QSPR-QSAR theory

Duchowicz, P.R., Castro, E.A., Fernandez, F.M. and Perez Gonzalez, M. (2005) A new search algorithm for QSPR/QSAR theories normal hoiling points of some organic molecules. Chan. Phys. Lett., 412, 376-380. 

Fernandez, F.M., Duchowicz, P.R. and Castro, E.A. (2004) About orthogonal descriptors in QSPR/ QSAR theories. MATCH Commun. Math. Comput. Chem., 51, 39-57. 

Keywords Aqueous solubility Anti-HIV-1 activity Carcinogenic potential Mutagenicity Optimal descriptors QSPR-QSAR theory... 

Although the pioneering studies in QSPR-QSAR theory were established by Wiener in 1947 [1-4], other mathematical models had been reported previously for the prediction of the properties of substances. For example, it is well known that simple additive schemes and group contribution methods were used before the first QSPR-QSAR analyses [5-7]. We begin by summarizing these approaches, simply for the fact that optimal descriptors have gained some insight from these particular methods. 

F. M. Fernandez, P. R. Duchowitz, and E. A. Castro, About orthogonal descriptors in QSPR/QSAR theories, MATCH—Commun. Math. Comput. Chem. 51 (2004) 39-57. E. J. Calabrese, Historical blunders How toxicology got the dose-response relationship half right. Cell. Mol. Biol. 51 (2005) 643-654. 

Pogliani, L. (2001b) The concept of graph mass in molecular graph theory. A case in data reduction analysis, in QSPR/QSAR Studies by Molecular Descriptors (ed. M.V. Diudea), Nova Science, Huntington, NY, pp. 109-146. 

P. R. Duchowicz and E. A. Castro, The Order Theory in QSPR—QSAR Studies, Mathematical Chemistry Monographs No. 7, Kragujevac, Serbia, 2006. 

A review of diverse uses of partial order in chemistry can be found in a special issue of MATCH Communication in Mathematical and in Computer Chemistry [52], in the books of P. R. Duchowicz and E. A. Castro, The Order Theory in QSPR— QSAR Studies [94], and Briiggemann and Larsen, Partial Order in Environmental Sciences and Chemistry [95]. 

Duchowicz, P. R., Castro, E. A. (2008). The Order Theory in QSPR-QSAR Studies, In Mathematical Chemistry Monographs, University of Kragujevac, Kragujevac. 

All the techniques described above can be used to calculate molecular structures and energies. Which other properties are important for chemoinformatics Most applications have used semi-empirical theory to calculate properties or descriptors, but ab-initio and DFT are equally applicable. In the following, we describe some typical properties and descriptors that have been used in quantitative structure-activity (QSAR) and structure-property (QSPR) relationships. 

In the present work, we will use a relatively low level of theory to derive 32 weakly correlated molecular descriptors, each based on the subdivision and classification of the molecular surface area according to three fundamental properties contribution to ClogP, molar refractivity, and atomic partial charge. The resulting collection will be shown to have applicability in QSAR, QSPR, and compound classification. Moreover, the derived 32 descriptors linearly encode most of the information of a collection of traditional mathematical descriptors used in QSAR and QSPR. 

Some basic concepts and definitions of statistics, chemometrics, algebra, graph theory, similarity/diversity, which are fundamental tools in the development and application of molecular descriptors, are also presented in the Handbook in some detail. More attention has been paid to information content, multivariate correlation, model complexity, variable selection, and parameters for model quality estimation, as these are the characteristic components of modern QSAR/QSPR modelling. 

The quantitative property-activity models, commonly referred to as those marking the beginning of systematic QSAR/QSPR studies [Richet, 1893], have come out from the search for relationships between the potency of local anesthetics and the oil/water partition coefficient [Meyer, 1899], between narcosis and chain length [Overton, 1901, 1991], and between narcosis and surface tension [Traube, 1904]. In particular, the concepts developed by Meyer and Overton are often referred to as the Meyer-Overton theory of narcotic action [Meyer, 1899 Overton, 1901]. 

Molnar SP, King JW. Theory and applications of the integrated molecular transform and the normalized molecular moment structure descriptors QSAR and QSPR paradigms. Int J Quantum Chem 2001 85 662-675. 

This section covers ab initio and density functional theory (DFT), semi-empirical and empirical, and molecular mechanics and molecular dynamics methods. For gas-phase structure determinations, a refinement to the use of ab initio calculations the SARACEN (Structure Analysis Restrained by Ab initio Calculations for Electron diffractioN) method, and other relevant theoretical and computational chemistry techniques, including quantitative structure-activity/property relationship (QSAR/QSPR) models for prediction of biological activity and physicochemical properties, are also covered. 

The theory of electric polarizability is of fundamental importance to the rational approach and interpretation of large classes of phenomena [1]. In particular, these properties are of fundamental importance to intermolecular interaction studies [2], nonlinear optics [3], collision-induced spectroscopy [4], and the simulation of fluids [5,6]. They are also routinely associated with general molecular characteristics as hardness [7], softness [8], hypersoftness [9], stiffness [10], and compressibility [11]. Understandably, polarizability is also linked to reactivity [12]. Another important field is QSAR, QSPR studies, and the understanding of pharmacological activity [13, 14]. 

---