Hetero-Tricyclic Lead Scaffold as Novel PDE5A Inhibitor for Antihypertensive Activity: In Silico Docking Studies

<P>Objective: To screen the phytochemicals for phosphodiesterase 5A (PDE5A) inhibitory potential and identify lead scaffolds of antihypertensive phytochemicals using in silico docking studies. </P><P> Methods: In this perspective, reported 269 antihypertensive phytochemicals were selected. Sildenafil, a PDE5A inhibitor was used as the standard. In silico docking study was carried out to screen and identify the inhibiting potential of the selected phytochemicals against PDE5A enzyme using vLife MDS 4.4 software. </P><P> Results: Based on docking score, π-stacking, H-bond and ionic interactions, 237 out of 269 molecules were selected which have shown one or more interactions. Protein residue Gln817A was involved in H-boding whereas Val782A, Phe820A and Leu804A were involved in π-stacking interaction with ligand. The selected 237 phytochemicals were structurally diverse, therefore 82 out of 237 molecules with one or more tricycles were filtered out for further analysis. Amongst tricyclic molecules, 14 molecules containing nitrogen heteroatom were selected for lead scaffold identification which finally resulted in three different basic chemical backbones like pyridoindole, tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline as lead scaffolds. </P><P> Conclusion: In silico docking studies revealed that nitrogen-containing tetrahydro-pyridonaphthyridine and dihydro-pyridoquinazoline tricyclic lead scaffolds have emerged as novel PDE5A inhibitors for antihypertensive activity. The identified lead scaffolds may provide antihypertensive lead molecules after its optimization.</P>