Sarikaya, S. Beyza Ozturk; Sisecioglu, Melda; Cankaya, Murat; Gulcin, Ilhami; Ozdemir, Hasan

Lactoperoxidase (LPO) catalyzes the oxidation of numerous of organic and inorganic substrates by hydrogen peroxide. It has very vital activity in the innate immune system by decreasing or stopping the activation of the bacteria in milk and mucosal secretions. This study's purpose was to investigate in vitro effect of some phenolic acids (ellagic, gallic, ferulic, caffeic, quercetin, p-coumaric, syringic, catechol and epicatechin) on the purified LPO. This enzyme was purified from milk by using different methods such as Amberlite CG-50 resin, CM-Sephadex C-50 ion-exchange and Sephadex G-100 gel filtration chromatography. LPO was purified 28.7-fold with a yield of 20.03%. We found phenolic acids have inhibition effects on bovine LPO enzyme to different concentrations. Our study showed lower concentrations of caffeic acid, ferulic acid and quercetin exhibited much higher inhibitory effect on enzyme, so these three of them were clearly a more potent inhibitor than the others were. All of compounds were non-competitive inhibitors.

Afsin Kaya, A.; Kaya, Elif Celenk; Sarikaya, S. Beyza Ozturk; Onaran, Abdurrahman

The new 3,4-dimethoxybenzoate complex of Cu(II) with nicotinamide was synthesized and characterized by elemental analysis, FT-IR spectroscopic study, UV-Vis spectrophotometry and mass spectrometry. The thermal behavior of the complex was studied by simultaneous TG, DTG and DTA methods in static air atmosphere. The infrared spectral characteristics of the complex is also discussed. In this complex, all ligands are coordinated to the metal ion as monodendate ligands. The final decomposition products were found to be the respective metal oxide. As it is well known, metal complexes of biologically important ligands are sometimes more effective than the free ligands. In this study the new compound was synthesized due to its functional groups such as veratric acid and nikotin amide, which have known biological characteristics and effective in terms of both enzyme and antifungal properties from recent studies. Therefore, antifulgal activity and enzyme inhibition properties of this complex have been examined.