A quantitative structure-activity relationship study on a series of selective non-zinc binding inhibitors of MMP13.

Two novel series of potent and selective matrix metalloproteinase (MMP) inhibitors, involving unique binding mode at the active site and not interacting with the catalytic zinc, were collectively investigated to quantify their inhibition actions in relation with chemometric descriptors. Significant correlations, between their MMP13 inhibition activity and 2D-descriptors, were obtained through the combinatorial protocol in multiple linear regression (CP-MLR) computational procedure. The derived bi-variant models, validated internally and externally, were able to account for 86.

QSAR of 2-(4-methylsulphonylphenyl)pyrimidine derivatives as cyclooxygenase-2 inhibitors: simple structural fragments as potential modulators of activity.

The cyclooxygenase-2 (COX-2) inhibitory activity of 2-(4-methylsulphonylphenyl)pyrimidine derivatives has been quantitatively analyzed in terms of Dragon descriptors. The derived QSAR models have provided rationales to explain the activity of titled derivatives. The descriptors (Me, Mp, GATS1p and GATS5p) identified in CP-MLR analysis have highlighted the role of atomic properties, such as Sanderson electronegativity and polarizability, to explain the inhibitory activity.

Modelling of serotonin reuptake inhibitory and histamine H₃antagonistic activity of piperazine and diazepane amides: QSAR rationales for co-optimization of the activity profiles.

Selective human serotonin reuptake transporter (hSERT) inhibition is the first line of treatment to deal with the depression. In clinical practice for managing depression, the stimulants are co-prescribed to overcome cognitive impairment and fatigue. Recently, histamine H(3) antagonists with serotonin reuptake inhibition activity have been proposed as alternative approach for the treatment of depression.

A QSAR study on 2-(4-methylpiperazin-1-yl)quinoxalines as human histamine H4 receptor ligands.

The histamine H(4) receptor binding affinity of 2-(4-methylpiperazin-1-yl)quinoxaline derivatives has been quantitatively analyzed in terms of Dragon descriptors. The derived QSAR models have provided rationales to explain the activity of titled derivatives. The descriptors identified in CP-MLR analysis have highlighted the role of path/walk 4-Randic shape index (PW4), mean square distance (MSD) index, topological charges (GGI9, JGI2, and JGI7), atomic properties in respective lags of 2D-autocorrelations (MATS7e, GATS7e, and MATS8p), and Burden matrix (BELm1) to explain the binding affinity.

A quantitative structure-activity relationship study on serotonin 5-HT6) receptor ligands: indolyl and piperidinyl sulphonamides.

The serotonin 5-HT(6) binding affinity of indolyl- and piperidinyl-sulphonamide derivatives has been analysed with topological and molecular features with DRAGON software. Analysis of the structural features in conjunction with the biological endpoints in combinatorial protocol in multiple linear regression (CP-MLR) led to the identification of 25 descriptors for modelling the activity. The study clearly suggested the role of an average Randic-type eigenvector-based index from adjacency matrix, VRA2, number of secondary aliphatic amines, nNHR, the sum of the topological distance between N and O, T(N.

A rationale for the activity profile of benzenesulfonamide derivatives as cyclooxygenase (COX) inhibitors.

The COX inhibition actions of benzenesulfonamides have been analyzed in terms of 0D-, 1D- and 2D-DRAGON descriptors using combinatorial protocol in multiple linear regression (CP-MLR). The derived QSAR models revealed that higher values of BEHm2 (the highest eigenvalue n.2 of Burden matrix) and C-009 (fragment CHRX2) and lower value of MATS2m (atomic masses weighted Moran autocorrelation of lag 2) are advantageous to the COX-2 inhibition activity.

A rationale for the activity profile of arylpiperazinylthioalkyls as 5-HT1A-serotonin and alpha1-adrenergic receptor ligands.

The 5-HT1A and alpha1-receptor binding affinities of the arylpiperazinylthioalkyl derivatives have been quantitatively expressed in terms of topological and molecular features. The analysis revealed that a lower value of atomic composition based index (AAC), higher values of structural information content (SIC3) and topological charge index (GGI9) would be beneficial to the 5-HT1A receptor binding. For the alpha1-receptor binding affinity the higher values of topological charge index (GGI9) and atomic Sanderson electronegativities weighted descriptor (GATS3e) and more number of hydrogen atoms attached to sp or sp3 hybridized carbon atoms in a molecular structure (H-047) would be favorable.

