METAL-CHELATING AND METAL-REDUCING PROPERTIES OF CARBOXYLATED DERIVATIVE OF TAXIFOLIN
Shatalin Yu.V.1,2, Shubina V.S.1,2
1Pushchino State Institute of Natural Sciences, Pushchino, Russia; 2 Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia; firstname.lastname@example.org
Flavonoids are widely studied for their antioxidant properties. The mechanism of action of flavonoids involves not only the scavenging of reactive oxygen species (ROS) but also the inhibition of ROS formation by binding metal ions of variable valency (especially iron and copper). Flavonoids have also been reported can exert prooxidant effects by reducing iron and copper ions and promoting the Fenton reaction. Due to their properties design of new
compounds (and materials) on the basis of flavonoids are carried out. The aim of the present study was to investigate the metal-chelating and metal-reducing properties of carboxylated derivative of taxifolin (Tfcar). Experiments were performed using the method of absorption spectroscopy. It was shown that Tfcar chelates both Fe (II) and Fe (III) ions. The apparent binding constants for 1:1 Fe (II)/Fe (III)-Tfcar complexes were estimated to be 26082 and 12226 M-1 respectively. Our results also showed that Tfcar effectively reduced Fe(III). According to our calculations, the redox potential of Tfcar is approximately 65 mV less than that of taxifolin. The data obtained suggest that the more effective reduction Fe(III) by CarTf versus taxifolin related to the presence of electron-withdrawing substituent (carboxyl group) on aromatic ring of CarTf. It is assumed that similar structure modifications of polyphenols may be the basis of the framework structure of new more effective antioxidant compaunds.
This work was supported by the Ministry of Education of the Russian Federation № 4.2399.2011.