摘要：The effect of four ortho -quinoid polycyclic aromatic hydrocarbons (PAHs) and seven para -quinoid PAHs on the viability of A549 cells were examined. The ortho -quinoid PAHs [1,2-naphthoquinone (1,2-NQ), 9,10-phenanthrenquinone (9,10-PQ), 5,6-chrysenequinone (5,6-CQ), and benzo[ c ]phenanthrene-5,6-quinone (B[ c ]P-5,6-Q)] overproduced hydrogen peroxide (H2O2) without being consumed themselves. These ortho -quinoid had strong cytotoxic effects except for 1,2-NQ, since of its tendency to covalently bind to thiol groups. The cytotoxicity appears to be due to the overproduction of H2O2 by ortho -quinoid PAHs in a redox cycle coupled with the consumption of thiol group. In contrast, the para -quinoid PAHs were not as strong cytotoxic and did not produce H2O2.
