• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.182-185
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• 2005

Bioassay-guided isolation of the dried roots of Aralia continentalis led to the isolation of (-)-pimara-8(14), 15dien-19-oic acid (continentalic acid) and $(24E)-Stigmasta-5,22-dien-3{\beta}-ol$ (stagmasterol). Their structures were elucidated using $^1H-NMR$, $^{13}C-NMR$, UV and mass spectra analyses. The gram-positive bacterial, including methicilline-resistant (MRSA), were more sensitive to the continentalic acid and stagmasterol than gram-negative bacterial.

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.283-289
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• 2015

The half-dried leaves of Stewartia. pseudocamellia were extracted with hot water (SPE) and partitioned with n-hexane (SPEH), dichloromethane (SPED), and ethyl acetate (SPEE) successively. SPE and SPEE showed significant inhibitory effects against melanogenesis and tyrosinase activities. By bioassay-guided isolation, ten phenolic compounds were isolated by column chromatography from SPEE. The whitening effect of the isolated compounds from SPEE were tested for the inhibitory activities against melanogenesis using B16 melanoma cells, in vitro inhibition of tyrosinase, and L-3,4-dihydorxy-indole-2-carboxylic acid (L-DOPA) auto-oxidation assay. A cytotoxic activity assay was done to examine the cellular toxicity in Raw 264.7 macrophage cells. Of the compounds isolated, gallic acid and quercetin revealed significant inhibitory activities against melanogenesis compared to arbutin. In particular, quercetin exhibited similar inhibitory activities against tyrosinase and L-DOPA oxidation without cytotoxicity. These results suggested that SPE could be used as a potential source of natural skin-whitening material in cosmetics as well as in food products.

• 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 $21.8\;{\mu}g/ml$.

• Korean Journal of Pharmacognosy
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• v.34 no.1 s.132
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• pp.14-17
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• 2003

In the course of screening Korean natural plants for acetylcholinesterase (AChE) inhibitory activity, we found that a methanolic extract of the leaves of Securinega suffruticosa showed significant inhibitory effects on AChE. Bioassay-guided fractionation of the methanolic extract resulted in the isolation of dihydrosecurinine, as a active principle. This compound inhibited AChE activity in a dose-dependent manner, and the $IC_{50}$ value of dihydrosecurinine was $18.9\;{\mu}g$.

• Ocean and Polar Research
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• v.33 no.3
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• pp.255-263
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• 2011

The aim of this investigation was to evaluate antioxidant activity of crude extracts from the halophyte Vitex rotundifolia, their solvent fractions, and isolated compounds (1-3). Antioxidant capacity was determined by measuring DPPH radical, and authentic $ONOO^-$ and $ONOO^-$ generated from 3- morpholinsydnonimine (SIN-1) in vitro as well as degree of occurrence of intracellular ROS, NO and GSH in mouse macrophage Raw 264.7 cells. From comparative analysis, MeOH extract, n-BuOH, and 85% aq. MeOH solvent fractions showed significant antioxidant effect in DPPH radical and $ONOO^-$ assay systems. Activity-guided purification of n-BuOH and 85% aq. MeOH fractions led to the isolation of flavonoids 1-3. Among them, compound 1 exhibited excellent antioxidant effect in all bioassay systems tested. On the other hand, compounds 2 and 3 revealed potent inhibitory effect against $ONOO^-$ generated from SIN-1, comparable with the positive control penicillamine.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2803-2807
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• 2014

Bioassay-guided chemical investigation of the roots of Anthriscus sylvestris (L.) Hoffm. resulted in the isolation of nine compounds, whose structures were determined by spectroscopic methods. Compound 1 was isolated from this plant for the first time and compounds 3 and 9 were first found from this genus. Different polar fractions of A. sylvestris extract and compounds 1, 6-8 and 9 were evaluated for antitumor activities against HepG2 (human hepatocellular carcinoma), MG-63 (human osteosarcoma cells), B16 (melanoma cells) and HeLa (human cervical carcinoma cells) lines by the MTT method. The petroleum ether fraction of A. sylvestris extract exhibited excellent inhibitory activity with an $IC_{50}$ value of $18.3{\mu}g/ml$. Among the isolates from the petroleum ether fraction, compound 7 showed significant inhibition against the growth of the four tumor cells with $IC_{50}$ values ranging from $12.2-43.3{\mu}g/ml$.

• 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.

• Archives of Pharmacal Research
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• v.28 no.9
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• pp.1037-1041
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• 2005

Geranium (Pelargonium inquinans Ait) leaves were extracted with $80\%$ MeOH, and partitioned into n-hexane, ethyl acetate, BuOH and $H_2O$ to isolate the anticoagulant principles. The EtOAc fraction was found to be the most active, and was further purified using silica and octadecylisilane column chromatography employing a bioassay-guided fractionation method. The active compound was isolated and identified as $1,2,3,4,6-pentagalloyl-\beta-D-glucopyranose$(PGG) (compound I). The isolated anticoagulant significantly prolonged the activated partial thrombin time (APTT) and thrombin time (TT) using normal human plasma. One microgram of $1,2,3,4,6-pentagalloyl-\beta-D-glucopyranose$ showed 0.063 heparin units in the APTT and 2.73 heparin units in the TT for anti-thrombosis. This is the first report of the isolation of PGG from geranium plants.

• Korean Journal of Pharmacognosy
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• v.30 no.3
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• pp.280-283
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• 1999

Using the bioassay-guided fractionation and isolation technique, two $PLC{\gamma}1$ inhibitors were isolated from the sarcotestas of Ginkgo biloba (Ginkgoaceae). The structures of these compounds were identified as (3R)-(-)-8-hydroxy-3-(6'-pentadecenyl)3,4-dihydroisocoumarin (1) and 3-heptadecen-2-one (2) by UV, IR, MS, $^1H-NMR$, $^{13}C-NMR$ and $^1H-^{13}C\;COSY$. Isolate compounds 1 and 2 have not been reported previously from the sarcotestas of G. biloba and Ginkgoaceae, respectively. In addtion, these compounds showed significant $PLC{\gamma}1$ inhibitory effects with the $IC_{50}$ of the 9.7 (1) and $25.6\;{\mu}M\;(2)$.

• Natural Product Sciences
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• v.12 no.2
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• pp.109-112
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• 2006

The chloroform-soluble fraction of the vinegar treated small black soybean [Glycine max (Leguminosae)] showed antiproliferative activity against human myeloid leukemia HL-60 cells, in terms of inhibition of proliferation and induction of apoptosis. Bioassay-guided chromatography of the chloroform-soluble fraction resulted in the isolation of two isoflavonoid compounds, genistein and daidzein, as active principles. Genistein showed more potent antiproliferative effects against HL-60 cells. Treatment of HL-60 cells with genistein induced apoptosis in a dose dependent manner. Apoptosis was judged by the detection of DNA fragmentation by a flow cytometry and the degree of apoptosis was assayed by RT-PCR.