QSAR study of flavonoid–metal complexes scavenging O₂^·−

Abstract

2014) QSAR study of flavonoid-metal complexes scavenging O 2Flavonoid-metal complexes have antioxidant activities. However, the quantitative structure-activity relationship (QSAR) of flavonoid-metal complexes and their antioxidant activities is not known. On the basis of 31 structures of flavonoid-metal complexes and their antioxidant activities scavenging O 2 ·− , we optimized their structures using the density functional theory method, and subsequently calculated 21 quantum chemistry descriptors such as dipole, charge, and energy. Then, we chose several quantum chemistry descriptors that are very important to the IC 50 of the antioxidant activities of flavonoid-metal complexes for scavenging O 2 ·− through stepwise linear regression. We obtained six new variables through the principal component analysis. Finally, we built QSAR models based on those important quantum chemistry descriptors, the six new variables as independent variables, and the IC 50 as the dependent variable using an artificial neural network. We validated the model using experimental data in references. These results show that the model in this article is reliable and predictive.

Benchmarking of Computational Methods for Creation of Retention Models in Quantitative Structure–Retention Relationships Studies

“…A brief overview of the literature shows that the computational methods used for finding the 3D structures of molecules for QSRR are many and varied. ,− While numerous researchers have compared outcomes from different methods for variable selection and regression analysis (such as artificial neural networks (ANN), genetic algorithms (GA), multiple linear regression (MLR), and partial least-squares regression (PLS) etc. ), ,,,,, a search of the literature has failed to provide any benchmarking studies on how the different computational methods for original structure determination (prior to descriptor calculation) may change the final error in the outcome of the QSRR models.…”

“…Methods found in the literature for defining the geometry of molecules prior to descriptor calculation vary from the very simpleSMILES (simplified molecular input line entry system)to molecular mechanics (MM), ,, semiempirical methods (SE), , (or a combination of MM and SE − ), and density functional methods (DFT). − A description of each of these levels of theory, along with examples of QSRR and QSAR (quantitative structure–activity relationship) studies utilizing them, is found in the Supporting Information. As no comparison study is available on the effects of the different geometry calculation methods, this present study includes a benchmarking of computational methods to elucidate which level of computational chemistry gives the lowest error of prediction of a chromatographic parameter.…”

Synthesis, characterization, and antioxidant activity of Zn2+ and Cu2+ coordinated polyhydroxychalcone complexes

“…Copper(II) and zinc(II) are our metals of interest, since they are endogenous metals and they have shown promising features as metallodrug candidates [ 24 , 25 ]. In fact Cu(II) and Zn(II) complexes of the flavonoids quercetin and rutin have been shown to greatly increase the antioxidant activity of this class of compounds [ 26 , 27 ]. In many complexes Zn(II) prefers a tetrahedral coordination sphere [ 28 ] while the Cu(II) cation prefers a square planar coordination.…”