Prediction of (13)C NMR Chemical Shift Sum Using Topological Indices: Role of Recently Introduced Balaban F and G Indices.

Present paper deals with the examination of Balaban F and G indices for estimating (13)C NMR chemical shift sums of alkanes. Set of 66 alkanes were used for this purpose, which have been divided into training set (50 compounds) and test set (16 compounds). The results have shown that Balaban G Index along with connectivity indices yields the best model.

QSPR Modeling of Bioconcentration Factors of Nonionic Organic Compounds.

The terms bioaccumulation and bioconcentration refer to the uptake and build-up of chemicals that can occur in living organisms. Experimental measurement of bioconcentration is time-consuming and expensive, and is not feasible for a large number of chemicals of potential regulatory concern. A highly effective tool depending on a quantitative structure-property relationship (QSPR) can be utilized to describe the tendency of chemical concentration organisms represented by, the important ecotoxicological parameter, the logarithm of Bio Concentration Factor (log BCF) with molecular descriptors for a large set of non-ionic organic compounds.

Prediction of intrinsic solubility of generic drugs using MLR, ANN and SVM analyses.

The machine learning methods artificial neural network (ANN) and support vector machine (SVM) techniques were used to model intrinsic solubility of 74 generic drugs. The models obtained were compared with those obtained using multiple linear regression (MLR) analysis. Cluster analysis was used to split the data into a training set and test set.

QSPR study on the estimation of solubility of drug-like organic compounds: a case of barbiturates.

The paper describes a method for the estimation of solubility (log S) of a series of 45 barbiturates employing 26 molecular descriptors. The molecular descriptors used being distance-based topological indices, information indices, valence connectivity index, shape indices, first-order Randic index. In addition, an indicator parameter was also used.

QSAR studies for the inhibition of the transmembrane carbonic anhydrase isozyme XIV with sulfonamides using PRECLAV software.

QSAR studies for the inhibition of isozyme XIV of human carbonic anhydrase (CA, EC 4.2.1.

Mutagenicity of nitrated polycyclic aromatic hydrocarbons: a QSAR investigation.

Quantitative structure-activity relationship studies were performed to describe and predict the mutagenic activity of a set of 48 nitrated polycyclic aromatic hydrocarbons. From a larger pool of molecular descriptors (topological indices) we arrived at much a smaller set consisting of three correlating parameters. Such a variable selection is made using ncss software in that successive regressions were attempted using maximum-R(2) method.

Comparative QSAR study on para-substituted aromatic sulphonamides as CAII inhibitors: information versus topological (distance-based and connectivity) indices.

Comparative quantitative structure-activity relationship studies on para-substituted aromatic sulphonamides carbonic anhydrase II (CAII) inhibitors are reported in this paper. The study is made utilizing (i) information indices along; (ii) distance-based and connectivity indices and (iii) combination of information, distance-based and connectivity type topological indices. The study has shown that distance-based and connectivity type indices are superior for modelling, monitoring and estimating CAII inhibition.

Estimation of human carbonic anhydrase II inhibition using topological indices and their combination with quantum-theoretical descriptors.

Mathematical models were developed for the estimation of human carbonic anhydrase (CA) II inhibition. A large set of 95 CA inhibitors incorporating diverse aromatic rings were used for this purpose. The numerical descriptors used were distance- and connectivity- based indices, quantum -theoretical descriptors and Balaban and Balaban type descriptors of molecular structure.

QSAR studies on the activation of the human carbonic anhydrase cytosolic isoforms I and II and secretory isozyme VI with amino acids and amines.

The first QSAR study on the activation of the human secretory isoform of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.

QSAR studies on benzopyran potassium channel activators.

QSAR studies on a series of benzopyrans as potassium channel activators have been carried out using a large set of distance-based topological indices. In addition, the molecular descriptors namely: negentropy and molecular redundancy indices have also been used. The relaxant potency in rat trachea, expressed as pEC(50) was used for biological characterization of the benzopyrans.

QSAR study on topically acting sulfonamides incorporating GABA moieties: a molecular connectivity approach.

A quantitative Structure-activity relationship study (QSAR) on a set of carbonic anhydrase (CA, EC 4.2.1.

Study on supramolecular complexing ability vis-à-vis estimation of pKa of substituted sulfonamides: dominating role of Balaban index (J).

The supramolecular complexing ability vis-à-vis pKa estimation of a large series of 43 sulfonamides was made using a series of molecular descriptors including topological indices. The set of topological indices chosen also contains Balaban (J) and a variety of Balaban type indices: J, Jz, Jm, Jv, Jc, and Jp. The results have shown that the most discriminating Balaban index (J) in multi-parametric regression analysis combined with indicator parameters yields excellent models and also establishes the superiority of the J index over other Balaban type indices.

QSAR study on carbonic anhydrase inhibitors: water-soluble sulfonamides incorporating beta-alanyl moieties, possessing long lasting-intra ocular pressure lowering properties--a molecular connectivity approach.

A QSAR study on a series of carbonic anhydrase (CA, EC 4.2.1.

A novel method of estimation of lipophilicity using distance-based topological indices: dominating role of equalized electronegativity.

Attempt is made to propose yet another method of estimating lipophilicity of a heterogeneous set of 223 compounds. The method is based on the use of equalized electronegativity along with topological indices. It was observed that excellent results are obtained in multiparametric regression upon introduction of indicator parameters.

QSAR studies on 1,2-dithiole-3-thiones: modeling of lipophilicity, quinone reductase specific activity, and production of growth hormone.

