Polycyclic aromatic hydrocarbons in air and their neurotoxic potency in association with oxidative stress: A brief perspective

Polycyclic aromatic hydrocarbons (PAHs) are a class of toxic organic chemicals widely distributed in the environment and in food stuffs. PAHs such as Benzo a pyrene, [B (a) P] essentially enters either through the ingestion of contaminated food and water or by the inhalation of particulates in the ambient air. The link between B (a) P metabolism and oxidative damage appears to be one of the key pleiotropic modulators which may be involved with several pathological processes because of its high affinity for lipid-rich tissues such as brain. B (a) P can enhance the generation of reactive oxygen species (ROS) by inducing cytochrome P450 enzymes and free radicals produced by B (a) P metabolism. This can alter physiological functions like neuronal development, differentiation, and signal transduction. Brain does not have a strong antioxidant defense system and has limited or poor ability to replace adult neurons. The molecular mechanism of oxygen derived species such as superoxide radicals, hydrogen peroxide, singlet oxygen and hydroxyl radicals produced by B (a) P metabolism and its implication in the etiology of wide array of neurological disorders remain elusive. ROS can be involved in the neuropathology of bipolar disorder, schizophrenia, and possible reduction in cognitive abilities among infants, and it is known to play janus like role of possessing both deleterious and beneficial effects. This review discusses the role of oxidative stress derived from B (a) P metabolism relating to neurological disorders, which can introduce new targets for the development of therapeutic interventions. doi : 10.5214/ans.0972.7531.2009.160109 Competing interests: None. Source of Funding: DBT, ICMR, DST, CSIR Received Date: 19 March 2009 Revised Date: 04 April 2009 Accepted Date: 20 April 2009