• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.1
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• pp.119-123
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• 2005

In the courses of in vitro screening for the angiotensin converting enzyme (ACE) inhibitory activity of the various extracts from medicinal plants, n-BuOH soluble extract of the seeds of Xanthium strumarium was found to exhibit distinctive angiotensin converting enzyme (ACE) inhibitory activity. Bioassay-guided fractionation and purification of the n-BuOH soluble extract of the seeds of Xanthium strumarium afforded a new $xanthiazone-11-{\beta}-glucopyranoside$. The ACE activity was significantly inhibited by the addition of a new $xanthiazone-11-{\beta}-glucopyranosidein$ a dose-dependent manner of which $IC_{50}$ value was $21.8\;{\mu}g/ml$.

• Applied Biological Chemistry
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• v.49 no.2
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• pp.149-152
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• 2006

The chemical constituents of Acer tegmentosum Max which belongs to Aceraceae has never been reported. The stems of A. tegmentosum were extracted with MeOH and then successively partitioned with $CH_2Cl_2$, n-BuOH, and $H_2O$ in order to investigate the major phytochemicals. Two compounds were isolated from the n-BuOH fraction through silica gel and RP-18 column chromatographies. Their chemical structures were elucidated as methyl gallate $4-O-{\beta}-D-glucoside$ and salidroside by comparing their spectral data with those in the literature.

• YAKHAK HOEJI
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• v.42 no.4
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• pp.353-358
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• 1998

The MeOH extract of the bark of Paeonia moutan showed potent inhibitory effect on the mushroom tyrosinase activity in vitro. The activity-guided fractionation of t he MeOH extract resulted in the isolation of three active compounds. The chemical structures of these compounds were elucidated by chemical and spectroscopic evidence as catechin, 1,2,3,6-tetra-O-galloyl-${\beta}$-D-glucose and 1,2,3,4,6-penta-0-galloyl-${\beta}$-D-glucose, respectively. Among them, the inhibitory activity by 1,2,3,6-tetra-galloyl-${\beta}$-D-glucose on mushroom tyrosinase was more potent $(IC_{50}=3.5\;{\mu}M)$ than that of kojic acid $(IC_{50}=8.7\;{\mu}M)$ ,but catechin enhanced the mushroom tyrosinase activity 50% in the concentration of 34.5M.

• YAKHAK HOEJI
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• v.40 no.2
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• pp.149-154
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• 1996

A high-performance liquid chromatographic method for the determination of ${\beta}$-sitosterol in the unsaponifiable fraction of Zea mays L. and its related drug preparations using a cholesterol as an internal standard was investigated. They were saponified with 20% methanolic KOH solution. Phytosterols in the reaction mixture were extracted with diethyl ether and separated on silica gel TLC plate with n-hexane-diethyl ether(40:60) as the solvent and then were scraped off. They were separated by reversed phase high perfomance liquid chromatography on Inertsil ODS-2 column with detection at 205nm. Cholesterol and ${\beta}$-sitosterol were resolved from interferences by adjusting the acetonitrile content in the MeOH-tetrahydrofuran-$H_2O$ eluent. The detection limit of ${\beta$-sitosterol was 0.43${\mu}$g.

• Natural Product Sciences
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• v.6 no.3
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• pp.135-138
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• 2000

MeOH extract of Cuscuta chinensis seeds was fractionated with n-hexane, EtOAc and BuOH successively, and antioxidant activities were tested for all fractions using DPPH free radical scavenging method. In the tested fractions, EtOAc fraction showed high antioxidant activity$(EC_{50},\;50\;{\mu}g)$ From the EtOAc fraction, five compounds have been isolated. On the basis of spectral data, these compounds were identified as ${\beta}-sitosterol$, methyl 4-hydroxy-3,5-dimethoxycinnamate, ${\beta}-sitosterol-3-O-{\beta}-D-glucopyranoside$, caffeic acid, quercetin, kaempferol and calycopteretin. Among these compounds, ${\beta}-sitosterol$ and ${\beta}-sitosterol-3-O-{\beta}-D-glucopyranoside$ showed no antioxidant activity. $EC_{50}$ values of methyl 4-hydroxy-3,5-dimethoxycinnamate, caffeic acid, quercetin, kaempferol and calycopteretin were 0.6, 8, 19, 17 and $12\;{\mu}g$, respectively.

