Role of Alkannin in the Therapeutic Targeting of Protein-Tyrosine Phosphatase 1B and Aldose Reductase in Type 2 Diabetes: An In Silico and In Vitro Evaluation.

Abstract

Alkannin is a plant-derived naphthoquinone that is isolated from the Boraginaceae family plants. In our previous studies, we found that shikonin, which is the R-enantiomer of alkannin, has potent antidiabetic activity by inhibiting the action of the aldose reductase (AR) enzyme and the protein-tyrosine phosphatase 1B (PTP1B). Therefore, in this study, we aim to explore the antidiabetic effect of alkannin targeting PTP1B and AR by employing in silico and in vitro techniques. For in silico, we used different parameters such as ADMET analysis, molecular docking, MD simulation, Root Mean Square Deviation (RMSD), protein-ligand mapping, and free binding energy calculation. The in vitro evaluation was done by assessing the inhibitory activity and enzyme kinetics of PTP1B and AR inhibition by alkannin. The in silico studies indicate that alkannin possesses favorable pharmacological properties and possesses strong binding affinity for diabetes target proteins. Hydrogen bonds (Val297, Ala299, Leu300, and Ser302) and hydrophobic interactions (Trp20, Val47, Tyr48, Trp79, Trp111, Phe122, Trp219, Val297, Cys298, Ala299, Leu300, and Leu301) are established by the compound, which potentially improves specificity and aids in the stabilization of the protein-ligand complex. The results from in vitro studies show a potent dose-dependent PTP1B inhibitory activity with an IC50 value of 19.47 μM, and toward AR it was estimated at 22.77 μM. Thus, from the results it is concluded that a low IC50 value of alkannin for both PTP1B and AR along with favorable pharmacological properties and optimal intra-molecular interactions indicates its utilization as a potential drug candidate for the management of diabetes and its end complications.