Elaeocarpus sylvestris extract (ESE) inhibits inflammatory mediators and increases the efficacy of sulfasalazine in rheumatoid arthritis

Abstract

Background: Interest in plant-based therapeutic products for treatment of several autoimmune diseases, including rheumatoid arthritis (RA), is increasing as current RA medications and treatments are either very expensive or ineffective. Purpose: We investigated the anti-inflammatory activity of Elaeocarpus sylvestris extract (ESE) and its therapeutic potential in collagen-induced arthritis (CIA) in the DBA/1 J mouse model and an in vitro model. Methods: In the in vitro assay, the effects of ESE and a combination of ESE + sulfasalazine (SLZN) on nitric oxide and proinflammatory cytokine expression induced by lipopolysaccharide in RAW264.7 cells were confirmed. Furthermore, enzyme-linked immunosorbent assays and real-time polymerase chain reactions were used to measure levels of RA-related inflammatory cytokines and biomarkers in serum and knee joints to evaluate the changes caused by co-administration of ESE and SLZN in our mouse CIA model. Micro-CT scans of knee joints were analyzed for all groups. Results: ESE and the combination of ESE + SLZN downregulated the expression of lipopolysaccharide-induced nitric oxide and proinflammatory cytokines in RAW264.7 cells. Also, combined ESE and SLZN treatment improved arthritis score, edema volume, and proinflammatory cytokine serum levels compared with the CIA group. In addition, chemokine expression was downregulated compared with the CIA group. Conclusion: These findings suggest that coadministration of ESE and SLZN can improve the efficacy of arthritis treatment with reduced side effects.

Keywords

• Rheumatoid arthritis
• Collagen-induced arthritis
• Inflammation
• Elaeocarpus sylvestris
• Sulfasalazine