CP-MLR/PLS directed QSAR study on apical sodium-codependent bile acid transporter inhibition activity of benzothiepines.

The apical sodium-codependent bile acid transporter (ASBT) inhibition activity of benzothiepine derivatives have been analyzed based on topological and molecular features. Analysis of the structural features in conjunction with the biological endpoints in Combinatorial Protocol in Multiple Linear Regression (CP-MLR) led to the identification of 21 descriptors for modeling the activity. The study clearly suggested that the role of Randic shape index (path/walk ratio 3) and topological charges of 2-, 5-, and 6-orders to optimize the ASBT inhibitory activity of titled compounds.

Chemometric descriptors in modeling the carbonic anhydrase inhibition activity of sulfonamide and sulfamate derivatives.

The carbonic anhydrase inhibition activities of sulfonamide and sulfamate derivatives have been quantitatively expressed in terms of MOE descriptors representing the 2D-features of compounds following combinatorial protocol in multiple linear regression (CP-MLR). The derived QSAR models have shown that partially charged and polarized surface areas in particular ranges, hydrophobicity, connectivity, information content, van der Waals surface area of the pharmacophore, and certain structural features such as the number of hydrogen and chlorine atoms, aromatic bonds of the molecules hold promise for rationalizing the different carbonic anhydrase inhibitory actions of titled compounds. The values, greater than 0.

Modeling of vascular endothelial growth factor receptor 2 (VEGFR2) kinase inhibitory activity of 2-anilino-5-aryloxazoles using chemometric tools.

The structure-activity models of the VEGFR2 kinase inhibitory activity of the derivatives of 2-anilino-5-aryloxazole have been investigated using Combinatorial Protocol in Multiple Linear Regression (CP-MLR) with nearly 500 topological descriptors which were calculated from DRAGON software. Among the descriptor classes considered collectively in the study, the inhibitory activity was, however, correlated with simple functional (FUN), topological (TOPO), atom centered fragments (ACF), molecular walk counts (MWC) and 2D-autocorrelation (2D-AUTO) descriptors. The developed models and participating descriptors in them have suggested that the substitutional modifications in the 2-anilino-5-aryloxazole moiety may have sufficient scope in optimization of prevailing inhibitory activity of these analogues.

Topological descriptors in modeling malonyl coenzyme A decarboxylase inhibitory activity: N-Alkyl-N-(1,1,1,3,3,3-hexafluoro-2-hydroxypropylphenyl)amide derivatives.

The malonyl-CoA decarboxylase (MCD) inhibition activity of derivatives of N-alkyl-N-(1,1,1,3,3,3-hexafluoro-2-hydroxypropylphenyl)amide has been analyzed through combinatorial protocol in multiple linear regression (CP-MLR) using different topological descriptors obtained from Dragon software for the energy minimized 3D-structures of these molecules. Among the topological descriptor classes considered in the study, the MCD inhibition activity is correlated with simple topological descriptors (TOPO) and 2D-autocorrelation descriptors (2DAUTO). The complementary information contents having neighborhood symmetry of 2-order, CIC2 from the TOPO class, the Geary autocorrelations-lag 8, weighted by atomic Sanderson electronegativities, GATS8e and the Moran autocorrelations-lag 6, weighted by atomic Sanderson electronegativities, MATS6e both from 2DAUTO class have contributed significantly in the development of a statistical significant model.

Quantitative structure-activity relationship study on affinity profile of a series of 1,8-naphthyridine antagonists toward bovine adenosine receptors.

The affinity profiles for the bovine adenosine receptors, A(1) and A(2A), of a series of 1,8-naphthyridine derivatives were quantitatively analyzed using physicochemical and structural parameters of the substituents, present at varying positions of the molecules. The derived significant correlation, for bovine A(1) receptor, suggested that a R(1) substituent having a higher van der Waals volume, a R(2) substituent being a hydrogen-bond donor and a R(3) substituent able to transmit a higher field effect are helpful in augmenting the pK(i) of a compound. Similarly the study, pertaining to bovine A(2A) receptor, revealed that a less bulky substituent at R(2) and a strong electron-withdrawing substituent at R(3) are desirable in improving the binding affinity of a compound while substituents at R(1) remain insignificant to any interaction.

