SPHK1 and rheumatoid arthritis: and Jaspis. sp., and in an in vivo rat model of complete Freund’s adjuvant rheumatoid arthritis (RA), showed it acted as a SphK1 inhibitor in vitro and significantly improved RA symptoms measured by decreased pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, swelling volume, and arthritis score [87].