• 월간산업보건
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• s.123
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• pp.38-41
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• 1998

• 월간산업보건
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• s.125
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• pp.22-24
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• 1998

• 월간산업보건
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• s.124
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• pp.31-33
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• 1998

• The Journal of Korean Medicine
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• v.18 no.2
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• pp.15-32
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• 1997

This study was undertaken to define the mechanism of Siegesbeckiae Herba-induced relaxation in rabbit common carotid artery contracted by agonists. In order to investigate the effect of Siegesbeckiae Herba on contracted rabbit carotid arterial strips, transverse strips with intact or damaged endothelium were used for the experiment using organ bath. To analyze the mechanism of Siegesbeckiae Herba-induced relaxation, Siegesbeckiae Herba extract infused into contracted arterial strips induced by agonists after treatment of lanthanum chloride, indomethacin, atropine, $N\omega-nitro-{_L}-arginine$, cobalt chloride or methylene blue. The relaxation effect of Siegesbeckiae Herba was dependent on the presence of endothelium, showing that Siegesbeckiae Herba-induced relaxation was not observed in the strips without endothelium. The endothelium-dependent relaxation induced by Siegesbeckiae Herba was suppressed by the pretreatment of lanthanum chloride, $N\omega-nitro-{_L}-arginine$, cobalt chloride or methylene blue, but it was not observed in the strips pretreated with indomethacin or atropine. These results demonstrated that Siegesbeckiae Herba may inhibit agonist-induced contraction through an increase in the cyclic GMP by the production of nitric oxide in the vascular endothelial cells.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.337-339
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• 2014

A facile one-pot synthesis of p-aminobenzoic acid from methyl 4-formylbenzoate which is a main by product in dimethyl terephthalate production process has been developed. This process involves the formation of amide intermediate obtained from the reaction of an aldehyde in methyl 4-formylbenzoate with chlorine in methylene chloride and the subsequent treatment of acid chloride with ammonia. The resulting amide was converted into amine using Hofmann degradation to afford a p-aminobenzoic acid. This facile one-pot process does not involve any expensive materials and should offer an attractive alternative to p-aminobenzoic acid production.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.2
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• pp.17-24
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• 2012

Tetrahydrotricyclopentadiene(below THTCPD) isomer is a good candidate materials for the high performance liquid fuel component because of its high density and heat of combustion value. The object of this study was to find out the proper reaction condition to improve the fluidity of THTCPD which is solid state at room temperature. Therefore, we have carried out isomerization reactions using aluminum chloride in the varying reaction condition such as reaction temperature and solvents. The results showed that when using aluminum chloride catalyst, THTCPD isomerization reaction was more active in the polar halogenated reaction media such as dichloromethane(methylene chloride: MC), 1,2-dichloroethane(ethylene chloride: EC) and chloroform than in non-polar hydrocarbon media such as n-Hexnae and toluene and was effected by reaction temperature variation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.800-803
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• 2010

Tetrahydrotricyclopentadiene(below THTCPD) isomer is a good candidate for the high performance liquid fuel component because of high density and heat of combustion value. But it has bad fluidity. The object of this study was to find out the optimal reaction condition to improve the fluidity of THTCPD because initial reactant is solid state, So we have carried out isomerization reactions using aluminum chloride catalyst under varying the reaction condition such as reaction temperature and reaction solvents. The results showed that when using aluminum chloride catalyst, isomerization reaction was more active in dichloromethane(methylene chloride: MC), 1,2-dichloroethane(ethylene chloride: EC) and chloroform than n-hexnae and toluene and was effected by reaction temperature.

• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2419-2421
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• 2009

A simple and efficient method has been developed for Knoevenagel condensation between aldehydes or ketones and active methylene group by stirring in methylene chloride at 60 ${^{\circ}C}$ under heterogeneous conditions using silica supported ammonium acetate. The products are obtained in excellent yields and are in a state of high purity. The structures of the products were confirmed by IR, $^1H$ NMR and mass spectral data and comparison with authentic samples available commercially.

• Korean Journal of Plant Resources
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• v.5 no.1
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• pp.49-56
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• 1992

In the preliminary antitumor screening tests of Crude Drugs and collected plants, the methanol ic extract of Forsythia Fruits in Korean marcket showed signif icant cytotoxic activity against Chinese hamster V-79 cells, but that in Japanese market did not. The former was identifid as Forsythia viridissima Lindley and latter as F.suspensa Vahl on the basis of the morphological observation. When an aqueous solution of the extract prepared from the fruits of F. viridissima (Oleaceae) was partitioned successively with n-hexane, methylene chloride, n-butanol, the cytoyoxic activitywas concetrated in the methylene chloride extract. Fractionation of the extract was made with the guidance of bioassay against V-79 cells to give cytotoxic lignans, matariresiol (1) and arctigenin (2). Their ICso values of compounds 1 and 2 were respectively $7.8{\;}\mu\textrm{g}/ml$ 1 and $1.65{\;}\mu\textrm{g}/ml$. Also, their structures were confirmed by comparison of physical and spectral data in the literature.

• YAKHAK HOEJI
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• v.45 no.5
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• pp.522-528
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• 2001

Tyrosinase plays an important role in the process of melanin biosynthesis, and it is a biochemical target enzyme for skin-whitening agents and the remedy for disturbances in pigmentation. We have screened 25 natural plant extracts for inhibitory effects against DOPA oxidase activity of tyrosinase. For the inhibitory effect against DOPA oxidase activity of tyrosinase, the recombinant human tyrosinase and the purified mushroom tyrosinase were used. Each of the dried plants extracted with methanol, and then the extracts were subjected to sequential fractionations with methylene chloride, ethyl acetate, n-butanol and water, respective The methylene chloride fractions of Angelica tenuissima, Nardostachys chinensis, Bombyx mop and Saposhnikovia divaricata, and the n-butanol fraction of Bombyx mori notably inhibited the human tyrosinase activity as well as mushroom tyrosinase activity (more than 90% inhibition). This study suggests that the above extracts have a potential as whitening agents as single ingredients or in combination with other of the extracts.