On the relevance of hydroxyl radical to purine DNA damage

Hydroxyl radical (HO) is the most reactive toward DNA among the reactive oxygen species(ROS) generated in aerobic organisms by cellular metabolisms. HO is generated also by exogenoussources such as ionizing radiations. In this review we focus on the purine DNA damage byHO radicals. In particular, emphasis is given on mechanistic aspects for the various lesion formationand their interconnections. Although the majority of the purine DNA lesions like 8-oxo-purine(8-oxo-Pu) are generated by various ROS (including HO), the formation of 50,8-cyclopurine(cPu) lesions in vitro and in vivo relies exclusively on the HO attack. Methodologies generally utilizedfor the purine lesions quantification in biological samples are reported and critically discussed.Recent results on cPu and 8-oxo-Pu lesions quantification in various types of biologicalspecimens associated with the cellular repair efficiency as well as with distinct pathologies arepresented, providing some insights on their biological significance.