A quantitative structure-activity relationship study of novel, potent, orally active, selective VEGFR-2 and PDGFRalpha tyrosine kinase inhibitors: derivatives of N-phenyl-N'-{4-(4-quinolyloxy)phenyl}urea as antitumor agents.

The tyrosine kinase inhibitory action of the derivatives of N-Phenyl-N'-{4-(4-quinolyloxy)phenyl}urea is quantitatively analyzed using multiple regression analysis. The analysis has helped to ascertain the role of different substituents in explaining the observed inhibitory actions of these compounds for two receptors, namely vascular endothelial growth factor receptor 2 (VEGFR-2) and platelet-derived growth factor receptor alpha (PDGFRalpha). From a derived significant correlation equation for inhibition of VEGFR-2, it was concluded that a less hydrophobic molecule with ortho-substituent(s), exerting less steric hindrance and para-substituent devoid of hydrogen-bond acceptor property augment the inhibition action.

Quantitative structure-activity relationship study of novel rhinacanthins and related naphthoquinone esters as anticancer agents.

The anticancer activity of rhinacanthins and related naphthoquinone esters is quantitatively analyzed through Fujita-Ban and Hansch approaches. The analyses have helped to ascertain the role of different substituents in explaining the observed inhibitory actions of these compounds. From both approaches it appeared that naphthalene ring instead of benzene ring, dimethyl substitution at R(1) and R(2), and hydrogen-bond acceptor substituents at R(3) (Figure 1) are advantageous to improve the activity of a compound against KB cell lines.

Quantitative structure-activity relationship study of ATP-sensitive potassium channel openers: derivatives of 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide.

The inhibitory activity of glucose-induced insulin secretion on isolated rat pancreatic islets and the contractile activity of KCl-depolarized rat aorta rings of the derivatives of 3-alkylamino-4H-1,2,4-benzothiadiazine 1,1-dioxide are quantitatively analyzed using multiple regression analysis. The study has helped to ascertain the role of different substituents in explaining these observed inhibitory activities. From a derived most significant correlation equation, it was concluded that a less hydrophobic 3-substituent and a less bulky 7-substituent in addition to a 3-aminoisopropyl and a 6-chloro substituent are advantageous to enhance the inhibitory action of a compound towards rat pancreatic islets.

Quantitative structure-activity relationship study of human A3 adenosine receptor antagonists: derivatives of 2-aryl-1,2,4-triazolo [4,3-alpha]quinoxaline.

A quantitative structure-activity relationship (QSAR) study was conducted on the antagonistic activities of derivatives of 2-aryl-1,2,4-triazolo[4,3-alpha]quinoxaline at the human A3 adenosine receptor. As per the structural framework, the title analogues were subdivided into two congeneric series, namely the 1,4-dione and the 4-amino-1-one series. A majority of substituents occurred at the R- and a limited number at the X-positions in both of these series.

Quantitative structure-activity relationship study of orally active cyclooxygenase-2 (COX-2) inhibitors of derivatives of 3-phenoxypyran-4-one.

The cyclooxygenase (COX) inhibition activities of the derivatives of 3-phenoxypyran-4-one were analyzed through multiple-regression analysis (MRA). Appropriate physicochemical parameters, identified for the substitutents of phenyl ring, attached to 3-phenoxypyran-4-one moiety were quantitatively correlated with COX-2 and COX-1 inhibition activities of these compounds. The derived significant correlation equation for COX-2 inhibition suggested that the ortho-substituent with negative resonance parameter, the para-substituent with lower dipole moment and the meta-substituent having higher resonance parameter were advantageous for the activity.

Quantitative structure-activity relationship study of benzylsulfanyl imidazoles as cytokine release inhibitors.

Benzylsulfanyl imidazole derivatives (Figure 1) have shown their ability to inhibit the release of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) from peripheral blood mononuclear cells or human whole blood. Such anticytokine actions of these congeners are quantitatively studied using Fujita-Ban and Hansch type analyses. The Fujita-Ban study resulted in the contributions of different substituents and the parent moiety for the inhibitions of cytokines TNF-alpha and IL-1beta.

Quantitative structure-activity relationship study of new potent and selective antagonists at the 5-HT(1A) and adrenergic alpha(1d) receptors: Derivatives of spiroethyl phenyl(substituted)piperazine.

