Suppression of Lipid Autoxidation by Small Amounts of Isotope-reinforced Polyunsaturated Fatty Acids
Polyunsaturated fatty acids (PUFAs) are vulnerable to damages by free radicals and other oxidative compounds. Facile abstraction of bis-allylic hydrogen atoms is responsible for initiation and propagation of PUFA autoxidation. PUFA oxidation products can react with other macromolecules affecting a wide range of biological functions. Replacing bis-allylic hydrogen atoms with deuterium makes PUFAs resistant to autoxidation. In this study, we showed that yeast coq mutants lacking lipophilic antioxidant coenzyme Q were exquisitely sensitive to PUFA autoxidation. Their loss of viability can be arrested by treatment of a PUFA mixture containing only a small fraction of deuterated-PUFA. The HPLC-MS/MS analysis has identified elevated levels of hydroxyoctadecadienoic acids (HODEs) and potential yeast ergosterol-derived oxysterols in linoleic acid supplemented yeast cells and found the amounts of these lipid oxidation products were significantly lower in cells treated with deuterated linoleic acid.