• The Korean Journal of Pharmacology
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• v.15 no.1_2 s.25
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• pp.45-56
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• 1979

With a view to searching after a new antihypertensive or hypotensive agents in the botanical crude plants, authors intended to reevaluate several natural products caltivated in Korea. This experiment was undertaken to compare pharmacogical actions of Machilus thunbergii Siebold et Zuccarini with those of Magnolia obovata Thunberg in anesthetized rats and in normal mice. Machilus thunbergii Sieb. et Zucc., a tree belonging to the Lauraceae family, is caltivated at Ull-ung Do, and their cortecies have been used as folk medicine mingled with those of Magnolia obovata Thunberg. These two cortecies have teen also applied in chinese medicine, it was advocated that these cortecies exerted good therapeutic effects on gastritis, convulsive abdominal pain, nausea, vomiting and urinary tract disorders. Therefore, we intended to determine the pharmacological action of two palnt of different family each other, especially their effects on blood pressure and heart rate, and also their mechanism of action were observed. We studied their action with extracts of hexane(MTHE), ether(MTEE), methanol(MTME) and water(MTWE) from Machilus thunhergii Sieb. et Zucc., and also fractionations of methanol(MOME), chloroform(MOCE) and water(MOWE) from Mapolia obovata Thunberg. The results of this experiment were as follows; 1) MTME, when intravenously administered to rats, elicited the significant hypotensive responses dependent on the administered dosage. 2) MOWE was also exhibited the hypotensive effect dependent on the treated dose. 3) Depressor effect of MTME was blocked by pretreatment with hexamethonium. 4) The hypotensive response of MOWE was blocked by pretreatment with hexamethonium or hrdralazine. 5) HTME and MOWE were also observed the anticonvulsive effect and sedative effect. These results suggested that MTME may induce the hypotensive response via central sympathetic effect, but the site of action in brain are not clarified, and the hypotensive effect of MOWE may be due to dual mechanism of central sympathetic action and direct vasodilation of blood vessel.

• The Korean Journal of Pharmacology
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• v.22 no.1 s.38
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• pp.1-23
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• 1986

• The Journal of the Korean Society for Microbiology
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• v.35 no.5_6
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• pp.344-345
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• 2000

• The Korean Journal of Pain
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• v.7 no.2
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• pp.155-161
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• 1994

• The Plant Pathology Journal
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• v.15 no.2
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• pp.93-98
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• 1999

• Bulletin of the Korean Chemical Society
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• v.16 no.11
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• pp.1013-1014
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• 1995

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.124.2-124.2
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• 2001

• Korean Journal of Clinical Pharmacy
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• v.14 no.1
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• pp.46-51
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• 2004

• The Korean Journal of Physiology
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• v.10 no.2
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• pp.1-10
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• 1976

The action of acetylcholine on the sodium plus potassium activated ATPase activity in the rabbit red cell membrane has been investigated and the experiments were also designed to determine the mechanism of action of acetylcholine on the ATPase activity. The following results were observed. 1. The activity of the NaK ATPase from red cell membrane is inhibited by acetylcholine. 2. The ratio of inhibition of NaK ATPase by acetylcholine is decreased by raising the potassium concentration, and is increased by raising the sodium concentration. 3. The ATPase activity is increased by small amounts of calcium but inhibited by larger amounts. The ratio of inhibition of the enzyme by acetylcholine is increased by raising the calcium concentration. 4. The inhibitory action of acetylcholine on the NaK ATPase activity was not related to the sulfhydryl group of cysteine, the hydroxyl group of threonine, or the carboxyl group of aspartic acid. 5. The inhibitory action of acetylcholine on the ATPase activity is due to amino group of the enzyme of NaK ATPase.

• Microbiology and Biotechnology Letters
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• v.48 no.2
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• pp.148-157
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• 2020

Eucalyptus oil is a rich source of bioactive compounds with a variety of biological activities and is widely used in traditional medicine. Eucalyptus citriodora is cultivated for the production of essential oils. However, the mode of antibacterial action of essential oils from E. citriodora is not well-known. This study aimed to determine the chemical components, microbial inhibitory effect, and mechanism of action of the essential oil from E. citriodora. The oil was extracted from E. citriodora leaves by hydro-distillation and the chemical components were analyzed using gas chromatography-mass spectrometry. The antibacterial activities of eucalyptus oil against gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus, and Staphylococcus intermedius) and gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) were screened by disc diffusion method and quantitative analysis was conducted by the microdilution method. The mechanism of action of the extracted essential oil was observed using SEM and analyzed by SDS-PAGE. The major components of E. citriodora oil were citronellal (60.55 ± 0.07%), followed by dl-isopulegol (10.57 ± 0.02%) and citronellol (9.04 ± 0.03%). The antibacterial screening indicated that E. citriodora oil exhibited prominent activity against all tested strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against B. subtilis were 0.5% and 1.0%, respectively. The MIC and MBC concentrations against S. aureus, S. intermedius, E. coli, and P. aeruginosa were 1% and 2%, respectively. As observed by SEM, the antibacterial mechanism of E. citriodora oil involved cell wall damage; SDS-PAGE revealed decrease in protein bands compared to untreated bacteria. Thus, E. citriodora oil showed significant antimicrobial properties and caused cellular damage.