Critical view on antimicrobial, antibiofilm and cytotoxic activities of quinazolin-4(3)-one derived schiff bases and their Cu(II) complexes.

A series of nine 2,3-disubstituted-quinazolin-4(3)-one derived Schiff bases and their three Cu(II) complexes was prepared and tested for their antimicrobial activities against reference strains ATCC 29213 and ATCC 29212 and resistant clinical isolates of methicillin-resistant (MRSA) and vancomycin-resistant (VRE). All the substances were tested against HRa ATCC 25177, DSM 44162 and ATCC 700084. While anti-enterococcal and antimycobacterial activities were insignificant, 3-[()-(2-hydroxy-5-nitrobenzylidene)amino]-2-(2-hydroxy-5-nitrophenyl)-2,3-dihydroquinazolin-4(1)-one () and its Cu(II) complex () demonstrated bacteriostatic antistaphylococcal activity. In addition, both compounds, as well as the other two prepared complexes, showed antibiofilm activity, which resulted in a reduction of biofilm formation and eradication of mature biofilm by 80% even at concentrations lower than the values of their minimum inhibitory concentrations. In addition, the compounds were tested for their cytotoxic effect on the human monocytic leukemia cell line THP-1. The antileukemic efficiency was improved by the preparation of Cu(II) complexes from the corresponding non-chelated Schiff base ligands.