• YAKHAK HOEJI
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• v.42 no.1
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• pp.59-69
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• 1998

To increase the solubility of quercetin, which is a practically insoluble flavonoid of Ginkgo biloba leaf, the effects of nonaqueous vehicles. Their cosolvents, water-sol uble polymers and modified cyclodextrins (CDs) were observed. Polyethylene glycols, diethyleneglycol monoethyl ether, and their cosolvents with water showed a good solvency toward quercetin. Also the aqueous solutions of povidone, copolyvidone and Cremophor RH 40 was effective in solubilizing quercetin. Complex formation of quercetin with ${\beta}$-cyclodextrin (${\beta}$-CD), dimethyl-${\beta}$-cyclodextiin (DMCD), 2-hydroxypropyl-${\beta}$-cyclodextrin (HPCD) and ${\beta}$-cyclodextrin sulfobutyl ether (SBCD) in water was investigated by solubility method at $37^{\circ}C$. The addition of CDs in water markedly increased the solubility of quercetin with increasing the concentration. AL type phase solubility diagrams were obtained with CDs studied. Solubilizaton efficiency by CDs was in the order of SBCD >> DMCD > HPCD > ${\beta}$-CD. The dissolution rates of quercetin from solid dispersions with copolyvidone, povidone and HPCD were much faster than those of drug alone and corresponding physical mixtures, and exceeded the equilibrium solubility (3.03${\pm}1.72{\mu}$g/ml). The permeation of quercetin through duodenal mucosa did not occur even in the presence of enhancers such as bile salts, but the permeation was observed when the mucus layer was scraped off. This was due to the fact that quercetin had a strong binding to mucin ($58.5{\mu}$g/mg mucin). However rutin was permeable to the duodenal mucosa. The addition of enhancer significantly increased the permeation of rutin in the order of sodium glycocholate.

• Bulletin of the Korean Chemical Society
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• v.22 no.2
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• pp.219-227
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• 2001

The silver colloidal effects on the excited-state structure and intramolecular charge transfer (ICT) of p-N,N-dimethylaminobenzoic acid (DMABA) in aqueous cyclodextrin (CD) solutions have been investigated by UV-VIS absorption, steady-state and time-resolved fluorescence, and transient Raman spectroscopy. As the concentration of silver colloids increases, the ratio of the ICT emission to the normal emission (Ia /Ib) of DMABA in the aqueous $\alpha-CD$ solutions are greatly decreased while the Ia /Ib values in the aqueous B-CD solutions are significantly enhanced. It is also noteworthy that the ICT emission maxima are red-shifted by 15-40 nm upon addition of silver colloids, implying that DMABA encapsulated in $\alpha-CD$ or B-CD cavity is exposed to more polar environment. The transient resonance Raman spectra of DMABA in silver colloidal solutions demonstrate that DMABA in the excited-state is desorbed from silver colloidal surfaces as demonstrated by the disappearance of νs (CO2-)(1380 cm-1 ) with appearance of ν(C-OH)(1280 cm -1) band, respectively. Thus, in the aqueous B-CD solutions the carboxylic acid group of DMABA in the excited-state can be readily hydrogen-bonded with the secondary hydroxyl group of B-CD while in aqueous and $\alpha-CD$ solutions the carboxylic acid group of DMABA has the hydrogen-bonding interaction with water. Consequently, in the aqueous B-CD solutions the enhancement of the Ia /Ia value arises from the intermolecular hydrogen-bonding interaction between DMABA and the secondary hydroxyl group of B-CD as well as the lower polarity of the rim of the B-CD cavity compared to bulk water. This is also supported by the increase of the association constant for DMABA/ B-CD complex in the presence of silver colloids.

• Journal of Electrochemical Science and Technology
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• v.14 no.1
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• pp.51-58
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• 2023

The effective detection of human chorionic gonadotropin (HCG) is considerably important for the clinical diagnosis of both of early pregnancy and nonpregnancy-related diseases. In this work, a simple and sensitive electrochemical sandwich-type immunosensing platform was designed by synthesizing b-cyclodextrin (CD) functionalized graphene (CD/GN) hybrid as simultaneously sensing platform and signal transducer coupled with rhodamine b (RhB) as probe. In brief, GN offers large surface area and high conductivity, while CD exhibits superior host-guest recognition capability, thus the primary antibody (Ab1) of HCG can be bound into the cavities of CD/GN to form stable Ab1/CD/GN inclusion complex; meanwhile, the secondary antibody (Ab2) and RhB can also enter into the cavities, producing RhB/Ab2/CD/GN complex. Then, by using Ab1/CD/GN as sensing platform and RhB/Ab2/CD/GN as signal transducer (in which RhB was signal probe), a simple sandwich-type immunosensor was constructed. Under the optimum parameters, the designed immunosensor exhibited a considerable low analytical detection of 1.0 pg mL^-1 and a wide linearity of 0.002 to 10.0 ng mL^-1 for HCG, revealing the developed sandwich-type electrochemical immunosensing platform offered potential real applications for the determination of HCG.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1708-1714
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• 2015

