• Journal of Microbiology and Biotechnology
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• v.23 no.9
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• pp.1206-1211
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• 2013

The selective inhibition of PTP1B has been widely recognized as a potential drug target for the treatment of type 2 diabetes and obesity. In the course of screening for PTP1B inhibitory fungal metabolites, the organic extracts of several fungal species isolated from marine environments were found to exhibit significant inhibitory effects, and the bioassay-guided investigation of these extracts resulted in the isolation of fructigenine A (1), cyclopenol (2), echinulin (3), flavoglaucin (4), and viridicatol (5). The structures of these compounds were determined mainly by analysis of NMR and MS data. These compounds inhibited PTP1B activity with 50% inhibitory concentration values of 10.7, 30.0, 29.4, 13.4, and 64.0 ${\mu}M$, respectively. Furthermore, the kinetic analysis of PTP1B inhibition by compounds 1 and 5 suggested that compound 1 inhibited PTP1B activity in a noncompetitive manner, whereas compound 5 inhibited PTP1B activity in a competitive manner.

• Natural Product Sciences
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• v.24 no.1
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• pp.59-65
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• 2018

An isoform of NADPH oxidase (NOX), NOX2 is a superoxide-generating enzyme involved in diverse pathophysiological events. Although its potential as a therapeutic target has been validated, there is no clinically available inhibitor. Herein, NOX2-inhibitory activity was screened with the constituents isolated from Schisandra chinensis, which has been reported to have antioxidant and reactive oxygen species (ROS)-scavenging effects. Among the partitions prepared from crude methanolic extract, a chloroform-soluble partition showed the highest NOX2-inhibitory activity in PLB-985 cell-based NOX2 assay. A total of twenty nine compounds (1 - 29) were identified from the chloroform fraction, including two first isolated compounds; dimethyl-malate (25) and 2-(2-hydroxyacetyl) furan (27) from this plants. Of these constituents, two compounds (gomisin T, and pregomisin) exhibited an NOX2-inhibitory effect with the $IC_{50}$ of $9.4{\pm}3.6$, and $62.9{\pm}11.3{\mu}M$, respectively. They are confirmed not to be nonspecific superoxide scavengers in a counter assay using a xanthine-xanthine oxidase system. These findings suggest the potential application of gomisin T (6) and other constituents of S. chinensis to inhibit NOX2.

• Archives of Pharmacal Research
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• v.29 no.7
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• pp.548-555
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• 2006

Three diterpenes (1, 8, and 9), three triterpenes (3, 4, and 7), one saponin (11), four sterols (2, 5, 6, and 12), and one cerebroside (10) were isolated from the EtOH extract of the aerial parts of Aralia cordata by repeated silica gel column chromatography. Their chemical structures were identified by comparing their physicochemical and spectral data with those published in literatures. All isolated compounds were evaluated for their cytotoxicity against L1210, K562, and LLC tumor cell lines using MTT assay. Of which, $3{\beta},5{\alpha}-dihydroxy-6{\beta}-methoxyergosta-7,22-diene$ (6) showed a potent cytotoxicity against all cell lines with $IC_{50}$ values of 11.7, 11.9, and $15.1\;{\mu}M$, respectively, while compounds 1, 5, and 11 showed a moderate or weak cytotoxicity. These isolates were also examined for their inhibitory activity against COX-1 and COX-2. Although most compounds, except for 2, 10, and 12, showed a strong inhibitory activity against COX-1, they exhibited a moderate or weak inhibitory activity against COX-2.

• Journal of Microbiology and Biotechnology
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• v.21 no.6
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• pp.582-589
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• 2011

Bioconversion of timosaponin A-III (TA-III), one of the major steroidal saponins isolated from the rhizomes of Anemarrhenae asphodeloides Bunge (Liliaceae), was investigated in Saccharomyces cerevisiae. Five bioconversion products, denoted compounds 2-6, were obtained. Biotransformation metabolite 2 was a stereoisomer of TAIII with a specific isotype F-ring and ${\beta}$-ranged $CH_3$-21, which rarely occurs in nature. The structure of 2 was elucidated by extensive spectroscopic analysis (H-H COSY, HSQC, HMBC), as well as by high-resolution mass spectral analysis. The growth inhibitory activity of compounds 1-6 was assayed against four human cancer cell lines, HepG2, H-1299, HT-29, and HCT-116. Compounds 1 and 2 obviously inhibited the growth of the four types of cancer cells with $IC_{50}$ values being less than 19${\mu}M$. A structure-activity relationship is discussed, and the spirostane-ring F in compounds 1 and 2 appears to be the critical bioactive moiety for the cell growth inhibitory property.

