A comprehensive computational analysis of cathinone and its metabolites using quantum mechanical approaches and docking studies

Conformers of the psychoactive compound of the Khat plant cathinone along with its amino alcohol metabolites norephedrine and norpseudoephedrine have been calculated using DFT (M062X/B3LYP) and MP2 levels of theory for gas and solution phases. Gas-phase studies revealed that cathinone has two, norephedrine has four and norpseudoephedrine has three low-energy conformations with all conformers connected by rotational transition states. To understand the solvent effect to the energetic profiles of the studied species, the conductor-like screening model is employed within aqueous medium. It explains lowering of energy of all studied conformers in solution. The molecular electrostatic potential surface data for each molecule revealed likely reaction sites for the studied molecules. The computed IR spectra for cathinone and its metabolites have been compared with experimental data and rotational transition states connecting all conformers have been reported. The natural bond orbital analyses for only ligands and separately for their complexes with amino acid residues in protein pockets from the docking results are also performed to corroborate the results obtained from the MP2 and DFT calculations. The comprehensive computational study explore important amino acid residues and stabilizing energy of the studied molecules with the interacting proteins along with the reason behind the difference in potency for cathinone’s metabolites.