Yeni̇ hi̇drazon türevleri̇ni̇n sentezlenmesi̇, radi̇kal gi̇derme akti̇vi̇teleri̇ni̇n ve i̇nsan serumundan saflaştirilan paraoksonaz-1 enzi̇mi̇ üzeri̇ne i̇n vi̇tro i̇nhi̇bi̇syon etki̇leri̇ni̇n araştirilmasi

In this study, four new hydrazone derivatives were synthesized and their structures have been elucidated by X-Ray Diffraction (XRD), Nuclear Magnetic Resonance (H-NMR), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectrophotometry (UV-VIS) scanning and elemental analysis techniques. All the newly synthesized compounds were subjected to screening for their free radical scavenging activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Compound B-2,4-MBPyH with the lowest IC50 value of (0.185 mg/mL) showed the highest free radical scavenging activity of DPPH. Paraoxonase-1 (PON1: EC 3.1.8.1) is a calcium-dependent enzyme associated with high-density lipoproteins (HDLs) and has a protective effect against oxidation of low-densitylipoproteins (LDLs) in mammals. In this study, human serum paraoxonase1 (hPON1) was purified using two-step procedures, namely ammonium sulphate precipitation and Sepharose-4B-L-tyrosine-1-naphthylamine hydrophobic interaction chromatography. SDS–polyacrylamide gel electrophoresis of the purified enzyme showed a single band with an apparent MW of 43 kDa. The purified enzyme had a specific activity of 21.22 U/mg. The overall purification fold and yield were found to be % 17.484 and 561.375 respectively. Furthermore, using the paraoxon as a substrate, we determined the Km and Vmax values of the purified enzyme, as 0.018496 mM and 114.955 U/mL, respectively. In this study, in vitro inhibition effect of these synthesized novel compounds on purified hPON1 were also investigated by using paraoxon as a substrate. The results showed that all the hydrazone derivatives inhibited the hPON1 enzyme activity in a concentration-dependent fashion. Among the studied hydrazone derivatives, B-2,3-MBPyH was found to be the most effective inhibitor for hPON1 activity, with the lowest IC50 values of (0.0138 mg/mL). The present study has demonstrated that hPON1 activity is very highly sensitive to studied hydrazone derivatives. Key Words: Schiff Base, Hydrazone Derivatives, DPPH, hPON1, Inhibition, Hydrophobic Interaction Chromatography.