Aromatic indolinic aminoxyls as antioxidants in cardiac sarcoplasmic reticulum lipid and protein oxidation.

The results presented demonstrate the influence of aromatic indolinic aminoxyls: 1,2-dihydro-2-ethyl-2-phenyl-3H-indole-3-phenylimino-1-oxyl (IA-C2) and 1,2-dihydro-2-octadecyl-2-phenyl-3H-indole-3-phenylimino-1-oxyl (IA-C18) on oxidation of lipids and proteins of cardiac sarcoplasmic reticulum membranes. We have used doxorubicin and t-butyl hydroperoxide as agents inducing oxidative stress in isolated rat cardiac sarcoplasmic reticulum membrane system. Carbonyl groups were measured as the end product of membrane protein oxidation, and thiobarbituric acid reactive substances were assessed as a marker of lipid peroxidation. Inhibition of peroxidation of certain membrane components depends on the length of acyl chain. Aminoxyl IA-C2 inhibits the lipid peroxidation process while IA-C18 is an efficient protector against protein oxidation.