• Biomolecules & Therapeutics
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• 제18권2호
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• pp.191-196
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• 2010

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl- 2-picrylhydrazyl (DPPH), a total extract of the twigs of Stewartia koreana (Theaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of six phenolic compounds, ampelopsin (1), catechin (2), proanthocyanidin-A2 (3), fraxin (4), (2R, 3R)-taxifolin-3-${\beta}$-D-glucopyranoside (5), and (2S, 3S)-taxifolin-3-${\beta}$-D-glucopyranoside (6), as active principles. Their structures were elucidated by spectroscopic studies. Compounds 1-6 were isolated for the first time from this plant. Among them, three compounds 1-3 showed the significant antioxidative effects on DPPH, and riboflavin originated superoxide quenching activity. In riboflavin-nitrobluetetrazolium (NBT)-light system, compound 1 showed better superoxide quenching activity than vitamin C.

• Biomolecules & Therapeutics
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• 제17권4호
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• pp.412-417
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• 2009

In the course of screening for antioxidant compounds by measuring the radical scavenging effect on DPPH (1,1-diphenyl- 2-picrylhydrazyl), a total extract of the twigs of Vitex rotundifolia (Verbenaceae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of three iridoid compounds, 10-O-vanilloylaucubin (1), 10-O-p-hydroxybenzoylaucubin (2) and aucubin (3), two C-glycoside flavones, vitexin (4) and orientin (5), and a quinic acid derivative, 3,4-di-O-caffeoylquinic acid (6). Their structures were elucidated by spectroscopic studies. Among them, compounds 5 and 6 showed the significant antioxidative effects on DPPH free radical scavenging test. In riboflavin-NBT-light and xanthine-NBT-xanthine oxidase systems, compounds 5 and 6 exhibited the formation of the blue formazan in a dose-dependent manner. Compounds 5 and 6 showed better superoxide quenching activities than vitamin C.

• 생약학회지
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• 제16권4호
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• pp.248-252
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• 1985

During the biological screening of Chinese drugs, it was found that alcoholic extract of the roots of Patrinia scabiosaefolia (Valerianaceae) caused a significant prolongation of hexobarbital-induced sleeping time and elevation of serum transaminase activities accompanied by severe histopathological changes in the hepatic tissues in mice on three day pretreatments. The systematic fractionation of the methanol extract monitoring by bioassay led to isolation of toxic saponins such as $3-O-{\alpha}-{_L}-arabinopyranosyl$ hederagenin $28-O-{\beta}-{_D}-glucopyranosyl\;(1{\rightarrow}6)-{\beta}-{_D}-glucopyranoside$ and its 2'-acetate and $3-O-{\beta}-{_D}-glucopyranosyl\;(1{\rightarrow}3)-{\alpha}-{_L}-rhamnopyranosyl\;(1{\rightarrow}2)-{\alpha}-{_L}-arabinopyranosyl$ oleanolic acid and its $28-O-{\beta}-{_D}-glucopyranosyl\;(1{\rightarrow}6)-{\beta}-{_D}-glucopyranoside$.

• 약학회지
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• 제40권2호
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• pp.225-229
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• 1996

The cytotoixic effect of Pylorae Herba (Pyrola japonica Klenze) against L1210 and K-562 cells was studied in vitro. The methanolic extract of Pylorae Radix was add ed to the culture of L1210 cells and K-562 cells for the cytotoxic activity and the ED50 values of hexane, ethylacetate, buthanol and water fractions from methanolic extract were determined using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide) assay. The active constituent isolated by bioassay guided fractionation followed by purification gave rise to a yellow needle crystal and was clarified to be chimaphilline by the comparison with the published data. The average life spans with it were not prolonged significantly on tumor growth in hybrid female mouse (BDF1-KIST) inoculated subcutaneously with P388 cells.

• Natural Product Sciences
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• 제17권4호
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• pp.261-266
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• 2011

During the process of screening for antioxidative effects of natural plants in Korea, by measuring the superoxide quenching activity, methanol extract of the whole plant, Galium verum var. asiaticum (Rubiaceae), was found to show potent antioxidant activity. Subsequent activity-guided fractionation of methanol extract of Galium verum var. asiaticum led to the isolation of five phenolic compounds. Using spectroscopic techniques, the chemical structures were elucidated as: caffeic acid (1), narcissin (2), rutin (3), luteolin-7-O-${\alpha}$-L-rhamnopyranosyl (1 ${\rightarrow}$ 2)-${\beta}$-D-glucopyranoside (4), and luteolin-7-O-${\beta}$-D-glucopyranoside (5). These compounds were isolated for the first time from this plant. Among them, compound 1 showed the most significant riboflavin-originated superoxide and xanthine-originated superoxide quenching activities. Compounds 3 and 4 exhibited mild superoxide quenching effects compared with vitamine C.

