Photoirradiation of polycyclic aromatic hydrocarbons with UVA light - a pathway leading to the generation of reactive oxygen species, lipid peroxidation, and dna damage

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a class of genotoxic environmental contaminants. We have long been interested in determining the mechanisms by which PAHs induce genotoxicity. Although the metabolic activation of PAHs leading to biological activities has been well studied, the photo-induced activation pathway has seldom reported. In this paper, we review the study of photoirradiation of PAHs with UVA irradiation results in (i) cytotoxicity and DNA damage (ii) DNA single strand cleavage; (iii) formation of 8-hydroxy-2'-deoxyguanosine adduct (8-OHdG), and (iv) formation of lipid peroxidation. Evidence has been shown that these photobiological activities are mediated by reactive oxygen species (ROS).

Figure 1

The three principal metabolic activation pathways of benzo[a]pyrene leading to tumour initiation.

Figure 2

Chemical structures of azulene, guaiazulene and naphthalene

Figure 3

Peroxidation of methyl linoleate into the isomeric 9- and 13-hydroperoxides.

Figure 4

Induction of lipid peroxidation by photoirration of chrysene and its methylated and ethylated derivatives by UVA light.