PTGS2 and colitis: Piperine impedes the progression of TNBS-induced colitis through regulating the nuclear factors of kappa light polypeptide gene enhancers in the B cell inhibitor-α/NF-κB signal pathway, to inhibit the overexpression of proinflammatory cytokines (TNF-α and ILs), cyclooxygenase-2(COX-2), colonic inducible nitric oxide synthase (iNOs), and oxidative-nitrous acid stress [53, 54] (Fig. 2).