Mn(II) Complexes of Enlarged Scorpiand-Type Azamacrocycles as Mimetics of MnSOD Enzyme

Living organisms depend on superoxide dismutase (SOD) enzymes to shield themselves from the deleterious effects of superoxide radical. In humans, alterations of these protective mechanisms have been linked to the pathogenesis of many diseases. However, the therapeutic use of the native enzyme is hindered by, among other things, its high molecular size, low stability, and immunogenicity. For this reason, synthetic SOD mimetic compounds of low molecular weight may have therapeutic potential. We present here three low-molecular-weight compounds, whose Mn2+ complexes can mimic, at least partially, the protective activity of SOD-enzymes. These compounds were characterized by NMR, potentiometry, and, to test whether they have protective activity in vitro, by their capacity to restore the growth of SOD-deficient strains of E. coli. In this report, we provide evidence that these compounds form stable complexes with Mn2+ and have an in vitro protective effect, restoring up to 75% the growth of the SOD-deficient E. coli.