• Archives of Pharmacal Research
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• v.29 no.12
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• pp.1102-1108
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• 2006

An in vitro bioassay-guide revealed that the methanol (MeOH) extract of the stem bark of Populus davidiana showed considerable inhibitory activity against cyclooxygenase (COX-1, COX-2). Continuous phytochemical study of the MeOH extract of this plant led to the isolation of ten flavonoids; sakuranetin (1), rhamnocitrin (2), 7-O-methylaromadendrin (3), naringenin (4), eriodictyol (5), aromadendrin (6), kaempferol (7), neosakuranin (8), sakuranin (9) and sakurenetin-5,4'-di-${\beta}$-D-glucopyranoside (10). Their structures were identified on the basis of their physicochemical and spectroscopic analyses. The isolated compounds, 1-10, were tested for their inhibitory activities against COX-1 and COX-2. Compound 7 was found to have potent inhibitory effect on COX-1 and a moderate effect on COX-2, meanwhile, compounds 1-6 showed moderate inhibition against COX-1 only. Moreover, compounds 5-8 exhibited suppressive effects on xanthine oxidase (XO). These results may explain, in part, the traditional uses of P. davidiana in ethnomedicine.

• Archives of Pharmacal Research
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• v.25 no.3
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• pp.270-274
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• 2002

Chromatographic separation of the stem bark extract of Mitragyna stipulosa afforded triterpene derivatives ursolic acid (1), quinovic acid (2), quinivic acid $3-O-{\beta}-D-glucopyranoside$ (3, quinovin glycoside C), quinovic acid 3-O-[$(2-O-sulfo)-{\beta}-D-quinovopyranoside$] (4, zygophyloside D) and quinovic acid $3-O-{\beta}-D-quinovopyranosyl-27-O-{\beta}-D-glucopyranosyl$ ester (5, zygophyloside B). These five compounds were subjected to the cytotoxicity on MTT assay system. Compound 1 among tested showed the most potent cytotoxicity. Quinovic acid showed less potent cytotoxicity than ursolic acid and sugar linkages to 2 decreased the cytotoxicity. Compound 4 more potent than 3 with indicate that the sulfonyl group significantly enhances the activity. This indicates that the glycosidic linkage in ursane-type triterpenoids has mainly negative effect on cytotoxicity unlike in oleanane-type glycosides.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.43-52
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• 2001

Living systems constantly suffer from atmospheric reactive oxygen species and also produce inevitably them by the course of metabolism. Therefore, antioxidants play important roles in protecting the systems from various diseased caused by them. In this study, we investigated various tinged autumnal leaves as antioxidant sources. Among the, the red leaf extracts of Acer Palmatum THUNBERG.(Aceraceae: maple tree) and Prunus Donarioum Sieb. Var. spontanea Makino(Rosaceae : cherry trees) showed the highest anti-oxidativities. The major antioxidants in their red leaves were isolated and identified as vitexin from maple leaves and isoscutellarein-4'-O-$\beta$-glucopyranoside from cherry leaves. Finally, we evaluated the efficacy of skin care products containing the extracts by human use study. As a result, the tinged leaves of maple and cherry trees were evaluated as good antioxidant sources on the bases of antioxidativities, cytotoxicities, cell proliferation effects and human use study.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.258-263
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• 1998

${\beta}$-Xylosidase was purified from the recombinant Escherichia coli carrying the Bacillus sp. KK-1 ${\beta}$-xylosidase gene (xylB). The molecular mass of the purified enzyme was estimated to be 62 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. However, the apparent molecular mass of the ${\beta}$-xylosidase was 140 kDa, indicating that the native ${\beta}$-xylosidase has an oligomeric structure composed of two identical subunits. The isoelectric point was determined to be pH 5.5. The enzyme was highly active on p-nitrophenyl-$\beta$-D-xylopyranoside but it barely hydrolyzed xylan substrates, and did not exhibit activity towards carboxymethylcellulose and p-nitrophenyl-${\beta}$-D- glucopyranoside. The enzyme had a pH optimum for its activity at pH 6.5 and a temperature optimum at $40^{\circ}C$. The enzyme activity was completely inhibited by the presence of $Hg^{++}$, and also markedly inhibited by D-xylose and D-glucose.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.270-276
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• 1998

Extracellular ${\alpha}$-glucosidase was purified to homogeneity from moderately thermophilic Bacillus sp. DG0303. The thermostable ${\alpha}$-glucosidase was purified by ammonium sulfate fractionation, ion-exchange chromatography, preparative polyacrylamide gel electrophoresis (PAGE), and electroelution. The molecular weight of the enzyme was estimated to be 60 kDa by SDS-PAGE. The optimum temperature for the action of the enzyme was at $60^{\circ}C$. It had a half-life of 35 min at $60^{\circ}C$. The enzyme was stable at the pH range of 4.5~7.0 and had an optimum pH at 5.0. The enzyme preparation did not require any metal ion for activity. The thermostable ${\alpha}$-glucosidase hydrolyzed the ${\alpha}$-1,6-linkages in isomaltose, isomaltotriose, and panose, and had little or no activity with maltooligosaccharides and other polysaccharides. The $K_m$ (mM) for p-nitrophenyl-${\alpha}$-D-glucopyranoside (pNPG), panose, isomaltose, and isomaltotriose were 4.6, 4.7, 40.8, and 3.7 and the $V_{max}$(${\mu}mol{\cdot}min^-1$$mg^-1$) for those substrates were 5629, 1669, 3410, and 1827, respectively. The N-terminal amino acid sequence of the enzyme was MERVWWKKAV. Based on its substrate specificity and catalytic properties, the enzyme has been assigned to be an oligo-1,6-glucosidase.

