Effects of ionic radius of redox-inactive bio-related metal ions on the radical-scavenging activity of flavonoids evaluated using photometric titration†
Abstract
Mg2+ enhanced the scavenging activity of (+)-catechin and quercetin against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙), while Al3+ decreased their activity. Such effects of Mg2+ and Al3+ were not observed for kaempferol. Na+ and Ca2+ with large ionic radii showed little effect on the DPPH˙-scavenging activity of these three flavonoids.