Hypercholesterolemia is a mediator for the etiology of
cardiovascular
diseases, which are characterized as the global leading cause of mortality.
We aimed to investigate the inhibitory activity of Withania coagulans compounds against 3-hydroxy-3-methylglutaryl-coenzyme
A reductase (Hmgcr) of Mus musculus using an extensive in silico approach. The 3D structure of the Hmgcr protein is not yet known, so we performed the homology
modeling using MODELLER and SWISS-MODEL tools, followed with structural
validation and assessment. The PROCHECK web server showed that the
top-ranked homology model from SWISS-MODEL has 93.4% of residues in
the most-favorable region, the quality factor was 98%, and the Verify3D score was 91.43%, compared to the other generated
models. The druggable protein-binding cavities in a 3D model of Hmgcr were investigated with the aid of commonly prescribed
statin compounds using the CB-dock approach. We compiled a 3D compound
library of W. coagulans, followed by
drug-likeness evaluation, and found 20 eligible compounds. The pattern
of consensus residues obtained from the CB-dock procedure was then
used for grid-box docking of W. coagulans compounds and statin drugs using AutoDock 4.2, respectively. The
results showed that withanolide R (−10.77 kcal/mol), withanolide
Q (−10.56 kcal/mol), withanolide J (−10.52 kcal/mol),
atorvastatin (−8.99 kcal/mol), simvastatin (−8.66 kcal/mol),
and rosuvastatin (−8.58 kcal/mol) were promising candidates
that bind Hmgcr protein. The key residues involved
in protein–ligand (withanolide R) interactions were Y516, C526,
V529, I530, M533, I535, and V537, and the formation of a H-bond was
at C526, M533, and I535 residues. M533 was the consensus residue having
a tendency to form a H-bond with withanolide Q, too. Molecular dynamics
simulations were used to validate the top-ranked docked complexes
for the stability of the modeled protein. We also predicted the pharmacokinetic
properties of binding affinity-based top-ranked compounds and concluded
that they could be used as potential inhibitors of Hmgcr. However, further in vitro and in vivo studies are essential to
completing the drug development process.