• Korean Journal of Pharmacognosy
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• v.30 no.2
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• pp.202-206
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• 1999

The MeOH extracts obtained from the leaves of Eucommia ulmoides were solvent-fractionated with EtOAc, n-BuOH, and $H_20$, successively. From the EtOAc extract showing Grab2-Shc inhibitory activity, a flavonol and a lignan compounds were isolated through repeated silica gel column chromatographies. By interpretation of several spectral data and adaptation of acetylation method, the chemical structures of the compounds were determined as 5,7,3',4'-tetrahydroxy-flavonol (quercetin), and 4,4',8',9-tetrahydroxy-3,3'-dimethoxy-7,9'-cyclolignan {(-)-olivil)}, respectively. The compounds exhibited $IC_{50}$ values in Grb2-Shc inhibitory activity to be 93 and $210\;{\mu}mole/l$, respectively.

• Korean Journal of Pharmacognosy
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• v.41 no.2
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• pp.97-102
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• 2010

Six triterpenoid compounds, friedelin (1), $3{\alpha}$-hydroxy-2-friedelanone (2), canophyllol (3), oleanolic aldehyde acetate (4), ursolic acid (5), and pachysandiol A (6) were isolated from the methylene chloride soluble fraction of the roots of A. japonica. The chemical structures of compounds 1-6 were determined by the basis of physico-chemical properties and spectroscopic methods such as 1D and 2D NMR. These compounds were isolated from this plant for the first time. For the isolated compounds (1-3), the inhibitory effect of IL-6 production in TNF-$\alpha$ stimulated MG-63 was examined. Among the isolates, $3{\alpha}$-hydroxy-2-friedelanone (2) showed potent inhibitory effect on IL-6 production in TNF-$3{\alpha}$ stimulated MG-63.

• Natural Product Sciences
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• v.23 no.4
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• pp.274-280
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• 2017

In a search for novel treatments for diabetic complications from natural resources, we found that the ethyl acetate-soluble fraction from the 80% ethanol extract of the leaves of Homonoia riparia has a considerable inhibitory effect on advanced glycation end product (AGE) formation. Bioassay-guided isolation of this fraction resulted in identification of 15 phenolic compounds (1 - 15). These compounds were evaluated in vitro for inhibitory activity against the formation of AGE. The majority of tested compounds, excluding ethyl gallate (15), markedly inhibited AGE formation, with $IC_{50}$ values of $2.2-89.9{\mu}M$, compared with that of the positive control, aminoguanidine ($IC_{50}=962.3{\mu}M$). In addition, the effects of active isolates on the dilation of hyaloid-retinal vessels induced by high glucose (HG) in larval zebrafish was investigated; (-)-epigallocatechin-3-O-gallate (6), corilagin (7), and desmanthine-2 (11) significantly decreased HG-induced dilation of hyaloid-retinal vessels compared with the HG-treated control group.

• Natural Product Sciences
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• v.5 no.2
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• pp.70-74
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• 1999

In the course of a search for tumor necrosis factor $(TNF)-{\alpha}$ inhibitory compounds from medicinal plants, we identified neolignans, honokiol and magnolol, from the alcoholic extract of Magnolia offcinalis as active inhibitory principles. These compounds dose-dependently inhibited $TNF-{\alpha}$ production without displaying cytotoxicity and their inhibitory activities measured by $IC_{50}$ values were 53.7 and $61.4\;{\mu}M$, respectively.

• Korean Journal of Medicinal Crop Science
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• v.10 no.4
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• pp.284-287
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• 2002

Four olefinic catechols, commonly referred to as urushiol were isolated from the sap of Korean Rhus verniciflua Stokes and had the stronger inhibitory effects on the reverse transcriptase of AIDS. The hexane extract with a inhibitory effects on reverse transcriptase was purified by silica and ODS gel column chromatography. The active compounds were identified by MS and $^1H-NMR$ as 3-[8' (Z), 11' (Z), 14' -pentadecatrienyl]catechol, 3-[8' (Z), 11' (Z)-pentadecadienyl]catechol, 3-[8' (Z)-penta- decenyl]catechol, and 3-pentadecylcatechol. All of these compounds showed strong inhibitory effects on reverse transcriptase of AIDS, in which 3-pentadecylcatechol exhibited the highest activity $(IC_{50}\;:\;10.87\;{\mu}g/ml)$.

• Biomolecules & Therapeutics
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• v.6 no.4
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• pp.364-370
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• 1998

Glycosidase inhibitors from urine of Bombyx mori were isolated and their inhibitory activities on glycosidases were evaluated. Six compounds were isolated by using several ion exchange columns, and their chemical structures were identified by the physicochemical and spectral data. Compound IV, V and Ⅵ were identified as 1-deoxynojirimycin, fagomine and 1,4-dideoxy-1,4-imino-D-arabinitol, respectively. Among six compounds isolated,1-deoxynojirimycin(IV) was the most potent inhibitor on $\alpha$-glucosidase and $\beta$-galactosidase of rat intestine, and its inhibitory activities for trehalase and almond $\beta$-glucosidase were relatively weak. Compound V and Ⅵl retained a little inhibitory potency toward $\alpha$-glucosidase and $\beta$-galactosidase. Compound II and III, however, have been found to have no effect on all glycosidases tested in this study.