MAPK8 and rheumatoid arthritis: EVOO-polyphenol extract (PE), which is extracted from extra virgin oil (EVOO), exerts anti-RA effects via downregulation of TNF-α, IL-1β, IL-6, PEG2, p38, JNK, p65, and lκB-α at a dose of 100 and 200 mg/kg when collagen-induced arthritis (CIA) rats were treated for 13 days [49].