Exploring the interaction of Valsartan and Valsartan-Zn(ll) complex with DNA by spectroscopic and in silico methods

Belonging to the Sartan family, antihypertensive drug - Valsartan (Val) had been found to possess antioxidant properties. Also, the zinc complex of Valsartan (VZn) has been recently recognized as inducing agents of the reductive stress effects thus possessing anticancer activity. Hence, in this work an attempt has been made to understand the interaction of Val and VZn with DNA using spectroscopic and in silico methods as DNA has been identified as the target for many anticancer drugs. VZn has been prepared in 2:1 M ratio and characterised by absorbance, FTIR, HRMS, NMR and Job's continuous variation method. VZn has been tested against human lungs cancer cell line which exhibited good anticancer activity (IC₅₀ = 89 µg/mL). Interaction of Val and VZn with ct-DNA under physiological conditions has been studied by spectroscopic techniques such as fluorescence, absorbance, FTIR, circular dichroism (CD) and in silico methods. Fluorescence quenching, DNA melting and viscometric studies confirmed that both ligand and complex bind to the grooves of the ct-DNA. The experimental results have revealed that VZn strongly bind with DNA compared to Val. Docking study suggested that, Val binds at major groove while VZn binds to both minor and major grooves of B-DNA.