• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.130-136
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• 1990

Four known cardiotonic steroids were isolated from roots of Adonis amurensis Regel et Radde and identified as digitoxigenin, cymarin, K-strophanthin and convallatoxin by chromatography on Amberlite XAD-2 resin and silica gel, high performance liquid chromatography and gel chromatography on Sephadex LH-20. In order to clarify the structure-activity relationship, thirteen related compounds of digitoxigenin were tested for the inhibitory activities for $Na^+,\;K^+$-adenosine triphosphatase from guinea pig heart. The inhibitory activities of related compounds of digitoxigenin were dependent upon the dicarboxylic acid and amino acid components. The compound having both the arginine and suberic acid moiety showed the higher inhibitory activity. The sulfate and glucuronide of digitoxigenin exhibited much less potency than the parent genin.

• Journal of the Korean Chemical Society
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• v.40 no.12
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• pp.711-718
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• 1996

The relationship between chemical structure and antifungal activity of benzene ring substituents of 1-phenylpyrrolidine-2,5-diones is studied by testing of model compounds and use of conformational data. The analysis revealed a number of structural features as essential for the antifungal effect: (1) the presence of an intact-NCO group and benzene moiety; (2) the distance between para substituents and the N atom within the 5.318∼5.320 ${\AA}$ range; (3) the distance between substituent X3 and X5 in the interval 5.437∼6.072 ${\AA}$ for the active analogues. And other parameters were discussed.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.162-167
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• 2004

In recent years, the diamondback moth (DBM), Plutella xylostella has become one of the most important pests for cruciferous plants in the world. A new type of the thiophosphoryl pyrazole insecticide, called KH502. Its outstanding insecticidal activity could be effective alternative against DBM. We investigated, using the comparative molecular field analysis (CoMPA) method, The structure-activity relationship of various thiophosphorylpyrazole derivatives and structure requirement for insecticidal activity. We found, the key substructures in pyrazole derivatives, the trifluoro-methyl group and the thiophosphoryl group. Both play an important role in insecticidal activity with the binding site. The three dimensional Quantitative Structure Activity Relationship (QSAR) analysis could provide useful information for the structural requirements of pyrazole insecticide as an insecticidal and the design of a new insecticide.

• BMB Reports
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• v.35 no.3
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• pp.291-296
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• 2002

Thanatin, a 21-residue peptide, is an inducible insect peptide with a broad range of activity against bacteria and fungi. It has a C-terminal disulfide loop, like the frog skin secretion antimicrobial peptides of the brevinin family. In this study, we tried to find the effect of a number of amino acids between the disulfide bond. Thanatin showed stronger antibacterial activity to Gram negative bacteria than other mutants, except Th1; whereas, the mutant peptides with deletion had higher activity to Gram positive bacteria than thanatin. An increase in the number of amino acid(s) using the alanine residue decreased the antibacterial activity in all of the bacteria. Th1 with deletion of threonine at position 15 ($Thr^{15}$) showed similar antibacterial activity against Gram-negative bacteria, but had higher activity against the Gram positive bacteria. In order to study the structure-function relationship, we measured liposome disruption by the peptides and CD spectra of the peptides. Th1 also showed the highest liposome leaking activity and α-helical propensity in the sodium dodecyl sulfate solution, compared with other peptides. Liposome disruption activity was closely correlated with the anti-Gram positive bacterial activity. All of the peptides showed no hemolytic activity. Th1 was considered to be useful as an antimicrobial peptide with broad spectrum without toxicity.

• YAKHAK HOEJI
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• v.10 no.2_3
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• pp.25-29
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• 1966

In the preceding paper, it was reported that two esculetin methyl ethers wre isolated from title plant, and exhibited good cholagogic activity. An experiment was made using the eleven coumarin compounds in order to know the relationship between the cholagogic activity and their chemical structure. The result obtained in this study shows that all compounds used possess cholagogic activity, among which daphnetin and esculin methylether are more potent.

• Natural Product Sciences
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• v.11 no.4
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• pp.220-224
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• 2005

Extensive chemical studies on the stem bark extracts of two Guttifereous plants namely Mesua daphnifolia and Garcinia nitida have led to the isolation of eight xanthones. Mesua daphnifolia gave cudraxanthone G (1), ananixanthone (2), 1,3,5-trihydroxy-4-methoxyxanthone (3) and euxanthone (4) while Garcinia nitida gave inophyllin B (5), 1,3,7-trihydroxy-2,4-bis (3-methylbut-2-enyl)xanthone (6), 3-isomangostin (7) and rubraxanthone (8). All these compounds were assayed against the MDA-MB-231 (human estrogen receptor negative breast cancer) cells. A structure-activity relationship study showed that structurally, all the 1, 3-oxygenated xanthones which carried unsaturated prenyl side chains (either 3-methylbut-2-enyl or 1,1-dimethyl-2-propenyl) at carbones C-2 and C-4 in the xanthone ring A are essential for the outstanding activities in the assay.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.371.3-372
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• 2002

We have reported cytotoxicities based on several types of sugar linkage in saponins in addition to antitumor and antiinflammatory effects. In order to find further structure-activity relationship on the cytotoxicity of saponins. we intended to isolate oleanane disaccharides Irom the saponin-containing extract of Akebia Quinata (Lardizabalaceae). (omitted)

• Korean Journal of Child Studies
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• v.28 no.4
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• pp.19-33
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• 2007

This study examined the effects of closeness of peer relationships on intersubjectivity in young children's joint story making of wordless picture books. The joint story making activity of 32 five-year-old children was videotaped and transcribed, and the structure and negotiation types of interaction were examined by Goncu's (1993a) measure of intersubjectivity. Results showed (1) closeness of peer relationship was related to the structure of intersubjectivity children working with very close peers exhibited more turns. (2) Children working with very close peers used more extension and acceptance negotiation types, whereas the children working with non-close peers used more building-on of own ideas and irrelevant acts of negotiation.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2433-2442
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• 2011

The three dimensional quantitative structure activity relationship (3D QSAR) models were developed using Comparative molecular field analysis (CoMFA), comparative molecular similarity indices analysis (CoMSIA) and docking studies. The fit of Quinazolinone antifolates inside the active site of modeled bovine dihydrofolate reductase (DHFR) was assessed. Both ligand based (LB) and receptor based (RB) QSAR models were generated, these models showed good internal and external statistical reliability that is evident from the $q^2_{loo}$, $r^2_{ncv}$ and $r^2_{pred}$. The identified key features enabled us to design new Quinazolinone analogues as DHFR inhibitors. This study is a building bridge between docking studies of homology modeled bovine DHFR protein as well as ligand and target based 3D QSAR techniques of CoMFA and CoMSIA approaches.

• YAKHAK HOEJI
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• v.58 no.1
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• pp.53-57
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• 2014

In recent, the abuse of newly-emerging psychoactive drugs, ('designer drugs') is a rapidly increasing problem in Korean society. Quantitative-structure activity relationship (QSAR) is an alternative method to predict bioactivities of new abused compounds. In this study, cathinone-related new designer drugs, 4-methylbuphedrone and 4-methoxy-N,N-dimethylcathinone were tested for prediction of the bioactivity with QSAR model. The bioactivity of 4-methylbuphedrone and 4-methoxy-N,N-dimethylcathinone was similar to those of methylone. These results suggest that the prediction with QSAR model may provide scientific evidences for regulatory decision.