ANTIRADICAL ACTIVITY OF L-GLUTAMINE, L-ASPARAGINE AND L-ASPARTIC ACID DERIVED REDUCED SCHIFF BASE COPPER(II) COMPLEXES

Abstract

Superoxide dismutases (SOD) are a group of metallo-enzymes, containing one or two coordinated metals, and their main role in the organism is protection against superoxide radicals, one of the reactive oxygen species (ROS). Among these Cu(II)-Zn(II) SOD is present in cytoplasm and acts as a scavenger of superoxide radicals. Cu(II)-complexes may act as low-molecule analogue of Cu-Zn SOD and therefore are being studied as antiradical agents. In this study a series of Cu(II) complexes were synthesizes, containing ligands prepared from salicyl aldehyde and amino acids: L-asparagine, L-glutamine and L-aspartic acid. Complexes prepared from L-asparagine and L-glutamine are novel and were compared with the already reported complex Cu(HSal-L-Asp) hydrate (6e). An assay based on the ability to inhibit reduction of iodonitrotetrazolium dye (INT) by superoxide anion-radicals was used to determine antiradical activity of these complex. The prepared complexes - Cu(HSal-L-Asn) acetate (6a), Cu(HSal-L-Asn) hydrate (6b) and Cu(HSal-L-Gln) acetate (6c) proved to be good antiradical agents compared to complex 6e. The IC₅₀ values of the radical transport were 19.2 ± 1.2 μM for 6a, 53.9 ± 9.4 μM for 6b and 4.11 ± 0.37 mM for 6c.