Quantum-chemical study of the active sites of camptothecin through their Cu(II) coordination ability

Abstract

The structures of camptothecin (CPT) lactone form and its complexes with Cu(II) were optimized at B3LYP/6-311G* level of theory. Their electronic structures were evaluated via QTAIM topological analysis of electron density and Mulliken population analysis. Stability, electron density distribution and geometrical factors of the optimized systems were compared. Both CPT nitrogen atoms show lower affinity to Cu(II) compared to the oxygen ones. Both the oxygen atom in the CPT lactone ring and the one in the neighbouring carbonyl group show the highest affinity to Cu(II) and the highest stability of Cu-CPT complexes which indicates the most probable CPT reaction sites.

Quantum‐chemical studies of the antioxidant effectiveness of para‐phenylene diamines

“…Therefore, further investigations of PPD antioxidant effectiveness are welcome. Nevertheless, some of the above mentioned quantum‐chemical treatments were successfully used for toxicity studies of phenols and quinones, [ 100–104 ] various forms of camptothecin, [ 105,106 ] and rutile nanoparticles. [ 107–109 ]…”

Modulating chelation with pH sensitivity for controlled structural defects and enhanced electrochemical and photocatalytic activities of LDH films

“…For these calculations, we utilized density functional theory (DFT) and the widely used B3LYP functional developed by Becke, incorporating three parameters and Lee-Yang-Parr for accuracy. 37 Furthermore, in order to acquire a comprehensive understanding of the electronic attributes and bonding characteristics inherent to the EDTA-Zn complex structure, a series of theoretical calculations are undertaken. These calculations encompassed various key parameters such as the total density of states (TDOS), projected densities of states (PDOS), molecular electrostatic potential (MEP), and electron localization function (ELF), as well as the reduced density gradient (RDG) and its corresponding scatter plot.…”

DFT studies of camptothecins cytotoxicity IV — active and inactive forms of irinotecan

“…Structure of the irinotecan lactone form has been determined by single crystal X-ray diffraction (Sawada et al, 1991), NMR measurements in DMSO solution (D'Amelio et al, 2012), and quantum-chemical model studies (Babu et al, 2012;Ivanova and Spiteller, 2012;Hussain et al, 2016). Relative cytotoxicity of various forms of campto thecin and lactone forms of irinotecan and SN-38 have been investigated in a series of studies (Steklac and Breza, 2018, 2021, 2022a) by means of quantum chemistry. This treatment was originally developed for antioxidants Ghio, 2009, 2009a;Mammino, 2013;Kabanda et al, 2014;Tsiepe et al, 2015;Serobatse et al, 2016Serobatse et al, , 2016aBreza, 2016, 2017;Jelemenska and Breza, 2021;Breza and Jelemenska, 2022) and is based on the complexation ability of their various active sites to Cu(II) with subsequent electron density transfer (ligand oxidation and metal reduction).…”