Antioxidative Activity of Potential Antihypertensives with Dual Effect

Abstract

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.