Lysozyme and DNA binding affinity of Pd(ii) and Pt(ii) complexes bearing charged N,N-pyridylbenzimidazole bidentate ligands

Abstract

New cisplatin analogue Pd(ii) and Pt(ii) complexes bearing charged pyridylbenzimidazole derivatives furnished with either an alkylated sulfonate or a phosphonium side chain were synthesized, fully characterized and tested for their antimicrobial and cytotoxic activities against noncancerous human embryonic kidney cells (HEK293). The interactions with CT-DNA were investigated using UV/vis spectroscopy. Assignment of the electronic transitions was performed with the aid of TDDFT. The complexes showed interesting antifungal activity against Candida albicans and Cryptococcus neoformans. The Pd(ii) complex conjugated with alkylated triphenylphosphonium exhibited higher cytotoxicity (CC = 8.932 μg mL, equivalent to 12 nM) than the others. The reactivity towards hen egg white lysozyme (HEWL) was investigated by electrospray ionization mass spectrometry. The formation of DNA- and HEWL-adducts was achieved via the noncovalent and covalent interactions.

Pyridylbenzimidazole‐Based Gold(III) Complexes: Lysozyme Metalation, DNA Binding Studies, and Biological Activity

“…The spectrum of free 2 is not involved in the growing of the isosbestic point. The wavelength of the isosbestic point coincides with that previously observed for [PdCl 2 (L SO3H )] . Therefore, same type of DNA interaction is supposed to happen.…”

“…The ligands (L CH2CH3 and L Phth ) were prepared by deprotonation of 2‐(2′‐pyridyl) benzimidazole (L Py ) with fresh sodium hydride in DMF and treated with iodoethane and N‐(5‐bromopentyl) phthalimide to give the corresponding product , . Reaction of L Py with 1,3‐propane sultone in acetonitrile yielded L SO3H . Au(III) complexes 1 – 3 (Scheme ) were synthesized from reaction of pyridylbenzimidazole based ligands and HAuCl 4 (at pH = 3) in methanol/water mixture.…”

“…The existence of PF 6 as a counterion of 1 and 3 is based on 19 F and 31 P NMR analysis, where doublet and septet signals are shown at δ = –70.2 ppm ( 1 J PF = 711 Hz) and –144.2 ppm ( 1 J PF = 711 Hz), respectively. The 1 H NMR signals of pyridine‐H6 and benzimidazole‐H4, are observed at δ = 8.70–8.93 and 7.67–7.89 ppm in the free ligands,, and move downfield to δ = 8.86–8.96 and 7.99–8.24 ppm in 1 – 3 as a consequence of coordination and the neighborhood of the Cl – ligand(s). The 1 H NMR spectrum of 1 , as a representative example, shows seven aromatic resonances (Figure S1).…”

“…Two isosbestic points, at 285 and 385 nm, grow upon increasing the quantity of DNA (> 2 µL). Hypochromism may be attributed to departure of the bulky appendage phthalimido group . Development of the isosbestic point may be taken as a sign of covalent mode of interaction.…”

Green‐Light‐Induced PhotoCORM: Lysozyme Binding Affinity towards MnI and ReI Carbonyl Complexes and Biological Activity Evaluation

“…The antimicrobial activity of Schiff‐base ligand and complexes ( 1 , 2 , 4 ) was evaluated in the dark using two fungi ( C. albicans and C. neoformans ), gram‐positive bacterium ( S. aureus ) as well as four gram‐negative bacteria ( P. aeruginosa, K. pneumoniae, E. coli , and A. baumannii ). Standard broth microdilution assays were used as endorsed by NCCLS for bacteria and yeasts (M07‐A8 and M27‐A2) and standards of European Committee on Antimicrobial Susceptibility Testing (EDef7.1). Initial screening was carried out at 32 µg/mL.…”