Owing to the various beneficial properties of the popular spice saffron, the interaction of safranal, a secondary metabolite of the former, with hen egg white lysozyme was investigated. The formation of a complex was evidenced by UV–visible spectroscopy. Fluorescence quenching experiments were also performed to understand the binding mechanism and to evaluate the forces involved in binding. The strong absorption of safranal in the range of excitation and emission wavelengths of lysozyme fluorescence required the correction of the inner filter effect for fluorescence spectra to obtain the apparent extent of binding. There was a considerable difference between the observed spectra and corrected spectra, and a similar observation was found in the case of synchronous fluorescence spectra. From the analysis of quenching data, it was found that the mechanism involved in quenching was static with 1:1 binding between them. The interaction was found to be driven, mainly, by hydrophobic forces and hydrogen bonding. Safranal had negligible impact on the secondary structure of lysozyme. The interaction was also studied by molecular docking, and the results were in good agreement with the results obtained experimentally. The binding site of safranal was in the big hydrophobic cavity of lysozyme. The amino acids involved in the interaction were Asp52, Ile58, Gln57, Asn59, Trp62, Trp63, Trp108, Ile98, Asp101, and Ala107.

Procaine is an anesthetic drug commonly administrated topically or intravenously for use in local anesthesia. Promisingly, some anticancer activities of procaine have also been reported. Therefore, the mechanism of interaction between anesthetic drug procaine with ct-DNA was determined collectively by means of various spectroscopic and molecular docking methods. Minor groove 1 : 1 binding of procaine to the ct-DNA was evidenced from absorption spectroscopy, fluorescence quenching, DNA melting, competitive binding measurements with EB and DAPI dyes, viscosity and CD spectroscopy together with molecular docking simulations and DFT calculations. Molecular docking on five different B-DNA structures (taken from the Protein Data Bank) shows that procaine binds in the AT rich region of all five B-DNA structures. Thermodynamic parameters, evaluated using van't Hoff's isotherm, shown that the interaction was feasible and the binding forces involved were hydrophobic as well as hydrogen bonding which were, further, confirmed by molecular docking. The frontier molecular orbitals (HOMO and LUMO) of procaine and DNA bases have been calculated by DFT method and the chemical potential (μ), chemical hardness (η) and fraction number of electrons (ΔN) from procaine to DNA bases were evaluated, which have shown that procaine acts as an electron donor to the DNA bases. Simultaneously, anticancer activities of procaine alone and in combination with doxorubicin were observed on the MCF-7 breast cancer cell line. The results showed that the combined treatment with both procaine and doxorubicin enhanced the cytotoxic and apoptotic inducing potential of doxorubicin.