Tin(II)-quercetin complex: Synthesis, spectral characterisation and antioxidant activity

The complex formation between quercetin (Q) and stannous chloride (SnCl2 center dot 2H(2)O) was studied using UV-visible, IR and H-1 NMR spectroscopic techniques. Spectroscopic data suggest that Q can chelate stannous cations through both 3-hydroxy-4-carbonyl and the 3',4'-dihydroxyl (catechol) chelation sites. The antioxidant activity of the complex was evaluated using 1,1-dipheny1-2-picrylhydrazyl (DPPH), 2,2'-azinobis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) diammonium salt and ferric reducing antioxidant power (FRAP) methods. It was shown that radical scavenging activity and ferric reducing potential of free Q was decreased after chelation of stannous cation. (C) 2011 Elsevier Ltd. All rights reserved.