Quercetin (3,3',4',5,7-pentahydroxyflavone) one of the most abundant dietary flavonoids, has been investigated in the presence of magnesium (II) in methanol. The complex formation between quercetin and magnesium (II) was examined under UV-visible, Infra-red and (1)H NMR spectroscopic techniques. The spectroscopic data denoted that quercetin can reacts with magnesium cation (Mg(+2)) through the chelation site in the quercetin molecule. The free radical antioxidant activity of the complex with respect to the parent molecule was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. It was observed that the free radical scavenging activity of quercetin was increased after complexation of magnesium (Mg(+2)) cation.
Keywords: Antioxidant activity; Flavonoids; Quercetin; Quercetin–magnesium complex; Radical scavenging activity; Spectral characterisation.
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