• Journal of the Korean Chemical Society
• /
• v.58 no.6
• /
• pp.543-552
• /
• 2014

A quantitative structure activity relationship (QSAR) study is performed for modeling and prediction of oral bioavailabilities of 216 diverse set of drugs. After calculation and screening of molecular descriptors, linear and nonlinear models were developed by using multiple linear regression (MLR), artificial neural network (ANN), support vector machine (SVM) and random forest (RF) techniques. Comparison between statistical parameters of these models indicates the suitability of SVM over other models. The root mean square errors of SVM model were 5.933 and 4.934 for training and test sets, respectively. Robustness and reliability of the developed SVM model was evaluated by performing of leave many out cross validation test, which produces the statistic of $Q^2_{SVM}=0.603$ and SPRESS = 7.902. Moreover, the chemical applicability domains of model were determined via leverage approach. The results of this study revealed the applicability of QSAR approach by using SVM in prediction of oral bioavailability of drugs.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.3
• /
• pp.417-422
• /
• 2002

Comparison studies of the Quantitative Structure Activity Relationship (QSAR) methods with new imidazo-quinolinedione derivatives were conducted using Comparative Molecular Field Analysis (CoMFA), Comparative Molecular Similarity Indices Analysis (CoMSIA), and the Hologram Quantitative Structure Activity Relationship (HQSAR). When the CoMFA crossvalidation value, q2, was 0.625, the Pearson correlation coefficient, r2, was 0.973. In CoMSIA, q2 was 0.52 and r2 was 0.979. In the HQSAR, q2 was 0.501 and r2 was 0.924. The best result was obtained using the CoMSIA method according to a comparison of the calculated values with the real in vitro cytotoxic activities against human ovarian cancer cell lines.

• Bulletin of the Korean Chemical Society
• /
• v.26 no.1
• /
• pp.85-90
• /
• 2005

MX and its analogs are synthesized and modeled by quantitative structure activity relationship (QSAR) study including comparative molecular field analysis (CoMFA). As a result, factors affecting this class of compounds have been found to be steric and electrostatic effects. Because hologram quantitative structure activity relationship (HQSAR) technique is based on the 2-dimensional descriptors, this is free of ambiguity of conformational selection and molecular alignment. In this study we tried to include all the data available from the literature, and modeled with the HQSAR technique. Among the parameters affecting fragmentation, connectivity was the most important one for the whole compounds, giving good statistics. Considering additional parameters such as bond specification only slightly improved the model. Therefore connectivity has been found to be the most appropriate to explain the mutagenicity for this class of compounds.

• The Korean Journal of Pesticide Science
• /
• v.6 no.3
• /
• pp.166-174
• /
• 2002

The fundamental concepts on the basis of linear free energy relationship (LFER), history of development, prediction of pharmacological effects, advantages and disadvantages, etc. according to the 2D and 3D QSAR methodologies were summarized in utilizing the quantitative structure-activity relation ship (QSAR) techniques for searching and development of new agrochemicals. Objectives, role of QSAR techniques in development process of pesticides and limitations in QSARs were discussed and introduced.

• Natural Product Sciences
• /
• v.19 no.1
• /
• pp.8-14
• /
• 2013

The inhibitory effect and the structure-activity relationships of luteolin and its related derivatives isolated from Taraxacum mongolicum against MAO activities were investigated. The activity-guided isolation of extract from Taraxacum mongolicum led to the isolation of three flavonoids, luteolin, diosmetin, and luteolin-7-glucoside, a polyphenol, chlorogenic acid, a tyrosine and a uridine. The inhibitory activities of luteolin and its related derivatives against MAOs activities are dependent on their molecular structures. The presence of the phenolic hydroxy group at para-position is the active site for MAO-A inhibition as well as of MAO-B. The methoxy group has no potential on MAO-A inhibition. An additional phenolic hydroxy group at the ortho-position alleviates about 4-fold MAO-A inhibitory activity of phenolic hydroxy group at para-position. A carboxylic group seems to be critical for DBH inhibition and has no effects on MAO.

• Journal of Pharmacopuncture
• /
• v.23 no.2
• /
• pp.88-89
• /
• 2020

• Bulletin of the Korean Chemical Society
• /
• v.30 no.12
• /
• pp.3147-3149
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• v.15 no.12
• /
• pp.1070-1079
• /
• 1994

Quantitative Structure-Activity Relationship (QSAR) studies are performed for the sets of 40 quinolones and 47 naphthyridines. Net charge, van der Waals volume, polarizability, and dipole moment are empolyed as theoretical descriptors(independent variables) to find the relationship between activity and physicochemical properties such as electrostatic effect, steric effect, and transferability. The results are analyzed by the regression and the factor analysis. It is found that for Gram-negative bacteria, the QSAR of quinolone and naphthyridine are substantially different: to describe the activity, the electrostatic effect is the most important for quinolone, and the steric effect and the transferability for naphthyridine.

• Genomics & Informatics
• /
• v.10 no.2
• /
• pp.128-132
• /
• 2012

To learn the differences between the structure-activity relationship and molecular vibration-activity relationship in the ligand-receptor interaction of the histamine receptor, 47 ligands of the histamine receptor were analyzed by structural similarity and molecular vibrational frequency patterns. The radial tree that was produced by clustering analysis of molecular vibrational frequency patterns shows its potential for the functional classification of histamine receptor ligands.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.2063-2066
• /
• 2012