MMP9 and rheumatoid arthritis: Yoon et al. [202] observed in FLS that gallic acid (a polyphenol found in grapes, tea, gall nuts, sumac, and wine) reduced the expression levels of proinflammatory cytokines (IL-1β and IL-6) and enzymes, including MMP-9 and COX-2, which are involved in the inflammation and oxidation-induced pathogenesis of RA.