Interaction of ferrocene appended Ru(II), Rh(III) and Ir(III) dipyrrinato complexes with DNA/protein, molecular docking and antitumor activity

Abstract

Efficacy of the ferrocene appended piano-stool dipyrrinato complexes [(η⁶-C₆H₆)RuCl(fcdpm)](1), [(η⁶C₁₀H₁₄)RuCl(fcdpm)](2), [(η⁶-C₁₂H₁₈)RuCl(fcdpm)](3) [(η⁵-C₅Me₅)RhCl(fcdpm)](4) and [(η⁵-C₅Me₅IrCl(fcdpm)] (5) [fcdpm = 5-ferrocenyldipyrromethene] toward anticancer activity have been described. Binding of the complexes with calf thymus DNA (CT-DNA) and BSA (bovine serum albumin) have been thoroughly investigated by UV–Vis and fluorescence spectroscopy. Binding constants for 1–5 (range, 10⁴–10⁵ M^-1) validated their efficient binding with CT-DNA. Molecular docking studies revealed interaction through minor groove of the DNA, on the other hand these also interact through hydrophobic residues of the protein, particularly cavity in the subdomain IIA. In vitro anticancer activity have been scrutinized by MTT assay, acridine orange/ethidium bromide (AO/EtBr) fluorescence staining, and DNA ladder (fragmentation) assay against Dalton's Lymphoma (DL) cells. Present study revealed that rhodium complex (4) is more effective relative to ruthenium (1–3) and iridium (5) complexes.