Biological Activity of Flavonoids Copper Complexes

Three flavonoid copper(II) complexes Cu 2 (quercetin)(CH 3 COO) 3 (CH 3 OH) ( 1 ), Cu(anthrarufin)(CH 3 COO)·1/2H 2 O ( 2 ) and Cu(naringin)(OCH 3 )(CH 3 OH) 2 ( 3 ) have been synthesized and characterized by elemental analysis, IR, electronic absorption and EPR (X‐band) spectroscopy. The complexes have a strong protective action over the Δsod1 mutant of S. cerevisiae against reactive oxygen radicals generated by an external source of free radicals (H 2 O 2 or the superoxide‐generating, menadione). On the other hand, the complexes cleave DNA efficiently even in the absence of reducing agents. The main reactive oxygen species responsible for the DNA strand cleavage have been determined using radical scavengers. A probably mechanism of the DNA damage is proposed.