Alsterpaullone is a potent ATP-competitive and cell cycle cyclin-dependent kinase inhibitor, that is reported to be the most active Paullone. The paullones belong to a family of benzazepinones, and are described to highly inhibit neuronal CDK5/p25 and glycogen synthase kinase-3β (GSK-3β). Studies report that Alsterpaullone activates caspase-9 and enhances apoptosis in Jurkat cells, inhibits CDK5/p25-dependent phosphorylation of DARPP-32 in in vitro mouse striatum slices, and blocks the phosphorylation of Tau by GSK-3β.