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. QSPR models were developed using multiple linear regression, partial least squares and neural networks analyses. Linear and non-linear QSPR models to predict log BCF of the compounds developed for the relevant descriptors. The results obtained offer good regression models having good prediction ability. The descriptors used in these models depend on the volume, connectivity, molar refractivity, surface tension and the presence of atoms accepting H-bonds

Topological modeling of antimycobacterial activity of 3-formyl rifamycin SV derivatives

The paper describes topological modeling of antimycobacterial activity of 3-formyl rifamycin SV derivatives using a large series of molecular vis-à-vis topological descriptors. For the set of 53 derivatives of 3-formyl rifamycin SV no one variable model is possible, however, in multiparametric regression excellent model is obtained for modeling the activity. The results are discussed using variety of statistical parameters

A Method of Computing the PI Index of Benzenoid Hydrocarbons Using Orthogonal Cuts

The Padmakar-Ivan (PI) index of a graph G is defined as PI (G) = Σ [neu(e|G)+nev(e|G)], where for edge e=(u,v) are neu (e|G) the number of edges of G lying closer to u than v, and nev (e|G) is the number of edges of G lying closer to v than u and summation goes over all edges of G. The PI index is a Wiener-Szeged-like topological index developed very recently. In this paper we describe a method of computing PI index of benzenoid hydrocarbons (H) using orthogonal cuts. The method requires the finding of number of edges in the orthogonal cuts in a benzenoid system (H) and the edge number of H - a task significantly simpler than the calculation of PI index directly from its definition

New topological matrices and their polynomials

574-585New polynomials and molecular graph spectra are derived on the basis of recently proposed matrices, DA, DP, and RDP, and of the previously defined RDe (reciprocal distance) matrix. The new molecular graph descriptors are exemplified on a collection of path-graphs L2-L5 and cyclic-graphs C3-C3•. The polynomials for the last two matrices (both based on a reciprocal relationship) are the first defined polynomials with non-integer coefficients. The sum of their absolute values, denoted as SumCh(RDe) and SumCh(RDp) can be viewed as global descriptors (i.e. topological indices), by analogy with the Hosoya's number Z. Values of the two indices as well as the minimum, MinSp(M), and maximum,  MaxSp(M), eigenvalues are listed for nonane isomers. The new structural descriptors have been tested for correlation with some physico-chemical properties and are found to give good results in modeling the properties of alkanes

QSAR studies on a series of 4-quinolinecarbinolamine, antimalarials

472-474The antimalarial activities for a series of 4-quinolinecarbinolamine were modeled using molecular orbital energies. The regression analyses of the data have shown that the univariate correlation with EH gave good results. Introduction of indicator parameters IR1 or IR2 gave excellent results. Here EH is the energy of highest occupied molecular orbital energy and IR1and IR2 are the indicator parameter

Use of distance-based topological indices in modeling antihypertensive activity: Case of 2-aryl-imino-imidazolidines

1426-1435This paper describes topological modeling of antihypertensive activity of 2-aryl-imino-imidazolidines. A large pool of distance-based topological indices consisting of W, B,χ,J, Sz, and log RB is initially used for this purpose. An excellent model is obtained in multi -parametric regression containing χ and logRB along with two indicator parameters

Quantitative structure-activity relationship studies on antituberculotic N₁- cyclopropylquinolones using Szeged Index (Sz)

1203-1208A novel application of Szeged index (Sz) for modeling antituberculotic activities  of N1- cyclopropylquinolones is described. The correlation  potential of Sz has been compared with correlation ability of the molecular orbital energies: energy of highest occupied molecular orbital (<i style="mso-bidi-font-style: normal">EH), energy of lowest unoccupied molecular orbital (EL) and total π-electron energy (ET). Mono-parametric regression analysis has indicated that Sz and ET are the appropriate parameters for quantitative structure-activity relationship (QSAR). The results are highly improved by the introduction of an indicator parameter using multiple correlation analysis. </span