Nature as a source and inspiration for human monoamine oxidase B (hMAO-B) inhibition: A review of the recent advances in chemical modification of natural compounds

Introduction: Over the past 5 years, we have witnessed intense research activity about the biological potential of natural products (NPs) as human monoamine oxidase B (hMAO-B) inhibitors. Despite the promising inhibitory activity, natural compounds often suffer from pharmacokinetic lissues, such as poor aqueous solubility, extensive metabolism, and low bioavailability. Areas covered: This review provides an overview of the current landscape NPs as selective hMAO-B inhibitors and highlights their use as a starting scaffold to design (semi)synthetic derivatives to overcome the therapeutic (pharmacodynamic and pharmacokinetic) limitations of NPs and to obtain more robust structure–activity relationships (SARs) for each scaffold. Expert opinion: All the natural scaffolds herein presented displayed a broad chemical diversity. The knowledge of their biological activity as inhibitors of hMAO-B enzyme allows the positive correlations associated with the consumption of specific food or the possible herb–drug interactions and suggests to the Medicinal Chemists how to address chemical functionalization to obtain more potent and selective compounds.