Hydrazone bimetallic complex: synthesis, characterization, in silico and biological evaluation targeting breast and lung cancer cells’ G-quadruplex DNA

Manganese complex of (N'1E,N'3E)-N'1,N'3-bis(2-hydroxybenzylidene)isophthalo-hydrazide [H4L] was designed, spectroscopically analyzed, and confirmed via GC-MS, FTIR, CHNS, UV-VIS, magnetic susceptibility measurements, and molar electric conductivity. The data confirmed the formation of ligand H4L and [Mn2(H2L)Cl]Cl.2H2O complex. Ligand H4L acts as a bi-negative hexadentate and tetra-negative hexadentate coordinating through two amide carbonyl, two azomethine, and two deprotonated OH groups. The magnetic and spectral data proposed a square-planar and a tetrahedral structure. The TGA data confirmed the final metal oxide form for the Mn ligand complex. Additionally, an in-vitro assessment of the ligand H4L confirmed its ability to control cancer cell proliferation in both breast (MCF7) and lung (A549) cancer cell lines while the Mn ligand complex possessed an anticancer effect in both cancer cells at the nano-molar level. Further, the in silico data showed four hydrogen bond interactions of the ligand with G-quadruplex DNA. This strengthens our hypothesis that the hydrazone complex acts as an anticancer agent by targeting the G-quadruplex DNA.