Protective effects of Syringic acid on joint inflammation and damage in a rat model of rheumatoid arthritis

Inflammation and joint damage are hallmarks of rheumatoid arthritis (RA), a chronic autoimmune disease.

This study investigated the anti-arthritic efficacy and mechanisms of Syringic acid (SA), a natural phenolic compound, in a Complete Freund's Adjuvant (CFA)-induced arthritis rat model.

Arthritis was induced in Wistar rats, which were then orally treated with SA (50, 100, 200 mg/kg) or prednisolone for 28 days. Paw swelling, arthritic index, body weight, motor functions, cytokine levels (Nuclear factor kappa B (NF-κB), Tumor necrosis factor alpha (TNF-α), Interleukin-6 (IL-6), Interleukin-1 beta (IL-1β)), antioxidant enzyme activities, histopathology, and radiological changes were assessed. Molecular docking studies were also performed.

SA significantly reduced paw swelling and arthritic index, improved body weight and motor functions, and modulated inflammatory cytokines (NF-κB, TNF-α, IL-6, IL-1β) and oxidative stress markers dose-dependently. Histopathological and radiological analyses confirmed SA's protective effects on joint integrity. Docking studies showed strong binding affinities of SA to NF-κB and TNF-α. SA exhibits significant anti-inflammatory and anti-arthritic properties in CFA-induced RA, modulating cytokine pathways and reducing oxidative stress.

These findings suggest SA's potential as a therapeutic agent for RA, warranting further clinical investigation. Key Points • Syringic acid (SA) modulated key pro-inflammatory cytokines (NF-κB, TNF-α, IL-6, IL-1β) and enhanced antioxidant enzyme activities. • Molecular docking demonstrated strong binding of SA with NF-κB and TNF-α, supporting its immunomodulatory role. • The findings highlight SA's potential as a natural immunomodulator for RA, warranting further clinical exploration.