Synthesis, DNA binding, hemolytic, and anti-cancer assays of curcumin I-based ligands and their ruthenium(III) complexes

Knoevenagel condensates of curcumin I were synthesized with p-hydroxybenzaldehyde and 4-hydroxy-3,5-dimethoxy benzaldehyde and allowed to react with semicarbazide to form the corresponding curcumin I-based ligands. The ligands were complexed with ruthenium(III) metal ions. These complexes (C1 and C2) were purified by chromatography and characterized as octahedral geometries by analytical techniques. The binding affinities of these compounds for calf thymus DNA were determined. DNA binding constants (K b ) for the two complexes were 1.46 × 104 and 3.54 × 104 M−1, respectively. Similarly, the binding constants (K sv) for C1 and C2 were 9.40 × 103 and 9.30 × 103 M−1, respectively. Hemolytic assays of the compounds showed less toxicity than the standard anti-cancer drug letrazole. The compounds showed good activity against the cervical cancer cell line (HeLa) and moderate activity against liver hepatocellular carcinoma (HepG2), breast cancer (MDA-MB-231) and human colon adenocarcinoma (HT-29) cells lines. These compounds showed potential for treatment of cervical cancer in the future.