Low density lipoprotein oxidizability by copper correlates to its initial ubiquinol-10 and polyunsaturated fatty acid content.

At an early stage of oxidation induced by Cu2+, the rate of oxidative modification of human low density lipoprotein (LDL) from healthy donors correlated negatively to its ubiquinol-10 (r = -0.58, P < 0.01) and positively to its polyunsaturated fatty acid (PUFA) (r = 0.53, P < 0.05) content. The PUFA/ubiquinol-10 ratio was the best predictor of LDL susceptibility to oxidation (r = 0.68, P < 0.01). No significant correlation between LDL oxidizability and its alpha-tocopherol content was found at any oxidation stage. It is suggested that ubiquinol-10 plays a central role in the early protection of LDL PUFAs against Cu(2+)-induced oxidation whereas alpha-tocopherol posesses both pro- and antioxidant activity.