Exploration of the Detailed Structure-Activity Relationships ofIsatin and Their Isomers As Monoamine Oxidase Inhibitors

Monoamine oxidase (MAO) is a protein with a key function in thecatabolism of neuroamines in both central and peripheral parts of the body. MAO-A and -B are two isozymes of this enzyme which have emerged to be considered asa drug target for the treatment of neurodenerative disorders such as Alzheimer'sdisease (AD) and Parkinson's disease (PD). Isatin is an endogenous smallfragment, reversible inhibitor for MAO enzymes and is more selective for MAO-Bthan -A. Isatin is responsible for increasing the dopamine level in the brain by theinhibition of an MAO enzyme. The very few selective and reversible inhibitorsexisting for MAO proteins and the intensity of neurological diseases in humanityhave opened a new door for researchers. Isatin has a polypharmacological profilein medicinal chemistry, is a reversible inhibitor for both the MAOs, and showshigh selectivity potent inhibition for MAO-B. In this review, we discuss isatins andtheir analogues phthalide and phthalimide with structure-activity relationships(SARs), and this comprehensive information accelerates the ideas for design anddevelopment of a new class of MAO inhibitors for neurodegenerative diseases