The regulative effect of EGCG on RA can occur through the expression of cytokines, chemokines, matrix metalloproteinases (MMPs), aggrecanase, reactive oxygen species (ROS), nitric oxide (NO), cyclooxygenase-2 (COX-2), and prostaglandin E2 (PGE2). Here, PTGS2 is linked to rheumatoid arthritis.