4-Methylumbelliferone

4-Methylumbelliferone (4-?U) is a synthetic coumarin with diverse biological activities.{52251,52252,27251} It inhibits hyaluronic acid synthesis in PC3-ML and DU145 cells (IC50s = ~0.4 mM for both).{52251} 4-MU inhibits the growth of PC3-ML, DU145, C4-2B, LNCaP, and LAPC-4 prostate cancer cells (IC50s = 0.2-0.4 mM) and invasion and chemotactic motility of PC3-ML and DU145 cells in vitro. It reduces tumor growth and microvessel density in a PC3-ML mouse xenograft model when administered at doses of 225 and 450 mg/kg twice per day. 4-?U is active against H. pylori and V. cholerae in vitro (MICs = 59 and 100-200 ?g/ml, respectively).{52252} Derivatives and conjugates of 4-?U have been used as fluorogenic substrates to measure enzyme activity.{39610,26284,47304} Upon enzymatic cleavage, 4-?U is released and its fluorescence can be used to quantify enzyme activity. 4-MU fluorescence is pH-dependent with excitation maxima of 320 and 360 nm at low (1.97-6.72) and high pH (7.12-10.3), respectively, and an emission maximum ranging from 445 to 455 nm, increasing as pH decreases.{27251}