ABSTRACT Recent studies indicate that toxic metals (lead, cadmium, mercury and arsenic) may increase the production of reactive oxygen species (ROS) such as hydroxyl radical (HO.), superoxide radical (O2.-) or hydrogen peroxide (H2O2). This increase may disrupt the balance between free radicals and the cells antioxidant defense leading to a condition known as “oxidative stress”. In the first part of this review, metal-induced oxidative stress has been discussed in detail. This second part will summarize the effects of various antioxidants on metal-induced toxicities, in particular redox-inactive metals including lead, cadmium, mercury and arsenic. Recent studies (including ours) indicate that various antioxidants play an important role in eliminating metal-induced oxidative damage. Among antioxidants, thiol-containing compounds deserve more attention due to the fact that thiols are well-known metal chelators. This prompts another discussion, that thiol-containing antioxidants are beneficial in metal toxicity because they remove metal from the system. Indeed, thiols most probably play a dual function in metal toxicities by both removing the metal and decreasing the oxidative stress. Therefore, this review will focus primarily on three groups of antioxidants in metal toxicities: 1) antioxidants with a potential chelation function, 2) antioxidant vitamins, and 3) miscellaneous antioxidants. Several antioxidants, in conjunction with a thiol chelator, can intervene in heavy metal poisoning by improving the mobilization and excretion of these metals
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