Answer to Question #310245 in General Chemistry for Yuki

Question

Describe the metal-chelating antioxidant activity of quercetin. 

Answer 1

Quercetin is a potential antioxidant and the main

flavonoid among flavonols. The biological activity of quercetin affects the

presence of metal ions. Hydroxyl groups present in the structure of quercetin are

capable of forming complexes with various ion of metals. Quercetin chelates

metal ions via 3’ or and 4’ phenolic group.

Antioxidant activity of flavonoids depends on the number and

position of hydroxyl groups in the flavonoid structure. Copper(II)-quercetin

complex has higher antioxidant activity than free quercetin. The same results

were obtained for cobalt(II)-quercetin and aluminum(III)-quercetin complexes.

The complexes of quercetin with trivalent rare metals can bind to the DNA

thereby changing its transcription, thus inhibiting growth of cancer cells.

Comparison of flavonoids

in the prooxidant processes emphasizes the connections between free radical

scavenging and metal chelation.