• Microbiology and Biotechnology Letters
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• v.20 no.2
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• pp.143-149
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• 1992

A bacterial strain No. 2, which highly produced a-glucosidase, was isolated from Kimchi and identified to be a similar species of Pediococcus halophilus. This enzyme was purified by protamine sulfate, ammonium sulfate fractionation, ion exchange and gel filtration. The maximal a-glucosidase activity was observed at pH 6.0 and this enzyme was stable at pH 6.0~ 7.5. The optimum temperature of this enzyme activity was $37^{\circ}C$, but enzyme activity was gradually lost above $37^{\circ}C$. This enzyme was activated by 10 mM MgCh and inhibited by 10 mM mercaptoethanol. The kinetics of PNPG(p-Nitrophenyl-a-D-glucopyranoside) and maltose were Kp0.52 mM/27.5 pg protein, $V_{max}$= 0.021 mM/min 27.5 ${\mu}g$ protein and $K_m$= 0.32 mMD7.5 ${\mu}g$ protein, $V_{max}$= 0.025 mM/min 27.5 ${\mu}g$ protein, respectively. The molecular weight of $\alpha$-glucosidase was about 37, 000.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.274-278
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• 2012

As part of ongoing study focused on the discovery of natural antioxidants from Korean plants by measuring the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect and superoxide quenching activity, ethanol extract of the aerial parts of Curcuma longa (Zingiberaceae) was found to show potent antioxidant activities. Subsequent activity-guided fractionation of the ethanol extract led to the isolation of two phenolic compounds, 1,2,3,4,6-penta-O-galloyl-${\beta}$-D-glucopyranoside (1) and gallic acid (2), as antioxidant compounds. Their structures were elucidated by spectroscopic studies. Compounds 1 and 2 were isolated for the first time from this plant. These compounds showed the significant antioxidative effects during the DPPH free radical scavenging test, and the riboflavin- and xanthine-originated superoxide quenching activity tests.

• Natural Product Sciences
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• v.20 no.3
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• pp.191-195
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• 2014

The n-BuOH soluble fraction of the whole plant of Persicaria thungergii showed acetylcholinesterase inhibitory activity. Four flavonoid glycosides and a flavonoid were isolated from this fraction, and identified as quercitrin (1), luteolin-4'-O-${\beta}$-D-glucopyranoside (2), quercetin (3), quercetin-3-O-glucuronide (4), and isorahmnetin-3-O-glucuronid (5), by chromatographed and spectral data, respectively. All isolated compounds were showed acetylcholinesterase inhibitory activity, with $IC_{50}$ values of 243.1, 10.5, 39.1, 8.2 and $23.2{\mu}M$, respectively.

• Natural Product Sciences
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• v.19 no.1
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• pp.66-70
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• 2013

Ten compounds (1 - 10), palmitic acid (1), 10-nonacosanol (2), pentacosan-1-ol (3), phytol (4), ${\beta}$-sitosterol (5), ${\beta}$-sitosterol-3-O-${\beta}$-D-glucopyranoside (6), 2,4-dihydroxycinnamic acid (7), hyperoside (8), uridine (9) and adenosine (10), were isolated from the n-hexane and EtOAc-soluble fractions of the aerial parts of A. dioicus var. kamtschaticus (Rosaceae). The structures of these compounds were elucidated on the basis of spectroscopic evidence. All compounds (1 - 10) were isolated for the first time from this plant. Cytotoxicity of 1 - 10 against Jurkat T (T-lymphocytic leukemia cells), HeLa (Human cervical epitheloid carcinoma cells), MCF-7 (Human breast cancer cells), and HL-60 (Human promyelocytic leukemia cells) cell lines was measured. Compound 6 showed good cytotoxicity against HL-60 cell line with $IC_{50}$ value of 8.13 ${\mu}g/mL$. In addition, compounds 7 and 8 exhibited antioxidant activity with $IC_{50}$ values of 16.30 and 12.42 ${\mu}g/mL$, respectively.

• Natural Product Sciences
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• v.17 no.3
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• pp.198-201
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• 2011

Tyrosinase is one of the important enzymes in the mammalian melanin synthesis. In the process of melanin synthesis, tyrosine is oxidized to DOPA (3,4-dihydroxyphenylalanine), and DOPA is further oxidized to dopaquinone. Tyrosinase is an enzyme catalyzing this oxidation of tyrosine, so chemicals that inhibit the activity of tyrosinase can be used as skin whitening agents. In this study, we isolated five constituents from the 80% MeOH extract of Morus bombycis cortex by bioactivity-guided fractionation. We performed mushroom tyrosinase inhibition assay. As a result, 7,2',4'-trihydroxyflavanone (1), 2',4',2,4,-tetrahydroxychalcone (2), and oxyresveratrol (3) showed the more potent inhibitory effect compared to kojic acid, a well-known skin whitening agent with antityrosinase effect. Moracinoside M (4) and moracin M-3'-O-${\beta}$-D-glucopyranoside (5) also showed the moderate tyrosinase inhibitory activities.