Fermented red ginseng concentrate is known as a healthy food source, whereas it has off-flavor such as bitterness and sour flavor based on fermentation. ${\beta}$- and ${\gamma}$-cyclodextrin (CD) were used to encapsulate the off-flavor of fermented red ginseng concentrate by using response surface methodology design on ${\beta}$- and ${\gamma}-CD$ combination. The reducing effects were analyzed by sensory evaluation for bitter and sour tastes, ginsenoside Rb1, and total acidity. The optimized mixing ratio of ${\beta}$- and ${\gamma}-CD$ for reducing bitterness was the least expected value of 2.07 at ${\beta}-CD$ 3.74% versus the soluble solid content of fermented red ginseng concentrate and the ${\gamma}-CD$ 20.63% mixture. The encapsulation effects of ginsenoside Rb1 were the most expected value of 96.75% at ${\beta}-CD$ 3.47% and ${\gamma}-CD$ 19.89% mixture. The encapsulation effects of sour taste were the least expected value of 5.63 at ${\beta}-CD$ 9.34% and ${\gamma}-CD$ 9.96% mixture. The encapsulation effects of lactic acid were the most expected value of 67.73% at ${\beta}-CD$ 16.0% and ${\gamma}-CD$ 13.18% mixture. Based on encapsulation and each optimized combination, the most effective entrapping ${\beta}$-and ${\gamma}-CD$ combination ratio was ${\beta}-CD$ 10% and ${\gamma}-CD$ 13%.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.2
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• pp.171-181
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• 2018

Genistein is one of the representative isoflavone compounds isolated from soybeans and has been studied very well for its anti-aging and anti-inflammatory activity through previous studies. However, although genistein exhibits high solubility in organic solvents, it shows low bioavaility due to the low water solubility. In this study, we compared directly the functional difference between genistein and genistein cyclodextrin complex which has the improved water solubility and stability by cell based assay. Cell cytotoxicity experiment were carried out on RAW264.7 with CCK-8 assay and cytotoxicity was appeared from $10{\mu}g/mL$, thereby maximum concentration was set to $10{\mu}g/mL$ in all condition. We discovered that genistein CD complex suppressed NO production and iNOS expression as concentration dependent manner in the condition of LPS rather than genistein. Also, we could understand that genistein CD complex was able to down-regulate mRNA expression of anti-inflammatory cytokines such as $IL1-{\alpha}$, $IL1-{\beta}$, IL-6, and $TNF-{\alpha}$ as concentration dependent manner in the presence of LPS. In addition, we verified that genistein CD complex increased TEER of HaCaT human keratinocyte cells as concentration dependent pattern and stimulated cell division and migration rather than genistein in cell migration assay. Thus, it is expected that it can be used as an effective cosmetic raw material for improving atopic dermatitis or skin barrier if clinical studies on skin regeneration and skin barrier of the genistein CD complex are carried out.

• The Journal of the Acoustical Society of Korea
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• v.36 no.6
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• pp.387-393
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• 2017

The dynamic interactions between benzoic acid derivative ($pH{\approx}7.0$)(guest) and ${\beta}$-cyclodextrin (${\beta}$-CD)(host) were investigated in an aqueous solutions in terms of ultrasonic absorption in the frequency range 0.2 MHz ~ 50 MHz with emphasis on the low-frequency range below 1 MHz at $25^{\circ}C$. We show that the interaction of ${\beta}$-CD and benzoic acid derivative complies with a typical spectrum of a single relaxation process around a few MHz. The ultrasonic relaxation observed in these solutions was due to a perturbation of a chemical equilibrium related to a reaction of an inclusion complex formed by the host and guest. The rate constant ($k_b=7.48{\times}10^6M^{-1}s^{-1}$) and equilibrium constant ($K=68.6M^{-1}$) were determined from the concentration dependences of benzoic acid on the relaxation frequency. The standard volume change (${\Delta}V=10.6{\times}10^{-6}m^3mol^{-1}$) of the reaction was also computed from the maximum absorption per wavelength. It was found that the hydrophobicity of guest molecules played an important role in the formation of the inclusion complex.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.302-308
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• 1997

