Ahmad, F.; Gupta, A.; Marzook, H.; Woodgett, J. R.; Saleh, M. A.; Qaisar, R.

Glycogen synthase kinase-3 (GSK-3) plays important roles in the pathogenesis of cardiovascular, metabolic, neurological disorders and cancer. Isoform-specific loss of either GSK-3 or GSK-{beta} often provides cytoprotective effects under such clinical conditions. However, available synthetic small molecule inhibitors are relatively non-specific, and their chronic use may lead to adverse effects. Therefore, screening for natural compound inhibitors to identify the isoform-specific inhibitors may provide improved clinical utility. Here, we screened 70 natural compounds to identify novel natural GSK-3 inhibitors employing comprehensive in silico and biochemical approaches. Molecular docking and pharmacokinetics analysis identified two natural compounds Psoralidin and Rosmarinic acid as potential GSK-3 inhibitors. Specifically, Psoralidin and Rosmarinic acid exhibited the highest binding affinities for GSK-3 and GSK-3{beta}, respectively. Consistent with in silico findings, the kinase assay-driven IC50 revealed superior inhibitory effects of Psoralidin against GSK-3 (IC50=2.26 M) vs. GSK-3{beta} (IC50=4.23 M) while Rosmarinic acid was found to be more potent against GSK-3{beta} (IC50=2.24 M) than GSK-3 (IC50=5.14 M). Taken together, these studies show that the identified natural compounds may serve as GSK-3 inhibitors with Psoralidin serving as a better inhibitor for GSK-3 and Rosmarinic for GSK-3{beta} isoform, respectively. Further characterization employing in vitro and preclinical models will be required to test the utility of these compounds as GSK-3 inhibitors for cardiometabolic and neurological disorders and cancers.