“…A concentration-dependent DNA cleavage was evaluated in the absence of any reducing agent by monitoring the relaxation of supercoiled, SC, form (Form I) of pBR322 DNA into nicked circular, NC, form (Form II) and/or linear, LC, form (Form III). [59] With an increase in concentration of complex 1a (5-30 μM), a more intensified Form II appeared ( Figure 6; lanes 2-7) with a gradual decrease in Form I, implying efficient single-stranded DNA cleavage by the complex. The cleavage activity of complex 1a was also assessed in the presence of exogenous activators, namely ascorbate (Asc), glutathione (GSH), H 2 O 2 and 3-mercaptopropionic acid (MPA), which demonstrated significant , which are hydroxyl radical scavengers, significant quenching was observed suggestive of the involvement of diffusible hydroxyl radicals in the oxidation of deoxyribose moiety of the sugar phosphate backbone, and therefore illustrates hydrolytic cleavage pathway mediated by complex 1a.…”