Introduction: The primary aim of this study is to understand the binding of curcumin
and its analogues to different PDE4 subtypes and identification of the role of PDE4 subtype inhibition
in the anti-inflammatory property of curcumin. Docking analysis has been used to acquire the
above mentioned structural information and this has been further used for designing of curcumin
derivatives with better anti-inflammatory activity.
Materials and Methods: Curcumin and its analogues were subjected to docking using PDE4A,
PDE4B, PDE4C and PDE4D as the target. A data set comprising 18 analogues of curcumin was
used as ligands for docking of PDE4 subtypes. Curcumin was used as the standard for comparison.
Docking was performed using AutoDock Vina 1.1.2 software integrated in LigandScout 4.1. During
this process, water molecules were removed from proteins, charges were added and receptor
structures were minimized by applying suitable force fields. The docking scores were compared,
and the selectivity of compounds for PDE4B over PDE4D was calculated as well.
Results: All curcumin analogues used in the study showed good binding affinity with all PDE4
subtypes, with evident selectivity towards PDE4B subtype. Analogue A11 provides the highest
binding affinity among all ligands.
Conclusion: Curcumin and analogues have moderate to strong affinity towards all PDE4 subtypes
and have evident selectivity towards PDE4B. Oxygen atom of methoxy groups plays a key role in
PDE4B binding and any alterations could interfere with the binding. Tetrahydropyran side chain
and heterocyclic rings are also suggested to be helpful in PDE4B binding.