• Proceedings of the Plant Resources Society of Korea Conference
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• 1993.08a
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• pp.14-20
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• 1993

We in anticancer drug development from natural resources have conceived and used a wide variety of experimental screening systems to support our efforts during the past 20 tears. Screens have been devided to address targets at the molecular, biochemical and cellular levels, both in vivo and in vitro. Screens have been essential for the experimental evaluation of the products from natural sources. In this congress, antitumor screening methods for deveol[ment of new drugs from natural sources and evaluation of their crude drugs are discussed.

• Natural Product Sciences
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• v.11 no.1
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• pp.41-44
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• 2005

Chemical investigation of the aerial parts of Chloranthus japonicus Sieb. led to the isolation a new compound, 9-hydroxy heterogorgiolide (1) and $isofraxidin-7-O-{\beta}-D-glucopyranoside$ (2), the isolation of which is reported for the first time from this plant, along with the known components, ${\beta}-sitosterol,\;{\beta}-sitosterol-3-O-{\beta}-D-glucopyranoside$, palmitic acid and octacosanoic acid. The structures of compound 1 and 2 were determined on the basis of spectroscopic data including two dimensional NMR and high resolution MS.

• Natural Product Sciences
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• v.15 no.3
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• pp.151-155
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• 2009

Phytochemical investigation of the MeOH extract of the aerial parts of Geranium eriostemon resulted in the isolation of one triterpene, three furofuran lignans, one syringic acid and four flavonoids. Their chemical structures were characterized by spectroscopic methods to be oleanolic acid (1), (-)-kobusin (2), (-)-eudesmin (3), (+)-magnolin (4), syringic acid (5), quercetin (6), juglanin (7), juglalin (8), and hyperin (9). All compounds (1 - 9) were isolated for the first time from this plant source and the compounds 2 - 4 were reported first from the genus Geranium. Compounds 4 - 6 exhibited moderate cytotoxicity against four human cancer cell lines in vitro using a SRB bioassay.

• Natural Product Sciences
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• v.20 no.2
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• pp.91-94
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• 2014

Column chromatographic separation of the MeOH extract from the tubers of Bletilla striata yielded seven phenolic components including four phenanthrenes, 3,7-dihydroxy-2,4-dimethoxyphenanthrene (1), 3,7-dihydroxy-2,4,8-trimethoxyphenanthrene (2), 9,10-dihydro-4,7-dimethoxyphenanthrene-2,8-diol (3), and 9,10-dihydro-1-(4'-hydroxybenzyl)-4,7-dimethoxyphenanthrene-2,8-diol (4) and three stilbenes, gigantol (5), 3',4"-dihydroxy-5',3",5"-trimethoxybibenzyl (6), and batatasin III (7). Their structures were determined on the basis of NMR spectroscopic data. Among them, compound 2, 3, and 6 were reported for the first time from this plant. The isolated compounds (1-7) were tested for cytotoxicity against four human tumor cell lines in vitro using a Sulforhodamin B bioassay.

• Natural Product Sciences
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• v.20 no.2
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• pp.71-75
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• 2014

Nine triterpenes were isolated from the petroleum ether and MeOH extract of Perilla frutescens var. acuta leaves. Their structures were determined to be arjunic acid (1), maslinic acid (2), oleanolic acid (3), euscaphic acid (4), tormentic acid (5), 3-O-trans-p-coumaroyltormentic acid (6), 28-formyloxy-$3{\beta}$-hydroxy-urs-12-ene (7), ursolic acid (8), and corosolic acid (9) by spectroscopic methods. The compounds 1, 2, 4, 6, and 7 were isolated for the first time from this plant and the Genus Labiatae. The isolated compounds (1-9) were tested for cytotoxicity against four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT-15) in vitro using a Sulforhodamin B bioassay.

• Natural Product Sciences
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• v.16 no.1
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• pp.32-38
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• 2010

From the polar fractions of a 70% EtOH extract of the flower buds of Lonicera japonica (Caprifoliaceae), ten constituents were isolated and identified as iridoid glycosides 7-dehydrologanin (7-ketologanin, 2), secologanin dimethyl acetal (3), (E)-aldosecologanin (centauroside, 5), dimethyl secologanoside (6), secoxyloganin (7) and epivogeloside (8). Other identified constituents were 1-O-$\beta$-D-glucopyranosyl-(2S,3S,4R,8E/Z)-2-[(2R)-2-hydroxy(docosanoyl, tricosanoyl, tetracosanoyl, pentacosanoyl)amino]-8-octadecene-1,3,4-triol (1), uracil (4), D-mannitol (9), and sucrose (10). Among them, 1, 2, 4, and 10 were isolated for the first time from this plant.

