Is a relay mechanism of antioxidant effect of tocopherols valuable for membrane systems?
Serbinova, E.; Tyurin, V.; Stoytchev, S.; Kagan, V.
Acta Physiologica et Pharmacologica Bulgarica 11(3): 55-60
1985
ISSN/ISBN: 0323-9950 PMID: 3008500 Document Number: 252165
The efficiency of the inhibitory action of 3 tocols derivatives-alpha-tocopherol (.alpha.-T), 2,2,5,7,8-pentamethylchromane (PMC) and alpha-tocopherylacetate (.alpha.-TA) on lipid peroxidation (LPO) in rat liver microsomes was compared. LPO was induced by O2+-generating systems (Fe2++NADPH, Fe2++ascorbate) or by ROO-generating system (Fe2+ + tert-butyl hydroperoxide). It was found that PMC was much more potent LPO inhibitor than .alpha.-T, whereas .alpha.-TA was ineffective in all LPO-initiating systems used. The protective effect against cytochrome P-450 (cyt. P-450) degradation induced by LPO-products was also maximal for PMC and minimal for .alpha.-TA. The data obtained suggest that the presence of phytyl radical is not necessary for antioxidant activity of tocols and contradict the hypothesis about a relay mechanism of antioxidant action of tocopherols in biomembranes.