Moringa rivae leaf extracts attenuate Complete Freund’s adjuvant-induced arthritis in Wistar rats via modulation of inflammatory and oxidative stress biomarkers

Moringa rivae is widely used as a traditional remedy against arthritis. The present research was designed to evaluate the anti-arthritic potential of Moringa rivae extracts. Treatment of rats with adjuvant-induced arthritis with methanolic and aqueous extracts of M. rivae (150, 300 or 600 mg/kg), and piroxicam (10 mg/kg) was started orally at day 8 post-administration of complete Freund’s adjuvant and continued till 28th day. The therapeutic effect of the plant extracts was assessed in arthritic rats by arthritic index, body weight, and haematological and biochemical parameters. Furthermore, the modulatory effect on gene expression (I-κB, IL-4 and IL-10, COX-2, IL-1β and IL-6, NF-κB, and TNF-α) in the blood was determined using qRT-PCR, while ELISA assay was used to find PGE2 and TNF-α concentrations in the serum. Oxidative stress parameters in the liver and ankle joint histopathology were also evaluated. Moreover, the most effective methanolic extract was further characterized by GC–MS for the presence of phytochemicals. Treatment with the plant extracts significantly restored arthritic index, change in the body weight and immune organ weight, and the histopathological indices. Both extracts significantly (p < 0.05) reduced the serum concentration of rheumatoid factor, C-reactive protein, PGE2, and TNF-α in arthritic rats. The extracts persuasively down-regulated the COX-2, PGE2, IL-1β, IL-6, NF-κB, and TNF-α, and up-regulated the mRNA expression of I-κB, IL-4, and IL-10. Both extracts increased the activities of CAT and SOD while reducing the formation of MDA in a dose- dependent manner in the liver. Histopathological evaluation showed that treatment with the plant extracts significantly (p < 0.05) reduced joint inflammation, pannus formation, and bone erosion in treatment groups in comparison to arthritic control. Phytochemicals detected by GC–MS in the methanolic extract included esters, alcohols, ketones, fatty acids, and vitamin E. These findings provide evidence of the anti-arthritic potential of M. rivae extracts in chronic polyarthritis model.