New phenolic antioxidants of PYA and PYE class increase the resistance S. cerevisiae strain SP4, its SOD- and catalase-deficient mutants to lipophilic oxidants.

Was demonstrate the protection ability against reactive oxygen species afforded to S. cerevisiae (wild-type strain SP4 and its mutants deficient in major antioxidant enzymes--catalase T and A, CuZnSOD) by PYA and PYE, new groups of phenolic antioxidants (quaternary ammonium salts of dihydrocinnamic acid amino esters with different alkyl chains; synthesized in this laboratory). The survival of strains exposed to the lipophilic oxidation inducers tert-butyl hydroperoxide (TBHP) and 1,1'-azobis(4-cyclohexane carbonitrile) (ACCN) with or without antioxidant pretreatment was determined by plating. S. cerevisiae mutant deficient in SOD was found to be hypersensitive to TBHP and ACCN while the sensitivity of the strain deficient in catalase T and A was about the same as in the wild-type strain. A 1-h preincubation of cells of both the wild-type and the mutant strains with the phenolic antioxidants prior to exposure to TBHP or ACCN substantially increased the cell survival. The magnitude of protection depended on the strain and the length of the alkyl chain of the antioxidant; the best average protection against TBHP was provided by PYE and PYA compounds with 12- and 16-membered alkyl chains whereas PYE-8 and PYA-12 derivatives afforded the best average protection against ACCN.