Ru(II)-based complexes with N-(acyl)-N′,N′-(disubstituted)thiourea ligands: Synthesis, characterization, BSA- and DNA-binding studies of new cytotoxic agents against lung and prostate tumour cells

Abstract Four ruthenium(II)-based complexes with N -(acyl)- N ′, N ′-(disubstituted)thiourea derivatives (Th) were obtained. The compounds, with the general formula trans -[Ru(PPh 3 ) 2 (Th)(bipy)]PF 6 , interact with bovine serum albumin (BSA) and DNA. BSA-binding constants, which were in the range of 3.3–6.5 × 10 4  M − 1 , and the thermodynamic parameters (ΔG, ΔH and ΔS), suggest spontaneous interactions with this protein by electrostatic forces due to the positive charge of the complexes. Also, binding constant by spectrophotometric DNA titration (Kb = 0.8–1.8 × 10 4  M − 1 ) and viscosity studies indicate weak interactions between the complexes and DNA. Cytotoxicity assays against DU-145 (prostate cancer) and A549 (lung cancer) tumour cells revealed that the complexes are more active in tumour cells than in normal (L929) cells, and that they present high cytotoxicity (low IC 50 values) compared with the reference metallodrug, cisplatin.