• Journal of radiological science and technology
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• v.8 no.2
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• pp.77-81
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• 1985

In this experiments the operation of the Geiger-Mueller tube is investigated by measuring the relationship between the count rate and the applied voltages, The length and slope of the plateau are characteristic of the tube. In our experiments, the average plateau length of the tube is extend for about 100 [V] and the slope 0.017 [%/V]. For normal counting purposes the working voltage is usually selected at value about 50 volts larger than the threshold of the plateau. To investigate the absorption of beta particles by matter. We performed an absorption experiments by using the Al absorber and Sr-90 ($0.125{\mu}Ci$) beta source. The maximum range of the beta radiation can be determined by visual extrapolation of the curve after subtraction of the constant background-rate and the maximum beta energy 2.09 [MeV] can be calculated from the range using an experimental relation.

• Archives of Pharmacal Research
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• v.28 no.3
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• pp.280-284
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• 2005

The chromatographic separation of the MeOH extract from the aerial parts of Syneilesis palmata led to the isolation of a new sesquiterpene glycoside 4, together with four known compounds. Their structures were characterized to be 4$\beta$,5$\beta$-epoxy-caryophill-8,(15)-ene (1), 3$\beta$­hydroxy-gultin-5-ene (2), 4$\alpha$,5$\beta$-dihydroxy-caryophill-8,(15)-ene (3), (-)-oplopan-4-one-10-$\alpha$-O­$\beta$-D-glucose (4) and 3-hexenyl-1-O-$\beta$-D-glucopyranose (5), based on spectroscopic and chemical methods. Compound 2 showed moderate cytotoxicity against five human tumor cell lines in vitro with its EDso values ranging from 5.90-1 0.83 $\mu$g/mL.

• YAKHAK HOEJI
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• v.39 no.3
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• pp.289-296
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• 1995

For the investigation of medicinal resources the studies were carried out to evaluated the pharmaco-constituents in the Leaves of Parthenocissus tricuspidata(Vitaceae), of which leaves have been used in Korea as folk remedies for the treatments of arthritis, jaundice, toothache, neuralgia, and etc. From 1-butanol fraction of the MeOH extract, Compound I ($C_{21}H_{18}O_{13}$, Quercetin-3-O-$\beta$-D-glucuronopyranoside), Compound II ($C_{21}H_{20}O_{12}$, Quercetin-3-O-$\beta$-D-glucopyranoside) and Compound III ($C_{25}H_{28}O_{12}$, Quercetin-3-O-(6"-n-butyl)-$\beta$-D-glucuronopyranoside) were isolated by column chromatographic separation using Sephadex LH-20 and ODS gel. Their structures were elucidated through instrumental analyses, such as $^{1}H$-NMR, $^{13}C$-NMR, IR, UV, El-Mass, FAB-Mass and GC. Especially compound III was Flavonol glycoside and named parthenosin.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.233-237
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• 2007

The roots of Brassica campestris ssp rapa were extracted with 80% aqueous MeOH, and the concentrated extract was partitioned with EtOAc, n-BuOH and $H_{2}O$. From the EtOAc and n-BuOH fractions, five compounds were isolated through the repeated silica gel column chromatographies. From the result of spectroscopic data including NMR and MS, the chemical structures of the compounds were determined as palmitic acid methyl ester (1), linolenic acid methyl ester (2), linoleic acid methyl ester (3), ${\beta}-sitosterol$ (4) and daucosterol (5).

• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1911-1914
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• 2008

Second-order rate constants (kN) have been measured for Michael-type addition reactions of a series of alicyclic secondary amines to 1-phenyl-2-propyn-1-one (2) in MeCN at 25.0 ${\pm}$ 0.1 ${^{\circ}C}$. All the amines studied are less reactive in MeCN than in $H_2O$ although they are more basic in the aprotic solvent by 7-9 p$K_a$ units. The Bronsted-type plot is linear with $\beta_{nuc}$ = 0.40, which is slightly larger than that reported previously for the corresponding reactions in $H_2O$ ($\beta_{nuc}$ = 0.27). Product analysis has shown that only E-isomer is produced. Kinetic isotope effect is absent for the reactions of 2 with morpholine and deuterated morpholine (i.e., $k^H/k^D$ = 1.0). Thus, the reaction has been concluded to proceed through a stepwise mechanism, in which proton transfer occurs after the rate-determining step. The reaction has been suggested to proceed through a tighter transition state in MeCN than in H2O on the basis of the larger $\beta_{nuc}$ in the aprotic solvent. The nature of the transition state has been proposed to be responsible for the decreased reactivity in the aprotic solvent.