Toxic industrial chemicals with central effects

Benzene, which has been widely used in chemical synthesis and frequently used as a solvent, is a toxic substance. The major adverse effects of chronic exposure are seen in the central nervous system and bone marrow it causes leukemia and aplastic anemia. A higher-than-average incidence of leukemia has been found in industrial workers with long-term exposure to as little as... 

The solvent hexane causes a different type of neurotoxicity, involving swelling and degeneration of motor neurones. This leads to paraesthesia and sensory loss in the hands and feet, and weakness in toes and fingers. Hexane has been widely used in industry as a solvent, and there have been many cases of neuropathy reported from different parts of the world. The toxicity is due to the metabolite 2,5-hexanedione which arises by co-1 oxidation at the 2- and 5-positions to 2,5-hexanediol, and then further oxidation to the diketone (figure 4.9). The 2,5-hexanedione then reacts with protein to form pyrrole adducts. The v-diketone structure is important, as 2,3- and 2,4-hexanedione are not neurotoxic. Methyl -butyl ketone also causes similar neurotoxic effects and is also metabolized to 2,5-hexanedione. The lipophilicity of the molecule allows distribution to many tissues including the nervous system. Thus, chemical structure and metabolism are important prerequisites for this toxicity. Exposure to the solvent carbon disulphide in industry causes neuronal damage in the central and peripheral nervous system. 

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