Naphthalene toxicity and antioxidant nutrients.

Naphthalene is a bicyclic aromatic compound that has wide industrial and commercial applications. It is used as the starting material for the synthesis of other compounds, as a moth repellent, soil fumigant and lavatory deodorant. Most exposure occurs through low dose chronic inhalation, dermal contact or ingestion through the food chain. The lungs and eyes appear to be most susceptible to toxicity, although biochemical markers of toxicity can be demonstrated in other tissues, such as the kidney, brain and liver. In addition to lens opacification (cataracts) and histological changes associated with pneumotoxicity, other biomarkers of toxic effects include glutathione depletion, lipid peroxidation, DNA fragmentation and the production of the active oxygen species as superoxide anion and hydroxyl radical. In addition, the urinary excretion of lipid metabolites occurs. A role for the tumor suppressor gene p53 has been demonstrated. Toxic manifestations of naphthalene are associated with its oxidative metabolism to various products including quinones. The ability to protect against the toxic effects of naphthalene by using various antioxidants and free radical scavengers has been demonstrated. Studies have been conducted with vitamin E, vitamin E succinate, melatonin, curcumin, various L-cysteine prodrugs, several aldose reductase inhibitors and spin-trapping agents. The ability to prevent the toxic manifestations of naphthalene is dependent on the pharmacokinetic properties of the agents, which have been studied. The appropriate selection of chemoprotectants can be useful in preventing naphthalene toxicity.