Synthesis of hydroxyferrocifen and its abilities to protect DNA and to scavenge radicals.

The aim of this work was to clarify the effect of the position of the hydroxyl group on the antioxidant capacity of hydroxyferrocifen by means of a chemical kinetic method. Propionylferrocene and benzoylferrocene condensed with 4-hydroxydiphenylketone, 3,4-dihydroxydiphenylketone, and 4,4'-dihydroxydiphenylketone to form FP3, FP4, FB3, and FB4 with a single hydroxyl group and FP34, FP44, FB34, and FB44 with two hydroxyl groups. These hydroxyferrocifens were applied in Cu(2+)/glutathione (GSH)-induced, hydroxyl radical (·OH)-induced, and 2,2'-azobis(2-amidinopropane hydrochloride) (AAPH)-induced oxidation of DNA, and in trapping 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+·)). It was found that these hydroxyferrocifens acted as prooxidants in Cu(2+)/GSH-induced oxidation of DNA and exhibited very weak effects on ·OH-induced oxidation of DNA. FP3, FP4, FB3, and FB4 can only retard the rate of AAPH-induced oxidation of DNA, whereas FP44, FB44, FB34, and FP34 can trap 11.9, 7.1, 6.2, and 4.9 radicals, respectively, in AAPH-induced oxidation of DNA. The ability to trap ABTS(+·) followed the order FB4 > FP44 > FB34 > FB44 > FP34. It was concluded that two hydroxyl groups at the para position of two benzene rings rather than at the ortho position in the same benzene ring were beneficial for hydroxyferrocifen to increase the antioxidant capacity.