${\beta}-Cyclodextrin\;({\beta}-CD)$ polymers were prepared using epichlorohydrin as a cross linking agent. The polymers were separated into ${\beta}-CD$ soluble polymer $({\beta}-CD\;SP)$ and ${\beta}-CD$ insoluble polymer $({\beta}-CD\;ISP)$ on a 10,000 molecular weight cut-off membrane (YM 10). Optimum separation conditions in the YM 10 were: transmembrane pressure 51.7 kPa, separation temperature $35^{\circ}C$, and volume concentration ratio 10. The flux was $0.025\;mL/cm^{2}/min$ under the optimum conditions. Gel permeation chromatography indicated that ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$ had a degree of polymerization of $2{\sim}8$ and over 10, respectively. The formation of an inclusion complex with hydrophobic compounds such as 4-dimethylaminoazobenzene, methyl red, and naringin was compared among ${\beta}-CD,\;{\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. The molar absorptivity for the two chromatic compounds was increased and the absorption peak was shifted in the presence of ${\beta}-CD$ polymers. Naringin, the principal flavonoid bitter tasting component of citrus fruit, had a low water solubility. The solubility of naringin was increased through the formation of an inclusion complex with ${\beta}-CD$ polymers. There was no significant difference in the formation of an inclusion complex between ${\beta}-CD\;SP\;and\;{\beta}-CD\;ISP$. Reduction of the bitter components from citrus products was shown to be possible when employing ${\beta}-CD\;SP$, while the usage of ${\beta}-CD$ monomer has been limited due to the low water solubility.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.363-369
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• 2016

A putative cyclomaltodextrinase gene (licd) was found from the genome of Listeria innocua ATCC 33090. The licd gene is located in the gene cluster involved in maltose/maltodextrin utilization, which consists of various genes encoding maltose phosphorylase and sugar ABC transporters. The structural gene encodes 591 amino acids with a predicted molecular mass of 68.6 kDa, which shares less than 58% of amino acid sequence identity with other known CDase family enzymes. The licd gene was cloned, and the dimeric enzyme with C-terminal six-histidines was successfully produced and purified from recombinant Escherichia coli. The enzyme showed the highest activity at pH 7.0 and 37℃. licd could hydrolyze β-cyclodextrin, starch, and maltotriose to mainly maltose, and it cleaved pullulan to panose. It could also catalyze the hydrolysis of acarbose to glucose and acarviosine-glucose. In particular, it showed significantly higher activity towards β-cyclodextrin and maltotriose than towards starch and acarbose. licd also showed transglycosylation activity, producing α-(1,6)- and/or α-(1,3)-linked transfer products from the acarbose donor and α-methyl glucopyranoside acceptor.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.31-36
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• 2001

Paenibacillus sp. JB-13 producing the cyclodextrin glucan-otransferase(CGTase) [EC 2.4.1.19] that glucosylated ascorbic acid(AA) at the C-2 position was isolated form soil and the optimal conditions for the production of 2-O-$\alpha$-D- Glucopyranosl L-Ascorbic acid(AA-2G) with CGTase were investigated. CGTase produced AA-2G efficiently using dextrin as a substrate and AA as an aceptor. Several AA-2-oilgosaccharides(AA-2Gs) were also produced in this reaction mixture, and these were efficiently hydro-lyzed to AA-2G and glucose by the treatment with glucoamylase. The optimal temperature for AA-2G production was $37^{\circ}C$ and the optimal pH was around 6.5. CGTase also utilized $\alpha$-,$\beta$-,${\gamma}$-CDs, soluble starch, com statch, dia-static solution from rice and diastatic solution from malt as substrate, but not glucose. The reaction mixture for the maximal production of AA-2G was following; 15% total substrate concentration, 2,500 units/ml of CGTase and a mixing ration of 3:2(g of AA: g of dextrin). Under this condition, 56 mM of AA-2G ,which corresponded to 12.4% yield based on AA. was produced after incubation for 44 hrs at $37^{\circ}C$ and pH 6.5.

• The Journal of Natural Sciences
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• v.16 no.1
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• pp.15-29
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• 2005

To produce a thermostable cyclodextrin by using thermotolerant cyclomaltodextrin glucanotransferase(CGTase), a thermophilic and alkalophilic bacterium isolate, designated B-13 showing the highest CGTase activity was isalated from natural sources and identified as Bacillus cereus B-13 based on the morphological and physiological characteristics, and 16S rRNA sequence. The maximal CGTase activity (130 U/ml) was obtained when Bacillus cereus B-13 was cultured in SYC medium containing 2.0% soluble starch, 1.0% yeast extracts, 1% corn steep liquor and 1% $Na_2CO_3$ (pH 8.5) at $50^{\circ}C$ for 24 h and about 80% of maximal activity was also showed in he culture broth of $60^{\circ}C$ for 18 h. Optimum reaction temperature and pH of the partial purified CGTase for soluble starch were $65^{\circ}C$ and pH 8.5-9.0 respectively. The partial purified CGTase were also stable below $80^{\circ}C$ and pH 5.0-10.0. When 1% soluble starch was digested with the partial purified CGTase, the yield of cyclodextrin was 49%.