PTGS2 and rheumatoid arthritis: In the treatment of rheumatoid arthritis (RA) and osteoarthritis (OA), flavonoids and triterpenoids have been shown to have good anti-inflammatory effects by inhibiting matrix metalloproteinase (MMP) and cyclooxygenase-2 (COX-2), reducing the production of inflammatory cytokines and chemokines such as tumor necrosis factor-α (TNF-α), IL-1, IL-6, and chemokine C-C motif ligand 5 (CCL5) by acting on different targets in the NF-κB (nuclear factor-kappa B) signaling pathway [29].