Investigating the anti-inflammatory and anti-arthritis effects of fucoidan from a brown seaweed

Severe inflammation in joints caused by the detrimental effects of the immune system is termed Rheumatoid arthritis. The unconstrained proliferation of immune cells and pro-inflammatory cytokines deteriorates Synovium which secretes synovial fluid to lubricate joints and cartilage. Non-steroidal anti-inflammatory drugs (NSAIDs) are the only therapeutics for treating rheumatoid arthritis, and long-term intake causes serious side effects on the organs. Fucoidan, a sulfated polysaccharide found on the cell walls of brown algae shows bioactive potential. In our study, fucoidan was extracted from Padina pavonica (PD), Stoechospermum marginatum (StM), Spatolossum macrodontum (SpM), Dictyota bartayresiana (DD), and Turbinaria decurrens (TD) and evaluated for anti-inflammatory and anti-arthritis activities. Fucoidan was extracted and evaluated for anti-inflammatory activity in vitro using RAW 264.7 macrophage cell lines, followed by in vivo anti-arthritis activity on Wistar male rats. Nitric oxide suppression was comparatively high in fucoidan from TD (IC₅₀ − 12.93 µg/mL). Purified fucoidan from TD, significantly reduced inflammation, size of paw edema, downregulated proinflammatory cytokines (IL-6, IL-1β, TNF-α), and upregulated anti-inflammatory cytokine (IL10) in CFA-induced arthritis in Wistar male rats. Biochemical parameters like SOD, CAT, GSH, GPX, and GST and haematological parameters like total-protein, albumin, haemoglobin, and RBC were upregulated, and other parameters like urea, uric acid, creatinine, bilirubin, SGOT, SGPT, ALP, WBC, ESR, RF, and CRP were downregulated. Histopathology of the liver, kidney, and ankle joints reveals that fucoidan intake restrained inflammation and tissue damage. Therefore, fucoidan extracted from TD is a potential candidate for the treatment of rheumatoid arthritis.