Estudo da inibição da monoamina oxidase por novos compostos sintéticos derivados de cumarina

Abstract

Monoamine oxidase [EC 1.4.3.4 (MAO)] is an enzyme located in the outer membrane of the mitochondria, which uses flavin adenine dinucleotide (FAD) as a cofactor to catalyze the oxidant conversion of an amine in its corresponding aldehyde, also producing ammonia and hydrogen peroxide. MAO activity regulates the levels of biogenic amines present in tissues, especially in the brain. MAO exists as two proteins: MAO-A and MAO-B. These isoforms were defined primarily by substrate affinities and inhibitor sensitivity. Accordingly, MAO-A oxidizes, preferably, serotonin, melatonin, noradrenaline and adrenaline. MAO-B preferably oxidizes phenylethylamine, an alkaloid from the metabolism of phenylalanine. The ingestion of phenylethylamine promotes the release of dopamine that acts in the brain stimulating euphoria. Concerning the inhibitors, MAO-A is preferentially inhibited by clorgiline. MAO-B is inhibited by deprenyl and pargyline. These inhibitors can be used in the treatment of degenerative brain diseases. Since studies have shown that molecules derived from coumarins achieved excellent results as inhibitors of these enzymes, several new drugs derived from coumarin have been synthesized, which a few are very promising in the treatment of Alzheimer's and Parkinson's diseases. This study aimed to promote in vitro inhibition tests of MAO with new substances derived from coumarin. Among the compounds tested, two of them were shown to be promising as MAO inhibitors of mitochondrial fraction of wistar rat brain, reaching more than 60% inhibition of monoamine oxidase activity.