The antagonistic activities of derivatives of spiroethyl phenyl(substituted)piperazine at the 5-HT(1A) and adrenergic alpha(1d) receptors is quantitatively analyzed employing physicochemical and structural parameters. The derived correlation equation revealed that a substituent, other than 2-CH3 in the phenyl ring, having higher molar refraction, MR, and a substituent producing higher positive field effect at the 3-position are beneficial in increasing the binding affinity at the 5-HT(1A) receptor. In addition, a less hydrophobic substituent at the 4-position is also helpful in augmenting the binding affinity.

Quantitative structure-activity relationship study of 5-iodo- and diaryl-analogues of tubercidin: inhibitors of adenosine kinase.

The adenosine kinase inhibitory (AKI) activity of 5-iodo and diaryl analogues of tubercidin is quantitatively analyzed using Fujita-Ban and Hansch type analyses. The Fujita-Ban analysis being a non-parametric approach assigned the highest contribution to Cl at the X-position, C6H4-4-Cl, C6H5, 2-furanyl and I at the Y-position and CH2NH2 and CH3 at the Z-position. In addition, a OH substituent at the C-position also emerged as a better choice possibly due to its engagement in hydrogen bonding with some active site function.

Quantitative structure-activity relationship study on N-(pyridin-4-yl)-(indol-3-yl) alkylamides as antiallergic agents.

The antihistamine activity of N-(pyridin-4-yl)-(indol-3-yl) alkylamides has been analyzed using Fujita-Ban and Hansch approaches. The analyses have helped to ascertain the role of different substituents in explaining the antiallergic actions of these analogues. From both approaches it is revealed that the small size substituents at R and R2 and non-hydrogen bond acceptor substituent at R improve histamine antagonist activity of a compound.

Quantitative structure-activity relationship study on tetrahydro-beta-carboline antagonists of the serotonin 2B (5HT2B) contractile receptor in the rat stomach fundus.

The antagonist actions of three sub-series of tetrahydro-beta-carbolines at the serotonin 2B (5HT2B) contractile receptor in the rat stomach fundus are analyzed in relation to the physicochemical properties of the molecules. Significant correlations are obtained between the 5HT2B receptor antagonist affinity and the hydrophobic, steric, electronic, hydrogen bond acceptor and some indicator variables of substituents. Based on these findings, the mode of actions of these congeneric series and future strategy to synthesize more potential compounds are discussed.

Quantitative structure-activity relationship study of novel alpha1a-selective adrenoceptor antagonists.

Two series of compounds were recently reported as novel alpha1a-selective adrenoceptor antagonists. In the first series, a dihydropyrimidone moiety is attached to a 4-phenyl piperidine containing side chain, while in the second, it is linked to a 4-substituted phenyl piperazine containing side chain. These compounds having potential for the treatment of benign prostatic hyperplasia, a urological disorder in the older age male population, were subjected to a quantitative structure-activity relationship study.

1,2-Diarylimidazoles as inhibitors of cyclooxygenase-2: a quantitative structure-activity relationship study.

The cyclooxygenase-2 (COX-2) enzyme inhibition activity of derivatives of 1,2-diarylimidazole is analysed through Fujita-Ban and Hansch approaches. The analyses have helped to ascertain the role of different substituents in explaining the observed inhibitory potency of these analogues. From both approaches it is revealed that the more hydrophobic X-substitutions that are present at the 3- and 4-positions of the aryl ring and are also non-hydrogen acceptor in character improve inhibitory action of a compound.

Quantitative structure-activity relationship study of iodinated analogues of trimetoquinol as highly potent beta 2-adrenoceptor ligands.

Trimetoquinol and its derivatives, reported to be highly potent beta 2-adrenoceptor (beta 2-AR) and site-selective thromboxane A2/prostaglandin H2 (TP) receptor ligands are subjected to quantitative structure-activity relationship (QSAR) study. From the significant correlation equation, obtained between the binding affinity, pKi (beta 2-AR) and the substitutional physicochemical parameters such as molar refraction, (MR), hydrophobic constant, (pi) and resonance parameter, (R), the receptor binding interactions associated with the varying sites of these compounds are discussed. The QSAR study has also explored the possibilities of having the analogous of improved binding affinities in future synthetic efforts.