Polymeric Flavonoids Obtained by Cross-Linking Reaction

Plant polyphenols are becoming more and more popular due to their strong antiaging properties. The best researched and largest group of polyphenols are flavonoids. Flavonoids have high antioxidant and pharmacological activities and these properties are closely related to their structure. Certain structural elements of these compounds condition their properties and improve or degrade the activities. As a result of the polymerization of flavonoids, macromolecular compounds showing more favorable properties, such as, for example, bactericidal and antioxidant activity, can be obtained. The aim of this study is to polymerize selected flavonoids (quercetin and rutin) in reaction with a crosslinking compound. Glycerol diglycdyl ether (GDE) causes the crosslinking of quercetin or rutin monomers and the formation of polymeric structures. The study analyzed the thermal stability of monomeric and polymeric flavonoids and their antioxidant activity. Poly(flavonoids) showed greater resistance to oxidation than their monomeric forms. Moreover, poly(quercetin) and poly(rutin) have a greater ability to reduce transition metal ions. Polymeric forms of quercetin and rutin can potentially be effective stabilizers, e.g., for polymeric materials.