• Natural Product Sciences
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• v.8 no.4
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• pp.162-164
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• 2002

The methanol extracts of 42 Korean indigenous plants were evaluated for the DNA strand-scission activity. As a result, the 17 extracts were found to be active in the criteria of $IC_{50}$}<$25\;{\mu}g/ml$. Among others, the MeOH extracts of Caesalpinia sappan and Mucuna birdwoodiana showed the most potent DNA strand-scission activity with $IC_{50}$ values of 5.9 and $4.9\;{\mu}g/ml$, respectively. Therefore, the partition and fractionation for C. sappan were performed and tested in the DNA strand-scission assay system for further bioassay-guided fractionation.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.14-14
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• 2020

In December 2019, the COVID-19 epidemic was discovered in Wuhan, China, and since has disseminated around the world impacting human health for millions. Herein, in-silico drug discovery approaches were utilized to identify potential candidates as Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) main protease (M^pro) inhibitors. We investigated several databases including natural and natural-like products (>100,000 molecules), DrugBank database (10,036 drugs), major metabolites isolated from daily used spices (32 molecules), and current clinical drug candidates for the treatment of COVID-19 (18 drugs). All tested compounds were prepared and screened using molecular docking techniques. Based on the calculated docking scores, the top ones from each project under investigation were selected and subjected to molecular dynamics (MD) simulations followed by molecular mechanics-generalized Born surface area (MM-GBSA) binding energy calculations. Combined long MD simulations and MM-GBSA calculations revealed the potent compounds with prospective binding affinities against M^pro. Structural and energetic analyses over the simulated time demonstrated the high stabilities of the selected compounds. Our results showed that 4-bis([1,3]dioxolo)pyran-5-carboxamide derivatives (natural and natural-like products database), DB02388 and Cobicistat (DB09065) (DrugBank database), salvianolic acid A (spices secondary metabolites) and TMC-310911 (clinical-trial drugs database) exhibited high binding affinities with SARS-CoV-2 M^pro. In conclusion, these compounds are up-and-coming anti-COVID-19 drug candidates that warrant further detailed in vitro and in vivo experimental estimations.

• Korean Journal of Pharmacognosy
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• v.31 no.4
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• pp.416-420
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• 2000

Ursolic acid was isolated from Prunellae Herba (Prunella vulgaris var. lilacina) and identified by direct comparison with an authentic sample. A method of analysis for the evaluation of ursolic acid was developed based on extraction of ground plant material, followed by quantitative determination using capillary gas chromatography of the TMS derivative. Quantitative analysis by GC after derivatisation under mild silylating conditions showed 0.31% ursolic acid in 20 samples collected throughout regions of Korea while no ursolic acid was detected in the samples of the whole plant of Thesium chinense, a substitute for Prunellae Herba in southern regions of Korean peninsula.

• Journal of Pharmaceutical Investigation
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• v.40 no.5
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• pp.269-275
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• 2010

P-gp plays a critical role in drug disposition and represents a mechanism for the development of multidrug resistance. Flavonoids, a major class of natural compounds widely present in foods and herbal products, have been shown to inhibit P-gp. Therefore, the aim of this study was to identify new candidate chemosensitizers by screening various plant extracts. The ability of natural plant extracts to inhibit P-gp activity was assessed by measuring cellular accumulation of calcein AM, daunorubicin and vincristine in P-gp overexpressing MDCKII-MDR1 cells. Among more than 800 plant extracts, eight were found to inhibit P-gp activity. Curcuma aromatica extract produced greatest inhibition, followed by Curcuma longa and Dalbergia odorifera extracts. Extracts of Aloe ferox, Curcuma zedoariae rhizome, Zanthoxylum planispinum, and Ageratum conyzoides showed moderate inhibitory effects. Curcumin and quercetin exhibited similar inhibition of P-gpmediated efflux of daunorubicin and vincristine, and flavones had a lesser effect. When chemosensitizing effect was evaluated by measuring daunorubicin sensitivity to MDCKII-MDR1 cells in the presence of natural plant extracts, Curcuma aromatica showed the most potent chemosensitizing effect based on daunorubicin cytotoxicity. In conclusion, natural plant extracts such as Curcuma aromatica can potently inhibit P-gp activity and may have potential as a novel chemosensitizers.