Ferrocenyl Schiff base as novel antioxidant to protect DNA against the oxidation damage

The antioxidant capacities of ferrocenyl Schiff bases including o-(1-ferrocenylethylideneamino)phenol (OFP), m-(1-ferrocenylethylideneamino)phenol (MFP), and p-(1-ferrocenylethylideneamino)phenol (PFP) were evaluated in 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH), Cu(2+)/glutathione (GSH), and hydroxyl radical (()OH)-induced oxidation of DNA, and in trapping 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS+(.)), respectively. OFP, MFP and PFP possessed similar activities to trap DPPH and ABTS+(.). All the ferrocenyl Schiff bases employed herein behaved as prooxidants in Cu(2+)/GSH- and (.)OH-induced oxidation of DNA except that OFP exhibited weak antioxidant activity in ()OH-induced oxidation of DNA. PFP, OFP and MFP can terminate about 15.2, 11.3, and 9.4 radical-chain-propagations in AAPH-induced oxidation of DNA. Especially, the introduction of ferrocenyl group to Schiff base increased the antioxidant effectiveness more remarkably than benzene-related Schiff bases.