Enzymatic synthesis and biological properties of flavonoid polymers

Enzymatic synthesis and biological properties of flavonoid polymers 

We have designed not only polymerized flavonoids but also flavonoid conjugates of various polyamines, in consideration of extension of the amplification of physiological properties of the flavonoids. Polymeric flavonoids were synthesized by the enzymatic oxidative coupling.  

The HRP-catalyzed polymerization of (-l-)-catechin was carried out in an equivolume mixture of 1,4-dioxane and buffer (pH 7) to give the polymer with molecular weight of 3.0 x 10 in 30% yield. Using methanol as co-solvent improved the polymer yield and molecular weight. In the polymerization of 

Superoxide anion scavenging activity of the enzymatically synthesized poly(catechin) was evaluated. Poly(catechin), synthesized by HRP catalyst, greatly scavenged superoxide anion in a concentration-dependent manner, and almost completely scavenged at 200 p.M of a catechin unit concentration. The laccase-catalyzed synthesized poly(catechin) also showed excellent antioxidant property. Catechin showed pro-oxidant property in concentrations lower than 300 jlM. These results demonstrated that the enzymatically synthesized poly(catechin) possessed much higher potential for superoxide anion scavenging, compared with intact catechin. 

Xanthine oxidase (XO) is not only an important biological source of ROS but also the enzyme responsible for the formation of uric acid associated with gout leading to painful inflammation in the joints. The XO inhibition effect by the enzymatically synthesized poly(catechin) increased as an increasing concentration of catechin units, while the monomeric catechin showed almost negligible inhibition effect in the same concentration range. ° This markedly amplified XO inhibition activity of poly(catechin) was considered to be due to effective multivalent interaction between XO and the condensed catechin units in the poly (catechin). 

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