MMP-9 inhibitor I is an inhibitor of matrix metalloproteinase-9 (MMP-9) that is selective over MMP-1 and MMP-13 (IC50s = 5, 1,050, and 113 nM, respectively). It also decreases the activity of TNF-α converting enzyme (TACE) in a dose-dependent manner (IC50 = 0.54 μM). MMP-9 inhibitor I decreases TNF-α secretion stimulated by LPS in BV-2 microglial cells when used at concentrations of 50 and 100 μM.