COMPARATIVE-EVALUATION OF THE ANTIOXIDANT ACTIVITY OF ALPHA-TOCOPHEROL, ALPHA-TOCOPHEROL POLYETHYLENE-GLYCOL 1000 SUCCINATE AND ALPHA-TOCOPHEROL SUCCINATE IN ISOLATED HEPATOCYTES AND LIVER MICROSOMAL SUSPENSIONS

The antioxidant activity of α-tocopherol polyethylene glycol 1000 succinate (TPGS) and of α-tocopherol succinate (TS) has been examined in isolated hepatocytes and microsomal fractions from rat liver. Both TPGS and TS require esterase activity to yield free α-tocopherol and, hence, antioxidant activity. TPGS and TS consistently exerted a more effective antioxidant protection than an equivalent amount of directly-added free α-tocopherol. The low antioxidant efficiency of directly added free α-tocopherol in such water-based experimental systems as used here seems to be due to its extreme hydrophobicity. TPGS, on the other hand, is an extremely hydrophilic compound that is being examined as a useful source of α-tocopherol in certain clinical situations and is here shown to be a convenient and effective source for experimental studies into lipid peroxidation and antioxidant mechanisms. © 1990.