Microalgae-Based Fucoxanthin Attenuates Rheumatoid Arthritis by Targeting the JAK-STAT Signaling Pathway and Gut Microbiota

Fucoxanthin, an abundant carotenoid in marine algae, has garnered attention for its diverse health benefits, including anti-inflammatory and anticancer properties. Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation and damage. This study investigated the therapeutic potential of fucoxanthin extracted from <i>Phaeodactylum tricornutum</i> in collagen-induced RA. Our results demonstrated that fucoxanthin significantly alleviated RA symptoms, including weight loss, joint swelling, and decreased appetite. Histological analysis revealed that fucoxanthin mitigated synovial inflammation, cartilage damage, and bone erosion. Mechanistically, transcriptomic analysis and cell experiments indicated that fucoxanthin suppressed the JAK-STAT signaling pathway by downregulating the expression of inflammatory cytokines, such as IL-6 and IL-1β. Furthermore, metagenomic analysis suggested that fucoxanthin restored the altered gut microbiota composition associated with RA. These findings highlight the therapeutic potential of fucoxanthin from <i>P. tricornutum</i> in the management of RA by targeting multiple pathways, including inflammation and gut microbiota.