Sustainable Synthesis, DFT, Docking and In Vitro Evaluation of 6-Mercaptopurine Syringic Acid Cocrystal: A Potent Drug for Breast Cancer Therapy

Abstract

The 6-mercaptopurine syringic acid (6MPSY) a new drug–drug cocrystal has been synthesized by the neat grinding method. The prepared cocrystal 6MPSY has been screened by the powder x-ray diffraction procedure and the single phase was confirmed. Using density functional theory with B3LYP/6-311++G (d, p) source set, the structural parameters were computed and associated with the structural parameters of the 6-mercaptopurine molecule and syringic acid molecule reported earlier exhibit good agreement. Experimental FTIR and UV–vis spectra were documented to identify and analyze the group vibrational frequencies and electronic behavior of the cocrystal. The NBO study was accomplished and the inter- and intra-molecular interactions were established. The inspection of the topological (MEP, ELF, LOL) and non-covalent (RDG, IRI, DORI) contacts has exposed diverse groups of inter- and intra-molecular links on the source of electron localization density and color gauge pointer, respectively. Mulliken and natural atomic charges have been calculated and depicted. Fukui studies gave the reactive site with high f⁺ and f⁻ for C10, C17, C33, and H14 of the drug–drug cocrystal. The FMO analysis exhibits a low energy gap of 3.7612 eV that shows the efficiency of the drug–drug cocrystal in terms of chemical reactivity and stability. In addition, the thermodynamical parameters were calculated. The anti-breast cancer activity of 6MPSY was investigated through in silico and in vitro analysis. The docking outcomes of 6MPSY range between −7.5 and −9.3 kcal/mol, and the calculated IC₅₀ value in MDA-MB-231 breast cancer cells was 83.2 μg/mL.