Palladium(II) complex bearing benzothiazole based O,N,S donor pincer ligand: Study of in-vitro cytotoxicity, interaction with CT-DNA and BSA protein

A new palladium(II) complex, [Pd(LS Et )Cl] ( C1 ) with benzothiazole based ONS donor pincer ligand (HLS Et ) was synthesized (where, HLS Et = 2-(benzothiazol-2-yl)-6-(((2-(ethylthio)phenyl)imino)methyl)phenol). Interaction of C1 with CT DNA was investigated, and its binding constant was found to be 4.0×10 5 M −1 . The proficiency of ethidium bromide (EB) displacement from its EB-CTDNA complex by C1 was performed by the fluorescence quenching method, and Stern-Volmer quenching constant (K sv ) was found to be 4.3×10 5 M −1 . Similarly, the interaction of C1 with BSA protein was investigated by UV-Vis and fluorescence methods. The apparent association constant (K a ) and K sv were determined (K a = 2.8×10 4 M −1 and K sv = 5.5×10 4 M −1 ). In vitro cytotoxicity of the complex, [Pd(LS Et )Cl] ( C1 ), towards human gastric cancer cell lines (AGS) was assessed by the MTT assay method. The half maximal inhibitory concentration (IC 50 ) of C1 (9.55 ± 1.23 µM) towards AGS cancer lines was found to be lower than cisplatin (23.13 ± 1.03 µM). Graphical abstract Herein, new palladium(II) complex, [Pd(LS Et )Cl] ( C1 ) with benzothiazole-based ONS donor pincer ligand (HLS Et ) was synthesized and characterized by several spectroscopic techniques. Interaction of C1 with CT DNA and BSA protein was investigated by UV-Vis and fluorescence methods. In vitro cytotoxicity of the complex toward human gastric cancer cell lines (AGS) was evaluated by the MTT assay method. The half maximal inhibitory concentration (IC 50 ) of the palladium(II) complex (9.55±1.23 µM) was found to be less compared to cisplatin (23.13±1.03 µM) towards AGS cancer lines.