• YAKHAK HOEJI
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• v.38 no.2
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• pp.123-130
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• 1994

Physicochemical properties and hydrolysis kinetics of new some oral cephalosporins were examined in buttered solution and human plasma or rat liver homogenate. The test cephalosporins were 7-[(Z)-2-(2-aminothiazole-4-yl)-2- methoxyiminoacetamido]-3-[4-(2-pyridyl)piperazinyl] thiocarbonylthhiomethyl-3-cephem-4-carboxylic acid (CEN1), 7-[(Z)-2-(2-aminoth iazole-4-yl)-2-methoxyiminoacetamido]-3-[4-(2-pyrimidyl)piperazinyl]th iocarbonylthiomethyl-3-cephem-4-carboxylic acid (CEN2), pivaloyloxymethyl-7-[ (Z)-2-(2-aminothiazole-4-yl)-2-methoxyiminoacetamido]-3-[4-(2-pyridyl)piperazi nyl]thiocarbonylthiomethy1-3-cephem-4-carboxylate (CEN1P), and pivaloyloxymethyl-7-[(Z)-2-(2-aminothiazole-4-yl)-2-methoxyiminoacetamido]-3-[ 4-(2-pyrimidyl)piperazinyl]thiocarbonyl-thiomethyl-3-cephem-4-carboxylate (CEN2P). The partition coefficient(Ko/w) of CEN1P, CEN2P were higher than those of CEN1, CEN2. The calculated pKa values of CEN1, CEN2, CEN1P, and CEN2P were 7.09, 7.75, 4.92, and 5.39, respectively. The hydrolysis of CEN1P and CEN2P were not depend on the composition of pH of the test medium except weak alkaline buffered solution (pH 8.00). CEN1 and CEN2 were very stable in pH 6.80 and 8.00 buffer solutions. CEN1P and CEN2P were rapidly deesterified to CEN1 and CEN2 in human plasma and in rat liver homogenate. Half-lives$(t_{1/2})$ of CEN1 and CEN2 were 3.49 and 4.93 hr in human plasma, 1.47 and 1.26 hr in rat liver homogenate, respectively.

• Korean Journal of Medicinal Crop Science
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• v.6 no.4
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• pp.305-310
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• 1998

Glucosidic bond at the $C_{20}$ position of the sapogenins was hydrolyzed easily in the lower pH, higher temperature and longer time to give prosapogenins and sugars. The glucosidic bond of saponin at the $C_3\;of\; ginsenoside-Rb_1\;$, which is secondary carbon, was relatively stable due to the low electron density of -0.2. But the bond of saponin at the $C_{20}$ position, which is tertiary carbon with the relatively high electron density of -0.3, was liable to be hydrolyzed even in weak acidic solution by the increase of heating time. On the other hand, fresh and white ginseng contained 4.12 mg/g, 13.05 mg/g of citric acid, 0.68 mg/g, 2.18 mg/g of malonic acid, 1.13 mg/g, 3.68 mg/g of oxalic acid, 2.68 mg/g, 8.62 mg/g of malic acid and 0.13 mg/g, 0.46 mg/g of succinic acid, respectively. Ginseng saponins were very stable in ginseng extract neutralized with sodium carbonate or sodium bicarbonate corresponding to the equivalent amount of the total organic acid in the ginseng.

• Journal of the Korean Applied Science and Technology
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• v.11 no.1
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• pp.7-16
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• 1994

Some seeds of the Rutaceae family, Zanthoxylum piperitum, Z. schinifolium officinalis, Poncirus trifoliata, Citrus unshin, were investigated to clarify their antioxidative components. Finely powdered samples were extracted by hexane, followed by dichioromethane and then 70% methanol in a hot bath. Its unsaponifiables containing X-and Y-tocopherol with trace amount of ${\beta}-and$\;{\delta}-tocopherol$. also showed comparatively weak activity, although the hexane fraction itself had no significant antioxidative effect on lard. Levels of total tocopherols in the samples averages 42. 24-154. 11 mg/lOOg total extractives. The dichloromethane-and 70% methanol extractives showed strong antioxidative activity, from which antioxidative substances were purified with benzene-acetone(6:5, V/V) on a silica gel column, and with a solvent mixture of acetonitrile-methanol-$H_2O$(40:40:20, V/V/V) on a Sep-Pak $C_{18}$ hydrolyzed by 5% KOH-ethanol. The recovered unsaponifiables were, then, separated on a column of high performance liquid chromatography. The unsaponifiables produced by hydrolysis of the isolates from dichloromethane extractives has epi-catechin(40.0-57.1%) and (+)-catechin<$l9.1{\sim}24.4%$ to total phenolic substances, on area base) as major component, accompanied by chlorogenic acid, gallic acid(?), trans-p-coumaric acid and tralls-p-ferulic acid including some unknown components, and those derived from 70% methanol extractives also comprise (+)-catechin($31.3{\sim}39.6%$ to total components, on area base), epi-catechin($2O.2{\sim}36.4%$), trans-p-cournaric acid(8.4-15.3%) and trans-p-ferulic acid($7.7{\sim}14.1%$) as predominant component with some minor coponents, but the fraction supposed to be gallic acid(?) is not present. The antioxidative activities of the phenolic components isolated in this work were in order of epi-catechin>catechin>chlorogenic acid>trans-p-ferluic acid>trans-p-coumaric acid.

