Elucidating the Multi-Target Therapeutic Mechanisms of Quercetin in Rheumatoid Arthritis: A Network Pharmacology, Molecular Docking, and In-Vitro Study.

Abstract
Background: Rheumatoid arthritis (RA) is a prevalent autoimmune disorder that causes
chronic inflammation, stiffness, and progressive destruction of synovial joints. Traditional
Ayurvedic formulations contain multi-target phytoconstituents that can modulate complex
inflammatory pathways. Network pharmacology provides a holistic, systems-based approach
to understanding these synergistic therapeutic mechanisms.
Objective: This study aims to elucidate the multi-target therapeutic mechanisms of quercetin,
a prominent Ayurvedic phytoconstituent, against RA by integrating network pharmacology,
molecular docking, and in-vitro experimental validation.
Methodology: Quercetin’s pharmacokinetic properties and targets were retrieved using
TCMSP and SwissTargetPrediction. RA-related genes were collected from GeneCards,
OMIM, and DisGeNET. Protein-protein interaction (PPI) networks were constructed via
STRING and Cytoscape, followed by GO and KEGG enrichment analyses. Binding affinities
were simulated using molecular docking. Finally, in-vitro validation was conducted using
TNF-α-induced Rheumatoid Arthritis Fibroblast-Like Synoviocytes (RAFLS), evaluated
through MTT assays, ELISA, RT-PCR, Western blotting, and flow cytometry.
Results: Network analysis revealed 58 intersecting therapeutic targets, with TNF, IL6, AKT1,
and MAPK1 identified as central hub genes. KEGG analysis demonstrated significant
enrichment in TNF and NF-κBsignaling pathways. Molecular docking showed strong binding
energies, notably with COX-2 (-9.0 kcal/mol) and TNF-α (-8.7 kcal/mol). In-vitro
experiments confirmed that quercetin dose-dependently reduced abnormal RAFLSproliferation, significantly suppressed inflammatory cytokines (IL-1β, IL-6, TNF-α),
downregulated NF-κB and MAPK protein expression, reduced oxidative stress, and promoted
cellular apoptosis.
Conclusion: Quercetin demonstrates significant potential as a multi-target therapeutic agent
for rheumatoid arthritis. By integrating computational predictions with in-vitro validation, the
study concludes that quercetin effectively mitigates disease progression by synergistically
modulating key inflammatory pathways, suppressing cytokine production, and reducing
abnormal cellular proliferation and oxidative stress.