Effects of mono and dinuclear copper(II) complexes derived from non-steroidal anti-inflammatory drug naproxen on human serum paraoxanase1 (PON1) activity

The inhibition of human paraoxonase 1 (PON1, EC 3.1.8.1) enzyme, with two Cu(II) complexes derived from naproxen was investigated by using the paraoxonase activity method with diethyl 4-nitrophenyl phosphate as substrate. The complexes [Cu 2 (µ-nap) 4 (3-pic) 2 ] (1) and [Cu(nap) 2 (H 2 O)(4-pic) 2 ] (2) decreased the in vitro PON1 activity with different inhibition mechanisms. The inhibition mechanism of complex 1 was uncompetitive whereas complex 2 was noncompetitive inhibitors. In this study, complexes mentioned above showed effective inhibitory activity on PON1.  IC 50 values for [Cu 2 (µ-nap) 4 (3-pic) 2 ] (1) and [Cu(nap) 2 (H 2 O)(4-pic) 2 ] (2) were of 0.109 mM and 0.103 mM for PON1, respectively. K i values for complex 1 and complex 2 were of 0.116 mM and 0.121 mM for PON1, respectively.