Multispectroscopic and molecular docking studies on DNA binding of guaifenesin drug

The link between relative stability constant of DNA- and BSA-chromenopyrimidine complexes and cytotoxicity towards human breast cancer cells (MCF-7)

In this study, we synthesized and characterized ten chromenopyrimidine derivatives using analytical and spectroscopic methods. Studies on DNA and albumin binding affinity, as well as cytotoxicity tests on human breast cancer (MCF-7) cells, of the chromenopyrimidines, were conducted. The natural logarithm of the relative stability constant of DNA- and BSA-chromenopyrimidine complexes [ln(K_DNA/K_BSA)] was used as a criterion for selecting compounds for cytotoxicity studies. We found that ln(K_DNA/K_BSA) was inversely related to IC₅₀ values of the compounds in MCF-7 cells. The antiproliferative effects of the compounds were found to induce apoptosis in MCF-7 cells, which is a desired mechanism of cell death. Correlations between the DNA and albumin binding affinities of chromenopyrimidines were established. We propose that this relationship approach can, for a given set of compounds, assist in predicting the cytotoxicity of potential drug candidates towards MCF-7 cells based on their experimentally determined CT-DNA and BSA binding affinities.

Structure and surface analyses of a newly synthesized acyl thiourea derivative along with its in silico and in vitro investigations for RNR, DNA binding, urease inhibition and radical scavenging activities

N-((4-Acetylphenyl)carbamothioyl)-2,4-dichlorobenzamide (4) was synthesized by the treatment of 2,4-dichlorobenzoyl chloride with potassium thiocyanate in a 1 : 1 molar ratio in dry acetone to afford the 2,4-dichlorobenzoyl isothiocyanate in situ which on reaction with acetyl aniline furnished (4) in good yield and high purity. The compound was confirmed by FTIR, ¹H-NMR, and ¹³C-NMR and single crystal X-ray diffraction studies. The planar rings were situated at a dihedral angle of 33.32(6)°. The molecules, forming S(6) ring motifs with the intramolecular N–H⋯O hydrogen bonds, were linked through intermolecular C–H⋯O and N–H⋯S hydrogen bonds, enclosing R₂²(8) ring motifs, into infinite double chains along [101]. C–H⋯π and π⋯π interactions with an inter-centroid distance of 3.694 (1) Å helped to consolidate a three-dimensional architecture. Hirshfeld surface (HS) analysis further indicated that the most important contributions for the crystal packing were from H⋯C/C⋯H (20.9%), H⋯H (20.5%), H⋯Cl/Cl⋯H (19.4%), H⋯O/O⋯H (13.8%) and H⋯S/S⋯H (8.9%) interactions. Thus C–H⋯π (ring), π⋯π, van der Waals interactions and hydrogen bonding played the major roles in the crystal packing. The electronic structure and computed DFT (density functional theory) parameters identified the reactivity profile of compound (4). In silico binding of (4) with RNA indicated the formation of a stable protein–ligand complex via hydrogen bonding, while DNA docking studies inferred (4) as a potent groove binder. The experimentally observed hypochromic change (57.2%) in the UV-visible spectrum of (4) in the presence of varying DNA concentrations together with the evaluated binding parameters (K_b; 7.9 × 10⁴ M⁻¹, ΔG; −28.42 kJ mol⁻¹) indicated spontaneous interaction of (4) with DNA via groove binding and hence supported the findings obtained through docking analysis. This compound also showed excellent urease inhibition activity in both in silico and vitro studies with an IC₅₀ value of 0.0389 ± 0.0017 μM. However, the radical scavenging efficiency of (4) was found to be modest in comparison to vitamin C.

A new acyl thiourea derivative was explored for its binding interaction with RNR and DNA and for excellent urease inhibition activity.