A Multidisciplinary Approach to Targeting PTP1B Inhibition Mechanisms in Metabolic Disorders Using Flavonoids From Scutellaria Salviifolia: An Integrative In Vitro and In Silico Analysis

Abstract

Protein Tyrosine Phosphatase 1B (PTP1B) is a key negative regulator of insulin signaling and a promising target for treating metabolic disorders like type 2 diabetes and obesity. Herein, a combined phytochemical, in vitro, and computational approach was employed to discover new PTP1B inhibitors from Scutellaria salviifolia. Phytochemical analysis isolated five flavonoids, three—cirsimaritin, eupatorin, and hispidulin—showed significant in vitro PTP1B inhibition. Dose-response assays revealed IC₅₀ values of 29.57 ± 4.11, 23.53 ± 1.90, and 15.93 ± 1.13 µM for cirsimaritin, eupatorin, and hispidulin, respectively, identifying the latter as the most potent inhibitor. Enzyme kinetics demonstrated noncompetitive inhibition by eupatorin and hispidulin, while cirsimaritin followed a mixed inhibition mode. Docking and MD simulations confirmed stable binding within the PTP1B active site, and principal-component-analysis (PCA) alongside Free energy landscape (FEL) evaluations showed that the enzyme-ligand complexes favored energetically stable conformations. Further corroboration using MM/PBSA free-energy-calculations supported the superior binding affinity of hispidulin, consistent with its in vitro potency. Finally, ADME (Absorption, Distribution, Metabolism, and Excretion) predictions indicated favorable drug-like properties for all three compounds, including high gastrointestinal absorption and no violations of Lipinski’s rule of five. Collectively, these findings establish cirsimaritin, eupatorin, and hispidulin as promising scaffolds for the development of novel PTP1B inhibitors targeting metabolic disorders.