Equisetum diffusum methanolic extract attenuates arthritis through the modulation of key inflammatory biomarkers like COX-2, TNF-α, IL-6, PPAR-γ and Iκβ expression in Adjuvant-induced rats.

Abstract Rheumatoid arthritis (RA) is a chronic inflammatory disease associated with subsequent damage to the bone joints. Equisetum diffusum D. Don, from the Equisetaceaefamily, is a native pteridophyte species of the sub-Himalayan region of India and has been reported to have a diverse array of pharmacological properties. The present research is focused on determining the anti-arthritic potential of E. diffusum whole plant methanolic extract (EDME) in adjuvant-induced arthritic rats. Treatment with EDME significantly restored paw-edema, arthritic scoring, and normal body weight. EDME treatment also normalized the haematological, biochemical, radiological, and histological status when compared to the arthritic control rats. The methanolic extract significantly (p<0.05) attenuated arthritis progression by downregulating the gene expression of pro-inflammatory mediators, like COX-2, TNF-α, IL-6, and upregulating the expression of anti-inflammatory mediators PPAR-γ, Iκβ in a dose-dependent manner. Significantly, EDME also reduced the serum concentration of COX-2, TNF-α, and IL-6 compared to arthritic control rats (p<0.05). The treatment with EDME also normalized the oxidative stress level in liver by restoring the GSH level, CAT and SOD activities and reducing the elevated MDA level. HPTLC and LC-MS/MS analyses of EDME confirmed the presence of potent polyphenols (chlorogenic acid, 4-hydroxycinnamic acid) and flavonoids (kaempferol), thereby suggesting the anti-arthritic property of the plant. All our findings established the anti-arthritic potential of E. diffusum extract in chronic arthritis model on a strong ground.