High Lipophilicity of meta Mn(III) N-Alkylpyridylporphyrin-Based Superoxide Dismutase Mimics Compensates for Their Lower Antioxidant Potency and Makes Them as Effective as Ortho Analogues in Protecting Superoxide Dismutase-Deficient Escherichia coli

Lipophilicity/bioavailibility of Mn(III) N-alkylpyridylporphyrin-based superoxide dismutase (SOD) mimics has a major impact on their in vivo ability to suppress oxidative stress. Meta isomers are less potent SOD mimics than ortho analogues but are 10-fold more lipophilic and more planar. Enhanced lipophilicity contributes to their higher accumulation in cytosol of SOD-deficient Escherichia coli, compensating for their lower potency; consequently, both isomers exert similar-to-identical protection of SOD-deficient E. coli. Thus meta isomers may be prospective therapeutics as are ortho porphyrins.