DPP-4-IN-8 (compound 27) is a potent and selective DPP4 ( dipeptidyl peptidase 4) inhibitor, with a K i of 0.96 μM. DPP-4-IN-8 blocks the dipeptidase activity of DPP4 in both Caco-2 and HepG-2 cells. DPP-4-IN-8 also dose-dependently suppresses the expression levels of the chemokines tumor necrosis factor-α (TNF-α), interleukin-6 ( IL-6 ), and interleukin-1β (IL-1β).