Chiral discrimination asserted by enantiomers of Ni (II), Cu (II) and Zn (II) Schiff base complexes in DNA binding, antioxidant and antibacterial activities

Abstract

Chiral Schiff base ligands ( S)-H 2L and ( R)-H 2L and their complexes ( S-Ni-L, R-Ni-L, S-Cu-L, R-Cu-L, S-Zn-L and R-Zn-L) were synthesized, characterized and examined for their DNA binding, antioxidant and antibacterial activities. The complexes showed higher binding affinity to calf thymus DNA with binding constant ranging from 2.0 × 10 5 to 4.5 × 10 6 M −1. All the complexes also exhibited remarkable superoxide (56–99%) and hydroxyl scavenging (45–89%) activities as well as antibacterial activities against gram (+) and gram (−) bacteria. However, none of the complexes showed antifungal activity. Conclusively, S enantiomers of the complexes were found to be relatively more efficient for DNA interaction, antioxidant and antibacterial activities than their R enantiomers. This study reveals the possible utilization of chiral Schiff base complexes for pharmaceutical applications.