Using molecular quantum similarity measures as descriptors in quantitative structure-toxicity relationships

In this paper molecular quantum similarity measures (MQSM) are used to describe molecular toxicity and to construct Quantitative Structure-Toxicity Relationships (QSTR) models. This study continues the recently described relationships between MQSM and log P values, which permits to use the theoretical MQSM as an alternative to the empirical hydrophobic parameter in QSPR studies. In addition a new type of MQSM is presented in this work: it is based on the expectation value of electron-electron repulsion energy. The molecular properties studied here, as application examples are aquatic toxicity, toxicology on Bacteria and inhibition of a macromolecule employing four different molecular sets.     

Using Molecular Quantum Similarity Measures as Descriptors in Quantitative Structure-Toxicity Relationships

Abstract

In this paper molecular quantum similarity measures (MQSM) are used to describe molecular toxicity and to construct Quantitative Structure-Toxicity Relationships (QSTR) models. This study continues the recently described relationships between MQSM and log P values, which permits to use the theoretical MQSM as an alternative to the empirical hydrophobic parameter in QSPR studies. In addition a new type of MQSM is presented in this work: it is based on the expectation value of electron–electron repulsion energy. The molecular properties studied here, as application examples are aquatic toxicity, toxicology on Bacteria and inhibition of a macromolecule employing four different molecular sets.     

A quantitative structure-activity relationship for antitumor activity of long-chain phenols from Ginkgo biloba L

With the aim of obtaining compounds with strong antitumor activity, a quantitative structure-activity relationship (QSAR) of antitumor phenolic compounds (long-chain phenols) was derived using the Hansch-Fujita equation. The ED50 values against Chinese hamster V-79 cells were analyzed in terms of log P as the hydrophobic parameter and the energy of the lowest unoccupied molecular orbital (ELUMO) calculated by using the modified neglect of differential overlap (MNDO) method as the electronic parameter, by means of multiple regression analysis. It was found that the activities mainly depended on log P (an optimum log P of 8.3) and a low-lying ELUMO value. 4-Undecylcatechol, selected on the basis of the above results, exhibited strong antitumor activity against Sarcoma 180 ascites and P-388 lymphocytic leukemia.     

Using molecular quantum similarity measures under stochastic transformation to describe physical properties of molecular systems

The application of molecular quantum similarity measures (MQSM) to correlate physicochemical properties is reported. Satisfactory quantitative structure-property relationship (QSPR) models are obtained for three molecular sets, where boiling points and chromatographic retention times and indices are studied. In this work, MQSM are scaled using a stochastic transformation and related to molecular properties using the partial least-squares technique.     

Modelling bioconcentration of pesticides in fish using biopartitioning micellar chromatography

Ecotoxicity assessment is essential before placing new chemical substances on the market. An investigation of the use of the chromatographic retention (log k) in biopartitioning micellar chromatography (BMC) as an in vitro approach to evaluate the bioconcentration factor (BCF) of pesticides in fish is proposed. A heterogeneous set of 85 pesticides from six chemical families was used. For pesticides exhibiting bioconcentration in fish (experimental log BCF > 2), a quantitative retention-activity relationships (QRAR) model is able to perform precise log BCF estimations of new pesticides. Considering the present data, the results based on log k seem to be more reliable than those from available software (BCFWIN and KOWWIN) and from log P (quantitative structure-activity relationships (QSAR)). It is also possible to perform risk assessment tasks fixing a threshold value for log k, which substitute two common threshold values, log P and experimental log BCF, avoiding the experimental problems related with these two parameters.     

取代苯胺及苯酚类化合物定量结构-生物降解相关性(QSBR)研究

采用MOPAC－AM1法计算了15种取代苯分子的三种量化参数,用QSAR程序计算了两种物化参数及一种电性参数,结合德华半径RW,对log Kb进行了回归分析,得到如下最佳方程：log Kb=0.329 pK-10.48kw-12.995应用所得QSBR模式预测了15种有机物的生物降解性,并分析了降解机理。