Biologically-active and chemically-reactive polycyclic hydrocarbon metabolites.

The mechanism by which polycyclic hydrocarbons produce tumours in mammalian tissues exposed to them involves biotransformation of the compounds to chemically-reactive species that covalently modify cellular informational macromolecules. In all cases known, epoxides of some form are the reactive species involved. The most common pathway is the formation of vicinal diol-epoxides, the reactive centre of the molecule commonly being adjacent to the 'bay-region'. With some hydrocarbons, the involvement in DNA binding of non-'bay-region' diol-epoxides, of a phenol epoxide and of a 'bay-region' diol-epoxide containing a phenolic function (a triol-epoxide) has also been demonstrated. The relative importance to the carcinogenic process of the different pathways leading to DNA-binding products may be reflected by the biological activities of the intermediates involved.