Synthesis, structural elucidation, biological, antioxidant and nuclease activities of some 5-Fluorouracil–amino acid mixed ligand complexes

Abstract

Some biologically active mixed ligand complexes (1–9) have been synthesized from 5-Fluorouracil (5-FU; A) and amino acids (B) such as glycine (gly), l-alanine (ala) and l-valine (val) with Ni(II), Cu(II) and Zn(II) ions. The synthesized mixed ligand complexes (1–9) were characterized by various physico-chemical, spectral, thermal and morphological studies. 5-Fluorouracil and its mixed ligand complexes have been tested for their in vitro biological activities against some pathogenic bacterial and fungal species by the agar well diffusion method. The in vitro antioxidant activities of 5-Fluorouracil and its complexes have also been investigated by using the DPPH assay method. The results demonstrate that Cu(II) mixed ligand complexes (4–6) exhibit potent biological as well as antioxidant activities compared to 5-Fluorouracil and Ni(II) (1–3) and Zn(II) (7–9) mixed ligand complexes. Further, the cleaving activities of CT DNA under aerobic conditions show moderate activity with the synthesized Cu(II) and Ni(II) mixed ligand complexes (1–6) while no activity is seen with Zn(II) complexes (7–9). Binding studies of CT DNA with these complexes show a decrease in intensity of the charge transfer band to the extent of 5–15% along with a minor red shift. The free energy change values (Δ‡G) calculated from intrinsic binding constants indicate that the interaction between mixed ligand complex and DNA is spontaneous.