• Journal of Applied Biological Chemistry
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• 제52권4호
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• pp.212-215
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• 2009

The inhibitory effects of Curcuma longa rhizome-derived materials against nitric oxide (NO) production were assessed. The inhibitory effect (57%) on NO production was evidenced by the methanol extract of C. longa at $1\;{\mu}g/mL$. In the fractionation of the methanol extract, the ethyl acetate fraction evidenced an inhibitory effect greater than 62.1% at $1\;{\mu}g/mL$. The active constituent was identified as curcumin. Curcumin exerted potent inhibitory effects of 78.7 and 65.7% at concentrations of 1 and $0.5\;{\mu}g/mL$, respectively. Furthermore, the inhibitory effect of ar-turmerone was measured as 31.3 and 15.8% at 1 and $0.5\;{\mu}g/mL$, respectively. The iNOS expression-suppressive effects of curcumin were assessed via western blot analysis. Our results suggest that curcumin and ar-turmerone may prove useful in the development of new types of NO inhibitors.

• 생약학회지
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• 제31권2호
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• pp.196-202
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• 2000

This study was conducted to search for the ${\alpha}-glucosidase$ inhibitor from the natural products. In the previous study, the water extract of Gyrophora esculenta exhibited a potent inhibitory effect on ${\alpha}-glucosidase$ activities. Then, by bioassay-guided fractionation followed by chromatographic separation of the water extract of Gyrophora esculenta, ${\alpha}-glucosidase$ inhibitor was isolated as GE974. GE974 showed significant inhibitory activities on some kinds of ${\alpha}-glucosidase$ in vitro. Its inhibitory mechanism seemed to be competitive for disaccharides. Also, it markedly inhibited ${\alpha}-glucosidases$ of intestine separated from both nondiabetics and diabetics.

• 생약학회지
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• 제17권1호
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• pp.91-99
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• 1986

The single treatment of mice with steam distillate, non-volatile ether extract and methanol extract from mace (Arils of Myristica fragrans) caused a significant prolongation of hexobarbital-induced narcosis and increase in strychnine toxicity as well as a significant decrease in hepatic microsomal drug metabolizing enzyme activities. On 7 consecutive daily administrations, however, the duration of hypnosis was markedly shortened and significant increases in the hepatic enzyme activities were shown. With systematic fractionation by $SiO_2$ column chromatography of non-volatile ether fraction monitoring by animal tests a new lignan (mp $70{\sim}72^{\circ}$, MW 328, $[{\alpha}]^{20}_D+5.28$) was isolated as an active principle and its structure was elucidated as (2R, 3S)-1-(3,4-methylendioxyphenyl)-2,3 dimethyl-4-(4-hydroxy-3-methoxyphenyl) butane.

• Archives of Pharmacal Research
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• 제21권3호
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• pp.344-347
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• 1998

To overcome multidrug resistance (MDR) in cancer chemotherapy, we prepared various plant extracts and searched for a component which is effective for inhibition of MDR. MDR inhibition activity was determined by measuring cytotoxicity to MDR cells using multidrug resistant human fibrocarcinoma KB V20C, which is resistant to 20 nM vincristine and expresses high level of mdr1 gene. Of various plant extracts, the MeOH extract of the root of Aconitum pseudo-laeve var. erectum was found to have potent inhibitory activity on MDR. The bioassayguided fractionation of the MeOH extract of the plant led to the isolation of an alkaloid, lycaconitine, as an active principle. And the $IC_{50}$ of lycaconitne for KB V20C cells was $74\mu{g}$/ml.

• 생약학회지
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• 제47권2호
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• pp.110-116
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• 2016

As a part of an ongoing search for natural plants with antioxidant compounds by measuring the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH), a total extract of the aerial parts of Bidens frondosa L. (Compositae) was found to show potent antioxidant activity. Subsequent activity-guided fractionation of the methanolic extract led to the isolation of five compounds, quercetin-3-O-${\beta}$-D-glucopyranoside (1), luteolin-7-O-${\beta}$-D-glucopyranoside (2), 7,8,3',4'-tertrahydroxy-flavanone (3), okanin-4-O-${\beta}$-D-glucopyranoside (4), and okanin (5). Their structures were elucidated by spectroscopic studies. Compounds 3-5 were isolated for the first time from this plant. Among them, compounds 3 and 5 showed the significant radical scavenging effects on DPPH, and compounds 3 and 5 also showed the potent riboflavin and xanthine originated superoxide quenching activities.