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

Was demonstrate the protection ability against reactive oxygen species affo rded to S. cerevisiae (wild-type strain SP4 and its mutants deficient in ma jor antioxidant enzymes - catalase T and A, CuZnSOD) by PYA and PYE, new gr oups of phenolic antioxidants (quaternary ammonium salts of dihydrocinnamic acid amino esters with different alkyl chains; synthesized in this laborat ory). 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 TB HP 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 ce lls of both the wild-type and the mutant strains with the phenolic antioxid ants prior to exposure to TBHP or ACCN substantially increased the cell sur vival. The magnitude of protection depended on the strain and the length of the alkyl chain of the antioxidant; the best average protection against TB HP was provided by PYE and PYA compounds with 12- and 16-membered alkyl cha ins whereas PYE-8 and PYA-12 derivatives afforded the best average protecti on against ACCN.