated and partially purified from porcine spleen. The molecular weight of porcine spleen PPlase was determined to be ~14,000 on the basis of SDS-PAGE. The purified enzyme was strongly inhibited by FK506, but not by CsA. The inhibition constant and the true concentration of enzyme preparations were determined by active site titration using the tight binding inhibitor FK506: $K_{i}=18.7$ nM and $E_{t}=172$ nM. The equilibrium ratio of conformer. [cis]/[trans], of prolyl peptide substrates (N-Suc-Ala-Xaa-Pro-Phe-p-NA) in anhydrous trifluoroethanol/LiCl solvent system varied from 0.24 to 0.85 depending on the nature of Xaa. Overall. in this solvent-salt system, the populations of the cis conformer of substrates in equilibrium are higher than in an aqueous solution so that the substantial error caused by high background absorption can be reduced. The reactivities of porcine spleen PPlase are shown to be highly sensitive to changes in the structure of substrates. Thus, $k_{cat}/K_m$ value for the most reactive substrate (Xaa Leu) is $4.007+10^{6}M^{1}s^{1}$ and, is 2,636 fold higher than that for the least reactive peptide substrate tested, Xaa=Glu.