Anthocyanin-metal complex

Anthocyanin-metal complexes are chemical structures formed when multivalent metal ions, such as aluminum (Al3+), iron (Fe3+), or magnesium (Mg2+), bind to the phenolic hydroxyl groups located on the B-ring of anthocyanin pigments. This chelation process is a fundamental mechanism in plant biology for stabilizing colors and is also responsible for the potent antioxidant properties of these flavonoids (Sigurdson et al., 2017). In a therapeutic context, this interaction is not a traditional drug target like a receptor or enzyme, but rather a biochemical mechanism by which dietary anthocyanins may sequester transition metals to prevent oxidative damage. The formation of these complexes can influence the bioavailability and pharmacokinetics of both the anthocyanins and the involved minerals within the gastrointestinal tract. Research suggests these interactions may play a role in mitigating metal-induced neurotoxicity and inflammation by reducing the pro-oxidant activity of free metal ions (Sarni-Manchado et al., 1997). These complexes are primarily studied in the fields of nutrition and food science for their potential health-promoting effects in preventing chronic diseases associated with oxidative stress. The specific affinity for metals depends on the hydroxylation pattern of the anthocyanin, with delphinidin and cyanidin being particularly effective chelators due to their catechol or pyrogallol structures.

Other names

Anthocyanin chelationMetal-anthocyanin complexationPhenolic metal chelationAnthocyanin-metal coordination complex

Chelation of multivalent metal ions by ortho-hydroxyl groups on the anthocyanin B-ring to form stable coordination complexes, which shifts the redox potential and spectral properties of the molecule.