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

Chiral Schiff base ligands (S)-H2L and (R)-H2L 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 × 105 to 4.5 × 106 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.

. Chiral Schiff base Ni (II), Cu (II) and Zn (II) complexes have been synthesized and characterized by various physico-chemical methods. All the complexes were subjected to DNA binding, antioxidant and antibacterial activities.Figure optionsDownload as PowerPoint slideHighlights
► Chirality in a molecules plays a significant role in medicinal chemistry.
► Where only one enantiomer shows desirable therapeutic effect.
► S enantiomer of complexes showed strong biological activity than R enantiomer.
► S enantiomer of Ni and Cu complexes bind with DNA through intercalation.