Flavonoids oxidative polymerization

Pourcel L, Routaboul JM, Kerhoas L et al (2005) TRANSPARENT TESTAIO encodes a laccase-like enzyme involved in oxidative polymerization of flavonoids in Arabidopsis seed coat. Plant Cell 17 2966-2980... 

Rutin is one of the most commonly found flavonol glycosides identified as vitamin P with quercetin and hesperidin. An oxidative polymerization of rutin using ML as catalyst was examined in a mixture of methanol and buffer to produce a flavonoid polymer [115]. Under selected conditions, the polymer with molecular weight of several thousands was obtained in good yields. The resulting polymer was readily soluble in water, DMF, and DMSO, although rutin monomer showed very low water solubility. UV measurement showed that the polymer had broad transition peaks around 255 and 350nm in water, which were red-shifted in an alkaline solution. ESR measurement showed the presence of a radical in the polymer. 

Peroxidase-catalyzed polymerization of various flavonoids was investigated in an equivolume mixture of 1,4-dioxane and pH 8 buffer [110]. Flavonols (quercetin) as well as isoflavones (diadzein and 5,6,4 -trihydroxyisoflavone) were subjected to the enzymatic oxidative polymerization to produce the flavonoid polymers. From diadzein, the polymer soluble in DMF and DMSO was formed in a high yield. 

Keywords Enzymatic oxidative polymerization Flavonoid Urushi Curing Conjugate... 

In the previous chapter Synthesis of Phenol Polymers Using Peroxidases , the enzymatic oxidative polymerization of monophenolic derivatives is described. This chapter deals with the enzymatic synthesis and properties of polymers from polyphenols, compounds having more than two hydroxyl groups on the aromatic ring(s). In particular, cured phenolic polymers (artificial urushi) and flavonoid polymers are examined from the standpoint of the enzymatic synthesis of functional materials. 

The first chapter by Reihmann and Ritter reviews the recent developments of peroxidase-catalyzed oxidative polymerization of phenol and derivatives with a phenolic OH group. The importance of enzymatic polymerization in general is emphasized. Properties of product polyphenols, characteristics of the enzyme catalysis, and significance of the process and the product are discussed. The second chapter by Uyama and Kobayashi is concerned with the oxidative polymerization of polyphenols, which are compounds containing more than two phenolic OH groups. These compounds include catechols and flavonoids... 

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 quantification of the procyanidins with a degree of polymerization higher than 2 also varied according to the cocoa source analyzed. For instance, cocoa powder showed the lowest content compared with the other cocoa sources studied, which could be related to the manufacturing process comprising oxidation steps and condensation reactions. Lacueva et al. [58] suggested a 60% loss of the flavonoid content during the process of alkalinization to obtain the cocoa powder. 

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