Pharmacophore-based 3D-QSAR modeling, virtual screening, docking, molecular dynamics and biological evaluation studies for identification of potential inhibitors of alpha-glucosidase

Alpha-glucosidase enzyme is considered an important therapeutic target for controlling hyperglycemia associated with type 2 diabetes. Novel scaffolds identified as potential alpha-glucosidase inhibitors from the Maybridge library utilizing pharmacophore modeling, molecular docking and biological evaluation are reported in this manuscript.

A total of 51 xanthone series scaffolds previously reported as alpha-glucosidase inhibitors were collected and used as training and test sets. These sets were employed to develop and validate a pharmacophore-based 3D-QSAR model with statistically meaningful results using Schrodinger software. The model showed a high F value (F, 80.1) at five component partial least square factors, a high cross-validation coefficient (Q², 0.66) and a good correlation coefficient (R², 0.95). Pearson correlation coefficient (r) of 0.8400 indicated a greater degree of confidence in the model. Subsequently, virtual screening was performed with PHASE module of Schrodinger software using the above model to identify novel alpha-glucosidase inhibitors, and mapped compounds were evaluated for their interactions with the protein. The X-ray co-crystallised structure of the alpha-glucosidase protein in complex with acarbose (PDB Code: 5NN8) was used for molecular docking analysis using GLIDE module and a total of eight compounds were further selected for biological evaluation. Molecular dynamics analysis using GROMACS software was performed in the active site of alpha-glucosidase protein to gain insights into binding mechanism of the four active compounds which were finally found to exhibit inhibitory activity in the biological assay.