• Biomedical Science Letters
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• v.18 no.1
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• pp.71-75
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• 2012

The PLA2G4A catalyzes the hydrolysis of membrane phospholipids to release arachidonic acid, which is metabolized into lipid-based cellular hormones that regulate inflammatory response. The circulating blood cell numbers can be influenced by stress, infection or inflammation. Quantitative blood cell count traits analysis for the 19 SNPs in the PLA2G4A gene in the Korean Association Resource (KARE) cohort (7551 subjects) was performed. The only one SNP (rs10752979) in the all blood cell count was satisfied with the Bonferroni corrected P-value (<0.00263). Furthermore, 6 of the 19 SNPs in the PLA2G4A gene showed a weak or moderate association with blood cell count (P-values: 0.0048~0.042), suggesting the clue of an association between the PLA2G4A gene and blood cell count, especially white blood cell count. This study may provide insight into the genetic basis of blood cell count related with reaction of infection.

• Bulletin of the Korean Chemical Society
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• v.1 no.3
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• pp.109-112
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• 1980

Ultraviolet spectrophotometric investigations were carried out on monoalkylbenzene-iodine systems in carbon tetrachloride. The results reveal the formation of one-to-one molecular complexes. On the basis of the equilibrium constants for these complexes of representative monosubstituted benzenes, the following order of increasing stability is obtained: i-propyl- ${\Delta}$H, ${\Delta}$G and ${\Delta}$S for the interaction of a number of monoalkyl substituted benzenes with iodine have been determined. In general, it can be said that as ${\Delta}$H becomes increasingly negative, corresponding decreases in the ${\Delta}$G and the ${\Delta}$S values are observed, and these variations are linear. The thermodynamic constants become increasingly negative with increasing monoalkyl substitution of the aromatic donor nucleus. The complex bond is therefore weak, and its formation is accompanied by relatively small entropy changes. Thus, analysis of these findings is discussed.

• Biomolecules & Therapeutics
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• v.22 no.2
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• pp.155-160
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• 2014

Thelephoric acid is an antioxidant produced by the hydrolysis of polyozellin, which is isolated from Polyozellus multiplex. In the present study, the inhibitory effects of polyozellin and thelephoric acid on 9 cytochrome P450 (CYP) family members (CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) were examined in pooled human liver microsomes (HLMs) using a cocktail probe assay. Polyozellin exhibited weak inhibitory effects on the activities of all 9 CYPs examined, whereas thelephoric acid exhibited dose- and time-dependent inhibition of all 9 CYP isoforms ($IC_{50}$ values, $3.2-33.7{\mu}M$). Dixon plots of CYP inhibition indicated that thelephoric acid was a competitive inhibitor of CYP1A2 and CYP3A4. In contrast, thelephoric acid was a noncompetitive inhibitor of CYP2D6. Our findings indicate that thelephoric acid may be a novel, non-specific CYP inhibitor, suggesting that it could replace SKF-525A in inhibitory studies designed to investigate the effects of CYP enzymes on the metabolism of given compounds.

