Glycogen synthase kinase 3 (GSK-3) inhibitors as new promising drugs for diabetes, neurodegeneration, cancer, and inflammation.

Glycogen synthase kinase 3 (GSK-3) was initially described as a key enzyme involved in glycogen metabolism, but is now known to regulate a diverse array of cell functions. Two forms of the enzyme, GSK-3alpha and GSK-3beta, have been previously identified. Small molecules inhibitors of GSK-3 may, therefore, have several therapeutic uses, including the treatment of neurodegenerative diseases, diabetes type II, bipolar disorders, stroke, cancer, and chronic inflammatory disease. As there is lot of recent literature dealing with the involvement of GSK-3 in the molecular pathways of different diseases, this review is mainly focused on the new GSK-3 inhibitors discovered or specifically developed for this enzyme, their chemical structure, synthesis, and structure-activity relationships, with the aim to provide some clues for the future optimization of these promising drugs.