Antioxidative Activity of Potential Antihypertensives with Dual Effect
a Institute of Chemistry, Slovak Academy of Sciences, Bratislava, b Department of Organic Chemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic, c Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic, d Laboratory of Growth Regulators, Palacky University, Olomouc, Czech Republic, e Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Banská Bystrica, Slovak Republic
The antioxidative properties of four 1-(2-benzofuran-2-yl-2-hydroxyethyl)-4-phenylpiperazines were studied by indirect spectrophotometric and direct ESR spin-trap methods. The radical scavenging activity of the tested compounds was determined. The compounds exhibit interesting structure-specific redox properties. Scavenging of DPPH radicals gave very poor results. The studied compounds did not affect the elimination of superoxide anion radicals; however, they caused stimulation of radical production. The hydroxyl radicals, however, were scavenged only by 2-fluoro¬phenyl derivatives, whereas the 4-fluorophenyl derivatives exhibited a slightly prooxidative effect. The capture of HO• radicals by 2-fluorophenyl derivatives was, according to the results of NMR analyses, attributed to the interaction with non-protonated piperazine nitrogen atom, which is stabilized by the hydrogen bond between the hydroxy group and fluorine atom.
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