Studies on modeling of lipophilicity (logP) quinone reductase specific activity (logCDQR) and production of growth hormone (logCDGH) of 1,2-dithiole-3-thiones have been carried out using distance-based topological indices. The regression analysis of the data has shown that the set of compounds exhibit 'familial' relationships in that excellent results are obtained by dividing the data set into two or more classes (families).

Novel use of chemical shift in NMR as molecular descriptor: a first report on modeling carbonic anhydrase inhibitory activity and related parameters.

A novel use of NMR chemical shift of the SO(2)NH(2) protons (in dioxane as solvent) as a molecular descriptor is described for modeling the inhibition constant for benzene sulfonamides against the zinc enzyme carbonic anhydrase (CA, EC 4.2.1.

QSAR studies on benzene sulfonamide carbonic anhydrase inhibitors: need of hydrophobic parameter for topological modeling of binding constants of sulfonamides to human CA-II.

The binding constants (logK) of benzene sulfonamides to human CA-II have been modeled using a large series of distance-based topological indices. The need or otherwise of the hydrophobic parameter (logP) for such topological modeling of logK has been examined critically. In both the cases excellent results have been obtained.

QSAR study on phosphoramidothioate (Ace) toxicities in housefly.

The present paper describes quantitative structure-activity relationships (QSARs) formulated for a series of phosphoramidothioate (Ace II) analogs. The k(e) values for Ace II-induced inhibition of fly-acetylcholinesterase as well as LD50 for housefly exposed to Ace II analogs were governed by distance-based topological as well as information theoretic indices. In addition, we have also modeled lipophilicity of the phosphoramidothioates used.

Novel estimation of lipophilicity using 13C NMR chemical shifts as molecular descriptor.

This paper describes the use of (13)C NMR chemical shift as molecular descriptor (molecular parameter) for modeling lipophilicity (logP). A set of 32 alcohols were chosen for this purpose. The regression analysis of the data showed that (13)C NMR chemical shifts of these alcohols can be used as a molecular descriptor (molecular property) for modeling the lipophilicity (logP).

QSAR study on the antibacterial activity of some sulfa drugs: building blockers of Mannich bases.

Sulfa drugs are building blockers of several types of Mannich bases. Consequently, the antibacterial activities of sulfa drugs are reported in this paper, which will help in explaining and understanding antibacterial activities of Mannich bases. Reported QSAR is carried out using distance-based topological indices and discussed critically on the basis of statistical parameters.

QSAR study on pK(a) vis-à-vis physiological activity of sulfonamides: a dominating role of surface tension (inverse steric parameter).

The paper describes the dominating role of surface tension (ST) on the modeling, monitoring, and estimating pK(a) for a large series of 43 substituted sulfonamides. Because of the direct correlation of ST with parachor (Pc) vis-a-vis molecular volume (MV), ST is considered as a steric parameter. Single as well as multi-parametric regressions have indicated that ST has a dominating role in QSAR of the set of sulfonamides used and that excellent results are obtained in multi-parametric regression analysis.

Topological modeling of lipophilicity, diuretic activity, and carbonic inhibition activity of benzene sulfonamides: a molecular connectivity approach.

A large series of distance-based topological indices has been used for modeling lipophilicity, diuretic activity, and carbonic anhydrase inhibition activity of a library of simple substituted benzene sulfonamides. The results have shown that the topological approach used is quite useful for modeling carbonic anhydrase inhibition and the use of molecular connectivity is the best for this purpose. Excellent results are obtained in multiparametric regressions.

Topological estimation of electronic absorption bands of arene absorption spectra as a tool for modeling their toxicity and environmental pollution.

A novel application of distance-based topological indices : Wiener (W)-, Szeged (Sz)-, Padmakar-Ivan (PI)-, and Sadhana (Sd)-indices in modeling electronic absorption bands of arene absorption spectra has been described. It is demonstrated that all these indices correlate linearly with the logarithm of beta and para electronic absorption bands in several series of arene systems. The results have shown that our methodology is best suited for the estimation--lnlambda(beta), while comparatively less significant results are obtained in case of the estimation of lnlambda(p).

QSAR study on carbonic anhydrase inhibitors: aromatic/heterocyclic sulfonamides containing 8-quinoline-sulfonyl moieties, with topical activity as antiglaucoma agents.

Quantitative structure-activity-relationship (QSAR) study on aromatic/heterocyclic sulfonamides containing 8-quinoline-sulfonyl carbonic anhydrase (CA) inhibitors has been carried out topologically using first-order valence connectivity index ((1)chi(v)). Excellent results are obtained against all the three isozymes; CA I, II and IV of the zinc enzyme CA by using indicator parameters along with (1)chi(v).

Carbonic anhydrase inhibitors: the first QSAR study on inhibition of tumor-associated isoenzyme IX with aromatic and heterocyclic sulfonamides.

QSAR study on the tumor-associated transmembrane carbonic anhydrase IX (CA IX) isoenzyme has been made using a large pool of distance-based topological indices : W, Sz, PI (0)chi, (1)chi, (2)chi,(0)chi(v), (1)chi(v), (2)chi(v). A combined set of 32 aromatic and heterocyclic compounds, including the six clinically used derivatives: acetazolamide, methazolamide, ethoxyzolamide, dichlorophenamide, dorzolamide, and brinzolamide are used for this purpose. The results have shown that the inhibition of the tumor-associated isoenzyme IX with aromatic and heterocyclic sulfonamides can be modeled excellently in multiparametric regression after introduction of indicator parameters.