A RAPID AND SIMPLE SCREENING-TEST FOR POTENTIAL INHIBITORS OF TOCOPHEROL-MEDIATED PEROXIDATION OF LDL LIPIDS

We report a rapid and convenient method for screening potential inhibi tors of the initiation of low density lipoprotein (LDL) lipid peroxida tion. The method uses positively and negatively charged micelles of ei ther cetyltrimethyl ammonium chloride or sodium dodecyl sulfate with a dded alpha-tocopherol. It is based on the capacity of an antioxidant t o attenuate alpha-tocopheroxyl radicals, generated by irradiation of t he alpha-tocopherol-containing micelles with UV light, and measured di rectly by electron spin resonance spectroscopy. To establish the relia bility of the method, we compared the alpha-tocopheroxyl radical atten uating ability (TRW) of 53 natural and synthetic potential antioxidant s with their respective ability to inhibit the early stages of LDL lip id peroxidation initiated by a low flux of water-soluble peroxyl radic als. The relationship between the measured TRAA and corresponding LDL antioxidation activity was highly significant (P < 0.00005, Rank test) . Thus, the potency of a co-antioxidant for LDLs alpha-tocopherol coul d be predicted with > 98% probability by the TRAA test alone. The resu lts suggest that this relatively simple method represents an effective and simple screening test that can be used for large numbers of poten tial inhibitors of the early stages of LDL lipid oxidation.-Witting, P . K., C. Westerlund, and R. Stocker. A rapid and simple screening test for potential inhibitors of tocopherol-mediated peroxidation of LDL l ipids.