An in Silico Study of Natural Compounds as Potential MAO-B Inhibitors for the Treatment of Parkinson’s Disease

Parkinson’s Disease (PD) is a neurodegenerative disease that causes damage to the cognitive and motor system due to the death of dopaminergic neurons, which are responsible for the synthesis of the neurotransmitter dopamine. The study aimed to compare the monoamine oxidase B (MAO-B) inhibitory activity of natural molecules described in the literature with Selegiline, as potential drugs for the treatment of PD through molecular modeling, molecular docking and prediction of ADME/Tox properties. Thus, it was found the structure of the four natural molecules, Amburoside A, Harman, Harmaline and Harmalol, showed antiparkinsonian biological activity. Maps Electrostatic Potential showed similar regions between the molecules, except for Amburoside A, and Harmaline had a greater similarity in the positive potential with Selegiline. Molecular docking demonstrated that the studied molecules interact with 4–6 amino acids from the active site of the MAO-B enzyme, indicating that it has an inhibitory action on the enzyme, through hydrogen bonding and hydrophobic interactions. For ADME property predictions, most of the molecules showed good human oral absorption, all showed average permeability in Caco-2 cells, most showed average permeability in MDCK cells, showed low binding to plasma proteins, and for permeability in the blood-brain barrier, they were between good and medium. Overall, Harmaline has more properties similar to Selegiline. For toxicological properties, all molecules including Selegiline showed a positive result for the possibility of mutagenicity, whereas for the parameter of carcinogenicity in rats only the molecules Harmaline and Harmalol were positive, but no molecule was positive for carcinogenicity in mice. Therefore, the molecule that presented the best results was Harmaline, opening perspectives for the execution of in vitro studies.