DFT studies and molecular docking approach for investigation of optoelectronic and biological properties of Pyrimethamine and Leflunomide

We have used density functional theory (DFT) and molecular docking (MD) techniques to study the optical and biological properties of Leflunomide (Lef.) and Pyrimethamine (Pyr.). Obtained results by DFT, predict an insulator nature of Lef. and Pyr. compounds with wide indirect band gaps of 3.66 and 3.35 eV, respectively. The stability and reactivity of compounds are studied using the main contributions of atomic states in the density of state spectra. The maximum static dielectric constants of 3.13 and 3.56 are obtained for Lef. and Pyr., respectively. The calculated absorption spectra for Lef. and Pyr. are in close agreement with the experiment. The refractive index, reflectivity, electron energy loss spectrum, and the oscillator strength sum rule (N_eff) are also calculated for Lef. and Pyr. compounds. The MD calculation findings indicated that the enzymes exhibit high- affinity energies, which provided strong binding with cancer-causing enzymes. The highest affinity energy of -7.73 Kcal/mol was found on Lef. binding to cytochrome-1A2. However, it is predicted about − 7.62 Kcal/mol for Pyr. binding to aromatase enzyme. Finally, the DFT calculations confirm the results obtained by the MD and the experimental data.