IN VITRO ANTIOXIDANT PROPERTIES OF BASIC ortho-/meta-ALKOXYPHENYLCARBAMIC ACID ESTERS BEARING 4-(4-FLUORO-/3-TRIFLUOROMETHYLPHENYL)PIPERAZIN-1-YL FRAGMENT

In order to find out if new perspective antagonists of beta-adrenergic receptors, ortho-/meta-alkoxyphenylcarbamic acid esters containing fluorinated N-phenylpiperazine fragment (labelled as 6a-6f and 8a-8e), might also act as the antioxidants, the aim of current study was to investigate their antioxidant profile by applying two in vitro methods. Following mentioned, the capability of these compounds to reduce relatively stable reference 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals in performed spectrophotometric analyses and to protect tyrosine from the peroxynitrite mediated nitration by applying the HPLC method was inspected. The position of alkoxy side chain bonded to lipophilic aromatic moiety as well as the ability of hydrogen bond formation and electrostatic effects, which have been induced by fluoro or trifluoromethyl substitution within the aromatic fragment of 4-phenylpiperazin- 1-yl, have been considered the essential factors, which have influenced an antioxidant potential of investigated molecules. It could be hypothesized that isosteric replacement of etheric bridge for carbamoyloxy moiety has not probably been favorable structural modification in terms of an antioxidant effect. Relatively high lipophilicity of all tested compounds might be important, however, it was not an essential aspect which has affected such potency. From the entire investigated set, ortho-methoxy substituted compound 6a involving 4-(4-fluorophenyl)piperazin-1-yl moiety has been able to reduce the DPPH radicals most markedly. The in vitro studies have also pointed to the most pronounced peroxynitrite ions scavenging potential of the substance 8c, a meta-propoxy substituted compound which has contained 4-(3-trifluoromethylphenyl)piperazin-1-yl group.