Amphiphilic amine-N-oxides with aliphatic alkyl chain act as efficient superoxide dismutase mimics, antioxidants and lipid peroxidation blockers in yeast

摘要

Amphiphilic 3-(alkanoylamino)propyldimethylamine-N-oxides with different length of the alkyl chain,i.e. different hydrophilic-lipophilic balance, act in micromolar concentrations as SOD mimics by lifting the inhibition of aerobic growth caused by SOD deletions inSaccharomyces cerevisiae. They also enhance the survival ofsod mutants ofS. cerevisiae exposed to the hydrophilic superoxide-generating prooxidant paraquat and the amphiphilic hydroperoxide-producingtert-butylhydroperoxide (TBHP), and largely prevent TBHP-induced peroxidation of isolated yeast plasma membrane lipids. Unlike the SOD-mimicking effect, the magnitude of these effects depends on the alkyl chain length of the amine-N-oxides, which incorporate intoS. cerevisiae membranes, causing fluidity changes in both the hydrophilic surface part of the membrane and the membrane lipid matrix. Unlike wild-type strains, the membranes ofsod mutants were found to contain polyunsaturated fatty acids; the sensitivity of the mutants to lipophilic pro-oxidants was found to increase with increasing content of these acids.sod mutants are useful in assessing pro- and antioxidant properties of different compounds.