PTGS2 and osteoarthritis: Olive and grape seed extract prevents post-traumatic osteoarthritis damage by inhibiting IL-1β-induced NO, PGE2, and MMP-13 expression [18], and wogonin (5,7-dihydroxy-8-methoxyflavone) protects cartilage by inhibiting the expression of inflammatory mediators (nitrite oxide, PGE2, COX-2, and iNOS) and ECM proteases (MMP-3, MMP-13, and ADAMTS-4) [19].