• Bulletin of the Korean Chemical Society
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• v.29 no.12
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• pp.2346-2348
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• 2008

• Bulletin of the Korean Chemical Society
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• v.28 no.5
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• pp.751-757
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• 2007

To develop new COX-2 inhibitors, 1,5-diarylhydantoins and 1,5-diaryl-2-thiohydantoins were synthesized from phenylacetic acids by esterification, bromination, C-N bond formation and cyclization. Esters 1-3 were efficiently synthesized from the starting materials by reflux in absolute methanol for 3 h containing concentrated sulfuric acid as catalyst. Bromination was carried out with N-bromosuccinimide at rt in dichloromethane. Bromides 4-6 were reacted with aniline, p-anisidine, sulfanilamide in ethanol (or N,N-dimethylformamide) to provide the amines 7-15. Hydantoins and 2-thiohydantoins 16-46 were synthesized from amines 7-15 by treating them with potassium isocyanate (or potassium thiocyanate) and triethylamine. The synthetic process from alkyl α-anilinophenylacetate 7-15 to 3-alkylhydantoins was carried out in a one-pot reaction using alkyl isocyanate (alkyl isothiocyanate).

• Journal of the Korean Society of Safety
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• v.6 no.4
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• pp.13-20
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• 1991

Ion-selective electrode responsive to the thiocynate ion prepared by using the quaternary ammonium salts as a active material and PVC as a membrane matrix. The effect of chemical structure and composition of active material, and the membrane thickness on the linear response. the detection limit, and Nernstian slope of the electrode studied. Under the above optimum conditions of membrane, the effect of pH and the selectivity coefficients to various interfering anions were compared and investigated. It was concluded that the functions of thiocynate ion-selective electrode(ISE) were closely related to the chemical structure of the quaternary ammonium salts. The linear response, and the detection limit of the electrode potential increased with the increase of the carbon chain length of the alkyl group in the quaternary ammonium salts in the ascending order of Aliquat 336T, TOAT, TDAT, and TDDAT. The optimum membrane thickness was 0.3mm. The electrode characteristics was better with the decrease of the concentration of active material, and the best concentration was 3 weight percent. The membrane potential was independent of the pH variation in the region from pH 2 to 12. The order of the selectivity coefficients is as follows：Cl $O_4$$^{[-10]}$ ＞ $I^{[-10]}$ ＞N $O_3$$^{[-10]}$ ＞B $r^{[-10]}$ ＞ $F^{[-10]}$ ＞C $l^{[-10]}$ ＞O $A_{c}$ $^{[-10]}$ 〓S $O_4$$^{2-}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1642-1647
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• 2011

The free radical scavenging activities of extracts from Ligustrum ovalifolium H. leaves (LOH) as well as various antioxidant activities such as ferric reducing antioxidant power (FRAP), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, reducing power and lipid peroxidation inhibition were evaluated by electron spin resonance (ESR). The total polyphenol and flavonoid contents of the water and ethanolic extracts from LOH were $105.5{\pm}1.31$ and $102.1{\pm}1.82$ mg gallic acid equivalent/g extract, respectively, and $84{\pm}1.72$ and $82.8{\pm}1.65$ mg catechin equivalent/g extract. In addition, $IC_{50}$ values for the 1,1-diphenyl-2-picryldrazyl (DPPH), alkyl, and hydroxyl radical scavenging activities of the water and ethanolic extracts were $0.021{\pm}0.002$ and $0.010{\pm}0.003$ mg/mL, $0.011{\pm}0.003$ and $0.012{\pm}0.002$ mg/mL, and $0.395{\pm}0.002$ and $0.443{\pm}0.002$ mg/mL, respectively. The ABTS radical scavenging activities of the water and ethanolic extracts from LOH and BHT were $0.073{\pm}0.12$, $0.130{\pm}0.06$ and $1.461{\pm}0.02$ mM Trolox equivalent/mg extract, respectively. The FRAP values of the extracts from LOH were higher than those of BHT, which was used as a positive control. The LOH extracts showed strong inhibitory effects on lipid peroxidation as measured by ferric thiocyanate (FTC) and thiobarbituric acid (TBA) assay compared to that of ${\alpha}$-tocopherol. Using MTT assay on human liver cells (Chang), extracts from LOH showed no toxicity at a concentration of 0.5 mg/mL. These results indicate that the LOH extracts possessed antioxidant activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1525-1531
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• 2011

Antioxidant activity and protective effects of extracts from Helianthus tuberosus L. leaves (HTL) on t-BHP-induced oxidative stress in human liver Chang cells were investigated. The total polyphenol and flavonoid content of the water and ethanolic extracts from HTL were 89.6${\pm}$1.96, 94${\pm}$2.03 mg gallic acid equivalent/g extract, and 65.1${\pm}$2.84, 54.6${\pm}$1.87 mg catechin equivalent/g extract, respectively. In addition, $IC_{50}$ values for 1,1-diphenyl-2-picrydrazyl (DPPH), alkyl, and hydroxyl radical scavenging activity of the water extracts were 0.010${\pm}$0.003 mg/mL, 0.014${\pm}$0.002 mg/mL, and 0.989${\pm}$0.003 mg/mL, respectively. Antioxidant activities of the extracts were also determined by ferric reducing antioxidant power (FRAP), 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and reducing power. The HTL extracts showed a strongly inhibitory effect on lipid peroxidation by measuring ferric thiocyanate (FTC) and thiobarbituric acid (TBA) values. In an MTT assay on the Chang cells, the extracts showed a protective effect by increasing cell viability and decreasing ROS on t-BHP-induced oxidative stress in Chang cells. These results indicate that the HTL extracts possess an antioxidant activity.