QSPR of the bioconcentration factors of non-ionic organic compounds in fish using extended topochemical atom (ETA) indices

Abstract

Bioconcentration refers to the absorption or uptake of a chemical from the media to an organism's tissues leading to greater concentration in tissues than that in the surrounding environment. Considering the importance of bioconcentration from the viewpoint of ecological safety assessment, a QSPR study was conducted based upon log BCF of 122 non-ionic organic compounds in fish using the recently introduced extended topochemical atom (ETA) indices. In deriving the models, principal component factor analysis (FA) followed by multiple linear regression (MLR), stepwise regression, partial least squares (PLS) and principal component regression analysis (PCRA) were applied as statistical tools. This was repeated with non-ETA (topological and physicochemical) descriptors and a combination set including both the ETA and non-ETA descriptors. The ETA indices suggested negative contributions of functionalities of nitro, amino and hydroxy substructures and positive contributions of branching, volume and functionality of chloro substituents. Again, the predictive ability of the developed models was compared with the previously reported models. Finally the validation of all the QSAR models was discussed based on random division, sorted log BCF data and K-means clusters for the factor scores of the original variable (ETA) matrix without the response property values. The results suggest that ETA parameters are sufficiently rich in chemical information to encode the structural features contributing to the bioconcentration of the non-ionic organic compounds in fish and thus these merit further assessment to explore their potential in QSAR/QSPR/QSTR modelling.

QSTR with extended topochemical atom (ETA) indices. 11. Comparative QSAR of acute NSAID cytotoxicity in rat hepatocytes using chemometric tools

“…Intercorrelation matrix for the best model Equation (18) is shown in Table 6, which indicates the absence of high intercorrelation among the predictor variables of Equation (18). Scatter plots of observed versus LOO predicted hepatotoxicity of NSAIDs according to Equations (18) and (23) are shown in Figure 2.…”

“…Scatter plots of observed versus LOO predicted hepatotoxicity of NSAIDs according to (a) Equation(18)and (b) Equation(23).…”

QSTR with extended topochemical atom (ETA) indices. 14. QSAR modeling of toxicity of aromatic aldehydes to Tetrahymena pyriformis

“…The ETA [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37] indices formulated based on modification of TAU descriptors [38][39][40][41][42][43][44][45][46][47][48][49][50], which were developed in the valence electron mobile (VEM) environment, have been used to develop the QSTR models for 40-h T. pyriformis toxicity of 77 aromatic aldehydes. Some basic parameters of the ETA scheme used in the development of QSTR models for the above mentioned dataset have been defined in Supplementary Materials section.…”

QSPR modeling bioconcentration factor (BCF) by balance of correlations

“…The significant number of articles which is dedicated to the bioconcentration factor indicates importance of this endpoint [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”