Identification of curcumin targets in neuroinflammatory pathways: molecular docking scores with GSK-3β, p38 MAPK, COX, ICE and TACE enzymes.

In the present study, the multiple targets have been identified in the mediation of anti-inflammatory response of curcumin. The anti-inflammatory pathway of curcumin was identified through docking with of curcumin with various inflammation inducing enzymes like glycogen synthase kinase (GSK-3β), p38 mitogen activated protein kinase (MAPK), COX, interleukin-1β converting enzyme (ICE) and tumor necrosis factor-α converting enzyme (TACE). Theoretical docking study was used for the prediction of the conformation orientation and position (pose) of the bioactive compound into the binding pocket and estimation of effective target-ligand interactions (scoring) was utilized for conformational sampling. The final docked conformations were selected according to their scores. The binding target GSK-3β (-6.44) was found to be more selective for curcumin binding when compared with MAPK (-4.08), COX (-7.35), ICE (-4.02), TACE (-6.38) and their respective native ligand. The binding takes place through hydrogen bonding interactions of curcumin with the amino acids in the substrate enzyme. The key amino acids involved were Vall35, Gln185 and Lys85 in GSK-3β. The binding efficiency of curcumin was compared with a standard molecule GF109203 which showed a docking score of - 4.97. These findings enabled us to identify the keto form of curcumin as a best choice of lead compound to target GSK-3β.