Browsing by Author "Safak, Cihat"

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    Electrochemical Detection of Antioxidant Activities of 4-Indolyl-5-Oxo-6,6 (Or 7,7)-Dimethyl-1,4,5,6,7,8-Hexahydroquinoline Derivatives
    (2021) Suslu, Incilay; Kablan, Sevilay Erdogan; Safak, Cihat; Simsek, Rahime
    Antioxidants used in different medical and industrial fields in order to prevent and delay oxidative stress. They play a crucial role in the protecting biological systems against many diseases. 1,4-dihydropyridines are known as calcium channel modulators. Electrochemical techniques are simple, cheap and fast detection techniques and require small amounts of sample, so they offer advantages over commonly used analytical methods. Voltammetric methods have been applied to investigated the antioxidant activity of compounds in different fields. The proposed work is aimed at examining the electrochemical behavior of the 1,4-dihydropyridines by differential pulse voltammetry and hence the assessment of its antioxidant activity from the cathodic reduction peak of oxygen values. The peak current due to oxygen reduction was found to be proportional to the 1,4-dihydropyridines concentration of 0.1 - 0.5 mg/mL. The coefficient of antioxidant activity of 1,4-dihydropyridine derivatives were calculated and compared each other. Nifedipine used as a reference drug that is known as the calcium channel modulator and it is used to compare the antioxidant activities of 1,4-dihydropyridine-derived compounds.
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    Theoretical and experimental investigation of 1,4-dihydropyridine-based hexahydroquinoline-3-carboxylates: Photophysics and bovine serum albumin binding studies
    (2022) da Luz, Lilian Camargo; Gunduz, Miyase Gozde; Beal, Roiney; Zanotto, Gabriel Modernell; Kuhn, Eduardo Ramires; Netz, Paulo Augusto; Safak, Cihat; Bruno Goncalves, Paulo Fernando; Santos, Fabiano da Silveira; Rodembusch, Fabiano Severo
    In this article, the binding affinity of 1,4-dihydropyridine-based hexahydroquinoline-3-carboxylates with bovine serum albumin (BSA) was studied by electronic spectroscopies, quantum calculations, and molecular docking. These compounds were obtained by the one-pot microwave-assisted method via a modified Hantzsch reaction. The photophysical characterization showed in organic solutions absorption maxima in the UV region, ascribed to spin and symmetry allowed electronic transitions (1)pi-pi*. In addition, they presented a main fluorescence emission in the violet-blue regions (406-445 nm), with a relatively large Stokes shift (54-81 nm), depending on the structure of the compounds. BSA fluorescence quenching experiments based on the intrinsic fluorescence of the Trp residues were successfully applied to these compounds, indicating strong interaction with BSA by a static mechanism. The docking simulations corroborated the strong interaction between the studied compounds and BSA, where the surroundings of Trp213 seemed to be the preferred interaction site for all compounds and were responsible for the fluorescence quenching effects.