• Natural Product Sciences
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• v.17 no.3
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• pp.183-188
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• 2011

A bisdesmosidic cholestane glycoside was isolated from the rhizomes of Polygonatum sibiricum and the structure was elucidated by spectroscopic methods and acid hydrolysis as (22S)-cholest-5-ene-$1{\beta}$,$3{\beta}$,$16{\beta}$,22-tetrol 1-O-${\alpha}$-L-rhamnopyranosyl 16-O-${\beta}$-D-glucopyranoside. This compound exhibited weak cytotoxic activity with the $IC_{50}$ value, $63.6\;{\mu}M$ in human MCF-7 breast cancer line, whereas it failed to show agonistic activity at $100{\mu}M$ in TGR5 assay with Chinese hamster ovary (CHO) cells. This is the first report of a bisdesmosidic cholestane glycoside from Polygonatum species and the full assignments of $^1H$, $^{13}C$ NMR by HMBC, TOCSY and NOESY experiments were provided.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.749-757
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• 2019

Methyltrimethoxysilane (MTMS) and trimethylethoxysilane (TMES) as starting materials were dissolved in various types of solvents, and hydrolysis with water and polycondensation reaction were carried out using various types of catalysts to prepare non-fluorinated water-repellent coating solutions. The coating solutions were spin-coated on cold-rolled steel sheets, and thermally cured to prepare water-repellent coating films. The effect of types of catalysts and solvents on the water repellency of the resulting coating films was investigated during this process. When hydrochloric acid and nitric acid, which are strong acids, were used as catalysts, the solutions showed a white opaque state due to the aggregation of siloxane polymers. On the other hand, when acetic acid, phosphoric acid, and oxalic acid, which are weak acids, were used, they were in a stable and transparent state without precipitation. As a result, the contact angles of the coated films, prepared from hydrochloric acid and nitric acid, were $58^{\circ}$ and $92^{\circ}$, respectively, showing low water repellency. On the other hand, when acetic acid, phosphoric acid, and oxalic acid were used, the contact angles of the coated films were $101^{\circ}$, $103^{\circ}$ and $116^{\circ}$, respectively, showing high water repellency. In addition, when isopropanol and ethanol were used as solvents, phase separation occurred in the solutions due to the aggregation of siloxane polymers. On the other hand, when methanol, ethyl acetate, and methyl ethyl ketone were used as solvents, the solutions were transparent and showed a stable state without sedimentation.

• Journal of Korean Society of Forest Science
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• v.39 no.1
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• pp.57-63
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• 1978

Enzymatic hydrolysis of the substrate from Alnus hirsuta (Spach) Rupr (8-14years) was investigated using cellulase preparations of Trichoderma viride Pers. ex. Fr. SANK 16374 and conduced on the optimum reaction conditions of the cellulase on saccharification. The crude cellulase was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate. The method of delignification from wood(Saw dust) was treated by the peracetic acid (PA) method. Reducing sugar was determined by the dinitrosalicylic acid (DNS) method. The results were summerized as follows; 1. The optimum pH of cellulase was 5.0 and the range of stability with respect to pH was generally from 4.0 to 6.0 2. The optimum temperature of cellulase was generally $40^{\circ}C$, but reducing sugar formation did not show significent differences at 5% levels in the reaction temperature from $40^{\circ}C$ to $50^{\circ}C$. 3. The redusing sugar were increased with increase of cellulase concentration. 4. The reducing sugar were decreased with increase of substrate concentration. 5. Fructose was a very good inhibitor of the enzyme from Trichoderma viride, but glucose inhibition was generally weak.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.3
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• pp.189-196
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• 2007

In order to investigate the potential of very low molecular weight hyaluronic acid(oligo HA) as a cosmetic ingredient, we first measured its cytotoxicity in fibroblast, keratinocyte, and SIRC cell lines. For efficacy test, its moisturizing effect and penetration rate were evaluated in an artificial skin system and Caco-2 cells. Oligo HA did not show any cytotoxicity at a concentration of 300 ${\mu}g/mL$ in fibroblasts and 1,000 ${\mu}g/mL$ in keratinocytes but it showed weak proliferation. In vitro ocular test, oligo HA showed negligible cytotoxicity at the maximum concentrations used(2,000 ${\mu}g/mL$) in SIRC cells. In the test of the single and repeated cutaneous applications, oligo HA under occlusive patch did not provoke any cumulative irritation and sensitization. Oligo HA at a concentration of 0.01 % exhibited a more potent moisturizing effect than hyaluronic acid at a concentration of 0.01 %. In the permeability test using artificial skin and Caco-2 cell lines, hyaluronic acid(M.W. $1.1{\times}10^6$) was hardly observed in the down medium of the inserts. On the other hand, oligo HA(M.W. 5,000) was detected in the down medium up to 16.0 % at 6 h in Caco-2 cell culture and up to 90 % at 6 h in an artificial skin system. These results suggest that oligo HA could be useful as an active ingredient for cosmetics.